In #9 we looked at an interesting paper (van Oldenborgh and co-authors from 2013) assessing climate models. They concluded that climate models were over-confident in projecting the future, at least from one perspective which wouldn’t be obvious to a newcomer to climate.
Their perspective was to assess spatial variability of climate models’ simulations and compare them to reality. If they got the spatial variation reasonably close then maybe we can rely on their assessment of how the climate might change over time.
Why is that?
One idea behind this thinking is to consider a coin toss:
- If you flip 100 coins at the same time you expect around 50 heads and 50 tails. Spatial.
- If you flip one coin 100 times you expect 50 heads and 50 tails. Time.
There’s no strong reason to make this parallel with climate models on spatial and time dimensions but climate is full of challenging problems where we have limited visibility. We could give up, but we just have the one planet so all ideas are welcome.
In the paper they touched on ideas that often come up in modeling studies:
- assessing natural variability by doing lots of runs of the same climate model and seeing how they vary
- comparing the results of different climate models
To see the whole article, visit the new Science of Doom on Substack page and please consider suscribing, for notifications on new articles.
But natural climate variability shows clear unequivocal signs of patterns that are directly attributable to solar cycles.
There is absolutely no human signal in the CO2 data let alone climate variability.
You first need to show through experiment that CO2 traps heat. As heat is a vector and cannot be trapped, that’s never going to happen.
If we split the world into climatic zones: Sahara, Mediterranean, Arctic, etc. each projection of a specific model should show very similar results (with respect of all climatic parameters: temperature, wind, precipitation, cloud cover, …) when we compare predictions for each region; and hindcasts should correlate with records for each region.
That would be my measure of model accuracy and reliability: how well does each specific projection compare to reality. But modellers don’t like that. They reduce the complexity of climate to one simple number: global average temperature anomaly. They do this because they are not scientists. They are astrologers – seeking influence with politicians by telling politicians what they want to hear, befuddling them, with sciencey-sounding words.
Mark,
Please provide citations for your amazing assertion.
SOD, when are you going to provide any evidence that CO2 traps heat? Emissions of IR @ 15μm cannot heat any molecules in the troposphere.
Will,
Having moved your comment in the new Science of Doom Substack version, you’ve arrived over here to press your claims. I’d prefer to stop every single article being faced with a barrage of confused rubbish. You can call it “hiding from the truth”.
Please pop over to:
https://scienceofdoom.com/2014/06/26/the-greenhouse-effect-explained-in-simple-terms/ and address the article there.
Or over to:
Part Six – The Equations – https://scienceofdoom.com/2011/02/07/understanding-atmospheric-radiation-and-the-%e2%80%9cgreenhouse%e2%80%9d-effect-%e2%80%93-part-six-the-equations/ – the equations of radiative transfer and address that article.
15μm radiation has a corresponding temperature of -80°C. It cannot and does not heat any molecules in the troposphere which is defined by molecules with a temperature of -60°C and above. It doesn’t matter how many more CO2 molecules you add or how much more 15μm radiation they absorb and emit, CO2 has never effected the temperature of the troposphere and the historical record proves it.
As does direct observation.
James P Joule to William Thomson (aka Lord Kelvin) June 14 1856 quote: “we find that when 7500 cubic inches of CO2 are mixed with 10000 cubic inches of air the temperature falls about 0.2° C.”
SOD, more than three days and still no evidence that CO2 is a heat trapping gas?!!
Will,
As I already suggested:
Go over to “Part Six – The Equations” – https://scienceofdoom.com/2011/02/07/understanding-atmospheric-radiation-and-the-%e2%80%9cgreenhouse%e2%80%9d-effect-%e2%80%93-part-six-the-equations/ – the equations of radiative transfer and address that article.
You find the equation of absorption – not something new; the equation of emission – not something new; combined into the equations of radiative transfer – again, not new.
Anyway, please comment over in that article as to which part of the equations are incorrect. The fact that you lack an intuitive understanding of the physics isn’t a failing of the physics.
Yes, I know about radiative transfer, but I did not ask you about that. I asked you to provide evidence that CO2 is a heat trapping gas. Radiation is not heat. Emission of 15μm radiation from CO2 cannot and does not heat any molecules in the troposphere. Prove me wrong!
Will,
“Yes, I know about radiative transfer, but I did not ask you about that.”
Know about? Are the equations in the article correct in your opinion?
Again, radiation is not heat. 15μm radiation has a corresponding temperature of -80°C. No amount of “radiative transfer” from CO2 @ 15μm can cause heating in the troposphere. Prove me wrong.
Will,
The radiation to space is reduced due to CO2 in the atmosphere. Less radiation to space means (due to conservation of energy) an increase in energy retained in the climate.
This is proven by the equations of radiative transfer, using the absorption/emission lines of CO2.
It’s nothing to do with the heat capacity of CO2.
Your lack of intuition as to the processes going on in the atmosphere is something only you can fix. Instead of eagerly posting new comments try studying this match between observations and equations and ask yourself, “why is there such a dip in outgoing radiation centered on 15um?”
You can see the whole article at – Theory and Experiment – Atmospheric Radiation.
Consider it, that is, if you want to understand basic atmospheric physics.
So again, energy/radiation is not heat. It makes no difference how much 15μm radiation is absorbed and emitted by CO2. 15μm has a corresponding temperature of -80°C. The troposphere is defined by molecules with a temperature of -60°C and above. Conservation of energy is preserved.
Air has a higher specific heat capacity than CO2 but I’m not talking about that.
The reason for the dip is obvious but it has nothing to with 15μ radiation heating molecules in the troposphere.
SOD, what you are describing is a heat engine. That is a violation of the laws of thermodynamics i.e. conservation of energy.
It’s the same mistake that every GHG adherent makes.
Take a block of solid H20 emitting radiation @ 10μm, 80k warmer than CO2. Let’s call it an ice cube. Now let’s add another ice cube also emitting radiation @ 10μm. What happens? Add another and another and another, tell me when to stop! What happens?
Answer: More ice emitting 10μm radiation.
Q: Any heating?
Answer: No!
Will
“SOD, what you are describing is a heat engine. That is a violation of the laws of thermodynamics i.e. conservation of energy.”
No, what I’m describing is something that slows the rate of energy loss to a colder environment. It’s as controversial as lagging a heat pipe to slow the rate of heat loss.
Energy comes in from the sun by radiation. Energy leaves the planet to space by radiation. Slow the rate of energy loss and, as energy is conserved, energy accumulates in the planet. This increases the temperature.
Probably my last comment in response. I’ve written many articles written to explain basic physics on this blog in response to people like yourself.
Good luck in your journey.
Do you deny that modellers reduce their projections to one magic number: global climate temperature anomaly? We can argue over why they do it, but not over whether. They do that.
I was giving my opinion; which is clear; I have no desire to cite everything I’ve read and studied which formed my opinion. So, no citations from me.
This stopped being a scientific debate in 1995 when Santer resorted to dishonesty to do the politicos bidding by blaming humanity for climate change – to cherry-pick data to find a finger print for man-made change where none existed. [ doi 10.1038/382039a0 – https://www.nature.com/articles/382039a0 ]
Exactly, there is no human signal in the CO2 data, absolutely nothing!
Mark,
If you don’t want to provide evidence for your clueless claims then I applaud you.
Claim victory and move on. Without evidence on this point, future comments of yours will be deleted due to my “desire to suppress the truth”.
For readers interested in evidence, here are a few examples of modelers *not* reducing their projections to one magic number:
p451 of AR6, chapter 3 of “Human Influence on the Climate System”:
p.452:
p.455:
If any *other* readers are interested in another 10 examples, please let me know.