[Note: This article was significantly updated August 5th, 2010. Therefore, many comments became obsolete, or at least proved their worth, by encouraging an update]
If there’s one area that often seems to catch the imagination of many who call themselves “climate skeptics”, it’s the idea that CO2 at its low levels of concentration in the atmosphere can’t possibly cause the changes in temperature that have already occurred – and that are projected to occur in the future. Instead, the sun, that big bright hot thing in the sky (unless you live in England), is identified as the most likely cause of temperature changes.
Argument from Inconceivability
I personally find it hard to believe that we are hurtling through space at 67,000 miles per hour on a big spinning rock. It doesn’t feel like it. (Actually that’s just the speed that we orbit the sun, and the sun is moving as well, so its more complicated..)
And is this table (you can’t see my table, but any table will do) really made of tiny atoms but science claims it’s mostly space between the little balls? What? Not likely.
Satire over.
For science, personal experience and imagination are not the deciding factors. They lead you astray. Instead, investigation of phenomena lead to hypotheses, experiments and eventually “theories” – as well-established science “facts” are known. Your intuition might be great for understanding people’s motivations, or whether a person can run 100m in 3 seconds, but not so great for the energy absorption characteristics of invisible molecules.
Let’s look at the science.
How do we analyze the Earth’s Climate?
It’s a tricky problem. And like most tricky science problems we start with some simplications. We analyze a simplified model and see where that gets us. Like, how does this simple model compare to reality? And how do we verify the results from the simplified model if the reality is so much more complicated?
Read on, it’s a journey.
Energy from the Sun
The sun is our source of heat. We are 150 million km from the sun, so how does that heat energy get here?
There are 3 mechanisms for heat transfer – conduction, convection and radiation. It’s a vacuum between the sun and the earth so energy from the sun can only arrive here through radiation. What does that radiation look like? A “body” emits radiation across a spread (a “spectrum”) of wavelengths, in a way that depends on that body’s temperature.
The fact that the wavelengths of the energy emitted vary with temperature is a key point, essential for understanding this aspect of climate science.
Here’s a few samples – each color represents a different temperature object. The blue line is a body at 5000K = 4727°C (8540°F).
Energy intensity versus wavelength for different temperature objects
For those new to the subject, K (“Kelvin”) is absolute temperature. It tracks degree Centigrade/Celsius one for one, but whereas °C starts at the freezing point of water, K starts at, well, absolute zero.
So 0°C = 32°F = 273K; and -273°C = -459°F = 0K
There are reasons why this temperature scale exists, but let’s just leave it at that.
So if you look at the graph you can see that the higher the temperature, the higher the total energy (which everyone would expect) and the lower the wavelengths of the peak energy.
At the end of the post I’ll show some maths, but many people don’t want to see any equations. Just as a preview, total energy is proportional to the 4th power of absolute temperature. Double the temperature and the energy goes up by 16 times.
And it’s worth stating as well at this point, none of this is in question. It’s reproduceable, non-controversial thermodynamics – a branch of physics. You can reproduce it in the lab and measure it everywhere in the real world.
Energy from the Earth
Now the earth also emits radiation according to the same formula. If the earth isn’t heating up or cooling down the energy absorbed will be equal to the energy emitted. (And we’ll leave discussions about how we know whether the earth is heating up and exactly what that means for another day).
If you do the maths (see the end of the post), you find that the equations say that the earth should be about -18°C (255K) when in fact it is an average +15°C across the globe. What’s going on?
First let’s look at the energy from the earth and sun on the same graph. The sun has a surface temperature of 5780K:
What’s happened to the earth’s radiation? It can barely be seen on a linear plot, it is so small in comparison. However, this is at source – picture a spaceship parked just off the surface of the sun taking the measurements.
By the time the solar radiation has reached the earth it has reduced in intensity by a factor of around 46,000 (see the Inverse Square Law or The Sun and Max Planck Agree – Part Two):
Here is a comparison of solar radiation (the 5780K curve) at the top of the atmosphere, compared with a few terrestrial radiation curves for 260K (-13°C) though to 300K (27°C). Note that it is a logarithmic plot.
Here is a linear plot of the same for comparison:
Notice how the wavelength of the peak value of radiation shifts to the right as the source of the radiation gets colder. The typical value for the earth is 10μm, while for the sun it is 0.5μm.
What’s great about the graph is you can see clearly how the radiation from the sun can be easily discriminated from the radiation from the earth. There’s no complicated deductive work, if you measure radiation below 4μm, you know it came from the sun, no matter how many things it bounced off in the meantime. If you measure radiation above 4μm, you know it’s generated by the terrestrial system.
Check out The Sun and Max Planck Agree and The Sun and Max Planck Agree – Part Two for more on this subject.
What does this mean? It means that we can confident of the amount of energy:
- Arriving from the sun at the top of atmosphere and at the surface
- From the sun that is reflected back into space by the atmosphere or the earth’s surface
- Emitted by the earth
How do we work out 3)? We have satellites in space that look at the energy coming from the earth’s surface in the longer wavelengths that correspond to the lower temperatures of the earth’s surface.
And the climate science convention is to call the energy less than 4μm: short wave radiation and the energy greater than 4μm: long wave radiation.
Note that “infrared” is radiation greater than 0.7μm – a different term than “longwave”.
Energy Absorbed by Gases in the Atmosphere
Let’s look at some more standard science.
Each gas in the atmosphere has different absorption characteristics, which vary according to the wavelength of the radiation. In detail it is very complex, but here is a broad overview of total absorption:
Absorption of different wavelength radiation in the earth's atmosphere
Note that the horizontal axis is a logarithmic scale. The vertical axis shows “opacity” or what proportion of the energy is absorbed by the atmosphere. I picked this graph because you can easily see where the visible light fits in. What you should notice is how much radiation is actually absorbed by the atmosphere. This graphic is a bit too simplistic.
Here’s solar radiation at the top of atmosphere, and at the surface:
From Vardavas & Taylor (2007)
The lighter color is what we observe at the earth’s surface, while the darker surrounding is the observation of solar radiation by satellite. The difference is absorption by various molecules in the atmosphere and you can see from the annotation which gases absorb at which wavelength.
Here is a measurement of outgoing longwave radiation (terrestrial radiation) measured by satellite at the top of the atmosphere:
Outgoing longwave radiation at TOA, Taylor (2005)
For those new to this kind of graph, they are usually shown in “wavenumber” rather than wavelength. It’s not important at this stage except to note that the longer wavelengths are to the left and the shorter wavelengths are to the right.
The reason for picking this measurement to show is that the emission curves for typical temperatures of the earth’s surface are shown overlaid. The highest one is 275K or 2°C. The surface of the earth emits radiation very close to the blackbody shape (see The Dull Case of Emissivity and Average Temperatures) but by the time the radiation leaves the earth’s atmosphere that isn’t what we see.
Here is another example, this time with a theoretical calculation (overlaid and displaced for comparison) which is something covered much later in this series:
Measured and theoretical spectra, from Goody & Yung (1989)
Click for a larger view
On this spectrum, the authors have noted the reduced areas of outgoing radiation and marked CO2, H2O, O3 (ozone) and CH4 (methane).
How do they know these gases are the cause?
And what effect does it really have?
Measurements in the Lab
Scientists have been measuring the absorption characteristics of each gas in the atmosphere at different wavelengths for many decades.
Here is a good summary of the main absorption bands:
The last bottom line shows the total in the atmosphere. You might notice that N2 (nitrogen) doesn’t show up. Is climate science ignoring this important gas? No – nitrogen absorbs almost nothing, for reasons that are touched on in Part Two. We can say that nitrogen is transparent to solar and terrestrial radiation.
You will also notice that O2 and O3 (oxygen and ozone) are shown. There is a chemical cycle in the upper atmosphere called the Chapman cycle which is responsible for generating ozone. In the very short wavelengths – below 0.3μm – oxygen and ozone both absorb solar radiation. In the longer wavelengths, ozone absorbs around 9.6μm. Oxygen doesn’t absorb at all in longwave – it is also (like nitrogen) transparent to terrestrial radiation.
What you can’t tell from the chart above is how influential each of the gases is in terms of total energy absorbed. That is a much more complex challenge – covered in later articles (but it isn’t as simple as the ratio of each of the absorbing gases in the atmosphere).
Before we leave the subject of absorption, it’s worth showing some lab measurements – from the HITRANS database. This might help see the main characteristics of CO2 and water vapor as well as the complexity.
First the main characteristics on a linear graph:
From the HITRANS 2008 database, via spectralcalc.com
You can see that CO2 has high absorption around 15μm and water vapor around 6.3μm.
Now on a log plot – this shows the complexity – but note that each horizontal line represents a factor of 100. O2 and N2 are included at the bottom for comparison:
From the HITRANS 2008 database from spectralcalc.com
Note the vertical scale for N2 and O2 – even at their peak they absorb less than a billionth the radiation of CO2 and water vapor.
What Effect Does it Have?
Outside the world of atmospheric physics there is a lot of confusion about some thermodynamics basics. There are many articles on this blog that address those specific points (checkout the Roadmap) and there is no way to cover all of the misconceptions in this article – without it being 100 pages long..
As the surface of the earth heats up from the solar radiation absorbed, it in turn emits radiation – as shown in the 3rd and 4th graphs above.
If the atmosphere didn’t absorb any of this radiation then we would measure a spectrum like one of the Planck curves (as they are known). Instead we see large “chunks” (to use a non-technical term) of energy removed by the time the radiation leaves the atmosphere – “chunks” corresponding to water vapor, CO2 and ozone (as well as a number of other gases). And the larger the “chunk”, the more energy has been absorbed by the corresponding gas from the radiation.
When the atmosphere absorbs radiation it heats up. The absorbed energy is shared thermally via collisions with all other gas molecules, so the whole atmosphere in that region heats up. And the gases like CO2 and water vapor emit radiation – more emission as they increase in temperature.
The atmosphere, once heated up, radiates equally in all directions. Some of this is downward. Here is a measured spectrum at the earth’s surface:
Wisconsin, Ellingson & Wiscombe (1996)
As you can see, the emission of radiation measured at the earth’s surface corresponds to the missing sections at the top of the atmosphere. See The Amazing Case of “Back-Radiation” and The Amazing Case of “Back Radiation” – Part Two.
Note: If a gas can absorb 15μm radiation it can also emit 15μm radiation. If a gas can’t absorb 15μm radiation it also can’t emit at that wavelength.
The energy radiated by the atmosphere which is received at the earth’s surface increases the temperature at the surface. (See The Amazing Case of “Back Radiation” – Part Three).
Although many people have become confused with imaginary second laws of thermodynamics to believe that this can’t happen, here is the easy way to understand the problem:
If we average the incoming solar radiation that is absorbed by the earth’s climate over the surface of the earth we get around 239 W/m2. (See The Earth’s Energy Budget – Part One).
If we average the outgoing longwave radiation from the top of atmosphere we get the same value: 239 W/m2.
If the atmosphere didn’t absorb any terrestrial radiation then the surface of the earth must also be emitting 239 W/m2.
The only way that the surface of the earth could emit this amount is if the temperature of the earth was around 255K or -18°C.
And yet we measure an average surface temperature of around 15°C – an emission of radiation of 396 W/m2. (See note 1).
If the atmosphere wasn’t absorbing and re-radiating longwave then the surface of the earth would be -18°C. This is the inappropriately-named “greenhouse” effect (and note that I haven’t used a greenhouse to demonstrate anything).
Conclusion
The question asked at the start was “Is CO2 an insignificant trace gas?” and the answer is no.
CO2 and water vapor are very significant in the earth’s climate, otherwise it would be a very cold place.
What else can we conclude? Nothing really, this is just the starting point. It’s not a sophisticated model of the earth’s climate, it’s a “zero dimensional model” or “billiard ball model” which takes a very basic viewpoint and tries to establish the effect of the sun and the atmosphere on surface temperature. It doesn’t look at feedback and it’s very simplistic.
Climate is a complex subject. Hopefully this explains some basics and we can start looking a little deeper in subsequent posts.
More in this series:
Part Two – why different gases absorb different amounts of energy, why some gases absorb almost no longwave radiation
Part Three – the Beer Lambert model of absorption and the concept of re-emission of radiation
Part Four – band models and how transmittance of CO2 changes as the amount of CO2 increases under “weak” and “strong” conditions
Part Five – two results from solving the 1-d equations – and how CO2 compares to water vapor
Part Six – Visualization -what does the downwards longwave radiation look like at the earth’s surface
Part Seven – The Boring Numbers – the values of “radiative forcing” from CO2 for current levels and doubling of CO2.
Part Eight – Saturation – explaining “saturation” in more detail
CO2 Can’t have that Effect Because.. – common “problems” or responses to the theory and evidence presented
The Maths
The Stefan-Boltzmann Law states:
j = εσT4
Where
j = total energy radiated per unit area per unit time
ε = emissivity, ranging from 0 to 1, where 1 is a perfect black body
σ = the Stefan Boltzmann constant, 5.67 x 10-8
T = temperature in K
The effective temperature of the sun is 5780K, its emissivity is quite close to 1, and so it radiates 6.3 x 107 W/m2
As the sun is a long way from the earth, its radiation by the time it reaches the earth is reduced according to Inverse Square Law.
The radius of the sun, rsun = 696 x 106m
Distance from the sun to earth, ao = 1.5×1011 m (150 million km)
Therefore the solar radiation is reduced by a factor of (1.5×1011/(696 x 106)2 = (215)2 = 46,225. Therefore, the solar radiation reaching the earth’s atmosphere = 6.3 x 107 / 46,225 = 1360 W/m2.
And from measurement by satellite we get 1367 W/m2.
Now we have to note two important facts:
- Some of the solar radiation is reflected
- The sun isn’t directly above all points on the earth at the same time
So how much energy is actually absorbed by the climate system?
The measured proportion of reflected solar radiation is 30% – we call this the albedo.
To work out the effect of the day and night and different angles of solar radiation sounds tricky but it’s actually an easy problem. The solar radiation from a long way away hits a disc of area = πr². But the surface of a sphere is 4πr² - (see The Earth’s Energy Budget – Part One for a fuller explanation). Therefore, to calculate the energy absorbed by the climate system averaged over the surface of the earth we can just divide by 4:
Esolar = 1367 x (1 – 0.3) / 4 = 239 W/m²
If the earth is not heating up or cooling down then the earth’s climate system must also be emitting radiation at the same rate. Note that these are global annual averages.
If there was no absorption of surface radiation by the atmosphere then the surface radiation would also be – on average – 239 W/m².
What temperature of the earth’s surface does this correspond to?
Remember the equation at the start of the maths section: j = εσT4
Rearranging to solve, T = (j/εσ)1/4
The emissivity of the earth is very close to 1 (see The Dull Case of Emissivity and Average Temperatures), therefore:
T = 255K or -18°C
Given that we actually experience much higher temperatures on the surface of the earth, we need an explanation. This can be found in the inappropriately-named “greenhouse gases”, which include water vapor, CO2 and methane (CH4).
When the earth emits its longwave radiation, these gases absorb energy and then re-emit, so that the earth’s energy doesn’t just fly off into space but instead it’s absorbed and re-transmitted, some of it back down to earth.
The “greenhouse gases” heat the earth’s surface up approximately 33°C higher than it would be otherwise.
Note 1:
There is a lot of confusion about the use of average temperatures in this approach to explaining the role of CO2 and water vapor in the atmosphere.
Calculating an average temperature has a lot of issues, as explained in Why Global Mean Surface Temperature Should be Relegated, Or Mostly Ignored. However, the explanation above doesn’t rely in any way on the arbitrary construct of average temperatures.
I simply used average temperatures to help newcomers visualize the issue more clearly. If I say that the earth’s average temperature should be -18°C everyone knows that I am wrong. If I say that the emission of surface radiation should be 239 W/m² who would know?
The use of energy per m² also confuses – the poles are colder, the equator is hotter – maybe the averages have lost something important. Once again, the averages just make it easier to understand. However, for those readers convinced that there is a problem in comparing average values, we can calculate the total energy:
Total solar energy absorbed globally annually = solar “constant” x (1 – albedo) x surface area the solar radiation irradiates x number of seconds in a year
Total energy = 1367 W/m² . (1 – 0.3) . πre² . 365.24.3600 = 3.8 x 1024 J
where re = radius of the earth = 6.37 x 106m.
How much energy does the surface of the earth radiate? Well, it can be calculated from the global temperature database and the Stefan-Boltzmann law.
This was done in Earth’s global energy budget, Trenberth and Kiehl, Bull. Amer. Meteor. Soc. (2009). They expressed the number as an global annual average – 396 W/m². We can simply multiply it back up the same way – using the surface area of the earth – to get
Total energy radiated from the surface = 396 x 4πre² . 365.24.3600 = 6.4 x 1024 J
Now there are no averages and no temperatures involved, but the same fundamental issue – the incoming and outgoing radiation balance at the top of the atmosphere, but the energy leaving from the surface of the earth is much higher than the incoming solar energy.
The absorption and re-radiation by “greenhouse” gases in the atmosphere is responsible.
As a physicist/geophysicist who has worked for the U. S. Naval Oceanographic Office and the U. S. Geological Survey for more than 30 years, and who has spent the last 8 years examining the Global Warming phenomenon (the first two of which were at the U. S. National Oceanic and Atmospheric Administration), I have come to two conclusions.
First Global Warming is real. Second, CO2 regardless of its origin (i.e., either natural or anthropogenic) does not drive Global Warming.
The CO2 Enhanced Greenhouse Effect Theory is totally irrelevant to the Global Warming phenomenon. Why? One finds on the secular time scale that both of the X- and Y- component temporal, annual-means profiles of the Earth’s Orientation mimic exactly the Global Temperature Anomaly (GTA) annual means profile On the decade time scale one finds that the GTA mimics the Geomagnetic Dipole variations and the variations in the Earths Anomalous Rotation Rate [i.e., Excess Length of Day (ELOD) Annual Means]. The Dipole Field, the GTA and the ELOD all have a 60 year period on the decade time scale. There are many other such correlations on both time scales.
Thus, if CO2 were driving the GTA, and given the geophysical parameters that change over time in sync with the GTA, CO2 enhancements would reasonably have to drive the Earth’s dynamo which creates the Dipole Field and somehow also affects the Earth’s orientation and its rotation rate. But CO2 cannot do this because it has no pondermotive force associated with it. Furthermore, CO2 on the decade time scale lags the GTA by about 9 years according to Mauna Loa, HI Observatory data collected since 1955, which is a period of time that is at the height of anthropogenic activity. Furthermore, on the millennium time scale the time lag averages about 800 years (Monin et. al., 2001). Therefore, if CO2 were the driver of Global Warming through the Enhanced Greenhouse Effect, then it would have to violate the Principle of Cause and Effect.
I have a short paperback book that explains this in more detail. It should be available in the book stores (e.g., Barnes and Nobel, Amazon.com, etc.) in late December 2009, or January 2010. Its title is:
GLOBAL WARMING: Geophysical Counterpoints to the Enhanced Greenhouse Theory
Publisher: Dorrance Publishing Co., Inc., Pittsburgh, PA, USA
ISBN: 978-1-4349-0581-9
While I do not know what precisely (though I know a little) causes Global Warming, I do know what does not cause it. CO2 and other greenhouse gases, anthropogenic or otherwise, are merely passive players that, like the GTA, are driven by other more dynamic forces associated with Earth’s core, the Sun, and even the Cosmos (referring to the Danish theory of cloud formation), all of which act, react, and interact in a very complex manner.
Note that the IPCC concentrates on Solar Irradiance, but ignores other solar energies such as that associated with Solar Magnetic Flux that has more than doubled since 1900. Gravity is another player in the Global Warming picture. Also note that Mars has global warming comparable to Earth’s without CO2 (Fenton, et. al., Nature, 2008). There are no Martians to either generate or enhance CO2 on Mars.
John M. Quinn
Lakewood, CO
USA
Mr. Quinn
I must get a copy of your book. Is the Chandler period part of what you are calling rotation and orientation? I firmly believe all this heating is caused by the sun (ha ha) with a variety of modulating functions that are not yet well understood. Of course CO2 and H2O are very important but our scientific understanding of the process must trump our beliefs. That is where I would like to see this discussion lead us. Thanks.
Bernie McCune
Hello John,
I am surprised your comments have been completely ignored (excluding Bernie’s request for book info) on this blog.
I commend you for speaking up, and I challenge science of doom to respond.
justcherrypicked:
Without buying the book I don’t know anything about this new theory.
And while John Quinn has posted a comment saying that CO2 has no effect on climate, what is really needed is for him – and everyone else interested – to deal with specific points in this seven part series. Then there’s something to “get my teeth into”.
I agree that CO2 does not cause global warming.
I have several major problems with this post.
First is the claim that the Sun is responsible for the temperature (heat) in the Earth.
1.Yes the solar radiation contributes, BUT also gravity and the transfer of energy by gravitons is the major source of energy to the Earth. The Sun’s gravity is responsible for the torque that spins the Earth to get its rotation. Friction of the various layers then results in heat.
Variations in the forces of gravity contribute to variations in the amount of energy coming into the Earth. Obviously the Earth’s eccentricity relativel to the sun (from .98AU to 1.02 AU) contibutes variation in both gravity and solar insolation.
There is also a 60 year cyclical variation in gravity from the Jupiter & Saturn resonance orbit, that is responsible for the Earth’s eccentricity that varies this energy input significantly. (see the http://www.scribd.com paper “Gravity Causes Climate Change” for further explanation.)
2. The equilibrium energy balance, says that at equilibrium the energy in equals the energy out. It does NOT say that the radiated energy in equals the radiated energy out. To be correct the energy balance MUST include the radiated E/M energy (ie solar insolation) plus gravity plus radiated magnetic fields etc . The measured 239W/m^2 is an incomplete measurement.
3. Finally the argument for more CO2 causing more warming is in itself self defeating in that it does not account for cooling. Whenever the temperature reduces and the temperature goes down, daily seasonally, yearly or in 30 year cycles, we find that the amount of CO2 has continued to go up (at least for the last 100 years.) The theory that CO2 causes the temperature variations FAILS.
I am not a scientist, but the graph shown above labelled ‘From The Oceans and Climate, Grant Bigg, 2003′ has been the one most helpful piece of information in understanding the background to the debate on AGW. To understand better the debate itself I would like to know how the graph of observed radiation has changed since then.
Jeremy R Monson
( part time telephonist )
London
UK
That’s a great question, something I hope to cover in a later post on this subject, maybe part two or part three, after I get on top of the available data.
Firstly let me say what a great article this was especially the maths section. Ever since I first took an interest in global warming (probably around the time “An Inconvenient Truth” appeared) I have struggled to understand firstly what the core of the argument is and secondly to find science to support it. At this point let me also say I have a PhD in Physical Chemistry and have worked in R&D for the last 25 years. Once I had taken the time to cut through all the hysteria, hype, personal attacks, disinformation, claim and counter-claims I finally worked out that the heart of the matter is extremely simple. Does increasing the CO2 content of the atmosphere from todays levels (about 380 ppm) to higher levels cause the atmosphere to heat up to the degree predicted by The AGW community? If so this should be relatively easy to calculate. However due to demands of work, family, running a household etc. I never found time to go back to the basics and try and work it out for myself. Your explanation has saved me the trouble of digging out those old physics and chemistry texts on spectroscopy and radiation!
What I would like to see posted would be an extension of your maths section to show the methods used to calculate the effect of changing the concentration of CO2 in a model system. For the sake of simplicity lets use a mixture of N2 and O2 in the ratio it is in the atmosphere today and then add CO2 upto say 1 % vol (10,000 ppm) and plot the result out on a graph (increased absorption on the Y axis versus ppm CO2 on the X. This is one piece of data I have never seen anywhere despite hours of searching.
On another point I think the whole debate gives us a fascinating insight into the pyschology of the modern mind. Global Warming has clearly become a new religion complete with its high priests, its believe systems and its heretics.
The only way science can make progress is by constantly trying to prove a hypothesis is false. This is “The Scientific Method” pure and simple! To label people who don’t buy into the AGW hypothesis as a 100 % proven certainty as “Deniers” is dispicable and frankly extremely frightening. As such I’m proud to be in the “Deniers” camp and will be happy to change my mind when I see convincing data.
A question:
O2 and 03 make up 20% (versus .038% for C02) of the atmosphere, and has an absorption in the roughly 10um range (infrared band). Why is it not considered a GHG and one with a much larger influence than C02? It seems to me given the straight forward math, that it would have a far greater affect on GTA than CO2 – by 3 orders of magnitude.
kevoka: Different molecules absorb energy in different proportions to their concentration in the atmosphere. They also absorb at different wavelengths. But it’s a good question and one I will delve into in one of the next posts in this series.
Truth Hunter: Thanks for the kind words. I agree that it would be good to work through the ideas you describe especially the painful maths, so keep an eye out – subscribe on RSS or by email to the blog and you will see future posts.
As a quick note, the IPCC point of view is that doubling CO2 to 560ppm will cause around 1′C rise in temperature – for a first order forcing. The projections of much higher temperatures are due to computer models showing positive feedback. I expect to find the 1′C to be reasonable, although I haven’t worked through the maths myself.
kevoka:
Looking at this again, there is something I don’t understand. The chart of absorption shows “O2+O3″ in the caption and yet O2 in the atmosphere is not a greenhouse gas. O3 (ozone) definitely absorbs in the ultraviolet section of the shortwave (solar) range and also at 9.6um in the longwave (terrestrial) range. However, the proportion of ozone in the lower atmosphere is very low – generally around 20 parts per billion (although occasionally much higher in big cities).
I believe that the caption “O2+O3″ refers to the cycle of ozone creation from oxygen and back to oxygen (Chapman reaction).
I see that the same caption “O2 + O3″ occurs in other graphics of spectral absorption.
In looking at the absorption spectrum, it appears that CO2 is responsible for the huge dip between 10 and 20 (microns?). If that is the case, how can increasing the amount in ppm of CO2 in the atmosphere make a significant change in the earth’s longwave radiation to space? I mean, whether a door is 1 inch thick or 1 foot — I’m still not getthing through it.
Tim
Tim, you are correct that CO2 is responsible for the 15um and above absorption.
There are 2 parts to absorption.
Firstly, the radiation in that wavelength is absorbed according to an e^-kz relationship.
(e to the power -kz), where z is height, and k is a constant for that gas for a given concentration and wavelength. This “constant”, k, doubles in value if the concentration doubles. This is the Beer-Lambert law.
Secondly, if a band is totally saturated increasing concentration won’t make any difference – your point is correct. But for CO2, as with other gases, the broad absorption spectrum is made up of many individual absorption lines. In the case of CO2, all bands are not completely saturated. The relationship then is more like a square root relationship – ie as the concentration goes up 4 times, the absorption through a given thickness only doubles.
The next post in the series will look at this in more detail.
Scienceofdoom,
Yes the graph has both O2 and O3. Which is what piqued my curiosity. O2 has absorption in the IR spectrum centered around 6.67um and then again starting at around 30um and beyond.
This comes from the HITRAN DB. A view of which can be found here:
http://www.atm.ox.ac.uk/group/mipas/atlas/index.html
You will see that O2 has at least as strong of absorption as N2O and CH4 – albeit in fewer bands. However, HITRAN does rank it as the 7th most absorptive molecule in the IR spectrum.
But I have not been able to find any calculations that treat it as the 7th most absorptive molecule in the atmosphere. I would think that if someone performed a relative forcing calculation for C2F6 (PFC-116) at 2.9 PPT – see IPCC AR4 ch.2 – then someone ought to have calculated RF for O2 at 20% of the atmosphere.
Yes it will be small. But is it more than C2F6 (PFC-116) with an RF of 0.0008 ?
Kevoka:
I checked a number of texts and it seems to be convention to represent O2+O3 as one group, for reasons that are probably tradition.
Nearly all of O2′s absorption is in shortwave – the UV absorption – where the high energy shortwave radiation separates O2 into O+O, then creation of O3, then destruction of O3 by UV back into O2. This is the Chapman cycle.
O3 absorbs in the 9.6um band but O2 has no part in this. Hence the confusion when O2+O3 is shown with all absorption spectra. I will add a note to the original blog article. For clarity, the SW absorption should be “O2+O3″ and the 9.6um band should be on a separate line for O3 only.
Now, O2 shows up in the webpage you identified as absorbing at 6.67um. But it is not noted for anything in LW absorption in any texts I have encountered. I think this is because its absorption is actually very low.
Note that your webpage has Optical Thickness on the vertical axis. Optical Thickness is the integral of (concentration x absorption cross-section) by the vertical distance.
This means that Optical Thickness takes into account the concentration (as it changes through the troposphere and stratosphere), as well as its ability to absorb radiation of that frequency.
So comparing H2O and O2 around the 6.5-7um band –
O2 has an optical thickness of about 0.3 (reading by eye) at 6.7um
H2O has an optical thickness of about 3×10^3 at the same wavelength
So according to the webpage, H2O is about 10,000 more effective than O2 at absorbing radiation around 6.7um – this is taking into account the much higher concentration of O2.
If the vertical axis on the website you have been looking at showed absorption cross-section instead of optical thickness you would see O2 a million times lower than H2O in LW.
Does this make the subject any clearer?
Whilst I disagree with your basic premise, it is to your great credit that you allow others to post opposing views without censorship or offensive comments.
I tend to approach this from a historic perspective, and from that viewpoint there is nothing unusual about todays conditions. Also an examination of the temperature record-which I undertook long before ‘climate gate’-demonstrates the extraordinary and illogical manner in which ‘global temperatures are calculated even before any alleged ‘wilful’ manipulation is carried out.
Going back to basics, do we have an accurate base global temperature from which to work, commencing in 1850/80? No, certainly not. Do we have one today. Again no.
A thermometer only measures its immediate micro climate. If you move that thermometer-often to an airport- it starts measuring something completely different. Let it become urbanised -as very many of the records are- and it will be affected by uhi. The absurd disdain for calculating the real effects of UHI by the Ipcc, Real Climate et al -a very measurable effect known about since Ancient Rome- do nothing to help the case of the warmists.
So measuring temperature rise ’caused’ by co2 is based on a very shaky foundation and you really need to prove why- although we have been this way climatically many times before- this time its different.
The only person I have seen calculate the complex maths involved in any transparent manner is miskolczi;
http://miskolczi.webs.com/ZM_v10_eng.pdf
Rather than do your own calculations it would be interesting to see you deconstruct the maths from this scientist.
Tonyb
[...] of “trace gases” cannot be deduced from our life experiences. Have a read of CO2 – An Insignificant Trace Gas? Part One to understand more about this [...]
tonyb:
You said “I disagree with your basic premise”
I make no comment in the post about the temperature record. I also see nothing unusual in today’s conditions.
I make no claim that recent (last 100-150 years) temperature increases are caused by CO2.
The point of the post is to explain the basics of atmospheric physics.
I said in the conclusion: “..CO2 and water vapor are very significant in the earth’s climate, otherwise it would be a very cold place. What else can we conclude? Nothing really, this is just the starting point..”
What is it you disagree with?
I disagree with your basic premise that you state as;
“The question asked at the start was “Is CO2 an insignificant trace gas?” and the answer is no.”
Has it no affect at all? Of course it does. Is that effect wildly overstated-particularly when including the positive feedbacks-yes it is.
Creating a correlation of rising co2 to temp increase since 1850/80 is I believe flawed as the Global temperature record does not allow us to do this with the precision claimed.
You seem to agree that we have been this way before without the help of added co2 (although I am inclined to believe Beck) so why is it different this time?
Will be interested to see your dissection of miskolczi.
Tonyb
tonyb:
Let me explain. Why the post in the first place? Many “skeptics” of the IPCC make the comment, “CO2 is an insignificant trace gas and, therefore, can’t have any significant impact on global temperatures”.
Not true. It can. Even though it is 0.04% of the atmosphere (by volume) it absorbs and re-emits a dis-proportionate amount of long-wave energy.
I don’t claim anything else for CO2, but for many, even allowing CO2 a significant role in the radiation budget of the planet is a controversial point.
Whether or not its current effect and future effect is wildly over-stated isn’t covered in the post. The climate is way too complex.
If I have helped people understand the basics of what CO2 does – then the post has succeeded.
If many people who read it conclude that I am claiming that CO2 is – or isn’t- responsible for the last 100 year’s temperature rise – then I haven’t done a good job in this post.
To: scienceofdoom; get a real name for starters. It does not matter if carbon dioxide emits a dis-proportinate amount of long-wave energy. As you have stated, 98% of the atmosphere, nitrogen and oxygen, are transparent to long wave energy. Meaning, this long wave energy is not captured by 98% of the atmosphere; where the temperature is set for humanity and all living things
and the only place it matters for measuring and /or aggregating global temperatures.
Further, the atmosphere is a thermodynamics heat transfer problem. With energy in from the sun and its interior 5000 deg K core. And energy out
mostly by radiation, however, as much as 20% of escaping energy
is simply highly energized atmospheric molecules; which furthers vertical convection all the way out to the inside of Earth’s magnetic bottle, and the Van Allen radiation belt.
The atmosphere is a completely dynamic system and can only be seen
through flows and movements of atmospheric heat and gases;
a heat transfer problem. Nothing you have presented addresses the
actual problem of atmospheric heat transfers and the resulting temperatures. Or you have present a really good distraction from reality.
You have missed the obvious reason in front of your face why carbon dioxide and all trace gases can never be significant with the 98% nitrogen
oxygen earth atmosphere, the transparent long wave energy you
have described just travels on through the nitrogen and oxygen.
So your conclusion that carbon dioxide and other rare atmospheric gases
have a significant effect on the 98% nitrogen oxygen earth atmosphere is false or not true.
And the facts are as strait forward as you have presented them supporting
the fact the rare atmospheric gases can not have an impact on the
98% nitrogen oxygen atmosphere.
Nothing you have listed here as summary is in my 65th edition of the Handbook of Physics and Chemistry. While some of your data is there,
your conclusions are clearly not there. The Handbook of PHysics and
Chemistry is the pre eminent source of reality; with my 65th edition having
139 authors.
Be responsible. Get a credible peer review with the authors of the
Handbook of Physics and Chemistry and stop hiding behind offensive
blogging names.
Maybe then, responsible people might start taking you seriously instead
of this criminal hiding you seem to have penchant for. Fancy and plausible
explanations not tied to the real problem are not only not helpful; they
provide false conclusions most attorneys would label as fraud if widely
publicised.
Avoid trouble. Make sure what you are publishing is actually true; especially
your conclusions, if you are drawing any.
tdwelander,
You have missed the whole point of this discussion.
The small amount of green house gases can absorb most of the IR radiation and also emit a similar amount of IR radiation. The GHG’s transfer immediately (within one nanosecond) the energy they have absorbed to the main atmospheric gases N2 and O2.
Simultaneously the main atmospheric gases excite other GHG molecules to a state where they can emit IR. Only a very small fraction (like one in billion) of the excited molecules emit IR before they’re brought back to ground state in other collisions.
The excitations of CO2, H2O and other GHG’s are always nearly in thermal equilibrium with N2 and O2. The energy is stored by N2 and O2, but the GHG’s are needed to transfer energy between the radiation and the atmospheric gases.
Dynamics of the atmosphere is very important, but the atmosphere is close enough to a stationary system to make discussing its stationary properties very useful.
THe GHE is more about how atmosphere affects IR radiation than how IR radiation affects atmosphere.
tdwelander,
The CRC Handbook is a useful resource. It isn’t the fount of all knowledge. If the atmosphere were indeed transparent to IR radiation from 10-2000 cm-1, then the IR emission spectrum as observed from high altitude would look like a black body spectrum. It doesn’t. Similarly, the emission spectrum as observed at the surface would be essentially non-existent. It isn’t.
The snide remarks about the blog host’s nom de plume don’t help your case either.
Pekka,
“The small amount of green house gases can absorb most of the IR radiation and also emit a similar amount of IR radiation. The GHG’s transfer immediately (within one nanosecond) the energy they have absorbed to the main atmospheric gases N2 and O2.”
This seems to be the conventional wisdom, but out of curiosity what is the evidence claimed to be in support of this? This implies the probability of ‘stimulated’ emission upon absorption of a photon by a GHG molecule is very low or near zero.
This kind of questions are fundamental in our understanding of physics. Quantum Mechanics and Quantum Electrodynamics give clear answers to those. Our belief that QM and QED are good theories are based on numerous very accurate empirical tests.
What happens to a molecule when a photon hits it cannot be described in simple terms of classical mechanics, it’s deeply a quantum process. It has nothing to do with stimulated emission unless another photon gets involved. Using my rough numbers billion molecular collisions occur before a spontaneous emission would take place based on average rates. The influence of stimulated emission is orders of magnitude less than that of spontaneous emission – as long as we are not looking inside a laser.
RW,
Another reason we think the theory is correct is that we can calculate atmospheric emission spectra that are in very good agreement with observed spectra using the assumption of spontaneous emission and local thermodynamic equilibrium. We can also calculate the parameters of nearly all of the CO2 and other small molecule emission lines from first principles or ab initio as the phrase goes.
Pekka & Dewitt,
So it can be verified or deduced that virtually all the emission at the TOA is broadband and not narrow band? I’m curious specifcally how this is established, as it seems to me much of the GHGs would be in a high enough energy state for stimulated emission to occur, especially in the clear sky, low humidity atmosphere that is infinitesimally ‘thin’ thermally.
Just to clarify, ‘stimulated’ emission is the absorption of a photon by a GHG molecule of a certain wavelength that results in the immediate emission of another photon at the same wavelength, right?
Broad band and narrow band are properties of the source of radiation (or of mathematical models used in calculations) not of the radiation itself. Every photon has a specific energy, not a band of energy.
Solids and liquids emit at all frequencies. The emissivity is not constant but typically a rather smooth function of wavelength.
Gas molecules absorb and emit mostly at specific wavelengths. Not at strictly fixed values, but with a sharply peaked spectrum. I posted recently links to graphs that tell, how narrow the peaks and droughts are. Gases do have also some continuum emission and absorption that’s linked to situations where two molecules happen to be close enough for interacting with each other at the moment of absorption or emission.
Because the surface emits at all frequencies, all frequencies are present also at TOA. Gases cannot stop radiation at frequencies they don’t emit themselves.
If the continuum absorption and emission happens to have a suitable strength, it may affect significantly the GHE. Continuum is important for water vapor, but of relatively little importance for CO2.
(As discussed recently in another thread the overly simplistic model of SoD would predict that continuum type absorption and emission by CO2 would get important at very high concentration, but that’s due to the unrealistic line shape used for CO2.)
On the stimulated emission.
The case where a molecule absorbs a photon and emits soon another is normally not stimulated emission. It’s either scattering or a combination of absorption and spontaneous emission. It gets stimulated emission only if another photon gets involved in the emission.
In lasers coherent light (or IR) bounces back and forth between two mirrors and creates an exceptionally strong electromagnetic field in the space between the two mirrors. That strong field influences excited molecules and induces them to emit a photon in the same direction and in the same phase the other photons maintain. That’s stimulated emission.
Pekka,
What do you have to say about what is in this paper? In particular, pages 8 & 9 (especially pg 9 “Line Strength Expressions”). The information given here would seem to contradict what you’re saying.
“Absorption Line Physics”:
http://nit.colorado.edu/atoc5560/week4.pdf
RW,
There’s nothing contradictory to what I have written on those pages. What made think that there would be.
Pekka,
That stimulated emission was not a factor or not something that occurs in the atmosphere.
The formula can be used to calculate the strength of the stimulated emission in the atmosphere. That turns out to be negligible. Only in lasers and some other situations of very high intensity of radiation that strength is large enough to be observable.
To Mr Pirila. The point of the discussion is whether rare earth atmospheric gasses, carbon dioxide in particular, affect the rest of the atmosphere to the point of adding or subtracting sufficient heat which would change global temperatures. Carbon dioxide being in the parts per million in the atmosphere, can not change global temperatures. The volume of carbon dioxide is too insignificant to change anything noticeably in the atmosphere.
Your explanations do not address this fundamental issue as suggested in the title of the article. Carbon dioxide is in fact insignificant on global temperature based on the less than tiny volume alone; no matter what
indirect effects may exist, which are distractions.
To Mr. Payne. Whether or not carbon dioxide affects global temperature
is fundamentally a thermodyamics and heat transfer question. Is there enough volume of carbon dioxide to move heat into earths nitrogen oxygen
atmosphere to change temperature? There is not; not even close.
My 65th edition of the Handbook of Chemistry and Physics has 139 authors.
None of them hide their names. The Handbook of Chemistry and Physics
is the pre eminent source of reality. If the info is not in the Handbook of Chemistry and Physics, it is someone or some groups speculation or theory.
Publishing speculation or theory as fact is fraud. Why the Handbook of Physics and Chemistry is critical to at least minimizing all of the sophisticated fraud floating around masquerading as fact.
Supposed well trained people for over 20 years have been saying carbon dioxide has some kind of undue influence on earths atmosphere. It does not, has never, and will never based on the above info and the Handbook of Physics and Chemistry. Why confronting fraudsters has become so important.
This is a heads up for you from my end. If your information is not accepted as fact in the Handbook of Chemistry and Physics, and you publish theory as fact and do not make it clear that it is theory, these days there is a reasonable probability you could be confronted by law enforcement for committing these sophisticated kinds of fraud. I thought it worthwhile to at least try to keep you out of trouble.
tdwelandar,
Thanks. I needed a good laugh today.
tdwelander,
The starting post of SoD and much of this thread explains, how a very small amount of CO2 can have a strong effect on temperature, when it interacts strongly with IR. That’s a very similar observation as observing that a very small amount of strong dye can give a strong color for a glass of water Your declaration that it’s not so, has zero weight in comparison with the valid arguments presented here.
tdwelander
This is another version of the argument from incredulity rather than an argument from physics.
Let’s take your last statement cited above: “The volume of carbon dioxide is too insignificant to change anything noticeably in the atmosphere”
And contrast it with some measurements of the atmosphere (shown in the article):
Given that the climate system and the sun/rest of the universe only exchange energy via radiation the actual emission of thermal radiation from the climate system is very significant. The “notch” in the emission of thermal radiation around the CO2 band is very significant in energy terms.
There is no law of physics which says that atmospheric radiative effect is linearly proportional to atmospheric concentration.
In fact, the carefully studied subject of radiative physics has determined that the equations of radiative transfer are the relevant equations. These are shown in Atmospheric Radiation and the “Greenhouse” Effect – Part Six- The Equations.
You can join the (so far) unanimous crowd of people determined to claim that physics says something different from standard atmospheric physics -while never actually stating whether:
a) these equations are wrong, or
b) the result of applying these equations to the real atmosphere with real boundary conditions produces a different result from standard atmospheric physics
I realize that many lurkers without maths background cannot understand that article.
Well, the passionate masses who believe something different from this article are equally unable to understand or engage with the maths written down in physics textbooks.
That should be sufficient to demonstrate the point.
Physics is a technical subject.
Followup to Mr. Pirilla. When I see or find your spectra charts posted in the Handbook of Physics and Chemistry, is when I and most other realists will take them seriously. If you would like to quote the edition and pages of where your spectra chart or charts are shown in the Handbook of Physics and Chemistry, I would likely then look them up. Until then, all you have presented is theory. Which puts you in a very onerous position.
Assuming what you have presented is factual and carbon dioxide does absorb and re emit substantial energy, at 400 parts per million in the atmosphere, it could not possibly be enough to show any measurable
change in global temperature.
As previously stated, earths nitrogen oxygen atmosphere is fundamentally
a thermodynamics and heat transfer question for temperature changes, if any. There are not any significant temp changes due to the long wave transparency of nitrogen and oxygen, even with your notch spectra for carbon dioxide considered, due to the less than small source of carbon dioxide at 400 parts per million in the atmosphere.
Give me your responsible sources and locations within the Handbook of Physics and Chemistry and then we will have a starting point. Until then, you are just blowing in the wind. And worse, people will take you to legal task for your expoundments if you publish these assertions as fact.
Oh, and I will put my factual understanding (which is the definition of physics) of the atmosphere up against yours based on the Handbook of Physics and Chemistry, probably any time.
Referring to a handbook in the way you do is one of the most ridiculous arguments I have ever seen in climate debate (and there have been plenty of ridiculous arguments.)
The Handbook has it’s own goals (i.e. collecting a wide variety of numerical data and some other straightforward factual data.
How can anyone propose that only those things are true that fit in one handbook.
Whatever your specialty you are likely to trust your knowledge on many issues not found in the Handbook of Physics and Chemistry. It’s not the ultimate repository of all knowledge.
tdwelander,
It’s called a Handbook, not an Encyclopedia for a reason. It contains a lot of useful data, but nowhere near all. The HITRAN database of spectroscopic parameters (2,713,968 lines) of 39 small molecules comes to mind. There isn’t room to put this in the Handbook and a printed version would not be very useful anyway. Your view that the Handbook is the equivalent of inerrant holy writ is quaint and amusing. Do you only handle it while wearing clean gloves?
tdwelander,
Oh, awesome parody! Nice work.
Just in case (oh no!!) you are not..
Don’t start with this blog. You urgently have a long list of journals to contact.
Start with these guys: Journal of Quantitative Spectroscopy & Radiative Transfer.
They have published literally tens of thousands of papers on the subject without so much as an Imprimatur from the Handbook of Physics and Chemistry.
They have papers like this one: The HITRAN 2008 molecular spectroscopic database. All out in plain sight, sucking in academics, researchers, bloggers..
Let us know how you go and I can give you a long list of other journals.
Then there’s university courses, university libraries..
I forgot to mention that I read your post over at WUWT and thought your criticism of the video pretty fair.
Skeptics have to put over a proper acurate case and it doesnt help to resort to the tactics of the warmists by making unsubstatiated or dubious claims.
Whether co2 is an impoprtant trace gas or not is the subject of a debate, but there is no doubt that many individuals believe it is present in far greater quantities than it actually is.
By the way where is the scene pictured on your blog photo at the top?
Tonyb
tonyb:
Thank you for your kind words.
The picture is just part of one of the themes that the wonderful people at WordPress provide. So I don’t know. But it looks good.
Hi scienceofdoom,
I also came here after reading your review of the John Coleman video at WUWT.
While the fact that CO2 lags temps in the ice cores doesn’t prove that CO2 has no effect on temps it doesn’t show that CO2 is amplifying those temps either as often claimed by climate alarmists.
The claim is made that once some other mechanism starts to raise temps CO2 kicks in and accelerates the warming. I don’t see any evidence in the record that shows that CO2 is accelerating the rate of warming. In fact as the CO2 level is peaking the temps take an abrupt downward turn despite the fact that CO2 is at its highest level and still increasing!
To ignore this anti-correlation and insist that CO2 displays an accelerating effect on temps is not supported by the evidence.
Do you have evidence to support their contention that CO2 is shown to be amplifying the warming when the data from the ice cores shows no such thing? If not perhaps you shouldn’t perpetuate these false claims.
A good read into the basic first layers of absorption. However, the true question that most skeptics have ( unless I am totally off my rocker which may be the case ) is does an increase in CO2 cause the kind of response that has been predicted by the IPCC. Not whether there is a spectrum absorption of CO2 ( any kid that has taken a physics class should be able to say “well duh” ) and that it is not needed for the stable temperature values that we have.
Nevertheless a good read. Thanks for the post.
Lance:
There were 2 parts to the claims in the first section of the Coleman video.
The second part commented that CO2 was a trace gas, the clear inference was, “therefore, it can’t be significant in affecting temperatures”
The reason for providing the link to this article was to show that even though CO2 is a trace gas it is influential.
That is, it is a mistake to ignore CO2 because it is only 0.04% of the atmosphere.
This article doesn’t claim anything else. I claim CO2 is “influential” because the science demonstrates it. I haven’t claimed that it is the reason for amplified warming during past warming periods.
So no I don’t have evidence to support this point, because I’m not claiming it.
Forrest:
You are right, the article is basic – anyone who has taken a physics class will agree. Most haven’t and this is the motivation for the article.
As to the final effects of CO2 and the claims of the IPCC, well that’s a lot more complicated. Watch out for later articles.
Science of doom
My original motivation for contacting you was that I had just come from delivering an address on ‘man made climate change’ to a group of verry bright 11 year olds at a school.
The amount of co2 and the effect it has (bearing in mind the logarithmic curve and lag times) is of course a subject of great debate. Howevere I was particularly struck by;
1) How doomed the youngsters felt by the science-it was accepted completely that we will cause the planet to fry unless we completely change our ways.
2) The knock on effect that had with their world view-very pessimistic about the future.
3) How completely mistaken they were about the quantities. They believed that between 50-100% of the atmosphere was comprised of co2 AND that 90-100% of that co2 was created by man-so virtually the whole atmosphere is comprised of co2 ‘we’ have created.
Now I’m sure I don’t remember what I knew of physics at that age, but the point is that we are scaring our youngsters without giving them the knowledge to put it into context.
I had a long conversation with a member of the UK green party a couple of months ago and his view of the atmosphere and our effect on it was not dissimilar to that of the youngsters. The difference being he was actively campaigning to do something about it-in his case he had been to a coal fired power station to try to close it down and taken part in a protest at an airport to do the same there.
So there is an awful lot of misconceptions about concentrations even BEFORE we start to talk about its actual effect.
Not sure there is anything you can do about it as you are aiming at a levelk of knowledge far beyond those examples. However if anyone reading this comes across a really basic AND objective physics for beginners I would be interested in pointing people towards it.
I do think we assume the average person has far more knowledge of physics than they actually do.
All the best
Tonyb
Thank you for this very illuminating article and the posts that follow. Very helpful for non-scientists like me. I came to it from the Coleman story, which in turn came from the UK’s AGW-sceptic blogger James Delingpole. My own AGW scepticism has been fueled by the lack of calm, reasoned debate on the issue – particularly the labelling of “Deniers” etc
Your article and the following posts are what the debate should be like. It is also the first time some one has properly explained to me why a gas being 0.04% of the volume of the atmosphere might have any effect on temperature. All the supposedly illuminating programmes on the BBC have consistently failed to do this.
As bit of info (without any statistical validity at all): of my 4 most intelligent friends (all of whom graduated from top UK universities) one is a strong advocate of AGW, while the remaining three are sceptics. Their sceptic reasoning is mainly due to the lack of certainty of data and the relative youth of climate science against mature scientific disciplines. Three of the four are scientists by degree (Physics, Chemistry and Medicine) and one is a lawyer – guess which one?
British Diogenes, Is it the lawyer who is the AGW advocate?
The foundational principles of climate science appear to be very strong.. in fact, climate science is mostly physics with some chemistry. But there are a lot of unknowns in climate science.
Glad you found the articles useful, I will be covering more on CO2 in Part Two soon.
Science,
Thanks.
I know that H2O is 1e5 to 1e6 times more absorptive than O2 around the 6.67 um range. However, the IPCC AR4 choose to ignore H2O in its forcing discussions and listing in chapter 2 table 2.1. So that makes me wonder then what is O2′s RF.
The H2O in this range is not 100% opaque, so the O2 absoption – albeit small – plays a part. By some really rough calculations the RF of O2 appears to be on the order of
HFC-152 at RF = .0004 and C2F6 (PFC-116) RF= .0008, which both get listed in the IPCC AR4.
At least I have seem to have gotten past the “its not a GHG, cause its a diatomic” argument. By definition, it is a GHG.
[...] Part One of the series started with this statement: If there’s one area that often seems to catch the imagination of many who call themselves “climate skeptics”, it’s the idea that CO2 at its low levels of concentration in the atmosphere can’t possibly cause the changes in temperature that have already occurred – and that are projected to occur in the future. Instead, the sun, that big bright hot thing in the sky (unless you live in England), is identified as the most likely cause of temperature changes. [...]
[...] Part One of the series started with this statement: If there’s one area that often seems to catch the imagination of many who call themselves “climate skeptics”, it’s the idea that CO2 at its low levels of concentration in the atmosphere can’t possibly cause the changes in temperature that have already occurred – and that are projected to occur in the future. Instead, the sun, that big bright hot thing in the sky (unless you live in England), is identified as the most likely cause of temperature changes. [...]
Thanks ScienceOfDoom,
Just found your site today and will return to learn more about CO2 and its effect on climate change (if any).
I do appreciate your effort.
I don’t quite follow why you say there is no solar radiation at the longer wavelengths. You say the graph was scaled down a million times to show the curve of the i/c (black body) radiation. Looking at the first graph there is a long tail into longer wavelenghts. Without working it thru it would seem that the sheer quantity of solar radiation would mean some at above 5 mu?
However, many thanks for this tutorial. I can see more easily how feedback mechanisms, +ve and -Ve, are so vital.
Still wonder tho’ about the ice core “CO2 lags temperatures, even when cooling” finding….
For Keith:
Good question. The two graphs compare the blackbody radiation in W/m^2 from the surface of those blackbodies at the 2 different temperatures.
Suppose the Sun and the Earth were the same size and near each other, then if we parked ourselves a little distance way from both then the sun’s radiation in the 5-30um would be a lot more than the earth’s in the 5-30um band.
Sun’s radiation in 5-30um spectrum = 329,000 W/m^2
Earth’s radiation in 5-30um = 339 W/m^2
So the Sun’s is 1000 times higher in this band if both Sun and earth were comparable distances away. And the Sun is a lot bigger, so the total energy would be higher again.
However, the Sun is a long way away from the earth.
We only receive 1 in two billionth of the sun’s energy that it radiates out (see the maths section at the end of the post).
That’s what makes the difference and is the reason why the Sun’s energy in the 5-30um band is so much less than the earth’s.
Hope this helps.
[...] Part One opened up the topic and introduced the simple “billiard ball” or zero-dimensional analysis of the earth’s climate system. The sun radiates “shortwave” energy which is absorbed in the atmosphere and the earth’s surface. This heats up the earth’s climate system and it radiates out “longwave” energy. [...]
Science of Doom – thank you for a very detailed explanation of the reason why a gas which comprises .04% of the atmosphere CAN have a disproprtionate warming effect. I have to admit that I started to glaze over through the maths – I am but a retired mechanical engineer who struggled with the maths at degree level, and try to avoid it as far as possible..!
However, since (recently) retiring I have taken an avid interest in the Skeptic viewpoint – which I share – and spend much time following the collapse of the AGW propoganda (to my wife’s undisguised despair).
The point which I WOULD like to make (Oh – at last) is this – none of the ‘warmists’ seem to have read the Kyoto Protocol, which talks quite clearly about reducing CO2 EQUIVALENT. NOT reducing CO2 itself..! Why, then, is the political/environmental establishment so keen to portray CO2 as a sort of horrid black cloud hanging over the country (that’s water vapour, that grey thing up there) – instead of the life-blood of plants which we all know about from basic biology..?
David:
Thanks for the kind comments. The maths is always painful. The challenge is to present the science in a way that can still shine through without any maths. I fear that I may have not succeeded in the later posts in the series.
On your first point
I haven’t read the Kyoto Protocol either. But if it refers to CO2 equivalents the same way as the IPCC..
The idea is to be able to compare the effect of all the “greenhouse” gases in a comparable way with CO2.
Looking at the change in ppm in the atmosphere – or absolute ppm – of different gases isn’t a good comparison as there are other factors. So the change in ppm of each gas is turned into “radiative forcing” at the top of atmosphere in W/m^2. This is a unifying concept so that the different gases can be compared.
Therefore, when the IPCC talks about CO2 equivalent it is with the idea that the increases in concentration of different “greenhouse” gases can be compared.
So – if the IPCC uses the same terminology as the Kyoto protocol – the idea is to be able to compare the effect of increases in different gases – CO2, methane, N2O and a whole raft of other CFC-**
And on the second point
In part I agree with you. The US EPA has denounced CO2 as a pollutant. This is not really true and perhaps this is more about the politics of the subject, rather than the science.
Leaving aside the politics. If CO2 – wonderful plant food that it is, and necessary for all life – if doubling CO2 will increase the temperature of the planet by a few degrees then it makes sense for people/governments to be concerned about it.
Therefore, the AGW community wants to reduce “greenhouse” gas emissions when they talk about “CO2 equivalents”. But what they are saying is “well, reducing CO2 emissions by 10ppm is the same as reducing CH4 (methane) by 1ppm so either one will be ok..”
I have a question regarding calculating the radiation balance. One uses the the “disc” area of the earth to calculate how much radiation the earth receives but the entire surface area for how much it emits. If we’re calculating a strict radiation budget in the absence of other mechanisms like convection, shouldn’t those areas be the same?
Dave:
Excellent question and one which is worth attention. In fact, I am thinking about doing a quick post on this specific topic, including a nice graphic – because when you start looking at this subject it’s all the little points – and the different numbers that get quoted – that easily trip you up.
So watch out for the next post..
The first question is, how much radiation does the earth receive? That’s easily calculated and since 1978 we have satellites measuring it from outside the earth’s atmosphere.
The number, the Solar “constant”, S = 1367 W/m^2
What area does that radiate over?
If we want to work out the total energy received by the earth, does it radiate over:
1. the entire surface area of the earth (4 x pi x r^2)? or
2. over the “2d disc” which is pi x r^2.
The answer is number 2.
Easy to understand in a conceptual way because the sun is not radiating equally over all points on the earth at the same time. Half the earth is in darkness at any one time, and some of the earth has the sun low down on the horizon.
I’ll show a nice graphic in the post on this topic.
So total energy received = S x pi x r^2
(where r is the radius of the earth)
So the second question, what about the radiation out? Your first instinct is a good one – shouldn’t we compare like with like?
But the earth doesn’t just radiate out from one side of the planet in one direction. It radiates out energy from every point on earth at all times (in proportion to T^4).
And the earth’s surface area is 4 x pi x r^2.
Energy is received from the sun and then the climate system spreads it all around.
Hope this answers the question, watch out for the next post..
Very clear explanation but somehow unsatisfying to me. Still not sure how x number of watts received in an average square meter can be emitted by some greater number of square meters. It really seems like the conditions of the initial equation have been altered.
It seems as though the calculations assume the earth is static when it receives the energy, but dynamic when it radiates that energy.
I look forward to an additional post on this vexing riddle
Hello,
If “Energy received from the sun = Energy emitted by the earth (if the temperature of the earth’s surface stays the same).” then there appears to be no energy left to be used (stored) by life on Earth. The biosphere should be part of the view. The surface of the oceans stores energy in algae, fish, and mammals. Same thing for most of the surface of the continents.
Also, there is the energy used to move the ocean water around the continents (oceanic currents, winds) this is kinetic energy that arrived as radiation from the Sun.
But if you look at the Earth from low orbit, you see clouds covering most of the planet. Water and water vapor seem to be the primary features of this planet.
Cheers!
[...] 6, 2010 by scienceofdoom In the first post about CO2 I included a separate maths section which showed the energy budget for the earth and also derived [...]
Dave:
Check out the new post:
The Earth’s Energy Budget – Part One
I might post a comment over there on your question above.
[...] Part One of the series introduced the shortwave radiation from the sun, the balancing longwave radiation from the earth and the absorption of some of that longwave radiation by various “greenhouse” gases. The earth would be a cold place without the “greenhouse” gases. [...]
Thanks for an illuminating article : clear, lucid and informative.
I am not a scientist, but ‘common sense’ tells me that the planet must have many ‘negative feedback’ systems – since almost any parameter we look at seems to oscillate back and forwards either side of a mean – within a fairly narrow range.
Just a personal anecdote: last February I was hiking in the Cheviot Hills, Northumberland here on the Scottish Border.
It had been bitterly cold with sub-zero temperatures for weeks on end, and the ground was still frosted every morning. That particular day we had a high-pressure system and the clear blue sky was cloudless, with no wind at all. The temperature climbed rapidly to about 20 degrees C – so hot that I removed my fleece and walked in a T shirt. I met a farmer and said that this looked good for the lambing season; he laughed and said ‘I wouldn’t count on it’. That night, the cloudless skies sent the temperature plummeting to minus 8 degrees C, and a few days later we were back to snow and frost until well into March.
My point is that there was no ‘heat storage’ on the land nor in our local atmosphere that day. The temperature range on that February day varied by a full 28 degrees C – but as soon as the clouds disappeared and the sun set – temperatures plummeted by 28 degrees within 8 hours.
My ‘common sense’ observation is that the heat must have re-radiated into space as infra-red – since none remained in the rocks or the air above them.
You could go to any desert in the world – and experience temperatures of 40-50 degrees C at noon – but the same night you could freeze to death if not suitably protected.
It seems clear that the Earth does not hold onto heat – and can radiate it into space in vast amounts very quickly. I realise that the oceans store heat much more than the land – but it still seems unlikely that there can be any runaway global warming, since – if my local hills can lose 28degrees of heat in justa few hours, so can the planet?
If a CO2 molecule can cause a warming of an spot on the earth can the earth warm the sun?
The pot cannot warm the burner.
The earth at a higher temperture than the CO2 molecule will not be warmed by a lesser energy emission. No where in radiative heat transfer does a cooler object warm a hotter object. At best they can be the same temperature and that would be what the sun caused.
Also using vector math the earth sends a photon that is intercepted by a CO2 molecule goes from a plus one to zero. The CO2 goes from zero to plus one then emits a photon (not the same one) out. So at best the earth would go from a zero where it was after emitting back to a one. So the two cancel each other and no warming of the earth takes place except that which comes from the sun to begin the process.
Also nowhere did you account for PV= nRT.
If the Second Law of Thermodyanmics means anything there is a increase in entropy during the exchange of photons between the earth and CO2 molecules. So there could not be any extra warming. Again at best it would stay even with what the sun caused.
Finally, you are the only site that doesnot show a H2O absorbtion line at the 15 spot.
William of Ockham:
Thanks for the kind words.
Your common sense observation is more or less correct. The earth – the rocks, soil, sand plus the atmosphere are very good at radiating heat away.
So is the ocean – although its specific heat capacity is much higher and so it will store heat for a lot longer.
However, although the overnight temperature in your example dropped to -8′C, it didn’t drop to say -50′C or -100′C. There is still heat stored in the climate system. But under a clear night sky the heat is effectively conducted, convected and radiated away. (Under a cloudy sky less so). Then when the sun rises the next morning that part of the earth warms up again.
In the absence of any positive feedbacks – and “all other things remaining equal” – the extra radiation because of the current level of CO2 simply moves the average temperature up “a notch”.
Remember if there were no greenhouse gases the average temperature at the earth’s surface would be -15′C. Clearly this absorption and re-radiation of longwave energy has a noticeable effect at the surface!
The extra longwave energy from higher CO2 doesn’t cause an immediate temperature rise, because the oceans take time to warm up. They have a large specific heat capacity and store around 1000x the energy of the atmosphere.
As the oceans warm up, they radiate more heat. Eventually a new balance is reached at a new higher temperature. (This is negative feedback – a new equilibrium is reached).
This certainly isn’t a “runaway” scenario. And the maths is fairly simple.
And of course – “all other things are not equal”, as so many other climate effects also have their impact on the global mean surface temperature.
Mike Kelly:
If I follow your reasoning correctly, putting a roof over a house wouldn’t warm the house because it’s not creating any extra heat?
What happens is the earth radiates out energy from its surface. With no greenhouse gases that energy would all be radiated out to space. That’s nice and simple
(Well, there might be some reflection and scattering on aerosols and other particles but we will leave out that extra complication).
With greenhouse gases in the atmosphere, energy is absorbed, the gas heats up and then re-emits radiation both upwards and downwards.
If you like you can think of it as heat reflected – like putting a roof on a house. That’s not what happens of course, it’s just an analogy that might help.
As we’ll see in Part Six !! – we can measure the downward longwave radiation at the earth’s surface. If the “greenhouse” effect didn’t happen there would be no downward longwave radiation at the surface.
Also what we see is the radiation coming back to the earth’s surface is in the energy bands (like the 15um CO2 band, the 9.6um O3 band, etc) that match the absorption we measure at the top of the atmosphere.
(And of course we can also measure the same absorption in the lab by taking each gas and shining radiation of various wavelengths through).
“Your common sense observation is more or less correct. The earth – the rocks, soil, sand plus the atmosphere are very good at radiating heat away.
So is the ocean – although its specific heat capacity is much higher and so it will store heat for a lot longer”
I would note that there is stored heat in the evaporated water vapour on that warm Scottish day.
The heat loss from the water vapour is due to net outbound radiation. As the temp drops, dew forms(condensation), and there is a heat transfer to the air and ground.
I think the maths of water vapour heat gain and retention would show it overwhelms CO2.
With greenhouse gases in the atmosphere, energy is absorbed, the gas heats up and then re-emits radiation both upwards and downwards.
Your quote.
Then following the second law entropy must increase and a less energetic photon is sent out. Since has less energy it cannot raise the temperature of the earth higher than what the sun did.
Also givenPV= nRT the earth’s temperture is roughly 0 deg C. So any effect by gases is only 15 deg not 33.
Two discs radiating at each other can only get to the higher of the two in temperture. So again that is what the sun causes not gases. If you snuggle with your wife at night does your temperture go up to 98.6+98.6= 197.2? No you both stay at 98.6. Even with covers on you stay at 98.6. Even with CO2 inside the covers you stay at 98.6.
CO2 cannot cause the earth to have increased.
Water vapor also has absorbtion line in the 15 range but you don’t show that was my point.
Don’t get me wrong I like your work it is very readable and I enjoy it. I just find no evidence that CO2 can cause an increase in the temperature of the earth and stay with the laws of physics and gases.
If CO2 could increase temperature and it has been known for so many years why hasn’t someone developed a blanket, coat, house wrap, anything that takes advantage of this and make money? Because it cannot be done.
EdB:
No one could doubt your point.
All that this first post in the series attempts to demonstrate is that the greenhouse gases in total have a significant effect on the surface temperature of the earth. And also that CO2 is one of these significant greenhouse gases.
How that compares with latent heat (movement of heat through evaporation and condensation of water) and “sensible heat” (due to convection) isn’t covered in this first part.
In the lower part of the atmosphere sensible and latent heat dominate heat transfer – you are correct.
Untangling the relative effects and getting to a point where some of the numbers are explained first requires an understanding that the effect exists.
In subsequent posts I try to work through some more specific issues.
Mike Kelly:
There is no violation of thermodynamic laws. There is no increase in total energy.
Let’s consider a simple comparison.
Case 1. Due to energy received from the sun, 2W are radiating up from the ground out to space.
Case 2. Exactly like case 1 but for whatever reason 1W keeps going out to space and 1W is “sent” back to earth.
(Case 2 could be reflection or absorption and re-radiation or any other phenomenon, doesn’t matter)
My questions:
1. Does this violate any thermodynamic principles?
2. In case 2 is the ground warmer?
[...] By the way, if you are new to this subject and think CO2 is an insignificant trace gas, then at least take a look at Part One. [...]
Part Six -Visualization of the series has just been added.
It shows the downwards longwave radiation at the earth’s surface, might be interesting for some people.
I did not say there was an increase in energy. I said that there must be an increase in entropy. Given a increase in entropy the photon emitted from the CO2 molecule must be of less energy than the one received from earth. That being true then the CO2 molecule cannot heat up the earth to a temperature as hot or hotter than what the sun did.
I do not disagree that gases in the atmosphere delay the exit of photons from the earth to space, but they are of less intensity and energy and cannot heat the earth up. Blankets keep me warm at night but not hotter than my body is.
There is no known example of a gas being used for anything other than heat dissipation. (Not counting burning gas for heat that is a different subject.) Gases dissipate heat they do not generate heat. Your car radiator, fins on electronic components, fans in the summer, etc.
Please address my inquiry about PV=nRT.
Mike Kelly:
Not wanting to press the point if you don’t want to.. but the blanket analogy is kind of what happens with CO2.
The photon emitted from the CO2 molecule is of less energy that the one received from the earth. But because a proportion get emitted back towards the earth they increase the surface temperature.
Take a look at Part Six – you can see the longwave radiation downwards at the earth’s surface. What is generating that downward longwave radiation? And why does it match absorption spectra of the gases that we know – CO2, methane, O3, etc?
Well onto your question about PV=nRT.
There were 2 questions and I didn’t really understand what you were getting at with either of them, I’m sorry to say.
First: “Also nowhere did you account for PV= nRT.
In the “billiard ball” model or zero dimensional model of the earth’s energy balance we just balance energy in from the sun with energy radiated out from the earth’s surface – using the well-known blackbody radiation according to Planck’s function. There is no need to introduce the ideal gas equation as we don’t need to work out the temperature, pressure or volume of any gases.
Second: “Also given PV= nRT the earth’s temperature is roughly 0 deg C. So any effect by gases is only 15 deg not 33.”
Can you elaborate?
[...] background is the series CO2 – An Insignificant Trace Gas? and especially the last post – which maybe should have come earlier! – CO2 – An [...]
Second: “Also given PV= nRT the earth’s temperature is roughly 0 deg C. So any effect by gases is only 15 deg not 33.”
Can you elaborate?
If gas laws are valid (which I belive they are) then the atmosphere of the earth all by itself must cause a certain temperature. By using a square meter up to 100 km one can figure what the temperature of the earth should be based on the pressure of air. I figure 0 deg C. If so then radiation only accounts for 15 deg C not 33 deg C.
“The photon emitted from the CO2 molecule is of less energy that the one received from the earth.”
Also if entropy is increased which you agree that it is then that photon cannot raise the temperature to a point as high or higher than what the sun did. Down hill flow of energy will not allow that.
Mike Kelly:
I’m not ignoring you, just thinking.
Well, not about entropy. Quoting a law doesn’t mean it applies to this situation although I’m sure you believe it does! Just that I don’t think I can help.
A roof on the planet would increase warming? Yes. But wouldn’t break the laws of thermodynamics? No. And this is different fundamentally from the “greenhouse” effect because… it’s a roof! Analogies often solve nothing!
10,000 physicists don’t think the greenhouse effect breaks the basic laws. The “skeptic” scientists (Lindzen, Spencer, Christy..) don’t think it breaks the laws.
So.. A test of any theory is the experimental evidence. So maybe a different approach – take a look at Part Six and explain where that downward longwave radiation is coming from.
According to your interpretation of thermodynamics, it can’t be from the “greenhouse” gas effect. So where is it coming from? Your turn.. You have the floor.
- I was thinking about the ideal gas laws. My first reaction was – A gas under pressure doesn’t create heat all by itself.
But anyhow, I will mull on it for a day or two and consider whether it is possible that the changes in pressure can account for some/any of the temperature gradient.. watch this space..
In the meantime, don’t forget to come up with your theory!
You should include why the absorption of upwards longwave radiation that we measure at the top of atmosphere is similar in spectral shape to the downward longwave radiation at the earth’s surface..
[...] a discussion on another blog when I commented about CO2 actually creating a “radiative forcing” – shorthand for “it adds a certain amount of W/m^2 at the earth’s surface” [...]
I don’t believe I have expressed myself correctly. You seem to think I disagree that there is IR being radiated both up and down in the atmosphere from GHG’s. I do not. As I stated earlier, gases delay the loss of heat but do not add to it.
What I disagree with is that the IR can raise the temperature of the earth as high as or higher than what the sun already did. The intensity is lower and the energy of the IR is less, as you agreed, so increase in heat is not possible.
Further two bodies radiating at each other can only get to the max temperature of the highest body which is the earth and the temperature comes from the sun.
Given the IPCC formula of dF=5.35*ln(C/Co) where C in the present level of CO2 and Co is a past level of choise. They say roughly 1.6 W/m2 is from CO2.
One Watt= 1 j/s (juole per second)
Given this and placed into the standard specific heat formula (Q=c*m*dT) there should be a warming of nearly 5 deg C. That is not happening. So something is awry. Even if you want to cut that in half because only half the earth receives sunshine at a time something is still wrong.
Of your 33 deg C as much as 95% of that is from water vapor. Three per cent for CO2.
So let’s do the math
33 X .95 = 31.35
33 x .03 = .99 for CO2
Human CO2 = roughly 4 per cent of total CO2
.99 x .04 = .0396 for human influence this is not mearsureable nor important.
But CO2 can only absorb approximately 8% of IR in its 14-16 mirco range. So the 33 x .03 should be really 33 x (.03 x .08) = or .0792 Then .04 X .0792 is .003 degree from human. That is not measureable nor important.
You may quibble with some of the percentage, but CO2 cannot warm the earth as you seem to be portraying.
[...] Part One of this series, in the maths section at the end (to spare the non-mathematically inclined), we [...]
Nicely done, I am in the “skeptic” camp but the foundation of the AGW theory are indeed solid, and the “0D” simplification is not really challenging mathematically, at least for who like math
.
If you welcome suggestions, I would modify slightly the presentation of the blackbody emisions of earth and sun: instead of scaling the sun emissions just to get it in the same graph (which raise the problem that a blackbody of higher temperature emit more at all wavelength than one at lower temperature – the “tail” of the sun emissivity is indeed much higher than the peak of the earth one as was mentioned in some comments), why not introduce immediately scaling due to distance, which would measure the emission right a the earth – keeping the earth curve as it is but scaling the sun by 1/r^2.
And another image that, imho, makes the 0D model more clear (and hightlight the simplifications) would be to say that it assume perfect conduction in the non-radial directions. It means that the earth is a perfectly conducting sphere, hence have only one temperature that does not vary between night and day, or places to places. This makes the area to consider for absorption (the disc for solar radiation, the sphere for longwave greenhouse back-radiation) and emissions (the sphere for earth surface blackbody radiation) quite clear….
Now time to go read the following parts
Thanks for those,
regards,
kai.
kai:
Thanks for the comments and the suggestions. Definitely a great idea to scale the two graphs and explicitly state that – also have a second graph with a zoom in on the overlap and add a bit of text specifically about that – or a reference to another post that has those numbers..
On the second idea I’m not sure whether that then confuses the non-mathematicians/scientists i.e., those that aren’t used to seeing models. Who say “oh well that doesn’t really happen so the model isn’t true.. and not valid..” – but anyway something for me to think about..
Comments from people who don’t get understand the theory here and on other blogs have been very illuminating, but clearly there is a lot more that can be done. So all suggestions about how to improve the material are good.
[...] 23, 2010 by scienceofdoom In the series CO2 – An Insignificant Trace Gas? we concluded (in Part Seven!) with the values of “radiative forcing” as calculated for [...]
Mike Kelly:
I’ll break it up into 2 comments..
First, you said:
Well, without any “greenhouse” gases, the earth’s (average surface) temperature would demonstrably be:
-18′C.
It’s not, so your interpretation of the 2nd law of thermodynamics is off.
And I don’t understand because you agree with that absorption and re-radiation of longwave energy happens – which raises the temperature above what it would be without these gases..
-Perhaps we can leave this part of the debate here and others can form their own opinions.
Mike Kelly
You raise an interesting question with a huge flaw..
What the radiative forcing increase of 1.6W/m^2 means is actually that the top of atmosphere longwave increase since pre-industrial times is 1.6W/m^2.
Suppose we take 1.6W/m^2 and heat the oceans – the major heat store – and ignore melting ice and warming of air..
What happens?
Let’s look at the oceans:
-Mean depth = 4km (4000m)
-70% of earth’s surface is covered by ocean so let’s say 1.6/0.7 = 2.3 W/m^2 going into the oceans
-Density is approximately 1000 kg/m^3
So each square meter of ocean has a volume of 4000 m^3, and therefore a mass of 4×10^6 kg.
Q = mc x dT
Q is energy, m is mass, c is specific heat capacity = 4.2 kJ kg-1 K-1,
dT = change in temperature
We have energy per second (W/m^2), so change in temperature per second, dT = Q/mc
dT per second = 2.3 / (4×10^6 x 4.2×10^3)
= 1.4 x10^-10 ‘C/second
dT per year = 0.004 ‘C/yr
—-
Let’s suppose – more realistically – that only the top “well-mixed” 100m of ocean receives this heat, so we would get (just scaling by 4000m/100m):
dT per year = 0.17 ‘C per year.
An interesting result.
So after 100 years the temperature increase will be 17′C
And after 1000 years the temperature increase will be 170′C.
Clearly radiative forcing can’t exist…
Or maybe there is a misunderstanding about how to apply it?
What we can do is use W/m^2 to look at how quickly that will warm the planet - we can investigate the very important subject of thermal lag
What we can’t do, is just use the formula for heat capacity and work out a new temperature – because as the climate warms up, it radiates more heat.
Which you can see in Part Seven, at the end.
Isn’t that 1.6 * 0.7 ?
Dan Hughes:
No. Here’s the reason why.
If the energy is divided into land and sea and ice – equally all around the world, the energy is 1.6W/m^2.
Now we are saying – just for the sake of this thought experiment – that all of the energy goes into heating the oceans.
If the oceans were half the surface area of the globe (50%) then the energy going into the ocean would be double = 3.2W/m^2. The energy flowing into every square meter of land diverts/flows on instead into a square meter of ocean.
Because the oceans are about 70% of the earth, 0.7, we multiply up by less than 2, by 1/0.7=1.4.
No wanting to labor the point.. but another way to look at it for sake of completeness:
Total energy,T (in this thought experiment):
T = 1.6 * S (S= surface area of the earth)
This total energy is all absorbed by the oceans. How much energy per m^2 of oceans?
E(total ocean) = T (because all the energy flows into the ocean, so this is just the definition)
E(per m^2 of ocean) = T/area of ocean
Area of ocean = S*0.7
E(per m^2 of ocean) = T/(S * 0.7)
What’s T? T= 1.6 * S (above)
So E(per m^2 of ocean) = (1.6 * S)/(S*0.7)
=1.6/0.7
[...] The IPCC, drawing on the work of many physicists over the years, states that the radiative forcing from the increase in CO2 to about 380ppm is 1.7 W/m2. You can see how this is all worked out in the series CO2 – An Insignificant Trace Gas. [...]
[...] yet there is a whole series on CO2 – An Insignificant Trace Gas? where the answer is “no, it’s not insignificant”. Doesn’t that support AGW? [...]
[...] an earlier series, CO2 – An Insignificant Trace Gas we delved into simpler numerical models. These were 1d models. They were needed to solve the [...]
[...] For a detailed explanation of these points, see the CO2 – An Insignificant Trace Gas? series at The Science of Doom http://scienceofdoom.com/2009/11/28/co2-an-insignificant-trace-gas-part-one/ [...]
[...] the CO2 series for a little more on this if you wonder why it’s longwave getting radiated out and not [...]
[...] This article will cover the first paper which appears to be part of a conference proceeding: Changes in the earth’s resolved outgoing longwave radiation field as seen from the IRIS and IMG instruments by H.E. Brindley et al. If you are new to understanding the basics on longwave and shortwave radiation and absorption by trace gases, take a look at CO2 – An Insignificant Trace Gas? [...]
[...] These numbers are global annual averages under a clear sky. Under a cloudy sky the numbers are different but similar – and still the radiation from the surface of the earth is a lot greater than that leaving through the top of atmosphere. For more on this take a look at CO2 – An Insignificant Trace Gas? – Part Six – Visualization and the followup CO2 Can’t Have That Effect Because.. as well as the start of the series on CO2. [...]
[...] of longwave radiation by trace gases – the “greenhouse” effect. See the CO2 – An Insignificant Trace Gas? series, and especially Part Six – Visualization and CO2 Can’t Have that Effect [...]
[...] are a few basics. For newcomers, you can take an extended look at the theory in CO2 – An Insignificant Trace Gas? It’s in seven parts! Actually it’s a compressed [...]
[...] radiative transfer equations using line by line calculations. For more on these equations, see the CO2 – An Insignificant Trace Gas series, especially Part Three, Four and [...]
Question: how can we be sure that we have accounted for all the elements of the energy balance equation?
I think radiation is the easiest mode to model. But I would imagine that orbital asymmetries deform the earth and those deformations result in heat. Also, we have an iron core spinning, precessing, orbiting and wobbling in the presence of a varying magnetic field — producing inductive coupling, which also trasfers energy and results in heat.
Given this, why do we say that the only mode of inbound heat transfer is EM wave radiation?
[...] Anyway, it’s just a mental picture I wanted to create. It’s not a perfect mental picture and it’s just an analogy – a poem, if you will. If you want real science, check out the CO2 – An Insignificant Trace Gas Series. [...]
gcv:
Orbital asymmetries cause small fluctuations in the solar energy received – or at least the location (latitude and time) of maximum and minimum energy. And the % variation during the year of the solar energy received.
Energy received from internal processes – mainly heat – is miniscule by comparison with the approx 240W/m^2 of solar energy absorbed over the surface of the earth (averaged globally and annually).
There is much more uncertainty about how much energy is actually absorbed by the earth’s climate system – as 30% “or so” of the incident solar radiation is reflected.
“Orbital asymmetries cause small fluctuations in the solar energy received – or at least the location (latitude and time) of maximum and minimum energy. And the % variation during the year of the solar energy received.”
I’m not about about changes in solar energy, I’m asking about inductive heating of the core. Do you know (or could you point me to) the amount of heat generated by this inductive effect?
gcv:
You are asking if inductive heating makes its way out to the earth’s surface to affect climate?
Geothermal energy is very small, believed to be 0.06W/m^2.
If you are asking about inductive heating just heating the core and not affecting climate then it’s not really a topic of interest for me unfortunately.
It is my understanding the the 1365 W/msq value is at the top of the atmosphere and that even in the solar spectrum there are significant water vapor and dust “blocks” to this flux.
I ran a solar furnace for several years and we used a calibrated normal incident pyrheliometer NIP to measure surface solar flux. The best we ever saw here in the southern NM desert was about 1100 W/msq during very low humidity days in the fall. Summer NIP readings (on clear days) were rarely above 950 W/msq. During one period we watched the NIP readings slowly drop to a steady 100 W/msq below normal as the cloud of ash that was blown into the stratosphere spiraled around the earth to finally block the view of the sun. This drop lasted for months and did slowly dissipate. Is there something wrong with “my” reality or is there something wrong with your theory (of insignificant solar [SW] atmospheric blockage)? Especially by water vapor (not clouds).
Bernie
Bernie McCune
You are spot on. The earth’s albedo, made up of clouds, certain types of aerosols and reflections from the earth’s surface is around 30%. From the article:
I think your average 30% figure is good for solar noon on many days of the year here in NM but I would guess that much less of the 1365 W/msq found at the top of the atmosphere gets to the surface here primarily due to components of water (vapor and clouds).
From my experience of a couple of years (1980-2) the local and regional solar surface flux averaged less than 70% from flux at the top of the atmosphere (and for some periods of months even much less). During solar noon surface flux was on most days 70% (of TOA irradiance) but early in the morning until about 11 am and from 2 pm to sunset it probably averaged 40 to 60% (more atmosphere including water to penetrate?). Maybe 20 days in the Fall at solar noon it was 80%. The volcano I referred to in the previous post was Mt. St. Helens.
Anyway the point is – the average regional solar surface flux is drastically variable throughout the day, the year and from year to year – primarily due to water vapor and clouds. Throw in a volcanic eruption and at least a drop of 100 W/msq for many months can almost be assumed.
Bernie
Bernie McCune
Take a look at Earth’s Energy Budget – Part One and a new part, to be added shortly, will cover albedo in some more detail.
The 30% is a global annual average. There’s a little more about albedo already, but in a post on a totally different topic, Positive Feedback, Albedo and The End of All Things
I have been looking deeper into the material here and welcome a clear relatively simple approach to explaining these concepts. My initial effort was to get a clearer explanation of the greenhouse theory. I will spend some time working here on this site and get back to you in a month or so – ha ha.
I am also trying to reconcile my earlier experience with surface solar irradiance values with these other more complex issues of atmospheric thermodynamics. Rather than continue into this discussion which may too quickly drift into opinion, I will go away and study this more. Thanks for having a place to do this without all the smoke and mirrors.
Bernie
[...] This concept can be found in CO2 – An Insignificant Trace Gas? Part One [...]
[...] where most of the longwave radiation takes place from the earth’s surface. Check out CO2 – An Insignificant Trace Gas? for more on [...]
[...] affect anything in climate – this post isn’t for you – check out the CO2 – An Insignificant Trace Gas? [...]
http://clivebest.com/blog/?p=1244
gives a fairly comprehensible explication of
Miskolczi’s work with an emphasis on the
way recent data accords with it. In particular,
the point is made that the climate is homeostatic
with respect to
g = 1/3
I will elaborate around that simple result:
g = 1/3 in the actuality of a vast amount of data
g = 1/3 in the theory of Ramanathan.)
Overall, the climate is a homeostatic system
which maintains g = 1/3.
The climate’s primary business is to maintain
a particular energy balance. The “name”
of that energy balance is “g = 1/3″.
The role of CO2 is incidental to maintaining
the energy balance at which g = 1/3. CO2 is
a relatively minor player in the overall climate
picture from a thermodynamic standpoint.
The temperature sensitivity of the global temperature
to a doubling of CO2 is way less than the IPCC
predictions.
I found Miskolczi’s paper hard going and it
may well have an error or two in it. One should not,
however, IMHO, get too hung up on Miskolczi’s slip ups
because it seems to me that there are alternative
ways to arrive at Miskolczi’s intermediate results. The thing to remember is that Miskolczi
is a physicist who works from data towards theory.
His constant optical depth theory was the result of
his long study of actual atmospheric data that had
been accumulated over quite a span of time.
The central result of all this data was that
g = 1/3, exactly what Ramanathan said it
must be. Miskolczi say that as being more than
coincidence.
IMHO, if one can really get a solid grasp of
Ramanathan’s
g = 1/3
, one can then extend to Miskolczi’s
central result
that
2 = tau + ( exp ( -tau ) )
(where tau = optical depth of the atmosphere)
g = 1/3 and
2 = tau + ( exp (-tau ))
go together
G.N. Plass in 1956 worked out the effect of increasing CO2 concentrations in the atmosphere. He found that doubling the CO2 concentration in the atmosphere would cause a 3.6 oC rise in the earth’s temperature. The temperature increase is much like we have been observing. See http://www.aip.org/history/climate/co2.htm -
I have a couple of question that I’ve yet to see answered. In the 1940′s, a nice fellow named Hottell did a bunch of work on radiant heat absorption by water and CO2 in the atmosphere. In the 1970′s, Hottell’s curves were updated by another nice fellow named Leckner. If one uses these curves to ascertain the emissivity of the atmosphere, and then calculates q, one comes up with a curve that is remarkably similar to the simplification of F=5.35lnCO2. In reading Ramanathan, there is no reference to any of this. He seems to have reinvented the wheel. Can anyone explain two things:
1: When I was taught heat balances (3rd year engineering), we were taught that radiative and convective transfers were independent. Did Ramanathan provide a justification for choosing to attempt to couple these?
2: Why was the HUGE amount of work on radiant heat transfer in the atmosphere, done prior to Ramanathan, never referenced by Ramanathan?
Just found your site today via CA. Enjoyed the radiation emission/absorption background. It was a well done presentation; however, you didn’t provide the maths to support the contention that LW radiation back to the earth was 55 – 75% H2O and 25% CO2. Are those numbers empirical? If they are, wouldn’t some if not all of the 25% CO2 LW be the result of H2O reradiating at a longer CO2 wavelength?
The answer to this connundrum will determine whether CO2 is a significant contribution to the GH effect as you claim. The ppm saturation point of CO2 is critical to determining the effect of increasing concentrations of CO2.
E.F. Zeamba
The explanation is in Part Five of the series.
Feel free to post a question there on any specifics. The numbers are calculated by solving the radiative transfer equations, which you will see in Part Three
John Eggert
He doesn’t really couple them. How do you work out the radiation of each layer in the atmosphere? It depends on temperature of that layer – as well as the concentration of each trace gas. How do you work out the temperature?
If you calculate the radiative equilibrium it isn’t what you find in the atmosphere because the temperature profile (lapse rate) is determined by convection (see, for example Tropospheric Basics )
So his justification for using the “Radiative-Convective Model” is that when the calculated lapse rate is lower than what is found (more negative) then the lapse rate is set to the known convective profile. And when the radiative lapse rate is high than what is found the temperature profile is set to the radiative calculation.
This allows a calculation of the absorption and emission within the atmosphere without needing to solve convective fluid calculations. You can see more about this paper in Part Five
I took a look at a paper by Leckner: Spectral and Total Emissivity of Water Vapor and CO2 (1972). In it his curves for emissivity go down only to 300K, whereas the atmosphere is mostly below 300K
He says:
and cites RM Goody, Atmospheric Radiation, vol 1, Theoretical Basis
Ramanathan cites RM Goody including this same volume. Goody does seem to be the source for this kind of work.
Perhaps some coincidence – because the solution to the radiative transfer equations requires emission and absorption using the temperature profile and concentration profiles for each trace gas. You can see the source of this 5.35lnCO2 equation in Part Seven
Holy smoke, someone actually answered a good many of my questions. Steve M. at climate audit was right, this is an excellent site.
As for your questions, I have written a paper outlining a method for calculating the path length (as defined by Hottell and Leckner) of the atmosphere. e-mail me if you want it.
Regarding temperature / lapse rate, I ignore it (well … consider it constant at 300K). Here is why.
The temperature variations in the atmosphere are relatively small compared to the ranges considered by Leckner and Hottell. 10s of degrees for the atmosphere, thousands of degrees for Leckner and Hottell. Also, the projection from Leckner’s data is very small. The critical aspect of Leckner’s work is that he showed that there is a point (a path length of about 200 barXcm) where further increases in CO2 concentration have no further impact on radiative heat transfer. This is consistent over a huge range of temperatures. The absolute emissivity at various temperatures varies a little, but the fact that there is no change from 200 to 500 barXcm is consistent over all temperatures. The change is insufficient to match the increases hypothesized by Ramanathan. Unless of course there is some huge deviation in the absorbance characteristics of CO2 that occurs from 200 K to 300 K compared to 300 K to 3000 K. This is possible and indeed provable (and disprovable, so to speak). I believe Hottell’s curves go to 0 F (255K). They do not show such a deviation.
Finally, no coincidence. This is exact the point of Hottell’s work. Provide a robust an simple solution to the radiative transfer problem without requiring a solution to the equations.
Once again, thanks for taking the time to indulge me.
I would appreciate receiving your paper
via email.
John Eggert
Which paper by Hottell should I be looking at to see his solution to the radiative transfer problem?
Firstly – great site! You have obviously put a lot and time and effort into this and I for one greatly appreciate this – it explains the science (to me at least) in a many which I can understand and make sense of.
I have a couple of question in order to help my understanding (points of clarification really).
Referring to the graph showing the theoretical “earth radiation curve” and the measured actuals (the one referenced from Grant Brigg 2003). You conclude that the difference between the observed and the theoretical curves (the shaded part) is a measure of the energy absorbed by the atmosphere. Inaddition, as we can work out which gases absorb at which frequencies we can determined the relative proportions each gas contribute to the “Greenhouse Effect”.
1) Based on the above is the “conclusion” that ~20% of the effect is due to CO2. i.e. 20% of the shaded area is at wavelengths where CO2 is the main / only absorbing gas? N.B. I have heard the 20% figure “banded around” on many sites and wondered if this is the scientific basis for this?
2) At ~15mico-meters there is total absorbtion. I assume this means that the CO2 blocks all energy at this wavelength (e.g. the door is shut!). By looking at the wavelengths that CO2 absorbs the energy and seeing how much energy currently gets through can we not determine the “maximum” effect CO2 can ever have? E.g. simply work out the amount of energy current not being absorbed at these wavelengths and this will give us the maximum impact etc? If this is correct has this been calculated?
Would love to be able to get a copy of the data for the graph to be able to do some simple analysis on it e.g. workign out the areas etc. Don’t suppose you know if this is in the public domain?
Once again many thanks for any help / insight you can give.
Regards
Neil:
Not really – this is just Part One of the series. By the time you hit Part Five you will see that the calculation depends on properly solving an equation which is complex. But don’t skip the parts in between..
Yes we can.
But if you work through the series you will see that even though CO2 might absorb strongly, each layer of the atmosphere also re-radiates (according to temperature and concentration of each trace gas).
The effect of doubling and quadrupling CO2 is outlined in Part Seven and is calculated by solving the radiative transfer equations.
Much better to properly understand the theory and how it is applied. However, you can see one example of the changes from doubling CO2 in the second set of graphs in CO2 in the Solar Spectrum
Science of Doom:
You asked where you could find Hottell’s papers. I can’t tell you for sure. My reference is a text book written in the 1950′s. The references are generally Hottell and ??Sarafin??. The work was done at MIT (I believe) in the 1940′s. Sorry I can’t give better at the present time. I’m working out of town and don’t have access to my hard copy notes.
I’ll post again when I get back home on Friday.
Science of Doom:
A friend has a heat transfer text, so was able to find the reference for Hottel.
Hottel H.C. & Egbert R.B.: Radiant Heat Transmission From Water Vapour: Trans AIChE, Vol 38, p531, 1942.
John Eggert
I tried to find this paper, but unsuccessfully. If you have a copy I would be very interested to see it. It would be interesting to see the method and results vs the later methodology.
Science of Doom:
You asked about the paper, results etc., versus later methods. I don’t have access to the paper (probably need to find a hard copy in a University library somewhere). The results of the paper and the methods can be found in most texts on heat transfer in the section on radiant heat transfer. Some texts still use Hottel’s curves (note that I spelt Hottel incorrectly previously). Others have switched to Leckner’s curves. I’ve reviewed Hottel’s curves and see that they DO NOT go to 0 F. I was definitely wrong about that. Need to be careful of statements without authoritative references handy!
John Eggert
That might explain why Ramanathan and others of the same era didn’t cite Hottel.
I’m still intrigued by the calculations of Hottel that match the later results solving the RTE. If you come across the paper please post a link.
The graph you borrowed:
“Radiation spectrum from the earth showing absorption from atmospheric gases”
appears to have some problems, and if I am right they are all too common with graphs of this type.
The vertical scale has the units W/m^2, which does not make any sense. If one judged by the horizontal scale (microns) one would expect W/m^2/micron or W/m^2/micron/steradian.
But then another problem is that the spectral peak is at or around 17microns which is I think correct for the radiance as a function of frequency (the spectral peak for radiance as a function of wavelength would I feel be at around 10microns).
This indicates to me that the values are derived from the frequency form of the function but a horizontal scale in the equivalent microns substituted when it came to making the graph. I am afraid that this does make a difference.
I have fiddled with the values as produced from the frequncy form of the radiance function to try and come up with the values indicated on the graph but I cannot. To be honest I do not know how they are scaled.
Compare this to your graph:
Radiation vs Wavelength – Sun and Earth
which does appear to have the right values and scales.
A small point that is just a “reader beware”: the flipping to a logarithmic scale can confuse as the integral of the radiance no longer corresponds to the “visual” area under the graph but that is a small point and is as I said just a case of “reader beware”.
Alex
Alexander Harvey:
You are right about the graph, thanks for pointing it out. I will replace it with a better one.
scienceofdoom:
OK, but when you do replace it, could you please annotate my entry to show that I am talking about something that has disappeared.
Alex
Hottel and Leckner data is intended to be used to calculate heat transfer in things like boilers and flue gas where the temperature is high and the concentrations of CO2 and H2O from fuel combustion are also high. Using that data to calculate atmospheric heat transfer is extending it far beyond its intended purpose. I’m not sure how much is empirical measurement and how much is an actual solution of the RTE either.
The principles are the same, DeWitt… Laws of thermodynamics works everywhere.
scienceofdoom:
I have to say that I think you be very brave to try to boil this kind of stuff down into bit sized chunks.
It ain’t easy. Some of the concepts are very slippery and promoting understanding vs bewilderment can turn on the interpretation of a single word; one example being equilibrium.
Anyway Good Luck, and Bon Voyage.
Alex
scienceofdoom:
Have been searching for absorption spectras regarding greenhouse gases and found a lot of graphs. One of them led to this site.
I have a question for you about the graph from Linacre and Geerts. The graph shows no absorbtion from H2O for longer waves than about 8 microns and that CO2 absorbs a lot from about 14 microns up to where the graph ends.
Several other graphs show that Co2 absorbs between 14-16 microns and nothing at longer waves. They also show H2o absorbing from 10 microns, increasing up to about 16 microns and then “full” absorption up in the microwave interval.
One example here: http://www.brneurosci.org/spectra.png
There are other graphs showing the same thing.
These frequencies are clearly important in the earth longwave radiaton spectra so this really has to matter.
Since I am far from an expert on the subject it would be helpful if you could explain the difference between the graphs.
Best regards
/G
Greg M:
Thanks for asking the question. I think the Linacre and Geerts graph isn’t so good and I’m glad you pointed it out. When I did this first post on CO2 I had some handy basic material that I used but just a few days ago Alexander Harvey (above) pointed out correctly that the Grant Bigg graph was flawed and now you have pointed out that the L&G graph is quite basic.
Both need replacing with better quality data otherwise they can cause confusion.
For water vapor the absorption across the longwave spectrum is very extensive. The subject gets “simplified” and perhaps that makes it harder to understand.
Here are two plots from http://spectralcalc.com/spectral_browser/db_intensity.php which uses the HITRANS database. You can play with it yourself.
The first graph is linear on the vertical axis, and you can see where water vapor is strongest. The second graph is logarithmic on the vertical axis and you can see that it has an effect across most wavelengths:
Of course, for people less used to seeing logarithmic graphs they can also confuse as each horizontal line represents a factor of 100.
Scinceofdoom,
thank you for your answer and the link to spectralgraphs.
I realize I´ll have to study this subject a bit more.
/G
I have been looking for a mathematical overview of global warming that develops the key equations & the physical underpinnings so I am delighted to find at this site exactly what I was looking for!
[...] is the long-promised eighth part of the seven-part series on CO2 basics. Part One introduced the idea of CO2 with some basic concepts. Part Three opened up the radiative transfer [...]
[...] 30, 2010 by scienceofdoom In the CO2 series we looked at the effect of CO2 without climate feedbacks. The “answer” to the doubling [...]
Science of Doom.
Thanks for an informative series. I am hoping you can help clear up some conceptual issues I have.
Where (at what altitude above the surface) in our atmosphere is downward ghg LW being radiated from?
My understanding is that the atmosphere cools by 7 deg C for each 1000m rise in altitude. If this is so, heat must be moving away from the earth, and not towards it.
Often one hears that ghg acts like a blanket trapping escaping heat and the re-radiating it in all directions. Is this a useful metaphor? If so, what proportion of LWR is directed downwards, and do your calculations take this into account?
cherry picked:
It varies depending on the wavelength – and in the case of water vapor, it depends on the concentration profile of water vapor. And it’s also important to realize that there will be a range of heights from which radiation will be coming. For some conceptual understanding on this, even though it is about the outgoing radiation, see The Earth’s Energy Budget – Part Three
The surface is hotter than the atmosphere. But the amount of heat received by the surface is the same as the amount of heat removed from the surface (otherwise it would be heating up or cooling down).
The same goes for the atmosphere.
The surface receives radiation from the sun (during the day) and from the atmosphere (24 hrs a day) and loses heat (to maintain balance) by radiation, by convection and conduction. Included in convection is latent heat (evaporation of water).
Note that strictly speaking this is considering a part of the surface in steady-state, but the concepts don’t really change for surfaces which are heating up or cooling down.
So the fact that the atmosphere is colder the higher you go doesn’t mean that no radiation is downward. Gases which absorb radiation will radiate in all directions.
For some more background take a look at Tropospheric Basics and Sensible Heat, Latent Heat and Radiation
I don’t like the metaphor myself because a blanket doesn’t really explain why solar radiation goes right through the atmosphere, but various trace gases absorb the terrestrial radiation.
But the second part is correct.
A simplistic way to think about it is that half is up and half is down. But in fact because the radiation is in all directions, the radiation from one layer in the atmosphere will radiate to many locations on the ground and less than half will be absorbed by the surface.
The full solution to the radiative-convective model (see CO2 – Part Five ) takes these factors into account.
Thanks for the considered response, SOD.
I will read the links you provided before asking folllow questions, if any.
Thanks
[...] attacking skeptics and defending questionable science like the famous hockey stick. The series of articles on CO2 as a greenhouse gas I would recommend to anyone and certainly have been useful to me better understand [...]
[...] of 230K (-43°C). The same calculation for the earth gives 255K (-18°C) – see CO2 – An Insignificant Trace Gas? – Part One. So in terms of a simple energy balance with the sun, Venus should be colder than the [...]
NASA has flown some interesting instruments that may help with understanding the radiation. These pictures were taken in the central US in 1996.
http://mas.arc.nasa.gov/gallery/comparison.html
The photos are from the visible (0.55 um) to far infrared (14.21 um). They appear to be calibrated but the details are not given. One easily notes the slight increase in land brightness as you go into the near infrared (0.7 to 1.75 um) as should be expected by anyone who has used IR photo film. Plants get very bright in this range. The clouds are white and reflecting in the range from 0.55 to 2.40 um. The land gets dark around 1.8 to 1.95 um and then brightens up again (perhaps ground vapor in the H2O band near 1.8). At 2.89 um the band goes gray, perhaps the CO2 absorption band. And surprise above 3.21 um, the clouds start to go dark and the land starts to become very bright. I would say we are starting to see the “blackbody” radiation from the land here.
Interesting how the clouds reflect the visible and near IR but go dark in the far IR. They appear to reflect most the incoming solar radiation but would absorb and re-emit the ground radiation.
The question I have is: why don’t we clearly see the CO2 absorption if it is such a problem? Perhaps the gray-out is CO2 at 2.89 and 14.21 um. We sure don’t see it obstructing the bands further out in the IR where the land is very bright but the clouds sure do. In fact, it is possible that the solar radiation is much smaller here and we are mostly seeing the outgoing land radiation and the clouds are simply dark because the sun doesn’t reflect much far IR off their tops. In this case I would expect the bottom of the clouds to be reflecting some of the far IR back down to the ground.
Perhaps SOD can comment on these sensor photos.
Here is a high resolution false color image of the IR images I previously posted (an area north of Denver):
http://mas.arc.nasa.gov/gallery/images/scene_9611028.jpg
We can now see that there are shadows to the lower left of clouds, jet contrails and some small water features (lakes or reservoirs). This helps in the analysis of the original spectral bands at lower resolution:
http://mas.arc.nasa.gov/gallery/comparison.html
I believe that the following analysis is correct, but as I am not an expert (only a BS in physics), some of the details may be wrong. Take it as an opinion.
It is noted that the spectral band images are calibrated for radiance and I will assume that equal brightness will mean similar radiation power flux (although radiance is not exactly equal to flux due to vector angle differences). These were shot by an E2 (modified U2) and could be from about 70,000 feet, but this is not mentioned in the data description. The fact that large jet contrails are in the images suggests it was much higher than the 40,000 feet that jets fly below. There is also very little atmosphere above this altitude so most of what we see will be similar to a view from space. I also assume that the grayed-out images at 2.89 and 14.21 um are caused by CO2.
In the incoming Sun shortwave flux the dark areas will indicate absorption while light areas indicate reflection back to space. For the outgoing “blackbody” longwave flux (above about 4 um where the cloud shadows disappear because the land is so bright) the bright areas indicate emission while dark areas indicate lower emission. The Sun has very low output in this region so the clouds will appear dark (reflecting very little IR from the Sun compared to the emissions from the land below).
While bands above 14.21 um were not captured by the sensor, they should look similar to 14.21 um. This is because CO2 has strong absorption in this region. There is still about 25% of the total longwave emission in this area so this is where CO2 has the most effect on warming.
Concerning the different features in the images:
Land: strongly absorbs in the visible and near IR, strongly emits in the far IR. Bare land heats the most and also emits the most. Urban features would be worse (pavement, etc.).
Vegetation: strongly absorbs in visible bands, some reflection in near IR, strongly emits in the far IR but would be cooler than bare land.
Surface Water: strongly absorbs in visible and near IR (more so than land), doesn’t emit much in far IR until you get above 5 um. Appears to reflect or emit around 3.21 to 3.52 um and absorb around 4 um.
Water Vapor: there appears to be strong absorption near 1.9 um which may be surface water vapor.
CO2: Appears to absorb at 2.89 and 14.21 um. The fact that it is a gray fog seems to suggest that it is re-emitting some radiation downward or transferring it to the surrounding air as thermal heat. It it were saturated (no longer able to absorb and emit) it would be as bright as the land and more transparent.
Clouds: Highly reflective for most incoming Sun near IR. Appears dark in longwave IR but may still be reflective. The Sun’s output in longwave IR may actually be reflecting off the top of the clouds but is much lower than the flux from the land below. Provided the clouds reflect longwave IR (and there are suggestions that cloud cover causes heat retention) this should cause warming due to partial downward (diffuse) reflecting of the outgoing earth flux.
The real question concerning AGW: is the CO2 really that important? It appears to be above 14 um and surface water appears to have some output above 5 um (it is a cooler blackbody than the hot land and should have more output at longer wavelengths). Clouds could be a negative feedback because they reflect so much of the incoming flux, but they also may reflect some of the outgoing flux back to the surface.
The spectral images have been contrast extended so no real conclusions can be drawn without access to the raw data and knowing the calibration factors. However, they do provide a layman’s view of what is actually happening by showing the CO2 fog bands, incoming flux absorption, cloud reflection and blackbody flux out.
There’s a sentence in the article where it says “If you measure radiation above 5μm, you know it’s generated by the terrestrial system.”, which is utter nonsense.
A hot object radiates more energy at _all_ wavelengths than a cold object. This can be seen from the figure “Energy intensity versus wavelength for different temperature objects”. The figure “Radiation vs Wavelength – Sun and Earth” conveniently scales the energy from the sun by 10e-6 to hide this.
The sun emits much more radiation at 5μm than the earth does.
Symon
Well, take a look at The Sun and Max Planck Agree and the followup in minute detail: The Sun and Max Planck Agree – Part Two
Seeing as the sun is a long way from the earth, the solar radiation is reduced according to the inverse square law.
You can take the total solar radiation and divide it by 2 billion to get the amount absorbed by the earth, or alternatively, the solar radiation per m^2 and divide by 215^2 to get the amount per m^2 reaching the earth.
Anyway, take a look at the graphs in The Sun and Max Planck Agree – Part Two.
Thanks for your reply. The link makes clear that the 5μm statement refers to measurements made on or near the earth, which this article doesn’t mention.
Thanks again.
No trouble. Your comment prompted me to the long overdue overhaul of this article in attempt to explain everything more clearly.
The article has now been significantly rewritten. Earlier comments might confuse current readers if they refer to specific diagrams or calculations.
Thanks to the many people who have made a contribution by asking questions, asking for clarification or explaining their alternative point of view.
[...] 6, 2010 by scienceofdoom Just a note that CO2 – An Insignificant Trace Gas? – Part One has been significantly [...]
I can see that a lot of work went into this revision,
and that is much appreciated. I will give this a
careful reading.
I still have the feeling that you have not yet
read Miskolczi’s papers, both the theoretical
and the experimental. If I am right in having
this feeling, then, to honor the commitment to
objectivity you seem to have made, you should
do so. I do not assert that Miskolczi is “right”, I argue that
he deserves to be heard.
As well as I am able, I make it my practice to listen
more carefully when I disagree than when I agree.
The lucid, orthodox exposition notwithstanding, an alternative approach which concludes that CO2 is after all an insignificant trace gas is worthy of consideration:
From K&T(1997) we see that the atmosphere emits to space 195 Wm-2 of the total 235 Wm-2 required to balance the net solar flux. It emits the heat that it takes in from the solar flux, 67 Wm-2, and from the surface: through evapotranspiration, 78 Wm-2; through convection, 24 Wm-2.; and, imlicitly, 26 Wm-2 through absorption by GHGs of surface radiation. Of the absorption, CO2 accounts for 26%. That is, CO2, which accounts for 0.06% of atmospheric mass accounts for 0.03% of the climate system’s radiation to space. The possibility, canvassed by K&T, that the atmosphere absorbs 25 Wm-2 more of incoming radiation than they have allowed, reducing absorption of surface radiation by GHGs to 1 Wm-2, virtually relieves CO2 of any significance in the climate system.
Correction: for 0.03%, read 3%.
John Millett:
I don’t understand your calculation.
What do you think the surface would radiate (global annual average) if there were no “greenhouse” gases?
What do you think the surface radiates in our current climate?
The surface radiates at an intensity determined by its own temperature and the temperature of the sink to which it radiates. The smaller the difference between these temperatures, the lower the intensity of radiation. If, as I have seen stated seemingly with some authority, most of the absorption by greenhouse gases of surface radiation occurs relatively close to the surface in the turbulent boundary layer, it seems likely that the temperature difference would indeed be small. This would be in accord with the analysis above of the K&T energy budget showing that radiation plays a small role in the transport of heat from the surface to the atmosphere for ultimate radiation to space.
In that tantalising imaginary world without life-essential CO2 and H2O, molecules with the added property of wavelength-specific absorption of radiation, would the sink temperature be much different? Not really, since the atmosphere gains its energy from the sun, directly by absorption and indirectly by non-radiative means of transport from the solar-heated surface. This imaginary atmosphere, the absence of its IR-absorbent molecules notwithstanding, would continue to diffuse the heat thus gained by radiation to space. The imaginary earth would be uninhabitable for lack of food and water not lack of shelter from the cold of deep space.
I suspect that the difference between the AGW view and this one reflects the apparent conflict between Kirchoff’s Law equating absorption and emission and the more general thermodynamic theorem that all matter with temperature above absolute zero radiates. Something to get your teeth into, scienceofdoom?
Hi, thanks for the update, it’s very clear now.
BTW., the reason I came to read this article a few days ago was because of an article on WUWT entitled “CO2 heats the atmosphere…a counter view” in which the author, Tom Vonk, says “Internet sites that are said to have a good scientific level like “Science of doom” publish statements similar to those quoted above . These statements are all wrong”. Anyway, I thought you might be interested.
[...] is composed of gases that can’t radiate any significant heat – N2 and O2. As shown in CO2 – An Insignificant Trace Gas? the absorption and emission ability of these gases is more than a billion times less than water [...]
how do you calculate respiration rate from a photosynthesis over PAR graph?
and how do you convert ul O2 g-1 min-1 to umol CO2 m-2 s-1 ?
should the respiration rate of a shade plant be greater than a sun plant in low light intensities? 20 – 60 PAR?
I’m unsure as to whether or not this is the proper place to ask this question, but…well, if not, my apologies.
First, am I correct in thinking that if Earth’s atmosphere had no greenhouse gases present, nothing that absorbed or emitted longwave IR at all, it would still show a typical blackbody spectrum for a gas at its temperate? And if so…well, why don’t gases like nitrogen absorb longwave IR? I believe I understand why they wouldn’t be able to absorb the energy to alter their vibrational energy levels, since the molecules are symmetrical, but why couldn’t the energy be absorbed to change their translational energy (I presume, in a normal blackbody, that’s where the emissions come from? Changes in translational energy as a result of sudden collisions between molecules, etc?) I would think that if the gas is capable of emitting light of a certain wavelength as a result of blackbody emissions, it should also be able to absorb it. That’s obviously not the case (if it were, nothing would be transparent to any wavelengths of light), but I don’t understand why not. If anyone can help me with this, many thanks.
Sam Yates:
If the atmosphere had no “greenhouse” gases present then the satellites orbiting the earth would see the blackbody spectrum for the surface of the earth – from the particular area the satellite was measuring.
The atmosphere would be completely transparent to the radiation from the surface of the earth.
If a gas can emit light of a particular wavelength it can absorb it. This is correct.
I think you are probably confused about “blackbody emissions”. What does this mean?
It means that a perfect emitter/absorber – called a “black body” – radiates according to Planck’s law.
No gas radiates like that. Gases have “discrete wavelengths” that they can emit or absorb at. Well, in practice these discrete wavelengths are broadened slightly for a number of reasons.
Take a look at Part Two for more about the characteristics of different gases.
Hm. I think that helps a bit, but I’m still a bit confused. I’m correct in thinking that, although Earth’s atmosphere is far from being a true black body, the light emitted by it roughly follows the expected curve for an object at its temperature, yes?
In Part two, you wrote that: “The layer itself will act as a blackbody and re-radiate infrared radiation. But it re-radiates in all directions, including back down to the earth’s surface. (If it only radiated up away from the earth there would be no “greenhouse” effect from this absorption).”
If I’m understanding this correctly, then, much of what’s doing the re-radiating is ordinary oxygen and nitrogen that have had the energy from excited CO2 (and other greenhouse gases) transferred to them by collisions. Is that so? Or does the energy from the greenhouse gases just get spread out only to other greenhouse gases (in which case, why do you get a curve at all, instead of just a bunch of somewhat-blurry peaks?)
And by the way, thank you for putting so much effort into this site; it’s clear, concise, and has helped clarify a lot of details of the greenhouse effect for me that realclimate.org (although a wonderful resource) hadn’t really made clear.
John Millett on August 15, 2010 at 1:10 am:
Not true unless you have overturned 100+ years of physics.
The surface radiates at an intensity determined by its own temperature and nothing else.
Here is the famous Planck equation for intensity of radiation:
The values of h, k and c0 are constants. T is absolute temperature and λ is wavelength.
You will notice that there is no variable in this equation for “temperature of where the radiation might end up“.
Thanks for that, sod; confusing intensity and heat transport wasn’t smart. What’s your take on the principal point of the post?
Sam Yates
Thanks for the kind comments.
I think I need to review some of Part Two. Probably some careless writing on my part.
On the other parts of your question, I have seen many other similar questions from other people so I will write a post on the topic.
John Millett:
I can’t work out the main point of your question. Maybe you can try and explain it another way?
But this is wrong. If the atmosphere can’t absorb or emit radiation how does it “diffuse” heat to space?
This, precisely, is the point. You say there can be no radiation to space from an atmosphere without the 1% of it capable of absorbing and emitting radiation. So, what does the other 99% do with the heat it gains from the sun-warmed surface by non-radiative means? Since it constitutes matter with a temperature above absolute zero wouldn’t it radiate it away to surrounding space ( the atmosphere, after all, is mostly space as your bycycle pump exercise on another page demonstrates)? If not, it would have to accumulate heat until an isothermal atmosphere is achieved. This world would be hotter than the real one, a direct contradiction of AGW hypothesis.
John Millett:
If the atmosphere can’t radiate and absorb heat it can’t radiate and absorb heat. The atmosphere will reach an equilbrium condition via conduction and convection with the surface (which is radiating).
Have a read of The Hoover Incident, it’s written to answer this exact question.
The Hoover Incident
You conclude, conventionally, that the post-hoovering equilibrium temperature equals the effective radiating temperature of the net solar flux as a consequence of the OLR exceeding the incoming net solar flux. The energy imbalance would be reduced by taking account of atmospheric reflection of surface OLR; and lower surface emissivity values ( I note from your piece on emissivity that the near unity value occurs over a limited spectral range; and various emissivity tables elsewhere show somewhat lower values); and using day-night hemispherical averages rather than global ones. But these adjustments wouldn’t change the result. What would change it is the accumulation of heat in the atmosphere gained by non-radiative means from the surface (which would be greater than before, as solar energy previously absorbed in the atmosphere is switched to the surface, compensating for the elimination of direct absorption of solar in the atmosphere). As the surface and atmosphere move towards a new thermal equilibrium by non-radiative means of heat transport, the rate of radiative heat transport from the surface decays, falling to zero when the surface-atmosphere system becomes isothermal. The post-hoover world heats up continuously, directly contradicting AGW hypothesis – unless we relax the imposed constraint that the non-absorbing 99% of air can’t radiate. What law says that heat gained by non-radiative means can only be lost by similar means? Don’t room heaters gain heat by conduction and lose it by radiation? Why is thermodynamics different for air?
John Millett:
I don’t think you have followed the argument.
No law says that heat gained by non-radiation means can only be lost by non-radiation means.
Re-read The Hoover Incident.
The point is that if a gas is unable to emit or absorb radiation – what will the world be like?
If the gas is still able to absorb and emit radiation then that is a completely different situation.
In the confused comment that you write I can’t extract enough to assist you in understanding the subject of heat transfer.
Perhaps if you would like to address specific aspects that you don’t understand/agree with of the chain of events explained in The Hoover Incident – at that article I might be able to explain a few things.
Extract from The Hoover Incident:
“And no matter what happens to convection, lapse rates, and rainfall this cooling will continue. That’s because these aspects of the climate only distribute the heat. Nothing can stop the radiation loss from the surface because the atmosphere is no longer absorbing radiation. They might enhance or reduce the cooling by changing the surface temperature in some way – because radiation emitted by the surface is a function of temperature (proportional to T4). But while energy out > energy in, the climate system would be cooling”.
Convection etc distributes the heat in ways that affect radiative heat transport from the surface. While the intensity of radiation is a function of temperature, radiative heat transport is a function of a temperature difference. No heat may be exchanged between regions with the same temperature. In an isothermal atmosphere there would be no temperature difference between it and the surface and therefore no heat loss from the surface. The accumulation of heat in a radiatively-constrained atmosphere by non-radiative means of heat transport from the surface would produce an isothermal atmosphere. Then, energy out = 0 and < energy in and the climate system would be heating.
John Millett:
In the light of your comment, I’ll shortly post a new article trying to explain the basics a bit better. Watch this space.
Now posted – Heat Transfer Basics and Non-Radiative Atmospheres
[...] one commenter said in response to this (but in another article): Convection etc distributes the heat in ways that [...]
[...] the surface of the earth would radiate at an average of around 240 W/m² (see The Hoover Incident, CO2 – An Insignificant Trace Gas? and many other articles on this [...]
[...] The higher up you go, the colder it gets. The explanation is somewhat involved, so check out the link and also the series: CO2 – An Insignificant Trace Gas? [...]
scienceofdoom I am very impressed with your website, excellent work. As a “skeptic” (those who call me that are now dubbed AGW extremists lol), of course I doubt the impact of CO2 on the climate, as H2O is by far the dominant greenhouse gas. Though you agree with me on this point, I suspect you think that CO2 is amplified by H2O.
So…
1) I would be interested in your hypothetical mechanism for amplification.
2) Could you please answer James Gibbons questions posted on July 25? He made some tough points that are worth of addressing.
Thanks, great site, and I hope to convert you to our camp soon.
Marcus Ortiz:
1. There are two obvious mechanisms that might cause positive feedback.
a) One is easy to understand and uncontroversial – snow/ice albedo. If more ice melts, then less solar radiation will be reflected.
However, this feedback is not so strong.
b) The second potential mechanism for positive feedback is more difficult to understand – water vapor.
There is a series on this Clouds and Water Vapor, which is currently up to Part Three.
It’s not a simple subject.
2. I didn’t really understand James Gibbons’ point.
Take a look at Theory and Experiment – Atmospheric Radiation, recently posted.
You will see one graph of top of atmosphere radiation, and one graph of downward surface radiation.
Maybe that article will answer some of your questions. But if not feel free to ask again.
You make the claim that without greenhouse gases the earth would be considerably colder, this is contrary to what I was taught about the water cycle. Which is, that without the greenhouse gases the earth would be 20-30 degrees hotter, because water vapour/water in the atmosphere has the effect of cooling the planet as it absorbs the great heat generated by the sun.
As your idea, that the earth would be colder, creates in effect the concept that greenhouse gases warm the planet I think this an important point to clear up.
Myrrh:
If the atmosphere did not absorb any radiation then the surface of the earth would end up radiating around 240 W/m^2 to balance the radiative heating from the sun.
Simple application of the first law of thermodynamics.
At the moment, the surface of the earth radiates, on average (globally annually) 396 W/m^2.
If the atmosphere was transparent to radiation then 396 W/m^2 would be lost to space.
And so the earth would cool down.
Check out The Hoover Incident.
Re the Hoover page,
“But without an atmosphere that absorbs longwave radiation there is no way that radiation from the surface can be greater than the radiation from the top of the atmosphere.”
- the sun isn’t the only heat source for the earth, so that doesn’t apply here.
Anyway, I was taught re the water cycle that the earth would be 20-30 degrees hotter, that it is the water vapour/water cycle primarily that cools down the earth, and makes life possible. This can be seen locally re deserts versus wetter areas, but globally as an ‘average’, it is the water cycle that takes out the greater heat and cools the earth via evaporation and rain, for example, which cycle is by displacement of hot air near the surface by colder air as gases heat and rise.
Myrrh:
If the atmosphere did not absorb radiation, then apart from geothermal activity what else are you thinking of?
If you are talking about water vapor? Well, we just posed the question – if the atmosphere (which includes water vapor) does NOT absorb radiation what happens?
Geothermal is estimated at way below 1W/m^2.
“What you were taught” isn’t gospel.
- you need to explain this, not state it.
What heat source?
Re the sun isn’t the only heat source for the earth.
Geothermal is a huge heat source, surely? Volcanoes are continually erupting, there are thousands of earthquakes going on in the land and in the ocean, the ocean boundary plates release great heat which rises to the surface, and so on, these can’t be insignificant in accounting for the difference. And, living matter itself. Plants give off heat, in transpiration, that’s all the trees, grass and other plants and then all the fauna. I don’t know what that is in total, but the planet and the life on it generate heat.
But my interest is still in this difference between your premise that the earth without greenhouses gases would be colder and what I was taught, that it would be hotter.
By saying “what you were taught isn’t gospel”, is a good reminder, for both of us.
However, the explanation as I was taught makes sense to me. If I can be convinced that the wisdom gained in science by the 60′s and 70′s has actually been overturned by present day science fact, then of course I’m prepared to change my view of it.
I was taught that the earth’s temperature, difficult as it is to measure such a thing anyway, was around 18 degrees centigrade, (65 degrees F), and it would be 20-30 degrees centrigrade hotter if there wasn’t the water cycle in our immediate atmosphere which reflects back into space some of the heat in one form or another, clouds, ice, and by the evaporation of water, which has a very high capacity to hold heat, which then rises up into the cooler layers of our immediate atmosphere where it precipitates out as rain, snow. Not just water vapour, so all gases in the atmosphere, as they heat they rise and redistribute heat energy around the planet, our winds.
In other words, I was taught the earth’s greenhouse effect, contra planets such the moon which doesn’t have an atmosphere, was what gave us the possibility of life on earth. The moon has massive extremes of heat and cold.
The earth’s atmosphere, its greenhouse, regulated those kinds of extremes; by stopping all the heat escaping it brought up the lower temperature it would be without the greenhouse and by blocking and releasing heat it brought down the higher temperature it would otherwise get to, the model was convection. As in a real greenhouse, when it gets too hot inside we open a window and release the heat. It made sense to me then and still does.
Plants and animals, all get their energy from the sun. Through photosynthesis, locking it in chemical bonds, and it is released through animals etc metabolizing it, breaking those bonds releasing the energy. But it should average out to be the same as the measured solar radiance.
Matter is energy, but atomic decay is the only way it is really released on earth in the planets core(maybe, also uranium etc do a little bit, but inconsequential in the larger scheme o things), the sun however has the mass for fusion en mass.
I seem to have jumped into two different aspects of the discussion when I thought I was only coming in to discuss one! Here it’s my off the cuff thoughts about the difference in energy received from the sun v the energy radiated back from the earth, which above is attributed to greenhouse gases making the difference as there is an imbalance, from earth the greater.
I think ‘geothermal’ is likely underestimated. Very little has been known about the heat generated from underwater; before the discovery of tectonic plates, the formation of crust, the ring of fire, all really very recent knowledge. There was something a few weeks ago about the discovery of more underwater volcanic activity than previously thought, and we’re learning more about what we thought we knew. Hawaii for example, we now know is a massive hot spot creating volcanoes and has thousands of underwater earthquakes a year, continually releasing heat (and CO2).
Plants, and animal life, don’t have a direct balance to energy received from the sun. Plants generate growing energy from food, water and carbon dioxide, besides needing blue and red light, so there are three sources of energy in this. In respiration they need oxygen and give out carbon dioxide and water and in that heat. The sun isn’t the only source of our energy on earth for life because as you remind, matter is energy. To establish a balance has to take that into consideration and also include time, for what is energy from the sun only will also take time to balance out.
So, my thought on this difference being attributed to greenhouse gases only is that these things have to taken into consideration and could account for the discrepancy at any given time, perhaps even for the majority or all of it?
One thing I’ve noticed is that descriptions of plant life in AGW gives the impression of a less than dynamic system, perhaps it’s just the wording, but describing plants as ‘carbon sinks’ appears to have confused some. I’ve had a couple of discussions where on mentioning that carbon dioxide is heavier than air have got replies saying that’s impossible because then our atmosphere would separate out into layers and we’d be walking around in a layer of CO2. It seems, from my limited forays into such discussions, that the concept of us and life on earth as carbon life forms and intrinsic to this the Carbon Life Cycle, is no longer taught. I don’t know which of us was more surprised the first time I came across this, me for discovering that this wasn’t taught, or those who had never heard that carbon dioxide was plant food..
Myrrh:
No, overall, it is a tiny heat source. Less than 0.1 W/m^2 (averaged over the globe).
So if the sun is the only significant heat source – and the atmosphere (including water vapor) didn’t absorb or emit radiation – what do you think would happen?
Well above reply to Mike, I think geothermal in all its forms could be very much underestimated, some say that the present cause of arctic ice melting is geothermal in origin.
I’m not sure I understand your question. Certainly the sun is provider of massive amounts of direct energy in the form of heat, but I’ve already said that without an atmosphere we would be like the moon, extremes of temperature.
Ah, OK, what I was saying at the beginning of our discussion is that I was taught something different from what you presented. You said that without greenhouse gases the earth would be colder, (I was taught hotter), so this is about ‘greenhouse’ gases specifically rather than the atmosphere in general.
Water is the main ‘greenhouse’ gas, so taking that out of the picture gives us a hotter atmosphere not a colder, mainly because water’s capacity to store heat and take it up higher into our troposphere, which also brings in colder air below it. ‘Averaged’ out, is what keeps what would be the greater heat in check globally, because without it the sun would still be heating up the atmosphere and earth. Locally, deserts are an example of this and easily compared with the cooler coastal regions because of this cooling effect of evaporation created by the sun. The earth’s surface is some 70% water and compared with what’s left as land, this makes it a major player in heat exchange.
How all this, the role of water, could be calculated mathematically I don’t know, because such things as cloud cover acting as a ‘blanket’ to delay heat loss from the earth, which helps in regulating the colder extreme temperature possible on earth, also has to be considered, and that’s a two way process, because too much cloud cover also cools by blocking the sun’s energy.
Overall though, I think the balance would go to making the atmosphere hotter globally without it as I was taught, the desert condition would prevail as we see locally. The other gases heating and rising and so creating colder air beneath just isn’t enough to cool a desert in the day time, while the heated earth is able to radiate that back out at night so keeping the atmosphere from going to extreme minus degrees – it can certainly be cold in the desert at night, but a good blanket or small fire sufficient for comfort.
I am a bit confused about the data from some of your graphs. From your ‘Wisconsin, Ellingson & Wiscombe (1996)’ source, we get an average value of about 133mW for CO2 radiance at the 15um band, as CO2 emits photon energy gained from earthshine.
However, when we look at earthshine in the ‘Outgoing longwave radiation at TOA, Taylor (2005)’ source, we see that it has a distinct drop at the 15um band. This drop is roughly 60mW, assuming the drop started at 0.10W.
If am am reading these graphs correctly, when we observe earthshine from space, we see about 60mW of energy missing at the 15um band, and correctly attribute this to CO2 absorption. But when we observe the atmospheric spectrum from sealevel, we see 15um radiation at 133mW power.
Since energy cannot be created or destroyed, where is the extra 73mW of power coming from?
[...] [...]
[...] [...]
Looks as though you may need to update your article again…
“Planet is ‘more sensitive to carbon dioxide than we thought
If carbon dioxide emissions continue at their current rate through to the end of this century, atmospheric concentrations of the greenhouse gas will reach levels that existed about 30 million to 100 million years ago, according to Jeffrey Kiehl from the US National Centre for Atmospheric Research (NCAR).”
http://environmentalresearchweb.org/cws/article/news/44990
Sod,
Still working my way through this so please bear with me (decided to start again just to make sure I understand everything). I think I understand the concept of energy arriving at the Earth from the Sun and the Earth radiating that energy back into space. However, one aspect I have not seen discussed (might have just missed this and apologies if that is the case) is what about the fact that the center of the Earth is infact very hot? Based on this I would expect that heat energy from this source must also be a factor in the calculations? Of the top of my head I guess this has the following possibilities:-
A) No energy escapes from the center of the earth and hence the Earth’s surface or mantel is in effect a perfect insulator? I guess this is highly unlikely?
B) Some energy does enter the “system” from the center of the earth (hence the center is actually cooling) but the amounts involved are neglible with respect the energy balance of the surface?
C) Relatively speaking a lot of energy enters the system from the Earth. If so how does this affect the equations?
I can only assume from your analysis that the answer is A or B (most probably B). If that is the case how do we know this?
Lastly, this assumes that infact no energy is in fact being “generated” in the center of the Earth? I had always thought that to be the case but recently I am sure I saw a Science program on the Earth Moon system which stated that in fact heat is being continually generated inside the earth (can’t recall if this was “nuclear” or from the movement of the Earth and Moon)? Obviously additional heat energy would compund the matters I raised above? Any comments of this?
Once again many thanks
Neil:
The answer is B. I have been asked about this a few times, so hopefully will get around to writing an article about it (eventually).
From Impact of Geothermal Heating on the Global Ocean Circulation:
Check out The Heat Flow from the Continents, by Pollack, which talks about some of the measurements techniques and the first calculation by Kelvin in the 1880s for the UK where he determined it was 68 mW/m^2.
And by the same Henry Pollack: Heat flow from the Earth’s interior: Analysis of the global data set, REVIEWS OF GEOPHYSICS, VOL. 31, NO. 3, PP. 267-280, 1993:
Many thanks
[...] with vertical gray lines." Sure doesn't look like saturation to me. Got any ad homs for scienceofdoom's explanation of saturation: [...]
I enjoy the content and tone of your blog. I’ve only recently discovered it.
I think of it this way. If earth were a perfect reflector, the incoming 239 watts would immediately leave with little effect. Instead gas solid and liquids at the surface of the earth do not perfectly reflect so that the time consumed as the non radiant energy of space translates into heat and temp for the surface of the earth. Time always strikes me as a critical component of the explanation. With time in mind, it seems sensible that any additional CO2 in the atmosphere should tend to slow the passage of that wattage back out to space.
One nitpick which doesn’t really interfere with the thrust of what you are saying, is the surface temp of the earth really 15C? Think about all the extreme cold in the depths of the ocean and compare that to temps at comparable depths under continents. I think of the depths of the ocean as being full of polar water. I may be wrong but I doubt that it is cold left in the oceans since the last ice age, and I don’t think it’s cold just because the ocean depths are dark.
[...] [...]
[...] [...]
Was hoping you could in more detail explain that interesting cross-over area around 4.3 microns in wavelength, where there is still some amount of incoming solar LW radiation and we also see some outgoing LW. As this is one of the major absorption bands for CO2, as it would seem logical that both the incoming and outgoing are then re-radiated in all directions, what would the net effect be related to CO2 at 4.3 microns?
R. Gates,
Someone has probably articulated the net effect at 4.3μm.
However, the net effect is encapsulated in solving the equations of radiative transfer using all of the spectroscopic data for CO2 (and other gases) at all wavelengths.
So the standard result includes 4.3μm but I don’t know whether if we removed the spectroscopic data at these wavelengths it would result in more or less heat into the climate system.
scienceofdoom,
Thanks for the reply. It would be interesing to see the some model results with 4.3 microns removed. Obviously the big effect is out at 15 microns, but we know all of that (or virtually all of it) is outbound LW. It seems 4.3 has about equal shares of solar incoming and outbound LW. The net effect of how CO2 responds to being “hit from both directions” so to speak, would be interesting to know.
From first glance it looks like downward directed radiation is very tiny. For instance, your Wisconsin, Ellingson & Wiscombe (1996) graph shows CO2 peaking at 135 mW/m^2.
Perhaps I am mistaken, but is such a tiny fraction of power really able to warm earths surface above its theoretical 255K blackbody temperature to its 288K observed temperature?
My guess is that, while CO2/H2O do indeed absorb energy, this in turn warms the surface primarily by conduction and convection (I would guess 95%?), with the remaining part being back-radiation.
Mark,
Your first glance is wrong.
You can see the actual measured values of total flux (W/m2) in The Amazing Case of “Back-Radiation”.
For example:
And in Part Two of that series I said:
and followed up with an explanation in the comments.
In essence the value you describe as peaking at 135 mW/m2 is actually peaking at 135 mW/m2 per steradian per cm-1. [mW/(m2. sr. cm-1)]
The measurement of cm-1 is wavenumber and you can see on the x-axis that there are around 1000 of them on that graph. So that means you would have to take the average value of the graph and multiply by the 1000 cm-1 to get W/m2 per steradian.
The measurement of steradian is solid angle, so you would have to multiply by the number of steradians in a hemisphere to get W/m2.
scienceofdoom, thank you for that prompt reply, it greatly helped to clear up my understanding.
Thinking about this CO2 forcing business, it seems to me that fairly simple calculations can show that the lower atmosphere becomes saturated with CO2 at around 10ppm, therefore adding more has minimal effect. This has in fact been recognised since 1905.
The notion was then proposed (around 1950) that stratospheric CO2 can provide additional warming. This was based on the premise that the colder gas (~-40C) in the stratosphere loses heat to space less easily than the troposphere, hence it is able to retain and re-radiate heat more effectively due to CO2 absorbtion. This, as I understand it, is the basis of the whole AGW campaign.
The fallacy that I see here is that while temperature affects black body radiation, it does not significantly affect spectral-line absorbtion. The upper-atmosphere does not in any case behave as a black body but a transparent one. Even if it were a black body though, its temperature would still be irrelevant to its scattering of photons through CO2 molecular resonance. Gas at -40C will perform this function just as effectively as gas at +20C. Or, even 1000C. Only the photon energy and quantum considerations determine whether this happens, or not.
This I see as the flaw in the argument of the AGW proponents, and the reason why anthropogenic upper-atmosphere CO2 does not in fact cause enhanced global warming.
Your thoughts on this?
Anteaus:
What “fairly simple calculations”?
And what do you mean by saturation?
In fact, solving the equations of radiative transfer for the real atmosphere it is very easy to demonstrate that doubling CO2 causes an increase in radiative forcing. See Understanding Atmospheric Radiation and the “Greenhouse” Effect – Part Six – The Equations for these equations and their derivation.
The subject of “saturation” was first covered in Part Eight of this series.
You can also see calculations of atmospheric transmittance across the whole CO2 band in Understanding Atmospheric Radiation and the “Greenhouse” Effect – Part Nine, for example:
There is no confusion or controversy about this subject in the science world. Radiative transfer is well understood and theory, derived from first principles, matches experiment (see Theory and Experiment – Atmospheric Radiation).
To demonstrate that a doubling of CO2 doesn’t cause the pre-feedback radiative forcing claimed you need to either:
a) show the equations of radiative transfer are flawed (well proven over 60 years)
b) demonstrate that the solution to these equations has been miscalculated by everyone for the last 40+ years
It is not a simple calculation that you can do on a pocket calculator. You need to integrate across all wavelengths using the spectroscopic data in the HITRAN database, and you need to integrate up through the atmosphere to take account of the various line width phenomena at different pressures.
The Atmospheric Radiation and the “Greenhouse” Effect series might be of interest.
The graph above seems to confirm that the lower atmosphere’s CO2 is saturated, there being zero difference between 280pppm and 560ppm in the centre of the absorbtion band.Whether the slight differences in the fringes of absorbtion affect tempertures significantly is a moot point, and would I imagine be very hard to calculate. If you do the math based on the mean free path of photons you find that saturation occurs at less than a tenth of the values in this graph at sea-level pressures, and still at less than the values for the stratosphere.
Though, I digress. The main point I am making here is that while the land is a black-body radiator, the atmosphere is not. Or, if it is, it is an exceedingly poor one. It is therefore correct that the Stefan-Boltzmann law will determine the amount and spectral distribution of infrared received by the atmoshere from the surface, but it is incorrect to apply black-body equations to the transmission of IR through the atmosphere.
AFAICS It is from this mixing of incompatible math that arises the statement that ‘the colder upper atmosphere will show an enhanced global warming effect.’ It will not, because molecular or atomic resonances are temperature-independent*.
You can’t extract more light from a neon indicator by applying a blowtorch to it, or change its color by freezing it. For that matter, the output wavelength of a CO2 laser is not determined by its temperature, but by the gas properties and, to a certain extent, the optics. In both cases it is not a thermal mechanism which produces the photons, but one of quantum physics. It is a spectral emission, similar to that of CO2 infrared scattering. Likewise, it would seem to me that you cannot change the photon-scattering effect of CO2, and hence the amount of IR leaving the atmosphere or being reflected back, by changing its temperature. Therefore the ‘cold upper atmosphere’ postulate is a red herring.
That is my take on the subject, anyway.
*Provided we ignore the doppler effect of molecule velocity, which is not significant here.
“ is a moot point, and would I imagine be very hard to calculate.” ? It is not a moot point and I already explained the calculation requires an integration across wavelengths and up through the atmosphere, so it is a numerically challenging calculation.
You haven’t done the calculation but you imagine it is irrelevant and also too difficult to calculate.
This is not a scientific approach. Do the calculation yourself (it will take a lot of time) or accept the results from people who have done the calculation.
If you decide you want to believe something different, up to you, but don’t call it science.
No one is applying these black-body equations to transmission of IR through the atmosphere.
At this point I realize you are not interested in learning anything. You haven’t even read the articles I just pointed you to that explain these fundamental points.
If you want to learn science, read some science.
Alternatively, if you want to randomly claim stuff and pretend those random claims are what climate science believes there is big community to join full of happy people, but it isn’t on this blog.
I don’t ‘believe’ anything, in that sense. Belief is a function of religion, not of science. I question, because only by picking holes in arguments can their validity or otherwise be determined. If the question can be answered satisfactorily, then that adds validity to the proof.
I don’t, for example, question special relativity because although I don’t fully understand Einstein’s proof of concept, I do understand enough of the math to know that his arguments make sense, and that real-world examples bear them out. Therefore I am prepared to accept that he was probably right. His work also has the hallmark of someone who checked his facts carefully, and always questioned his own assumptions. This gives me confidence in his findings.
WIth climate science we are faced with arguments which at a superficial level seem plausible (which is why it gains so many supporters among non-scientists) but which when examined more closely don’t make sense. The proofs offered are couched in math so impenetrable that it would be hard even for a World-class genius to say whether they are valid or not. If we question these proofs we are simply told that since we don’t have the IQ to understand them, we should just accept them.
We also see a situation, again and again, where one AGW postulate being disproved simply results in another postulate being produced which allegedly proves the same hypothesis but in a different way.
The objective, clearly, is not so much to discover the truth, but to prove the original hypothesis at any cost. Cost being the operative word, since large amounts of money are now staked-on its being vindicated.This is not the behaviour typical of scientists, but that of a bunch of panicking investment speculators.
[...] Incorrect. The science and math is well known to anyone who cares to learn. From ScienceofDoom: Part One of the series started with this statement: [...]
[...] [...]
pretty graphs – I can see you like pictures
-again co2 significant – NO certainly not
just more well written rubbish as far as most can tell
simon,
This is a science blog, so no one’s opinions are particularly interesting.
If you have a scientific point it will be welcome. A science point will be identified by experimental evidence demonstrating something relating to the topic of this article, or deriving a new or contrary result from established theory. Please stay on topic and please use science.
The physics of radiative transfer is well established and derived from fundamental physics.
And as you don’t like pictures – neither do I particularly, I prefer maths – perhaps as a start you can review Understanding Atmospheric Radiation and the “Greenhouse” Effect – Part Six – The Equations and EITHER explain which of the equations are wrong (and why of course) OR demonstrate the result you get from applying the radiative transfer equations to the atmosphere (and as a nice extra you could touch on why every other person solving these equations has got the wrong result).
If you prefer to voice opinions you will be more welcome at many other blogs which happily for you have much larger audiences.
The problem with all of this is that there is more solar than terrestrial IR radiation entering the atmosphere, even with the 46,000 fold reduction.
So as CO2 increases more of the solar IR will be absorbed and re-radiated back into space thus reducing surface warming. This is clearly demonstrated by the graph titled “solar radiation at the top of atmosphere, and at the surface:”
Yes, GH gasses will store the heat thus providing warmth during the night, but dont forget they insulate the surface from heat during the day aswell. If not earth would have a daytime high similar to the moons.
So increasing GH gasses does not so much cause warming as narrowing the extremes of temperature variation.
You’re making the same mistake Wood made in 1909. The IR energy in sunlight is in the range of 0.8-5 μm. The thermal IR emitted by the atmosphere and surface is in the range of 5-50μm. CO2 only has a few bands in the 0.8-5μm wavelength range and most of those are severely overlapped by water vapor. The emission of CO2 from those bands is infinitesimal because the temperature of the surface and the atmosphere is too low. The total absorption of incident solar radiation by CO2 is about 2 W/m². Doubling CO2 would increase that absorption by about 0.4 W/m². That’s not going to have much effect on surface warming compared the the 3.7 W/m² of outgoing radiation that is absorbed.
matt,
What is clearly demonstrated is that CO2 absorbs both terrestrial radiation (“longwave”) and solar radiation (“shortwave”).
But these are not absorbed equally. CO2 does not absorb X% across all wavelengths, it is very wavelength dependent.
So to determine the effect of more CO2 we need to calculate the effect on shortwave and the effect on longwave.
You write as if this calculation is a simple one that can be done in your head.
When you write “..as CO2 increases more of the solar IR will be absorbed and re-radiated back into space..” it indicates that perhaps you haven’t examined this subject at all.
The calculation is very complex. CO2 at atmospheric temperatures (220K-300K) absorbs solar radiation at specific wavelengths (e.g. around 1.4μm) and then emits at what wavelength? CO2 at these low temperatures cannot emit any significant radiation at 1.4μm. CO2 at atmospheric temperatures emits strongly in the 14 – 16μm region (as well as others).
In effect what has happened to solar radiation as a result of more CO2 is that the atmosphere has absorbed a little more radiation at the expense of the surface.
To solve the problem and find the net effect (what happens to the temperature of the surface and the temperature of the atmosphere) under specific conditions you need to solve the equations of radiative transfer.
These equations are slightly more complicated than “it sorts itself out without changing anything”. They calculate the transfer of energy between each layer in the atmosphere as a result of absorption and emission of radiation. Absorption depends on incident radiation and the absorptivity of the atmosphere at the wavelengths of the incident radiation. Emission depends on temperature and the emissivity of the atmosphere at these temperatures.
Apologies it this has been mentioned, but the conversation is focused on CO2 being .04% of the atmosphere. Which is correct.
But the man-made portion is only 4% of the total atmospheric CO2.
So the question is, how does or how can the man-made CO2, which is .0016% of the atmosphere, heat up the other 99.9986%.
I would label the man-made portion at .0016% insignificant. No?
Nope. The man-made portion of the CO2 in the atmosphere is whatever the concentration is today less the pre-industrial level of about 280 ppmv. That’s on the order of 100 ppmv or about 25% of the current concentration. The 4% number is relative to the annual fluxes between the biosphere and the atmosphere which are on the order of 100Gt/year and is dated to boot. It’s more like 8% now. But the flux into the biosphere and the flux out of the biosphere are essentially equal over the course of a year causing no net change in the atmospheric concentration. The flux into the atmosphere from burning fossil fuels, producing cement and changes in land use/land cover stays in the system for on the order of 100,000 years.
Next you’ll probably trot out the residence time of an individual molecule of CO2 in the atmosphere of only about 5 years, not 100,000 years. While that’s true, it doesn’t change the rate of accumulation in the atmosphere, ocean and biosphere system. It’s the residence time of CO2 in the system as a whole that counts, not how long it resides in one part of the system. We’re currently adding about 40 times as much to the system each year as is removed in the geologic carbon cycle every year. And the addition rate is increasing.
You can put whatever label you like on the proportion of anthropogenic CO2 out of the total atmosphere. I don’t think your 4% is correct, but that’s not an interesting question for me.
Physics questions are not solved by your approach of “it’s so small how can it have any effect” but instead by understanding the fundamental physics, and solving the relevant equations for whatever changes have occurred or are expected.
In this case, the solution comes from the Radiative transfer equations which have been well-known and proven for more than 60 years.
So what you need to do is prove the equations wrong, or prove that they can be solved to give a different answer from what the climate science community has calculated.
Amazingly you can’t do the calculation with a pocket calculator or in your head. Take a look at the link provided.
More insignificant than you think – or astoundingly significant! CO2 concentration of 0.04% of atmospheric matter, which accounts for 90 ppm of the volume of the spherical shell we call the atmosphere (the rest comprising radiation), therefore represents spatial occupancy of 36 parts per billion. Prior to a couple of centuries of life-enhancing industrialisation, occupancy was 11 ppb lower and, according to mainstream climate science, rendered life possible by raising surface temperature 33 degrees C. However, the mainstream continues, that increase in spatial occupancy has raised surface temperature a further 0.8 degrees C and models warn of a business-as-usual two degree increase this century, when CO2 occupancy doubles from pre-industrial levels (to 50 parts per billion), and a consequential great and dangerous regress in the human story. Given the sparseness of CO2′s presence in the climate system, its capacity to raise surface temperature (by absorbing ougoing LW radiation from the surface) must rely on extremely efficient unit absorptivity about which, strangely, little is said.
John Millet ends his comment “.. efficient unit absorptivity about which, strangely, little is said”. That’s a rather strange comment in this thread where many comments have discussed how the well known quantitative values of that absorptivity are used in detailed calculations whose results have also been in many ways been verified by empirical data.
Every comment where MODTRAN is mentionned is on that and so are many others.
Has no one here ever heard of the SUN? There is direct correlation between the activity of the Sun and temps on the Earth based on historical data. And the other planets. What little warming has taken place on Earth has also taken place throughout the Solar Syetem.
Has no one here ever heard of the Milankovitch Cycles. The Earth is headed for an Ice Age over the next 1- to 40,000 years. Celestial mechanics cannot be denied. Google Milankovitch Cycles and Procession of the Axis.
Recent research has shown that the variation in solar radiation is less than had been thought.
The Milankovitch cycle isn’t headed for a big drop for ~50,000 years. We’re currently in a period where all the variations cancel each other out.
http://en.wikipedia.org/wiki/File:MilankovitchCyclesOrbitandCores.png
Of course there are those like Ruddiman that think that if we hadn’t started major land use changes by the invention of agriculture 8,000 years ago, we’d already be well on our way to an ice age. CO2 is just icing on the cake.
http://en.wikipedia.org/wiki/William_Ruddiman
Oh, Dewitt you assuming that ALL of the change in CO2 concentration is from man-made sources. There is no proof of that. CO2 in the atmosphere can increase from natural sources as temps increase. Coincidence is not causality. And yes, I am familiar with the C12/C13 ratio argument.
Anthropogenic CO2 emissions are nearly twice as large as is necessary for the measured increase in atmospheric CO2. The 13C/12C ratio argument is simply icing on the cake. There is no proof of anything in science. There is only disproof. The people who claim that the CO2 increase is not anthropogenic have never outlined a consistent explanation of how that could happen in the face a massive human emissions. They just wave their hands. The anthropogenic mechanism, however, is self consistent.
So if as you say we can measure and distinguish between
(a) the energy arriving from the sun, and
(b) the energy leaving the earth
that means we can straightaway tell if the earth is warming up or not.
And since I’m sure we can also measure atmospheric CO2 concentration, we are thus in a position to easily see if the planet warms in line with CO2 increases or not.
Case closed or what?
Handel,
It would be if we could measure with sufficient precision. We can’t yet.
Dewitt
Yes, the inability to accurately measure the incoming and outgoing energy from the earth system, does seem to be what is standing in the way of settling the AGW hypothesis one way or the other.
Seems like such a basic and obvious issue – so why don’t they prioritize it? Why not divert some of the $millions/billions wasted on models that can’t seem to predict anything, into the empirical side? Don’t the people controlling the funds want the issue convincingly resolved?
One of the problems is that we don’t have a flyable, high precision IR detector that goes to long enough wavelength. By flyable, I mean something that can be launched into orbit and stay active for years. This isn’t a problem that can be solved by throwing money at it. It requires some research breakthroughs.
The Glory satellite would have helped a lot with the problem of aerosols, but the launch failed. Now that is something that could have been fixed with money by building more than one satellite. When I put my tinfoil hat on, I sometimes wonder if they didn’t really want to know because aerosols are a major tuning kludge used in climate models.
hi out there
(First excuse me – i am not english speaking // im not a scientist)
What we not know despite of all the scientific facts is:
How long do the atmospherical phaenomena last.
For example:
before i was born, my mass was close to zero
after i die my mass will be zero
so you might guess – from a scientific viewpoint – that i never existed
second example: water in a storage reservoir
Flowing out = Flowing in minus evaporation minus what s.o. may have drunk
(note the easy maths)
as a result there is no water in it
see where this may lead us to (Handel)
“(a) the energy arriving from the sun, and
(b) the energy leaving the earth
that means we can straightaway tell if the earth is warming up or not.”
But no we can´t! Cause we do only look at the system from outer space ignoring that there are lots of processes working between incoming and outgoing radiation.
Look at the second example and you will see, that the amount of water in the reservoir depends on its dimensions, not on the flow.
The main questions are: How long is energy kept in the biospherical system and what makes it stay? What are the main characteristics of the thermal capacity of the whole system?
I think we are far away from any answer yet. The incidental relationship between co2 and temperature in any vostok icecube can only be a hint. Stop linear thinking in polydimensional systems.
[…] might be a factor but it is not Here is an explanation of why saturation does not apply http://scienceofdoom.com/2009/11/28/…-gas-part-one/ Beyond that – argue it with Mannie or PB they have a lot better understanding than I of the […]
The use of green bags will immediately be the solution to
this problem that we are looking for. It is predicted that “global warming” will increase water shortages in the near future.
We cannot use technology to refreeze disappearing glaciers or
the ice caps, refill rivers, remake their entire ecology or stop rising oceans due to
global warming.