When I started this blog I said:
Opinions are often interesting and sometimes entertaining. But what do we learn from opinions? It’s more useful to understand the science behind the subject.
Of late I’ve been caught up with work, other intellectual interests and (luckily) some fun stuff and haven’t spent any time on climate. So I feel it’s time to put forward a few opinions on climate.
The often-cited consensus on climate is:
a) we add CO2 and other GHGs to the atmosphere by burning fossil fuels (and other human activity)
b) these increase the inappropriately-named “greenhouse effect”
c) this increases the surface temperature over some time period
This scientific consensus is rock solid, like gravity or momentum. It’s not particularly intuitive, but tough luck, physics is often like that. By itself, the consensus doesn’t tell you a lot. It just says that if we keep burning fossil fuels then the earth’s surface temperature will increase.
This scientific consensus doesn’t say that urgent action is needed on climate, or that without urgent action society is doomed, or that rapid adoption of renewable energy towards 100% of current energy consumption is a net cost benefit.
These are different propositions.
Note to commenters – if you want to question the “greenhouse” effect post your comment in one of the many articles about that, e.g. The “Greenhouse” Effect Explained in Simple Terms. Comments placed here on the science basics will just be deleted.
“The often-cited consensus on climate is …”
I agree about the *real* consensus, but the “often-cited” part often gets twisted into greatly exaggerated doom and gloom that in my opinion is not warranted because of large uncertainties. For over ten years now I’ve been reading all sides of the issues related to climate and have come to the conclusion that we really don’t have any high confidence answer to what the climate will be in 30 years or 100 years. We can’t even predict with high confidence what next year will be like.
Consequently, my opinion is that human adaptation has worked quite well for hundreds of thousands of years and is still the best approach, provided we let the markets be as free as possible to determine how best to accomplish that adaptation. Forcing expensive energy source “mitigation” is likely to be disastrous for those who cannot afford more expensive energy.
Bryan,
I think you are making some false assumptions, specifically:
1) That uncertainty cannot be adequately quantified;
2) That “high confidence” is needed;
3) That mitigation has worked in the past, so it can work now.
4) That mitigation is too costly and disastrous.
IPCC projections come with uncertainty bounds that are fairly broad, say, a factor of two in global average surface temperature in year 2100 for a given emissions scenario. It is high confidence that the projection will fall into the broad range. If, say, all consequences of the business as usual emissions scenario are bad, then something should be done about emissions. The problem becomes one of risk management given the uncertainty. Broader uncertainty adds to the risk.
High confidence in next year is not required because random fluctuations are expected. It is the long term projections and trends that are of concern.
Adaptation has worked in the past because changes were much slower in comparison to the present warming, and humans were essentially nomadic. Current warming is about a factor of 100 faster than prior natural changes, and humans now live in large coastal cities that would be costly to protect.
The question of mitigation vs. adaption is an economic one, after you add the cost of human death and suffering, usually left out. Most studies show that it is much cheaper to mitigate emissions than to repair the damage or abandon the damaged infrastructure of you do nothing. Furthermore, green energy is a change in economic basis, not a disaster. Think of green jobs. Think of the economic damage of the 9/11 attack and multiply that by a large number.
smithpd1, you say
“The question of mitigation vs. adaption is an economic one…”
Exactly, and we agree here. However the evaluation needs be a thorough and realistic risk/cost/benefit analysis, not just a worst case cost analysis. By thorough, I mean including *all* associated costs as well as benefits. I suspect that many important mitigation costs have been ignored, underestimated, or intentionally excluded, while many benefits have been ignored, underestimated, or intentionally excluded. By realistic, I mean evaluating a broad range of climate change scenarios. For instance, what happens to the cost/benefit analysis if the earth cools more rapidly than expected (which our climate models cannot predict). Would less cooling because of higher CO2 emissions be less costly than more cooling resulting from a reduction in CO2 emissions? What happens if the earth warms and there is very little effect from CO2 emissions (basically all this mitigation for naught plus the costs associated with a warming earth)?
As for “green energy”, I don’t believe there are any forms of large scale “green” or “renewable” energy because all aspects of the cost and environmental impact of the extraction of raw materials, transport, manufacturing, installation, infrastructure (including energy storage), maintenance, and decommissioning *must* be included and evaluated. It is not clear that current wind and solar power options are fully sustainable in that regard. The energy they produce may not be sufficient to sustain the current level of energy production without help from other energy sources, and consequently the energy they produce is not likely to be independently sufficient for greatly increasing energy production in order to quickly and totally replace fossil fuels.
Also, for policy decisions when evaluating possible risks from anthropogenic CO2 emissions, we must also compare and evaluate other similar large scale risks that might possibly be averted or mitigated, including major meteor strikes, major solar flare events, major tsunamis, major earthquakes, major explosive volcanic eruptions, major hurricanes, and so on. Humanity cannot afford to ignore these other risks. Funding must be more equitably distributed rather than being focused largely on one possible risk. I have yet to see such a comprehensive risk analysis.
What will happen next year is called weather, not climate. And you are quite correct in believing that we can’t state with certainly exactly what the climate will be like in 100 years. What can be said with certainty is that it won’t be the same as it is today. However I have no compelling reason to convince you.
Bryan – oz4caster
Next ýear will be slightly different from this year. If an El Nino develops it could be quite a bit warmer. The trajectory of climate over the next 30 to 100 years and beyond is almost certainly that global temperatures will generally increase and will probably increase significantly.
Can free markets produce sufficient adaption to mitigate climate change? So far there has been no indication that they can! At present to harms caused by burning fossil fuels are paid for indirectly by the general population through health care costs and environnental damage. If the markets were truly free and had to pick up the tab for all the damage caused by burning fossil fuels, the cost of mitigation would look like a bargain!
As for previous human adaption working in the past, it hasn’t been challenged globally before. In most places the climate has been relatively stable throughout the history of human civilisation. Where it has changed dramatically, civilisations have failed but there have always been other civilisations that continue progress. This time we’re all affected at the same time and, unless we get seriuos about fixing the market failure, the developed world is likely to be threatened with multiple failures and possible total collapse.
I wonder if adaption to a changing environment has become easier in most places. Perhaps a little fewer people dead from freezing. As SoD has shown there has been little change in impacts the last 100 years globally. Local disasters will always persist. I think climate is more stable now than through parts of the little ice age.
And I agree with SoD about what deserves to be called scientific consensus. And not all the speculations and doomsaying that we witness in the name of science.
[…] « Opinions and Perspectives – 1 – The Consensus […]
The consensus on the GHE is hardly as rock solid as gravity or momentum, but I agree it’s probably correct. Or at least I haven’t seen it credibly disproven.
However, this is most definitely not correct:
“It just says that if we keep burning fossil fuels then the earth’s surface temperature will increase.”
What it says is that among all the influences and/or pushes on the climate, natural and anthropogenic, it will provide a warming push. It does NOT mean the climate must warm. It could just cool a little less, for example. NOR does it mean the anthropogenic influence is net warming. It may or may not be.
SOD wrote: c) “this [rising GHGs] increases the surface temperature over some time period”.
Do you need some caveats?
1) Sometime I add the qualifier “if nothing else changes”, such as a change in solar output or possibly cloud nucleation. It is also a stupid caveat, because many things (especially TOA OLR) will change as the planet warms.
2) The other possible caveat is “increases the surface temperature higher than it otherwise would be”. That way you can allow for naturally-forced temperature change (including ice ages?) and internal (or unforced) variability.
3) Must that increase in surface temperature be detectable against the background of naturally-forced and unforced temperature change?
Note: I don’t necessarily disagree with your statement as written.
I’m trying to keep this series as non-technical as possible and address questions in the comments, plus some “further reading” links.
SOD: AFAIK, you conclusion is derived from the law of conservation of energy and the laws of quantum mechanics, which govern the interaction between radiation and GHGs. Isn’t this more than “an opinion”? Deductive reasoning?
Suppose I add that “these two laws are all the physics one needs to know to predict the existence of warming mediated by rising GHGs”. Perhaps now I am expressing an opinion.
(An earlier comment went into moderation.)
Frank,
It’s more a note on the series.
I would have a very slight quibble with c) as written above, it should perhaps be amended with “in an otherwise stable system.” Natural variability is certainly real and can be very significant in both directions. This fact seems to be ignored by the alarmist community, indeed the temperature (and sea level) rise between 1910 and 1940 seems to be fairly equivalent to the recent record.
Incidentally, this is the best climate blog I’ve seen, and I’ve see many. It seems the most honest thing anybody should say on either side of the debate is “We really don’t know yet what the full effects of the huge anthropogenic increase in CO2 and other gases will be.” As you have demonstrated in another series, climate sensitivity is the key, and we really don’t have a handle on that, even in a hypothetical “otherwise stable system.”
I’d like to suggest the topic of a series which would interest me greatly, though of course it’s your blog so I certainly wont be offended if you have better things to do!
In 2015 Karl et al. published the “pause-buster” paper, “Possible artifacts of data biases in the recent global surface warming hiatus.” I’ve tried to get a handle on whether this was an invalid but convenient way to make the “hiatus” problem go away, as many of the more confrontational skeptics assert, of whether the redrawing of the historical temperature record is scientifically justified. I’ve read a few analyses on either side which are to me inconclusive. I was struck by the fact that the entire community which was responsible for the “erroneous” measurements for decades seemed to accept the paper as valid with very little discussion or dissent, which seems a bit of a red flag to me. A broader discussion of global temperature measurements in general would be welcome as well, there seems to be a lot of controversy on the subject, and I think the basic (certainly not simple) question of determining the actual and accurate temperature rise in the recent and future record is pretty fundamental to any discussion of global warming or climate change.
Whether you decide to address this issue or not, keep up the good work, it’s a pleasure following your blog!
You need 30 years to tell a climate trend. An 18-year pause doesn’t cut it.
Which 30 years?
I prefer 1600-1629 😉
Just use a running 30 years period to suggest were we are going.
Why would 30 years cut it and 18 won’t. Not being confrontational just inquisitive.
I think it is best to use 60 years to tell climate trend. There are cycles and variations over long periods, as AMO. “The Atlantic Multi-decadal Oscillation (AMO) has been identified as a coherent mode of natural variability occurring in the North Atlantic Ocean with an estimated period of 60-80 years. It is based upon the average anomalies of sea surface temperatures (SST) in the North Atlantic basin, typically over 0-80N.” From NCAR Climate data.
We are now into a long global brightening period, from about 1983, with thinning of clouds and more sunshine reaching earth. This followed a dimming period from about 1945 to 1980, with more clouds. And the period from 1915 to 1945 was a global warming period, probably with less clouds. Higher temperatures in arctic and Greenland glaciers melting shows this.
For shorter trends we have to adjust for natural variations, which is a difficult task.
And there may be even longer natural variations linked to change in ocean currents and heat content.