Steve Hsu, who I trust*, interviewed Tim Palmer of Oxford and the Royal Society, who I know nothing about, about how reliable climate models are. Palmer seems very reasonable. His short answer is that WRT the basics they are very good, as it is just 19th C physics, but the deeper structures still have too much variance. However, as the models improve they are slowly pointing toward worse outcomes rather than better.
They started by discussing how to get top physicists into fields of practical application, as most want to study the (sexier) theoretical issues and take their PhD's and post docs there. Palmer notices a trend in that group in their late twenties of deciding later to want to move to physics of practical import, but they have difficulty transitioning to what are essentially new fields.
He asserted quite blandly the high level of certainty that some recent warming (about 1 degree Celsius) has happened and high certainty it is caused largely by greenhouse gases and human activity. Because there is a known heightened warming effect from increased water vapor, that is an intensifier and it isn't going away. Such things are frequently asserted by journalists and politicians, and even from scientists who have a high drive to activism, but my experience has been that the other scientists are more cautious and measured. Yet as Palmer went on to say that it is the subsequent questions that are more complicated and difficult, and this is sometimes obscured, it seemed to me that this was a clearer distinction than what I have been making.
One particular difficulty is that "cloud cover" is a term thrown around with imprecision, and two aspects of it in particular have very different effects. Low lying clouds reflect sunlight back into the atmosphere and off the planet, so an increase in water vapor at that level is mitigating effect on warming. But increased cloud cover higher in the atmosphere is an intensifier of warming. Modeling of this has been difficult and shows high variance. Nearly all models show a worrisome increase in upper level cloud cover. Palmer thinks the question is so large and so important that we should be spending much more money on studying it.
There is uncertainty whether the moisture at high levels is ice or supercooled water droplets. The later would be worse in terms of intensifying warming. Recent observations and calculations are indicating that there is more supercooled water and less ice, and models are being adjusted accordingly. The projections from this change point to strong possibilities of much higher warming and greater variance in extreme weather.
Interestingly, Palmer focuses on the secondary effects of warming. It may be that there will be more hurricanes and droughts and a greater rise in sea levels, but most of these are manageable (though very expensive) in developed areas. People shrug that things being a little warmer in Scotland might not be a bad thing, but Palmer notes that decreased sunlight will mean more depression and alcoholism, and worse cardiovascular outcomes. However, what really worries him are the places that are becoming unliveable, such as parts of Iraq and into Central Asia, and especially much of central Africa. This latter is about the only place where population is still growing, and when people find a place unlivable, they historically just move. In large numbers. And they are impossible to stop. He notes this is already happening and doesn't believe Europe has quite come to grips with this.
However, a different point of view comes from Hsu discussing Steve Koonin's book Unsttled: What Climate Science Tells Us, What It Doesn't, and Why It Matters, and the WSJ article about him. Koonin was, of all things, chief scientist for Obama's Energy Department. Perhaps it is not that different a POV after all, as he believes that the climate science we are doing is pretty good, but the reporting and posturing about it are dangerous. I appreciated the use of the word "overegged," which one hardly sees anymore. Koonin also believes that because even a slight chance of catastrophe is too much, we need to assess this risk mfar better than we have been.
*I very much trust in science. Professor of Theoretical Physics and Computational Mathematics at Michigan State. He was VP of for research there but stepped down because of political controversies around human genetics. Basically, he asserted that the data says what it says and would not back down. He was the one who got me into a study where they did a full genome on me at a time when those things cost about 10K. It has never been useful to me, however, as I don't have the tools to read it. It just sits on my computer now. I don't know his other politics.
Judith Curry was previously Chair of the School of Earth and Atmospheric Sciences at Georgia Tech. She is now an independent consultant and researcher. In explaining her resignation from Georgia Tech, she said:
"A deciding factor was that I no longer know what to say to students and postdocs regarding how to navigate the CRAZINESS in the field of climate science. Research and other professional activities are professionally rewarded only if they are channeled in certain directions approved by a politicized academic establishment — funding, ease of getting your papers published, getting hired in prestigious positions, appointments to prestigious committees and boards, professional recognition, etc.
How young scientists are to navigate all this is beyond me, and it often becomes a battle of scientific integrity versus career suicide (I have worked through these issues with a number of skeptical young scientists)."
You can follow some of her current work and opinions at her blog.
Note that Scientific American referred to her as a "Climate Heretic", in an article titled "Climate Heretic: Judith Curry turns on her colleagues."
Yes, and there are others, some with excellent credentials. But I found Palmer quite reasonable, and he seemed to stick with facts. Low on opinion. And Hsu actively encourages examining counternarratives, which is why I like him.
here in CT we were under a mile of ice not so long ago. When i was in high school in the early 1970's all the climate guys were (correctly) noting that we were due for another ice age.
If we stipulate that human released carbon is the primary cause of a global temperature rise of a small amount, then this may be a good thing (or not). Only an environmentalist who differentiates between things humans do and those of meteors, volcanos etc. would be contrary to this. Much like a 1950s Sci-Fi movie we have the weather control knob at our fingertips. When do I get to vote on the desired climate? What was so magic about 1953's climate?
(I spent a lot of time on some heavy duty modelling and statistics for nuclear work in the 1980s and find the climate model validation pretty suspect so I tend to agree with Koonin (I have his book) on his worries about technique and validation. )
"WRT the basics they are very good, as it is just 19th C physics"
Even when the basic cause-and-effect relationships in a system are known and deterministic, it can be very difficult to model reliably. As an example, modeling the flight of a rocket is just a matter of 19th century physics. But the Soviets found that the differential equations they were using did not adequately account for the sloshing of the (liquid) fuel in the tanks.
With rockets, you can discover issues like this...fire it, find out it does something you weren't expecting, and then try to figure out why. Can't do that with a planet.
I don't know enough to evaluate the models on their merits. However, it seems to me that the models have many variables, and it's difficult to differentiate AGW from non-AGW in any time frame shorter than many decades. More specifically:
-There is significant uncertainty about global temperature measurements,
-There is significant uncertainty about the magnitudes of any future temperature changes,
-There is significant uncertainty about the contributions of human activities to future temperature changes,
-There is significant uncertainty about mitigation costs for any harmful temperature changes,
-It seems certain that increased wealth will facilitate any needed mitigation efforts,
-Wealth undergoes compounded growth with economic development, which requires time and light economic regulation,
-The mitigation measures that are being discussed seem certain to reduce economic growth and thereby lead to lower global wealth levels in the future,
-It might be best, contra the "precautionary principle", to do less now, so as to facilitate economic growth and climate research, so that if GW turns out to be a problem in the future we will have more resources (wealth and knowledge) to deal with it than we do now.
The "precautionary principle" stands on the unstated assumption that forestalling one conceivable anticipated risk - that might never amount to a real problem, or that might amount to a problem that might be easily mitigated in the future - is worth trading off (by imposing new regulation) a colossal amount of future economic growth and compounded wealth. Given the historically poor accuracy record of human predictions, and especially of politicized bandwagon predictions such as those made for AGW, the better precautionary principle might be the one expressed by the old quip that legislation that's supported by both parties and enacted in a hurry is probably no good. The best course of action for the time being might be to do nothing.
David Foster: Can't do that with a planet.
Not knowing everything doesn't mean not knowing anything.
Jonathan: -There is significant uncertainty about global temperature measurements
Satellite, ground station, and ocean radiosondes show similar warming trends.
Jonathan: -There is significant uncertainty about the magnitudes of any future temperature changes
True enough, but even the lower estimates will result in significant disruption of climate.
Jonathan: -There is significant uncertainty about the contributions of human activities to future temperature changes
Humans can certainly reduce their carbon emissions, if that is what you mean.
Jonathan: -There is significant uncertainty about mitigation costs for any harmful temperature changes
True, but . . .
Jonathan: -It seems certain that increased wealth will facilitate any needed mitigation efforts
True, but . . .
Jonathan: -Wealth undergoes compounded growth with economic development, which requires time and light economic regulation
True, but the environmental damage and economic costs also compound.
Jonathan: -The mitigation measures that are being discussed seem certain to reduce economic growth and thereby lead to lower global wealth levels in the future
True. However, while some costs are inevitable, the economic costs will be lower the sooner the investment, and the more permanent environmental damage that can be averted. More specifically, the industrial infrastructure took a century to build and is replaced every few decades. Instead of investing in old technology, it makes sense to spend those same investment dollars in new, green technology.
Jonathan: -It might be best, contra the "precautionary principle", to do less now, so as to facilitate economic growth and climate research, so that if GW turns out to be a problem in the future we will have more resources (wealth and knowledge) to deal with it than we do now.
Humans have the gift of foresight informed by modern science. The trick is to maintain robust growth while also addressing the very real problem of global warming. People the world over have the right to the fruits of industrial development, but people also have the right to their shared natural inheritance. While some economic costs and environmental damage is inevitable, much of it can be averted with proper management.
"Jonathan: -The mitigation measures that are being discussed seem certain to reduce economic growth and thereby lead to lower global wealth levels in the future
True. However, while some costs are inevitable, the economic costs will be lower the sooner the investment, and the more permanent environmental damage that can be averted. More specifically, the industrial infrastructure took a century to build and is replaced every few decades. Instead of investing in old technology, it makes sense to spend those same investment dollars in new, green technology."
You are dodging. Enormous costs are certain if industrialized countries adopt the policies advocated by GW alarmists. Yet the amount, if any, of "permanent environmental damage" that might be prevented by those policies is highly uncertain. First, do no harm.
Jonathan: Enormous costs are certain if industrialized countries adopt the policies advocated by GW alarmists.
And even higher costs if nothing is done. Keep in mind that energy infrastructure gets replaced every few decades anyway, so upgrading and while researching new energy solutions makes sense.
Jonathan: Yet the amount, if any, of "permanent environmental damage" that might be prevented by those policies is highly uncertain.
Uncertainty does not mean unknown. The range of uncertainty is such that there is a high probability of serious disruption of Earth's natural climate. One of the most significant effects will be mass human migration with all the attendant political, social, and economic consequences.
If climate change is a problem that we urgently need to address, nuclear power is the only way. Plus, it would be good whether or not climate change is an urgent issue.
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