I am with you, in particular on the idea that the public policy proposals of the leftists here are for the most part insane.
But to steelman the one legit/reasonable leftist argument, the focus should be on the (small) probability that the destabilized (2 then 3 degrees of warming which then leads to rapid acceleration from there…) case might occur.
And you and I at least probably agree that the chance is small. But non-zero.
But then you need to ask the 3rd question: will the leftist policy prescriptions be the difference between avoiding that “destabilized” case or not. The Paris Accords if implemented fully by everyone will supposedly reduce global average temperatures by between 0.1 and 0.3 degrees. What are the odds that THAT would be the difference between destabilization and not? Vanishingly small imo. And the odds that the world would agree on the energy consumption reduction needed to *actually* have a chance of making the difference between destabilization and not are also incredibly tiny.
And THAT is my issue with most of the leftist policy prescriptions here - especially the immoral immediate constriction of supply of fossil fuels preventing the billions of the world’s poorest from better access to highly available reliable low cost energy. The chances they will actually help are minimal, but the harm to the overall economy, and especially to the world’s poorest in the short and medium term, is significant.
There is a much clearer mechanism for warming stabilizing than destabilizing, given that we are in an interglacial that has already lasted as long as they usually last.
Yes, I agree that this is why the probability of destabilizing (2 and 3 degrees of warming and then accelerating) is *low*, and surely much lower than most leftists state or imply. But you cannot rule it out completely.
And this is why it’s important to address the likelihood of leftist policy prescriptions to be the difference between destabilization or not, and why the economics matter.
CO2 and “global warming” are the exception to the common sense understanding that “well, every little bit helps”.
Bu unlike for “clean air” and “clean water”, in fact in the case of global warming, for all the other reasons you cite, every little bit helps ONLY IF it is the difference between avoiding “destabilization” or not. If it is not - as IMO is overwhelmingly likely - than most of the “every little bit helps” not only did not help, but it actively hurt, since the resulting economics hurts world GDP, and is disproportionately harmful to the world’s poor by immorally denying them access to low cost highly available reliable energy to prosper (and in addition, adapt to any harmful regional effects of global warming that may occur).
I have no doubt that they are largely pushing the idea for political power means. If they were serious about doing a transition from fossil fuels, a Carbon tax that grows with time would be the ideal mechanism of implementing it - and would allow compensating projects that permanently remove Carbon from the atmosphere. The moralistic and self-interested motivations of the left though do not invalidate the climate change issues.
Correct. You will note that none of my arguments were based on "the left says it so it must be false."
My claim is, first, that the predictable negative effects of climate change over this century are much smaller than the catastrophist rhetoric implies and, second, that there are predictable positive effects which might be larger.
AI will make interstellar travel possible, allowing humans to expand infinitely to other planets in the universe, with endless resources. Until the universe expands too far and starts thinning.
It is amazing what a scientist like me can extrapolate using a small amount of evidence and some theorizing.
Mark Twain has a wonderful discussion of that, using the example of the changing length of the Mississippi, which had been shortening itself by cutting off loops, extrapolated both backwards and forwards.
By coincidence, just today I came across a remarkable wish list for the future by Robert Boyle from the late 17th century. Most of his science and technology wish list has been realized. I'm especially looking forward to the first two also being achieved.
The argument that temperatures rising a couple degrees will cause mass extinction is the most laughable one. Most species have been around since long before the glaciers retreated about 12000 years ago. At that time they coped just fine with a rapid 10 degree C warming, so they should be able to take a couple degree warming in stride.
“ The argument that temperatures rising a couple degrees will cause mass extinction is the most laughable one.”
I agree wholeheartedly.
But the one and only argument for actions (beyond research) here that is legit is the idea that temperatures will go up a couple degrees, and *then* go up at an accelerating rate after that. So that needs to be the proper framing of ANY AND ALL policy discussions. And yet it is not.
If we insisted and succeeded in making this the frame of the discussion, then things like the Paris accords would lose all credibility, since the idea they are a *positive* “down payment” on anything is borderline absurd, yet the deadweight loss costs borne - especially on the billions of the world’s poorest who lack low cost reliable highly available energy - are unconscionably immoral [I refer here to constrictions on fossil fuel supply in particular].
The Soviet Union started and encouraged all sorts of activism in the West. It’s easy. You need merely pay for their recreational chemicals. The only drawback is that you can’t get them to do anything before noon.
This fails to engage with the most common argument I hear for global warming being very bad: that it will cause a major increase in hurricanes, regional droughts, regional floods, etc.--in general, more of the rare but very bad weather events that cause death, property destruction, and crop failures whenever they happen. I agree that wealthy societies can adapt to these issues, but poorer countries with next to no slack are going to be hit much harder by any increase in natural disasters.
The IPCC projections don't imply a major increase in hurricanes. They imply a decrease in low level (categories 1-3) ones, an increase in the strength but not the number of category 4 and 5.
Note that CO2 fertilization decreases drought, since it decreases water requirements for plants. It also substantially increases the yield of C3 crops (wheat and rice but not maize).
Just stumbled in here on 2024-11-06 by chance; I gather Prof. Friedmans post "... increase in the strength, but not the number of cat. 4 and 5 [hurricanes]" is dated 2024-04-26, isn't it. Did some research on this conjecture and found this (https://www.nsf.gov/news/news_summ.jsp?cntn_id=104428), apparently dated 2005-09-15, saying: "... The number of Category 4 and 5 hurricanes worldwide has nearly doubled over the past 35 years, according to a study by researchers at the Georgia Institute of Technology and the National Center for Atmospheric Research (NCAR). ... "What we found was rather astonishing," said Georgia Tech's Webster. "In the 1970s, there was an average of about 10 Category 4 and 5 hurricanes per year globally. Since 1990, the number of Category 4 and 5 hurricanes has almost doubled, averaging 18 per year globally." Just saying. Best regards from Europe.
I was reporting the projections in the IPCC report. I don't know whether the facts in the article you cite are correct, but I am pretty sure they are inconsistent with the modeling that goes into the IPCC report, given how fast the reported change is.
I couldn't find a summary of annual number of category 4 and 5 tropical cyclones in recent years, but there is a wikipedia article on tropical cyclones in 2024 with a very detailed account: https://en.wikipedia.org/wiki/Tropical_cyclones_in_2024. I went through it counting category 4 and 5 tropical cyclones (whether they are called hurricanes depends on where they originate) and there were seven. That's lower than the article's average for the 1970's. So perhaps the article was responding to a temporary high in the 1990's.
If you know of a source for the number of tropical cyclones of various categories in past years, it would be interesting to see if it is consistent with the article you cited.
I did find a source for total number of hurricanes, not divided by category, from 1990-2023. It seems to have been slightly decreasing over that period:
"Somewhere, I believe it was among these posts here, there was the argument, that substantial higher temperature changes than 1.5 to 3° K have been outlived by former creatures on earth. Yeah, some have for sure survived very very harsh periods, but many of them had quite a different metabolism than humans, had they not."
The most recent high was survived by mammals, so not a different metabolism than humans. Note that humans currently live and prosper across a wider range of temperatures than the predicted increase for the next two centuries. Given the existence of technology, I would expect humans to be less vulnerable than other species, not more, which explains why our species lives across such a wide range of environments.
I think a better argument for your point is that although average global temperatures has been higher in the (geologically) recent past and much higher in the more distant past, we don't have evidence of rates of change comparable to what we can expect in the near future.
Thanks for suggesting and clarifying with respect to change rate.
"... better argument for your point ... [as of yet no] evidence of rates of change comparable to what we can expect in the near future."
I was not aware that my wording in the (rhetorical) question "... able to adapt to such changes quickly enough?" did not make it clear enough that I implied change rate (too) ("adapt to such changes quickly enough") and possibly even accelaration of change rates insofar seen as yet e.g. due to transgression of climate tipping points (e.g. albedo decreasing with each square meter of glaciers melting to the ground) .
"... adapting quickly enough to (rapid) climate/temperature change conditions in conjunction with the notion "different metabolism": True, I exaggerated in alluding to (or rather not excluding) "very" different kinds of metabolisms in very different species (e.g. reptiles vs. pre-mammals vs. mammals; s. (A) https://evrimteorisionline.com/2011/01/26/ursprung-und-evolution-der-saugetiere/ and (B) "https://www.researchgate.net/publication/239469017" - Phylogenese des Stoffwechsels der Säugetiere) and admittedly more than I should have.
But in earnest, as for metabolism and temperatures, I bore in mind especially ambient (air) temperatures rising well beyond 40° or even 50° C (e.g. in long standing heat waves - the duration of which is expected to be rising too in the near future, as far as I know, and likely with rising numbers in heat-related fatalities) and (ground) temperatures even beyond 70° C (e.g. in China's provinces Hebei, Henan, Shandong, Inner Mongolia and Tianjin in 2023-06 according to local media) in conjunction with enzyme activity (enzyme optimum) in human cells/body tissues depending on temperature (and pH-value which itself depends on temperature, getting more acidic as body temperature rises and converges to or even exceeds 40° C);
Alluding to the second law of thermodynamics, how can a human sustain homeothermy of 37° C core body temperature in a sourrounding with 40° C (or more, even closing to 50° C) outdoors and among the shades, especially when humidity approaches high or very high values simultaneously so that perspiration in effect starts transmitting heat energy into the body instead of getting rid of it?
Enzymes are proteins after all (which can be denatured by temperature) and their specific function in the various tissues depends on the kind of tissue, the kind of enzyme, the temperature and the pH-value; s. Abb.10 in (B) where it says (translation from German into English by deepL.com): "Significance of the pH setting for the extent of turnover reduction in hypothermia. Measured by the temperature-dependent shift of the neutral point (pN) of water, the alpha and pH-stat regimes can be distinguished (a), which have an effect on enzyme proteins in the sense of “optimal function maintenance” (alpha-stat) or “additional metabolic support” (pH-stat) (b)."
Note that in (B) Abb.10 (a) temperature ranges from 0 to 40° C and the pH-values of pN (H2O) drops to 6.8 (acidic) at the latter temp. Temperatures of 40°C or more are not even accounted for in that chart, but I deem it unlikely that in a human body enzyme activity is kind of "revived" or enzyme optima were at least bimodal when temperatures rise to and beyond 40°C (s. https://en.wikipedia.org/wiki/Denaturation_(biochemistry), especially the 3 charts "The effects of temperature on enzyme activity.", those charts show that enzyme activity is at a (unimodal) optimum at approx. 47/48°C, passing through a sharp drop at about 50° C and converging to 0 % at about 55°C.
Well, perhaps that is said too much and I am loosing myself in irrelevant particulars. Do I?
Correction "... shear number of hurricances ..." should be "... sheer number of hurricances ...": I am sorry, I am not native in the English language.
Yes, it was my intention to hint at the differences of the IPCC projections quoted by Prof.Friedman on the one hand and the information in the article on nsf.gov I referenced.
Of course, neither do I know if the facts in the nsf.gov-page I hinted at are correct.
So I did some further research (using "brave.com" as a search engine) asking (exactly) "number of category 4 and 5 cyclones worldwide in 2024" and got this answer: "Category 4 Cyclones: BOB 04 (September 7-13, 2024), Krathon (Julian) (October 19-28, 2024), Dana (March 25-28, 2024), Pulasan (Helen) (September 15-21, 2024), Trami (Kristine) (October 19-28, 2024), Kong-rey (Leon) (October 24-November 1, 2024), Ewiniar (Aghon) (May 22-30, 2024), Mocha (May 16-22, 2024)"
which count to 8 cat.4
and "Francine (September 9-12, 2024), Helene (September 24-27, 2024), Milton (October 19-22, 2024), Beryl (June 28-July 9, 2024)"
which count to 4 cat.5, in sum 12,
which is well above the 7 counted based on the wikipedia article cited by Prof.Friedman.
Again, neither do I know whether the answer of the search engine "brave.com" is correct or at least representative nor if the wikipedia article (or Prof.Friedman's counting therein) is.
But, as Prof.Friedman certainly is well aware, relating the estimator for a single 1-year/season-period to averages over 5, 10, 20, 50 years always bears the non-zero possiblity that the single-year value ex-post will turn out to have been an outlier or to have been caused by (energy) storage, conversion and balance effects (e.g. El Niño, La Niña, change in albedo), stochastic irregularities etc.
Be that as it may, I also found an article in the TIME magazine (https://time.com/6218275/strongest-hurricanes-us-map/) edited September 29, 2022 3:23 PM EDT which under the title "Here’s Where All The Strongest Hurricanes Have Hit the U.S. in the Past 50 Years" states (in the graph titled "Hardest hitters"): "Nine category 4 and 5 hurricanes have hit the mainland U.S. in the last 50 years - 6 in the past five years."
Putting that straight (according to the information in TIME): 3 cat.4/5 hurricanes hit land within 45 years up to the year 2022-5 and 6 hit land within the past 5 years rel. to 2022.
And I found another source (EPA's Climate Change Indicators in the United States: www.epa.gov/climate-indicators, Figure 1. Number of Hurricanes in the North Atlantic, 1878–2022, Data source: NOAA, 2023; Vecchi and Knutson, 2011
Web update: June 2024, Units: Number of hurricanes) and downloaded the data (under the link to cyclones_fig-1.csv there).
The data cited (applying simple linear regression using maxima, s. https://maxima.sourceforge.io) suggest that there is at least a significant rise in the numbers of total hurricanes (colum adjusted smoothed as explained on the website) in the period 1970 to 2020 (model=0.064*x-121.4, with x denoting the years and b=0.064 being the point estimator for the rise over the years; corr=0.69, confidence interval of the rise b [0.045,0.083] and p-value=1.5462*10^-8 for H0: b=0);
whereas the regession for the period 1990 to 2020 yields: model=0.056*x-106.0, corr=0.43, confidence interval of the rise b [0.011,0.1]], and p-value=0.015 for H0: b = 0.
And a difference of means test of the NOAA-data split into the two periods 1980-1999 and 2000-2020 (using maxima function test_means_difference and options set to calculated standard deviations and asymptotic=true so that variances are NOT assumed to be equal and an asymptotic test based on the central limit theorem is executed) yields a difference estimate in the 20/21-years-period averages of 1.901 at confidence level 0.95 with confidence interval [-2.451,-1.351] and p-value=.2371*10^-11 on testing H0: mean1 = mean2,
in short, statistically significant different average numbers of (total) hurricanes within the 2 time periods 1980-1999 and 2000-2020.
The above regression and difference of means test findings based on the cited NOAA data seem to be corroborated, at least by trend, in the graph in https://en.wikipedia.org/wiki/Tropical_cyclones_and_climate_change#cite_ref-NYTimes_20220929_30-0 where is stated: "The 20-year average of the number of annual Category 4 and 5 hurricanes in the Atlantic region has approximately doubled since the year 2000."
In that wikipedia article (s. cite_ref 62) there is also information about cost, saying "The number of $1 billion Atlantic hurricanes almost doubled from the 1980s to the 2010s, and inflation-adjusted costs have increased more than elevenfold.[62] The increases have been attributed to climate change and to greater numbers of people moving to coastal areas. [62]".
Conclusion: Prof.Friedman was right to question the data cited primarily (nsf.gov), yet, there seems to be significant (other) evidence that IPCC projections as cited by Prof.Friedman signifcantly underestimate(d) the true rise in numbers. And well, it is not the shear number of hurricances that should bother us imho, but the soaring kinetic energy they (and other climate change moderated extreme weathers/conditions) transport to land and homes and the damages to property, harvests and eco systems world wide, should it not.
P.S. Somewhere, I believe it was among these posts here, there was the argument, that substantial higher temperature changes than 1.5 to 3° K have been outlived by former creatures on earth. Yeah, some have for sure survived very very harsh periods, but many of them had quite a different metabolism than humans, had they not. And at least the bigger of those former species certainly never at any time outnumbered the shear mass of humans now living, did they. So, how many of the approx 10 billion of humans of today would be able to adapt to such changes quickly enough? Those living in an Elysium-like Blue Origin space station with a Neuralink-controlled metabolism far beyond the Lagrange points in spaces with very weak shielding against high and ultra high energy radiation? Just asking.
And the fundamental problem with any of the "go green" BS is that it will keep poorer countries poor! The advice to review Dr. Pielke's work on disasters and their diminishing effects is seconded. Over the past 100 years, our response to disasters has been to reduce deaths 100-fold! ALL made possible through development of energy. If you want to understand trends in extreme weather, look at weather data, not economic data.
You will also observe from Pielke's work that there is no attribution to hurricane frequency, or other natural disasters, to humans. Finally, no where in the IPCC documents will you find suggestions that civilization is threatened. Nada. Rien. Nothing.
I believed the implication was there, particularly when you said "poorer countries...are going to be hit much harder by any increase in natural disasters." It was not my intention to offend, only rather to point out the obvious discrepancies between those who are energy rich and those who are energy poor.
I agree, you never said directly that civilization was threatened, though I'm sure you agree that there are many climatists who make such claims. Your words, heartfelt I'm sure and no disrespect intended, imply that climate change is something to be feared.
It isn't. To paraphrase Dr. Curie, nothing in the natural world should be feared; it should only be understood.
You said it doesn’t address “the most common argument I hear”. But in fact it does: the prescriptions of leftists in the name of those who will supposedly be at more risk (deny them low cost fossil fuels) in fact puts those billions of the world’s poorest at MUCH HIGHER risk!
Our understanding of climate is not nearly sophisticated enough to predict that there will be both regional droughts and regional floods as a result of a slight increase in the average temperature. I could find it plausible that we could understand things enough to say "There will be more rain" or "There will be less rain." But the assertion that there will both be more rain in a bad way and less rain in a bad way is such an obvious alarmist ploy that I can't believe proponents aren't laughed out of the room.
“ more of the rare but very bad weather events that cause death,”
In fact cold causes far more deaths than these very rare events.
And more to the point, the lack of low cost highly available reliable energy for the poor in poor regions is responsible for FAR more death and discomfort.
It is no coincidence that as we have started to use more fossil fuel, the number of weather related deaths has gone down by more than 9% in the last 125 years. Having cheap energy to be able to power machines helps people avoid weather related deaths far more than any reduction in global warming ever could .
Don’t distract yourself worrying about catastrophes. giggling or not giggling. Figure out the most cost effective mitigation and adaptation policies to respond to the increase in CO2 concentration in the atmosphere.
If we are going to do ANYTHING we should do lower cost things. But your assertion implies that “doing something” is required.
BTW you left out “build out nuclear power plants in all the countries that are allowed to have nuclear weapons” as answer #1 if in fact AGWC really is an existential threat. The fact that so many leftists oppose this puts to the lie that global warming and carbon emissions are an existential threat. And if it ain’t an existential threat, they can’t use it as justification for political power and anti-capitalist policies.
If we can adapt well to climate change, we should also be able to adapt well to El Niño years, which are effectively temporary climate change spikes. We demonstrably cannot, not because of the increased temperature but because of all the downstream effects on severe weather it produces.
Sea level rise may only extend in a few miles, but the safe buildable area in many places, including the entire Gulf of Mexico and most of the Eastern Seaboard, recedes substantially more due to increased hurricane severity. An increase in temperature is an increase in energy, and peak severity of extreme weather therefore rises, even for blizzards.
"An increase in temperature is an increase in energy, and peak severity of extreme weather therefore rises, even for blizzards."
The current projection is that peak wind speed of tropical cyclones increases a little, number of tropical cyclones decreases a little (both from the IPCC report).
Your general argument sounds plausible but is not correct. A cyclone is a heat engine, and the available energy depends not on the temperature of the source but on the temperature difference between source and sink. If both are warming the effect is ambiguous.
A heat engine that simply turns heat into work without dumping some of it to a cooler sink is a perpetual motion engine of the second kind, thermodynamically impossible.
What do you make of this recently published study: https://www.nature.com/articles/s41586-024-07219-0? Would be astonishing if true. Assume the fact that it was published in Nature rather than an econ journal is a tipoff.
Data on heat deaths seem to be incomplete and often unreliable. Based on what is available (EM-DAT.bet), the most recent decade has many fewer deaths from heat compared to the previous decade.
The mortality they find is not mostly from extreme temperatures, just from temperatures above or below the optimum. That's probably the source of the nine to one factoid.
However, The Lancet could not resist distorting the presentation of the data. On the left side (cold-related) the graph used increments of 50, while the right side (heat) used increments of 10.
Even if the work is honest, as I think Gasparini's probably is, measuring the relation between temperature and mortality is a hard problem. What you want to know is not the total mortality from heat and from cold but how it will change due to global warming. The logic of Gasparini's analysis, if I understand it, is that the marginal effect of warming is greater on heat deaths (increase) than on cold death's (decrease) even though total heat deaths are less than total cold deaths. That isn't impossible although it's surprising, given the size of the difference in total mortality.
…but even this claim if true UTTERLY misses the mark.
Giving the world’s poorest billions access to low cost realizable highly available energy (that of course fossil fuels provides) would do FAR more to reduce deaths than any effort to impact global climate.
So the discussion is “dishonest” in that sense. At least until we take off the table artificial restriction of fossil fuel supplies that can enable the world’s poorest to be less poor, closer to rich western living standards and better able to adapt to any changes in weather/climate.
But of course this is the policy that leftists (most of them anti-capitalists) push first and foremost when they make their global warming claims. While mostly still being opposed to nuclear power. Despite the obscene immorality of fossil fuel restriction policy.
Humans have adapted to large climatic changes in the past largely through migration. As climate change makes equatorial region less habitable, other regions like Russia and Canada, will become more so. The obvious solution to a changing climate is for hundreds of millions to move away from those regions most severely affected and into regions less affected or even positively affects. Do you think the Russians will let 100's of millions of climate refugees into their country? WIll the Canadians? Or the Americans?
THIS is the threat posed by climate change, not the 10 meter rise in sea level over the next millennium that is already baked into the cake (assuming we stop adding CO2 into the atmosphere on this century).
You are exaggerating the scale of the effect by a couple of orders of magnitude. Why would you expect an increase of average equatorial temperatures of two degrees to cause hundreds of millions of people to leave?
Take a look at the maps of average temperature and population density that I linked to and think about the implications.
There were scattered societies that reached fairly high levels of sophistication during the Ice Age, here's an example from 23,000 years ago that had developed sedentism and appears to have been doing an early form of farming (I found the vid fascinating).
The reason why these Ice Age settlements are scattered and there seems to be little progress is because one climate shift creates a favorable environment that allows progress to happen, and then another climate shift causes the end of that progress as the settlement is abandoned and the people revert to lower level of societal complexity.
So here and there humans already had the necessary ingredients to develop complex civilizations 11,000 years before the earliest megalith building cultures appeared in the Levant. In the span of time from Ohalo II to Gobekli Tepe we see little change in human societal complexity. Over the same span of time after Gobekli Tepe, we developed our modern civilization. What happened?
A plausible candidate was the end of the highly variable climate around 11,000 years ago. After that is was off to the races. Through industrialization humans are now restoring that world of fluctuating climate.
A likely effect of changing climate are changes in rainfall patterns and soil moisture that will make current lifeways untenable in various spots. The historical solution for when this happens was migration., which I pointed out. You wish to hand wave this away. How are you so sure you are right?
I don't understand your point. If we observe dense populations at temperature X that's evidence that raising the local temperature elsewhere from X-2 to X is unlikely to displace much of that population. Do you disagree? If you do, what is your basis for thinking that warming at the projected rate will cause hundreds of millions to migrate?
You are ignoring why the initial population densities are what they are. Simply because dense population exists at location X at temperature T and at location Y at temperature T-2, does not mean that going to temperature T at location Y will not pose a problem.
Suppose both locations support large populations through dryland farming. Further suppose location Y is dryer than X. Temperature T at location Y makes the climate unsuitable to dryland farming, whereas it does not at X.
In the Sahel region land once suitable for grazing can become more arid with warming, causing the populations who once lived there to more south into already settled areas, which can result in political instability.
We saw this happen recently with the poor harvest in 2012 driving up grain prices, causing discontent and political unrest in Syria, which developed into civil war. War sent waves of migrants heading for Europe, which has created political instability there.
As temperature rises more marginal places will suffer hard times and the political instability that generates.
You are attributing migration to climate change, as if bad harvests and wars did not happen without it.
There is no reason to assume that all change is bad. One of the things you can discover in the IPCC report is that some projections show climate change greening the Sahara and Sahel.
Waves of migrants, about a million a year, came to the US in the years before and after WWI without global warming. Waves of migrants have been coming to Europe because European welfare states are better places to be than Syria or Africa.
All I am saying is you are assuming that changing the climate from where it has been for the entire period in which human civilization existed will have no serious effects and so nothing should be done to move off of fossil fuel. I think you are overly optimistic, but you are going to believe what you believe and that is ok. I'm not going to still be alive in the second half of this century to find out.
Actually, most important is that leftists can use the issue as a means to political power, and secondarily as a means to promote anti-capitalist policies.
I am with you, in particular on the idea that the public policy proposals of the leftists here are for the most part insane.
But to steelman the one legit/reasonable leftist argument, the focus should be on the (small) probability that the destabilized (2 then 3 degrees of warming which then leads to rapid acceleration from there…) case might occur.
And you and I at least probably agree that the chance is small. But non-zero.
But then you need to ask the 3rd question: will the leftist policy prescriptions be the difference between avoiding that “destabilized” case or not. The Paris Accords if implemented fully by everyone will supposedly reduce global average temperatures by between 0.1 and 0.3 degrees. What are the odds that THAT would be the difference between destabilization and not? Vanishingly small imo. And the odds that the world would agree on the energy consumption reduction needed to *actually* have a chance of making the difference between destabilization and not are also incredibly tiny.
And THAT is my issue with most of the leftist policy prescriptions here - especially the immoral immediate constriction of supply of fossil fuels preventing the billions of the world’s poorest from better access to highly available reliable low cost energy. The chances they will actually help are minimal, but the harm to the overall economy, and especially to the world’s poorest in the short and medium term, is significant.
There is a much clearer mechanism for warming stabilizing than destabilizing, given that we are in an interglacial that has already lasted as long as they usually last.
Yes, I agree that this is why the probability of destabilizing (2 and 3 degrees of warming and then accelerating) is *low*, and surely much lower than most leftists state or imply. But you cannot rule it out completely.
And this is why it’s important to address the likelihood of leftist policy prescriptions to be the difference between destabilization or not, and why the economics matter.
CO2 and “global warming” are the exception to the common sense understanding that “well, every little bit helps”.
Bu unlike for “clean air” and “clean water”, in fact in the case of global warming, for all the other reasons you cite, every little bit helps ONLY IF it is the difference between avoiding “destabilization” or not. If it is not - as IMO is overwhelmingly likely - than most of the “every little bit helps” not only did not help, but it actively hurt, since the resulting economics hurts world GDP, and is disproportionately harmful to the world’s poor by immorally denying them access to low cost highly available reliable energy to prosper (and in addition, adapt to any harmful regional effects of global warming that may occur).
On the assumption, implicit or explicit, that the recent/pre-industrial temperature is optimal, see Roger Pielke's piece: https://rogerpielkejr.substack.com/p/when-the-climate-was-perfect
I have no doubt that they are largely pushing the idea for political power means. If they were serious about doing a transition from fossil fuels, a Carbon tax that grows with time would be the ideal mechanism of implementing it - and would allow compensating projects that permanently remove Carbon from the atmosphere. The moralistic and self-interested motivations of the left though do not invalidate the climate change issues.
Correct. You will note that none of my arguments were based on "the left says it so it must be false."
My claim is, first, that the predictable negative effects of climate change over this century are much smaller than the catastrophist rhetoric implies and, second, that there are predictable positive effects which might be larger.
If they were truly serious we'd be building nukes.
AI will make interstellar travel possible, allowing humans to expand infinitely to other planets in the universe, with endless resources. Until the universe expands too far and starts thinning.
It is amazing what a scientist like me can extrapolate using a small amount of evidence and some theorizing.
Mark Twain has a wonderful discussion of that, using the example of the changing length of the Mississippi, which had been shortening itself by cutting off loops, extrapolated both backwards and forwards.
By coincidence, just today I came across a remarkable wish list for the future by Robert Boyle from the late 17th century. Most of his science and technology wish list has been realized. I'm especially looking forward to the first two also being achieved.
https://ghostarchive.org/archive/6nkYj
The Robert Boyle link is bad…
The argument that temperatures rising a couple degrees will cause mass extinction is the most laughable one. Most species have been around since long before the glaciers retreated about 12000 years ago. At that time they coped just fine with a rapid 10 degree C warming, so they should be able to take a couple degree warming in stride.
“ The argument that temperatures rising a couple degrees will cause mass extinction is the most laughable one.”
I agree wholeheartedly.
But the one and only argument for actions (beyond research) here that is legit is the idea that temperatures will go up a couple degrees, and *then* go up at an accelerating rate after that. So that needs to be the proper framing of ANY AND ALL policy discussions. And yet it is not.
If we insisted and succeeded in making this the frame of the discussion, then things like the Paris accords would lose all credibility, since the idea they are a *positive* “down payment” on anything is borderline absurd, yet the deadweight loss costs borne - especially on the billions of the world’s poorest who lack low cost reliable highly available energy - are unconscionably immoral [I refer here to constrictions on fossil fuel supply in particular].
Species extinction is much more likely due to loss of appropriate environment, hunting and/or introduction of new species into the ecology.
The first part of the argument is by no means open and shut:https://www.sciencedirect.com/science/article/pii/S2666496823000456
The Soviet Union started and encouraged all sorts of activism in the West. It’s easy. You need merely pay for their recreational chemicals. The only drawback is that you can’t get them to do anything before noon.
I thought we’re supposed to make charcoal for gas masks from the peach pits.
This fails to engage with the most common argument I hear for global warming being very bad: that it will cause a major increase in hurricanes, regional droughts, regional floods, etc.--in general, more of the rare but very bad weather events that cause death, property destruction, and crop failures whenever they happen. I agree that wealthy societies can adapt to these issues, but poorer countries with next to no slack are going to be hit much harder by any increase in natural disasters.
The IPCC projections don't imply a major increase in hurricanes. They imply a decrease in low level (categories 1-3) ones, an increase in the strength but not the number of category 4 and 5.
Note that CO2 fertilization decreases drought, since it decreases water requirements for plants. It also substantially increases the yield of C3 crops (wheat and rice but not maize).
Just stumbled in here on 2024-11-06 by chance; I gather Prof. Friedmans post "... increase in the strength, but not the number of cat. 4 and 5 [hurricanes]" is dated 2024-04-26, isn't it. Did some research on this conjecture and found this (https://www.nsf.gov/news/news_summ.jsp?cntn_id=104428), apparently dated 2005-09-15, saying: "... The number of Category 4 and 5 hurricanes worldwide has nearly doubled over the past 35 years, according to a study by researchers at the Georgia Institute of Technology and the National Center for Atmospheric Research (NCAR). ... "What we found was rather astonishing," said Georgia Tech's Webster. "In the 1970s, there was an average of about 10 Category 4 and 5 hurricanes per year globally. Since 1990, the number of Category 4 and 5 hurricanes has almost doubled, averaging 18 per year globally." Just saying. Best regards from Europe.
I was reporting the projections in the IPCC report. I don't know whether the facts in the article you cite are correct, but I am pretty sure they are inconsistent with the modeling that goes into the IPCC report, given how fast the reported change is.
I couldn't find a summary of annual number of category 4 and 5 tropical cyclones in recent years, but there is a wikipedia article on tropical cyclones in 2024 with a very detailed account: https://en.wikipedia.org/wiki/Tropical_cyclones_in_2024. I went through it counting category 4 and 5 tropical cyclones (whether they are called hurricanes depends on where they originate) and there were seven. That's lower than the article's average for the 1970's. So perhaps the article was responding to a temporary high in the 1990's.
If you know of a source for the number of tropical cyclones of various categories in past years, it would be interesting to see if it is consistent with the article you cited.
I did find a source for total number of hurricanes, not divided by category, from 1990-2023. It seems to have been slightly decreasing over that period:
https://www.statista.com/statistics/1297656/number-hurricanes-worldwide/
Thanks. Interesting.
"Somewhere, I believe it was among these posts here, there was the argument, that substantial higher temperature changes than 1.5 to 3° K have been outlived by former creatures on earth. Yeah, some have for sure survived very very harsh periods, but many of them had quite a different metabolism than humans, had they not."
The most recent high was survived by mammals, so not a different metabolism than humans. Note that humans currently live and prosper across a wider range of temperatures than the predicted increase for the next two centuries. Given the existence of technology, I would expect humans to be less vulnerable than other species, not more, which explains why our species lives across such a wide range of environments.
I think a better argument for your point is that although average global temperatures has been higher in the (geologically) recent past and much higher in the more distant past, we don't have evidence of rates of change comparable to what we can expect in the near future.
Thanks for suggesting and clarifying with respect to change rate.
"... better argument for your point ... [as of yet no] evidence of rates of change comparable to what we can expect in the near future."
I was not aware that my wording in the (rhetorical) question "... able to adapt to such changes quickly enough?" did not make it clear enough that I implied change rate (too) ("adapt to such changes quickly enough") and possibly even accelaration of change rates insofar seen as yet e.g. due to transgression of climate tipping points (e.g. albedo decreasing with each square meter of glaciers melting to the ground) .
"... adapting quickly enough to (rapid) climate/temperature change conditions in conjunction with the notion "different metabolism": True, I exaggerated in alluding to (or rather not excluding) "very" different kinds of metabolisms in very different species (e.g. reptiles vs. pre-mammals vs. mammals; s. (A) https://evrimteorisionline.com/2011/01/26/ursprung-und-evolution-der-saugetiere/ and (B) "https://www.researchgate.net/publication/239469017" - Phylogenese des Stoffwechsels der Säugetiere) and admittedly more than I should have.
But in earnest, as for metabolism and temperatures, I bore in mind especially ambient (air) temperatures rising well beyond 40° or even 50° C (e.g. in long standing heat waves - the duration of which is expected to be rising too in the near future, as far as I know, and likely with rising numbers in heat-related fatalities) and (ground) temperatures even beyond 70° C (e.g. in China's provinces Hebei, Henan, Shandong, Inner Mongolia and Tianjin in 2023-06 according to local media) in conjunction with enzyme activity (enzyme optimum) in human cells/body tissues depending on temperature (and pH-value which itself depends on temperature, getting more acidic as body temperature rises and converges to or even exceeds 40° C);
Alluding to the second law of thermodynamics, how can a human sustain homeothermy of 37° C core body temperature in a sourrounding with 40° C (or more, even closing to 50° C) outdoors and among the shades, especially when humidity approaches high or very high values simultaneously so that perspiration in effect starts transmitting heat energy into the body instead of getting rid of it?
As for the "50° C" ambient temperature outdoors s. e.g. UN secretary general Guterres on the 25th of July 2024 in New York saying: Billions of people are “facing an epidemic of extreme heat and are stewing in increasingly deadly heatwaves with temperatures of over 50 degrees Celsius” according to the article in https://www.kleinezeitung.at/service/newsticker/chronik/18703184/uno-konstatiert-epidemie-extremer-hitze (translated using deepL.com).
Enzymes are proteins after all (which can be denatured by temperature) and their specific function in the various tissues depends on the kind of tissue, the kind of enzyme, the temperature and the pH-value; s. Abb.10 in (B) where it says (translation from German into English by deepL.com): "Significance of the pH setting for the extent of turnover reduction in hypothermia. Measured by the temperature-dependent shift of the neutral point (pN) of water, the alpha and pH-stat regimes can be distinguished (a), which have an effect on enzyme proteins in the sense of “optimal function maintenance” (alpha-stat) or “additional metabolic support” (pH-stat) (b)."
Note that in (B) Abb.10 (a) temperature ranges from 0 to 40° C and the pH-values of pN (H2O) drops to 6.8 (acidic) at the latter temp. Temperatures of 40°C or more are not even accounted for in that chart, but I deem it unlikely that in a human body enzyme activity is kind of "revived" or enzyme optima were at least bimodal when temperatures rise to and beyond 40°C (s. https://en.wikipedia.org/wiki/Denaturation_(biochemistry), especially the 3 charts "The effects of temperature on enzyme activity.", those charts show that enzyme activity is at a (unimodal) optimum at approx. 47/48°C, passing through a sharp drop at about 50° C and converging to 0 % at about 55°C.
Well, perhaps that is said too much and I am loosing myself in irrelevant particulars. Do I?
Correction "... shear number of hurricances ..." should be "... sheer number of hurricances ...": I am sorry, I am not native in the English language.
Yes, it was my intention to hint at the differences of the IPCC projections quoted by Prof.Friedman on the one hand and the information in the article on nsf.gov I referenced.
Of course, neither do I know if the facts in the nsf.gov-page I hinted at are correct.
So I did some further research (using "brave.com" as a search engine) asking (exactly) "number of category 4 and 5 cyclones worldwide in 2024" and got this answer: "Category 4 Cyclones: BOB 04 (September 7-13, 2024), Krathon (Julian) (October 19-28, 2024), Dana (March 25-28, 2024), Pulasan (Helen) (September 15-21, 2024), Trami (Kristine) (October 19-28, 2024), Kong-rey (Leon) (October 24-November 1, 2024), Ewiniar (Aghon) (May 22-30, 2024), Mocha (May 16-22, 2024)"
which count to 8 cat.4
and "Francine (September 9-12, 2024), Helene (September 24-27, 2024), Milton (October 19-22, 2024), Beryl (June 28-July 9, 2024)"
which count to 4 cat.5, in sum 12,
which is well above the 7 counted based on the wikipedia article cited by Prof.Friedman.
Again, neither do I know whether the answer of the search engine "brave.com" is correct or at least representative nor if the wikipedia article (or Prof.Friedman's counting therein) is.
But, as Prof.Friedman certainly is well aware, relating the estimator for a single 1-year/season-period to averages over 5, 10, 20, 50 years always bears the non-zero possiblity that the single-year value ex-post will turn out to have been an outlier or to have been caused by (energy) storage, conversion and balance effects (e.g. El Niño, La Niña, change in albedo), stochastic irregularities etc.
Be that as it may, I also found an article in the TIME magazine (https://time.com/6218275/strongest-hurricanes-us-map/) edited September 29, 2022 3:23 PM EDT which under the title "Here’s Where All The Strongest Hurricanes Have Hit the U.S. in the Past 50 Years" states (in the graph titled "Hardest hitters"): "Nine category 4 and 5 hurricanes have hit the mainland U.S. in the last 50 years - 6 in the past five years."
Putting that straight (according to the information in TIME): 3 cat.4/5 hurricanes hit land within 45 years up to the year 2022-5 and 6 hit land within the past 5 years rel. to 2022.
And I found another source (EPA's Climate Change Indicators in the United States: www.epa.gov/climate-indicators, Figure 1. Number of Hurricanes in the North Atlantic, 1878–2022, Data source: NOAA, 2023; Vecchi and Knutson, 2011
Web update: June 2024, Units: Number of hurricanes) and downloaded the data (under the link to cyclones_fig-1.csv there).
The data cited (applying simple linear regression using maxima, s. https://maxima.sourceforge.io) suggest that there is at least a significant rise in the numbers of total hurricanes (colum adjusted smoothed as explained on the website) in the period 1970 to 2020 (model=0.064*x-121.4, with x denoting the years and b=0.064 being the point estimator for the rise over the years; corr=0.69, confidence interval of the rise b [0.045,0.083] and p-value=1.5462*10^-8 for H0: b=0);
whereas the regession for the period 1990 to 2020 yields: model=0.056*x-106.0, corr=0.43, confidence interval of the rise b [0.011,0.1]], and p-value=0.015 for H0: b = 0.
And a difference of means test of the NOAA-data split into the two periods 1980-1999 and 2000-2020 (using maxima function test_means_difference and options set to calculated standard deviations and asymptotic=true so that variances are NOT assumed to be equal and an asymptotic test based on the central limit theorem is executed) yields a difference estimate in the 20/21-years-period averages of 1.901 at confidence level 0.95 with confidence interval [-2.451,-1.351] and p-value=.2371*10^-11 on testing H0: mean1 = mean2,
in short, statistically significant different average numbers of (total) hurricanes within the 2 time periods 1980-1999 and 2000-2020.
The above regression and difference of means test findings based on the cited NOAA data seem to be corroborated, at least by trend, in the graph in https://en.wikipedia.org/wiki/Tropical_cyclones_and_climate_change#cite_ref-NYTimes_20220929_30-0 where is stated: "The 20-year average of the number of annual Category 4 and 5 hurricanes in the Atlantic region has approximately doubled since the year 2000."
In that wikipedia article (s. cite_ref 62) there is also information about cost, saying "The number of $1 billion Atlantic hurricanes almost doubled from the 1980s to the 2010s, and inflation-adjusted costs have increased more than elevenfold.[62] The increases have been attributed to climate change and to greater numbers of people moving to coastal areas. [62]".
And there is also a nice stacked bar diagram splitting "North Atlantic tropical storms and hurricanes" up by categories (s. subsection https://en.wikipedia.org/wiki/Tropical_cyclones_and_climate_change#Intensity).
Conclusion: Prof.Friedman was right to question the data cited primarily (nsf.gov), yet, there seems to be significant (other) evidence that IPCC projections as cited by Prof.Friedman signifcantly underestimate(d) the true rise in numbers. And well, it is not the shear number of hurricances that should bother us imho, but the soaring kinetic energy they (and other climate change moderated extreme weathers/conditions) transport to land and homes and the damages to property, harvests and eco systems world wide, should it not.
P.S. Somewhere, I believe it was among these posts here, there was the argument, that substantial higher temperature changes than 1.5 to 3° K have been outlived by former creatures on earth. Yeah, some have for sure survived very very harsh periods, but many of them had quite a different metabolism than humans, had they not. And at least the bigger of those former species certainly never at any time outnumbered the shear mass of humans now living, did they. So, how many of the approx 10 billion of humans of today would be able to adapt to such changes quickly enough? Those living in an Elysium-like Blue Origin space station with a Neuralink-controlled metabolism far beyond the Lagrange points in spaces with very weak shielding against high and ultra high energy radiation? Just asking.
See Roger Pielke’s “The Honest Broker” Substack for an authoritative answer on extreme weather events. Or even the IPCC.
And the fundamental problem with any of the "go green" BS is that it will keep poorer countries poor! The advice to review Dr. Pielke's work on disasters and their diminishing effects is seconded. Over the past 100 years, our response to disasters has been to reduce deaths 100-fold! ALL made possible through development of energy. If you want to understand trends in extreme weather, look at weather data, not economic data.
You will also observe from Pielke's work that there is no attribution to hurricane frequency, or other natural disasters, to humans. Finally, no where in the IPCC documents will you find suggestions that civilization is threatened. Nada. Rien. Nothing.
Did I claim that poor countries should do anything in particular? No. Did I claim that civilization is threatened? Also no (it is not).
I believed the implication was there, particularly when you said "poorer countries...are going to be hit much harder by any increase in natural disasters." It was not my intention to offend, only rather to point out the obvious discrepancies between those who are energy rich and those who are energy poor.
I agree, you never said directly that civilization was threatened, though I'm sure you agree that there are many climatists who make such claims. Your words, heartfelt I'm sure and no disrespect intended, imply that climate change is something to be feared.
It isn't. To paraphrase Dr. Curie, nothing in the natural world should be feared; it should only be understood.
You said it doesn’t address “the most common argument I hear”. But in fact it does: the prescriptions of leftists in the name of those who will supposedly be at more risk (deny them low cost fossil fuels) in fact puts those billions of the world’s poorest at MUCH HIGHER risk!
Our understanding of climate is not nearly sophisticated enough to predict that there will be both regional droughts and regional floods as a result of a slight increase in the average temperature. I could find it plausible that we could understand things enough to say "There will be more rain" or "There will be less rain." But the assertion that there will both be more rain in a bad way and less rain in a bad way is such an obvious alarmist ploy that I can't believe proponents aren't laughed out of the room.
“ more of the rare but very bad weather events that cause death,”
In fact cold causes far more deaths than these very rare events.
And more to the point, the lack of low cost highly available reliable energy for the poor in poor regions is responsible for FAR more death and discomfort.
It is no coincidence that as we have started to use more fossil fuel, the number of weather related deaths has gone down by more than 9% in the last 125 years. Having cheap energy to be able to power machines helps people avoid weather related deaths far more than any reduction in global warming ever could .
Don’t distract yourself worrying about catastrophes. giggling or not giggling. Figure out the most cost effective mitigation and adaptation policies to respond to the increase in CO2 concentration in the atmosphere.
The point is we need to do easy lowest cost things: tax net emissions of CO2 and methane.
No, you have it only half right.
If we are going to do ANYTHING we should do lower cost things. But your assertion implies that “doing something” is required.
BTW you left out “build out nuclear power plants in all the countries that are allowed to have nuclear weapons” as answer #1 if in fact AGWC really is an existential threat. The fact that so many leftists oppose this puts to the lie that global warming and carbon emissions are an existential threat. And if it ain’t an existential threat, they can’t use it as justification for political power and anti-capitalist policies.
If we can adapt well to climate change, we should also be able to adapt well to El Niño years, which are effectively temporary climate change spikes. We demonstrably cannot, not because of the increased temperature but because of all the downstream effects on severe weather it produces.
Sea level rise may only extend in a few miles, but the safe buildable area in many places, including the entire Gulf of Mexico and most of the Eastern Seaboard, recedes substantially more due to increased hurricane severity. An increase in temperature is an increase in energy, and peak severity of extreme weather therefore rises, even for blizzards.
"An increase in temperature is an increase in energy, and peak severity of extreme weather therefore rises, even for blizzards."
The current projection is that peak wind speed of tropical cyclones increases a little, number of tropical cyclones decreases a little (both from the IPCC report).
Your general argument sounds plausible but is not correct. A cyclone is a heat engine, and the available energy depends not on the temperature of the source but on the temperature difference between source and sink. If both are warming the effect is ambiguous.
A heat engine that simply turns heat into work without dumping some of it to a cooler sink is a perpetual motion engine of the second kind, thermodynamically impossible.
What do you make of this recently published study: https://www.nature.com/articles/s41586-024-07219-0? Would be astonishing if true. Assume the fact that it was published in Nature rather than an econ journal is a tipoff.
Data on heat deaths seem to be incomplete and often unreliable. Based on what is available (EM-DAT.bet), the most recent decade has many fewer deaths from heat compared to the previous decade.
There is a literature that tries to estimate the effect of temperature on mortality by statistical analysis of massive amounts of data, for each city every day's temperature and mortality. I discussed it in two past posts, https://daviddfriedman.substack.com/p/temperature-mortality-and-climate and https://daviddfriedman.substack.com/p/temperature-income-and-mortality.
The mortality they find is not mostly from extreme temperatures, just from temperatures above or below the optimum. That's probably the source of the nine to one factoid.
Studies differ in the multiplier for cold-related deaths vs. heat-related deaths (from 3 to 13, if I recall). I was thinking of The Lancet for the 9 cold-related death for each heat-related death. However, on checking, it was actually 10:1. https://www.thelancet.com/journals/lanplh/article/PIIS2542-5196(23)00023-2/fulltext
However, The Lancet could not resist distorting the presentation of the data. On the left side (cold-related) the graph used increments of 50, while the right side (heat) used increments of 10.
https://wattsupwiththat.com/2023/07/29/the-lancets-scientific-chicanery-on-mortality-exposed-by-co2-coalition/
I see that in one of your posts, you note a different Lancet piece with a 17 cold to 1 heat ratio.
Even if the work is honest, as I think Gasparini's probably is, measuring the relation between temperature and mortality is a hard problem. What you want to know is not the total mortality from heat and from cold but how it will change due to global warming. The logic of Gasparini's analysis, if I understand it, is that the marginal effect of warming is greater on heat deaths (increase) than on cold death's (decrease) even though total heat deaths are less than total cold deaths. That isn't impossible although it's surprising, given the size of the difference in total mortality.
…but even this claim if true UTTERLY misses the mark.
Giving the world’s poorest billions access to low cost realizable highly available energy (that of course fossil fuels provides) would do FAR more to reduce deaths than any effort to impact global climate.
So the discussion is “dishonest” in that sense. At least until we take off the table artificial restriction of fossil fuel supplies that can enable the world’s poorest to be less poor, closer to rich western living standards and better able to adapt to any changes in weather/climate.
But of course this is the policy that leftists (most of them anti-capitalists) push first and foremost when they make their global warming claims. While mostly still being opposed to nuclear power. Despite the obscene immorality of fossil fuel restriction policy.
Humans have adapted to large climatic changes in the past largely through migration. As climate change makes equatorial region less habitable, other regions like Russia and Canada, will become more so. The obvious solution to a changing climate is for hundreds of millions to move away from those regions most severely affected and into regions less affected or even positively affects. Do you think the Russians will let 100's of millions of climate refugees into their country? WIll the Canadians? Or the Americans?
THIS is the threat posed by climate change, not the 10 meter rise in sea level over the next millennium that is already baked into the cake (assuming we stop adding CO2 into the atmosphere on this century).
You are exaggerating the scale of the effect by a couple of orders of magnitude. Why would you expect an increase of average equatorial temperatures of two degrees to cause hundreds of millions of people to leave?
Take a look at the maps of average temperature and population density that I linked to and think about the implications.
How would you know this? Temperatures have been quite stable since the end of the last Ice Age.
https://cdn.uanews.arizona.edu/s3fs-public/styles/az_small/public/Fig2_5xStretch.jpg?VersionId=EOg6varxkNs8GVgb5jI2q7jynpjpGzBz&itok=DLzE9Hum
There were scattered societies that reached fairly high levels of sophistication during the Ice Age, here's an example from 23,000 years ago that had developed sedentism and appears to have been doing an early form of farming (I found the vid fascinating).
https://www.youtube.com/watch?v=NjUCbk8MSQY&t=1s
The reason why these Ice Age settlements are scattered and there seems to be little progress is because one climate shift creates a favorable environment that allows progress to happen, and then another climate shift causes the end of that progress as the settlement is abandoned and the people revert to lower level of societal complexity.
So here and there humans already had the necessary ingredients to develop complex civilizations 11,000 years before the earliest megalith building cultures appeared in the Levant. In the span of time from Ohalo II to Gobekli Tepe we see little change in human societal complexity. Over the same span of time after Gobekli Tepe, we developed our modern civilization. What happened?
A plausible candidate was the end of the highly variable climate around 11,000 years ago. After that is was off to the races. Through industrialization humans are now restoring that world of fluctuating climate.
A likely effect of changing climate are changes in rainfall patterns and soil moisture that will make current lifeways untenable in various spots. The historical solution for when this happens was migration., which I pointed out. You wish to hand wave this away. How are you so sure you are right?
I don't understand your point. If we observe dense populations at temperature X that's evidence that raising the local temperature elsewhere from X-2 to X is unlikely to displace much of that population. Do you disagree? If you do, what is your basis for thinking that warming at the projected rate will cause hundreds of millions to migrate?
You are ignoring why the initial population densities are what they are. Simply because dense population exists at location X at temperature T and at location Y at temperature T-2, does not mean that going to temperature T at location Y will not pose a problem.
Suppose both locations support large populations through dryland farming. Further suppose location Y is dryer than X. Temperature T at location Y makes the climate unsuitable to dryland farming, whereas it does not at X.
In the Sahel region land once suitable for grazing can become more arid with warming, causing the populations who once lived there to more south into already settled areas, which can result in political instability.
We saw this happen recently with the poor harvest in 2012 driving up grain prices, causing discontent and political unrest in Syria, which developed into civil war. War sent waves of migrants heading for Europe, which has created political instability there.
As temperature rises more marginal places will suffer hard times and the political instability that generates.
You are attributing migration to climate change, as if bad harvests and wars did not happen without it.
There is no reason to assume that all change is bad. One of the things you can discover in the IPCC report is that some projections show climate change greening the Sahara and Sahel.
Waves of migrants, about a million a year, came to the US in the years before and after WWI without global warming. Waves of migrants have been coming to Europe because European welfare states are better places to be than Syria or Africa.
All I am saying is you are assuming that changing the climate from where it has been for the entire period in which human civilization existed will have no serious effects and so nothing should be done to move off of fossil fuel. I think you are overly optimistic, but you are going to believe what you believe and that is ok. I'm not going to still be alive in the second half of this century to find out.
Most important is that it is unlikely that humans can control the climate in any case.
Actually, most important is that leftists can use the issue as a means to political power, and secondarily as a means to promote anti-capitalist policies.