Part of the problem with AGW hysteria is that the benefits of fossil fuels are ignored and the costs of solar and wind generation are ignored. The real world always gives you choices with costs and benefits, and all you can do is trade-off between the choices. If you aren't counting the other side of the scale, then you will NEVER arrive at a good trade-off. NEVER.
Very nice, thank you. I assume you've read "Unsettled" by Koonin. I wonder if you have found any good references for the chances of glaciation in the absence of AGW. The references I find to this are now all in the vein of, "Well the next glacier is at least 10k years away, so no threat and so shouldn't be part of our calculation." They all seem to be suffering from motivated reasoning... AGW bad.
I think there is moderately good evidence that that problem has already been solved by anthropogenic warming, starting seven or eight thousand years ago with the invention of agriculture resulting in a massive increase in human population and large scale deforestation. That's the Early Anthropogenic Hypothesis, which I discussed some time back on my blog.
Thank you, So man has already had a positive effect on the climate by pushing back the next ice age. We all should get some credit for that... to counterbalance all the crappy things we've done.
“ the U.S. Atlantic coast shifts in by about a hundred feet for every foot of sea level rise. ”. That seems very wrong to me. An extra foot in many places wouldn’t breach a beach at high tide.
you're missing a major dynamic of climate change: mass migration and the social problems created by people of different cultures moving into new places. any analysis like this must also consider the social impact.
What is the reason to expect change on the order of a tenth of degree a decade, possibly two tenths, to produce mass migration? Observed migration seems due now, as it was a century or two ago, primarily to people moving to countries where they could make a better living than where they were.
Surely increasing the amount of habitable land comes at the cost of some other land becoming uninhabitable. The net cost is substantial as people have to move from uninhabitable land around the equator and develop new land at the poles. Likewise, that only a small amount of coastal land is lost to sea-level rise ignores the fact that almost all major human settlements are built on coastal land.
More generally, we only have one earth. There are strong reasons to suspect the existence of climate change tipping points, going beyond which would result in irreversible and unpredictable things happening. You also seem overly ready to gloss over the total loss of biodiversity on Earth. We may be reliant on nature in ways that we don't fully understand.
The core assumption here seems to be that humans can adapt to any change in climate or surroundings, which is true, but the cost of such adaptation is massive. It seems better to make some effort to stop climate change now rather than continuing to blindly wonder towards the edge of a cliff. In the case of population growth, that is a fixable problem. If the population gets too high, it will likely be reduced through people dying. The climate is not self-balancing like this, but self-destructive (e.g. through the release of methane trapped in permafrost).
"Surely increasing the amount of habitable land comes at the cost of some other land becoming uninhabitable."
Why "surely"? Try superimposing a map of population density on a map of average temperature. You discover that some of the hottest regions are densely populated, the coldest empty. A little land will be lost to sea level rise, but not very much, orders of magnitude less than is gained. Take a look at the calculations in https://daviddfriedman.substack.com/p/land-gained-and-lost.
"There are strong reasons to suspect the existence of climate change tipping points"
Take a look at a graph of temperature over geological time — there is one covering the past five hundred million years at the end of https://daviddfriedman.substack.com/p/does-climate-catastrophe-pass-the. Current global temperature is high in terms of the recent past, low in the longer term, some fifteen degrees below the high of the past hundred million years. If that did not cause a tipping point, why do you expect this to?
Projected warming by the end of the century gets Minnesota to about the temperature of Michigan. Do you think the cost of adapting to a change of that size, with most of a century to do it in, is "massive"?
"Try superimposing a map of population density on a map of average temperature"
I notice that the hot and cold regions are quite far apart. So it will be quite costly to move all the people in the hot areas to the cold ones. As you point out, most human settlements are in the areas most effected by climate change, moving all of them elsewhere will likely cost quite a lot. The cost I talk about is in building new houses in the unsettled cold regions, rather than the potential value of new habitable land.
"If that did not cause a tipping point"
It seems to have caused a tipping point. Notice that the graph is dominated by sudden changes rather than smooth curves. I'm not a climate scientist, but this is a graph which seems highly consistent with the theory of tipping points, where temperature is stable until a certain threshold is reached then begins to suddenly change. Climate scientists seem to agree that such tipping points exist and that the changes in that graph are examples of them. Even supposing your interpretation, a change of 1 degree every million years might have a different effect than a change of one 1 degree every few decades. I am inclined to trust the climate researchers on this matter because they seem to have done more research on it than you. You are at your most persuasive when you take those results from research and attempt to show a minimal economic impact, rather than when you dispute the science directly.
"Projected warming by the end of the century gets Minnesota to about the temperature of Michigan"
This is disingenuous. A rise of just a few degrees in climate can lead to vastly different weather. In my own country of the England, many houses now need air conditioning as they were designed for colder climates. Say everyone finds an AC unit for as cheap as $40 across 25 million homes, that's still a billion dollars in costs for one very simple thing in a country that isn't much effected . Floods in Africa and Fires in Australia due to disruptions in the Indian ocean dipole are likely to cause much more severe damage than can be solved with air conditioning. Some of the most productive land on the planet around California is experiencing a clear and consistent increase in the size of wildfires.
It's quite difficult to know the exact cost of these things when compared with a green transition but I (and most world governments) think it is best to play things on the safe side. Meanwhile you suggest that everyone being forced to move away from the most densely populated areas on the planet is a net positive because there will be a new habitable land in undeveloped areas while downplaying the cost needed to re-develop infrastructure in those places. Even the outlook you present seems very costly when properly examined.
I am not disputing the accepted views of climate science — on the contrary, I base most of my calculations on IPCC projections. You are confusing the wildly exaggerated view of climate change in the media with the actual view of serious scientists.
I am not suggesting moving people from hot areas to cold areas. I am pointing out that some of the hottest regions of the world are densely populated, that there is no region which is depopulated due to its current temperature. There are regions which are empty because they are both hot and dry, such as the Sahara, but hotter regions that are densely populated. So what is your reason to believe that if the summer temperature of hot regions went up by a degree or two — greenhouse gas warming is greatest in cold regions and seasons, least in hot — suddenly vast numbers would have to move?
Do you think that a rise of two degrees in average temperature, less than that in summer temperature, means that lots of people have to get air conditioning?
Try actually reading the IPCC report for numbers, to get a feel for the scale of the effects, which is wildly exaggerated in the sort of catastrophist literature you are taking seriously.
I don't know if you are old enough to remember the similar scare over population in the the sixties and seventies. You had the same pattern of lots of high status media insisting that there was a terrible threat that had do be dealt with, and quite a lot of people in India were sterilized as a result. Population in poor countries continued to rise and instead of their getting poorer and hungrier they got richer and less hungry.
Ehrlich's prediction of mass famine in the 1970's, with hundreds of millions dying, was taken seriously by the same sort of authorities that take seriously the idea that places where people manage to live fine now will somehow become uninhabitable if average temperature goes up by two degrees.
"Notice that the graph is dominated by sudden changes rather than smooth curves."
You are being misled by the scale. What you see as a sudden change on that graph is taking something like a million years.
Simple test you can apply to yourself. My post lists a bunch of positive effects some, such as CO2 fertilization, large. Before you read it how many of them were you aware of? If the answer us few or none, that is evidence that you have been exposed to a very biased selection of the relevant facts.
"I am not disputing the accepted views of climate science"
You can say that, but you did just dispute the widely held scientific belief of climate tipping points based on your personal interpretation of a graph.
"I am not suggesting moving people from hot areas to cold areas."
But you are saying that people live in these areas, and we know they will become substantial less habitable. So, what happens to those people? Wet bulb temperatures are set to rise above 35° in some inhabited regions and that means you die if you go outside. This phenomenon used to be rare but is increasingly common.
"that there is no region which is depopulated due to its current temperature"
Well this isn't true, but I'll interpret it charitably. While humans to live in very hot places, they tend to be poorer. So if more places became hot, it is likely they also would become poorer.
"Try actually reading the IPCC reports"
Have you? The IPCC target of 1.5° is chosen specifically because it reduces the risk of climate change tipping points, which you are denying exist.
"So what is your reason to believe that if the summer temperature of hot regions went up by a degree or two suddenly vast numbers would have to move?"
Primarily economic reasons. We already see large numbers of economic migrants moving away from these areas. The effect of climate change will be to increase the cost of food and decrease the productivity of these areas, as well as making them less enjoyably places to live. If you are dirt poor and there are days of the year where going outside kills you, you'll probably want to move somewhere else.
"Do you think that a rise of two degrees in average temperature, less than that in summer temperature, means that lots of people have to get air conditioning?"
Yes, because I have experienced it. An increase in average temperatures means that high temperatures can be vastly higher, the result is people buying AC. Also, this is factually inaccurate. According to the IPCC, climate change is accelerated at about 3 times the temperate regions of the world. So 2° average increase is 6° in Europe.
"Population in poor countries continued to rise and instead of their getting poorer and hungrier they got richer and less hungry."
And how do you think that crisis was averted? The answer is that advances in technology improved agricultural output. Would it not then be reasonable to invest in climate mitigating technology to avoid the climate crisis as investments in agricultural technology avoided the population crisis?
"where people manage to live fine now will somehow become uninhabitable if average temperature goes up by two degrees"
The people in these places aren't exactly fine. The heat is already a present threat in their lives, which will become much aggravated by climate change. There are periods of time when going outside is dangerous, and these are set to greatly increase due to climate change. A lot of important economic activities happen outside, so not being able to go there is a big problem.
"You are being misled by the scale."
No, I appreciate that the "suddenness" of these changes is in fact millions of years, but they are sudden relative to the periods of consistent temperatures surrounding them. I am confident of this because I didn't personally interpret that graph. I looked it up and found some papers by climate scientist which said that the changes in that graph were proof of climate tipping points.
"Before you read it how many of them were you aware of? If the answer us few or none, that is evidence that you have been exposed to a very biased selection of the relevant facts."
I was aware of a number of the points you mentioned. Perhaps their omission from climate discourse (including from those IPCC reports you mention) is evidence that you miscalculating their benefits. For instance CO2 fertilisation seems good, but it also decreases the nutritional value of crops. Combined with losses due to flooding and increased temperature variation, the result is a net loss. It simply doesn't make sense talking about a factor that increases crop yield if the overall effect is decreased crop yield. Every moneyed interest in this area wants to downplay the risks of climate change, so if these effect are relevant I think they would be overall more prominent.
You frequently talk about "one or two degrees" as if that is a small amount. But here the IPCC devotes an entire document to the massive damages that would result from just 0.5° difference in climate change. 7-10% of all livestock being lost between those numbers is not a small difference. 420 million extra people being exposed to extreme heatwaves is not a small difference. That would result in a massive loss of productivity. And yet you try to downplay changes because the absolute number in degrees is small. The increased flooding and fires is something we can already see happening and is very damaging.
When I wrote "I am not disputing the accepted views of climate science" I was referring to the views of climate science on climate, such as future temperature, not to their view on the consequences of climate change, which involves a variety of other fields, including mine (economics).
I am not competent to critique the climate part of the literature, beyond very simple things such as comparing IPCC projections to what happened thereafter. But I have critiqued, in some detail, work in the climate literature that is about consequences. From doing so I have concluded that most of the literature is biased and some of it, including respectable sources such as an article in _Nature_, is dishonest. Given that, I don't take "a published article says climate change will have consequence X" as a reason to believe it unless I have actually gone over the analysis pretty carefully. I accept the climate predictions because I have no better options, but not with much confidence given what I have observed of parts of the literature I was able to critique.
Obviously that is not a reason for you to refuse to believe published articles in respectable sources unless and until you have made similar observations. Elsewhere in the thread I have offered links to, I think, three examples of work that is either fraudulent or irresponsibly incompetent, along with the evidence to support that conclusion. One is an article in _Nature_ which the EPA says it is considering as a possible basis for regulation:
If you are curious about the basis for my skepticism of sources of information you trust those three should show part of my reason. For more of my work along these lines, see:
Where in the IPCC report does it make your claim about likely tipping points?
So far as the graph, you agree that your "tipping point" involves a change occurring over a million or more years — longer than our species has existed, a hundred times longer than our history. Given how fast human civilization has changed over the past thousand years, do you think it makes sense to base present policies on projections about effects a million years off?
When people in the climate debate talk about tipping points, do you think they mean, and intend their hearers to think they mean, changes occurring over a million years or more?
"According to the IPCC, climate change is accelerated at about 3 times the temperate regions of the world. So 2° average increase is 6° in Europe."
Can you link to a quote from the report supporting that? It doesn't fit the maps of projected temperature I have seen.
I responded to the claim about reduced nutrition here in
under the subhead And Nutrition (it's a long post).
Were you aware that what was meant by reduced nutrition was a reduction in (some) nutrients per calorie, due to an increase in yield of calories, not a reduction in nutrient yield per acre? The implicit assumption, explicit in other work by some of the same authors, is that when yield goes up poor people continue to eat the same number of calories as before.
"Where in the IPCC report does it make your claim about likely tipping points?"
The nature of some tipping points is discussed in sections 3.5.2.5 and 3.5.5. Additionally its worth noting that high-risk large-scale tipping points are referred to as "large-scale singular events" and constitute one of the five primary "Reasons For Concern" laid out in the document.
"do you think it makes sense to base present policies on projections about effects a million years off?"
I lack expertise on the matter, but climate scientists think tipping points are relevant.
"Can you link to a quote from the report supporting that?"
"Temperature means and extremes are also projected to be higher at 2°C compared to 1.5°C in most land regions, with increases being 2–3 times greater than the increase in GMST projected for some regions (high confidence)."
"The strongest warming of hot extremes is projected to occur in central and eastern North America, central and southern Europe, the Mediterranean region (including southern Europe, northern Africa and the Near East), western and central Asia, and southern Africa (medium confidence)."
"Were you aware that what was meant by reduced nutrition was a reduction in (some) nutrients per calorie"
I had assumed that more food was growing faster, but it was less nutritious as a result. Though as for the part about increased yields, the IPCC report I linked has some interesting views on the matter:
"observations of trends in actual crop yields indicate that reductions as a result of climate change remain more common than crop yield increases, despite increased atmospheric CO2 concentrations (Porter et al., 2014). For instance, McGrath and Lobell (2013) indicated that production stimulation at increased atmospheric CO2 concentrations was mostly driven by differences in climate and crop species, whilst yield variability due to elevated CO2 was only about 50–70% of the variability due to climate. Importantly, the faster growth rates induced by elevated CO2 have been found to coincide with lower protein content in several important C3 cereal grains (Myers et al., 2014), although this may not always be the case for C4 grains, such as sorghum, under drought conditions (De Souza et al., 2015). Elevated CO2 concentrations of 568–590 ppm (a range that corresponds approximately to RCP6 in the 2080s and hence a warming of 2.3°C–3.3°C (van Vuuren et al., 2011a, AR5 WGI Table 12.2 ) alone reduced the protein, micronutrient and B vitamin content of the 18 rice cultivars grown most widely in Southeast Asia, where it is a staple food source, by an amount sufficient to create nutrition-related health risks for 600 million people (Zhu et al., 2018). Overall, the effects of increased CO2 concentrations alone during the 21st century are therefore expected to have a negative impact on global food security (medium confidence)."
As for what should be done, I think it's reasonable to avoid climate change even if the effects on food supply were completely ambiguous. We presently have enough food, and I think we should avoid upsetting that situation even if there's a chance we get more. We don't need more, but less would be a big problem. It's just not a smart bet to make.
(Edit) and if you're going to try that whole guilt by association thing on people concerned about climate change, the people who aren't concerned about climate change are generally much more suspect and separated from the facts. Three of four inaccuracies on the side of climate concern are pretty much dwarfed by the volume of blatant disinformation surrounding climate denial.
About the population costs and benefits: I wonder whether you included the benefit *to the newly-created people* of getting to live, which is probably the biggest potential benefit.
I did not. The context of my piece was not a dispute among utilitarians over the optimal size of population — I have a different article relevant to that, a chapter in one of Julian Simon's books. It was the widely believed claim that population increase made existing people worse off.
Are the predicted mass third-world migrations resulting from climate change likely?
If so, this is a negative externality that will absolutely dwarf any conceivable positive ones. Europe and the US will be at risk of societal collapse if hundreds of millions of unselected third-world people move to thse places.
To anyone who thinks this is sensationalist: Sub-saharan africa is a mess because of the people living there, its not something intrinsically wrong with the climate or resources of these places, it's the people. We know for a fact that unselected immigrant populations from these countries do not rapidly assimilate into developed countries, and we should expect doing so to be much much easier under current relatively lower immigration rates than potential future higher immigration rates. Which is to say: We don't know how to assimilate unselected third world migrants at the moment, and these migrants have impose a huge per capita cost on developed countries in the form of fiscal impact and crime. There's absolutely no reason to think this will become less the case with radically more immigration, so even if it doesn't get worse the costs these additional immigrants will impose on developed countries will already be staggeringly large (and this says nothing of the political, cultural and institutional externalities of these people), though in reality the per capita cost will be dramtically higher.
Americans and especially euopeans demonstrate self-destructive levels of compassion and tolerance towards these kinds of people, but under such conditions it should be expected that enough of them will rightfully object to their way of life and their societies being completely upended in these ways, and this will have enormous political and social consequences.
Thanks for your advice regarding linking substack. No good deed goes unpunished, so naturally I will be reading anything you write.
That said, I sincerely enjoyed this. We need more humility and the ability to say, I do not know. You'd actually probably enjoy my latest post - it's even somewhat relevant :)
"**IPCC projections have been conservative (emissions trajectories, sea level rise, attribution,...)"
I have heard both that claim and the opposite, so some years ago I tested it by reading the first few IPCC reports and comparing the prediction you got from each report to what happened to temperature thereafter. The first report predicted high — actual warming was below it predicted range. Since then there has been no clear pattern of high or low.
Did you do a similar calculation? If not, what is your reason for believing that the IPCC projections have been conservative
"CROPS:
--benefits of CO2 fertilization are limited:
**excess CO2 produces no benefit for C4 plants"
That is not correct. It produces little or no benefit for C4 plants that have adequate water but reduces water requirements for both C3 and C4 plants — they don't have to pass as much air through their leaves to get the carbon they need, so lose less water. For water stressed C4 plants increased CO2 increases yield.
You cite skeptical science.com. That site is run by John Cook. I believe I have shown, with publicly available evidence you can check, that he has lied in print about his own work.
I agree with your characterization of IPCC prediction error for surface warming (with the caveat that, if you control for short-term influences like ENSO, the projections match the observed trend). My comment referred to IPCC projections about emissions, sea level rise, and attribution. Additionally, I could have referenced their projections about sea ice decline. If their track record is 'accurate,' 'conservative,' 'conservative,' 'conservative,' and 'conservative,' I think it is reasonable to infer that their institutional bias is more conservative than alarmist.
re 'That is not correct.'
When I said 'excess CO2 produces no benefit,' I had in mind the direct effect on photosynthesis. You're right that elevated CO2 can reduce water requirements, but causing plants to reduce their stomatal conductance is more of a mixed bag than you let on. Ironically, by impairing thermoregulation, it makes plants more susceptible to heat stress. More importantly, there is the issue of the competitive dynamics.
re 'You cite skeptical science'
The article is (a) not written by Cook, (b) cites sources for the relevant claims (make sure you to click on the 'advanced' tab rather than the 'basic' tab). None of the sources that it cites are written by Cook either.
Re Cook and Skeptical Science, did you read my piece? If so and you agree with my conclusion, you should be careful of trusting a site he controls. As before, the question is whether the article is convincing if you don't assume it is written by an honest author, which requires you to actually read the sources it cites.
I only checked the IPCC temperature predictions. Is there a webbed equivalent to what I did for SLR? At some point I may try to do it.
Cook 2013 is deeply flawed for a number of reasons. While I find your specific criticism/his response less conclusive than you do, there are other reasons to question the integrity of the authors. For instance, there are reports that the authors were marketing their results before they began conducting their research and changed their operational definitions in the middle of conducting their research. Additionally, I have a general attitude of skepticism towards Cook because his 'expertise' is in advocacy rather than science.
What is wrong with my specific criticism? Do you agree that his 97% was for Categories 1-3? That only Category 1 is humans as the main cause, and a tiny fraction of the total? That in the second piece he claims that 97% is for humans as the main cause?
The fact that Cook lies in print does not tell us much about the climate literature in general, but the fact that his lie is widely repeated by reputable sources and almost nobody points it out does.
I'm not saying there is anything wrong with your criticism. My point is just that if I were to find out that someone like you made a similar misstatement and then doubled-down or deflected, I would find motivated reasoning/stubbornness more plausible than willful deception. It would not appreciably decrease my confidence in anyone who ever approvingly cited unrelated work of yours. I would be unlikely to become so suspicious of you that I would bring up the incident whenever someone cited a website affiliated with you.
Rest of my comment got cut-off... not going to rewrite but happy to dialogue. Here are some helpful references for the parts of comment that were preserved:
First, your empirical claim is grossly misleading. Agricultural productivity growth has declined to its lowest level in sixty years. Evidence suggests that climate change is an important (perhaps the primary) driver of that decline.
Second, your implicit methodology is wrongheaded. In assessing the expected value of a climate response, evidence about physical processes should often trump the observed relationship between variables for two reasons:
--The relationship between variables is often non-linear (and even non-monotonic). The present example (relationship between temperature anomaly and yields) is a case in point. Observations are either confined to a narrow range of values of a parameter or rely on a dubious paleoclimate record.
--The climate is a complex dynamical system. Observed relationships will be confounded by at least dozens (most likely, hundreds) of other significant inputs. Further, in the case of a dependent variable like agricultural yields, many of the most important inputs are exogenous to the climate system.
"Evidence suggests that climate change is an important (perhaps the primary) driver of that decline. "
Can you offer a link to that evidence?
According to the IPCC report, the Earth is greening and the likely explanation is CO2 fertilization. That is many facts from the report that did not make it into the Summary for Policy Makers, which is the most reporters read.
Thanks for the link; I haven't yet read it. Have you gone over the article carefully enough to be reasonably confident that the conclusion is correct or are you merely assuming that an article in _Nature_ can be trusted?
I ask because I did a very careful critique of a different _Nature_ article on a related topic and concluded that it could not be. Its calculation of the cost of carbon included the implicit assumption of no medical progress in the next three centuries and the implicit assumption that a ten-fold increase in per capita income would have no effect on people's vulnerability to temperature. That part of the argument was responsible for about half the total calculated cost.
It is one of the things that convinced me that the field is sufficiently corrupt so you have to go over the analysis of a published article carefully before you have any reason to trust it. If you read my critique you can decide for yourself whether that is a justified conclusion.
This post was my first, and I have made many more on that topic (and others, of course) since. You can find links to all of them at: http://www.daviddfriedman.com/Sorted_Posts.html#Climate. I believe they provide additional support for the conclusion. Another that does is:
Of course, the fact that I say something is also not an adequate reason to believe it. That is why I try, as in my piece on John Cook and the 97% claim, to provide my reader with evidence he can check for himself. That policy limits how sophisticated my analysis can be; it has to be something that an intelligent layman willing to take some trouble can check for himself. In my piece on increased usable land I include links to published articles that do a much more sophisticated job of looking into the question. The advantage of my cruder analysis is that the reader can check it.
That is the cost of professional scientists being willing to do dishonest work if it produces the right result. It is part of the reason that my overall conclusion is that we simply do not know whether climate change will make us better or worse off.
> That is in a model in which per capita consumption roughly triples by then. So the difference between the world without climate change and the world with climate change is, by his model, the difference between an increase in per capita income by 2100 of 300% and an increase of 292.5%.
It's a grift. Think of all the sinecures it produces! The people who profess to care with no skin in the game are just the useful idiots getting mulcted.
And, pleasure to see you are on Substack, I'm a great fan.
Common version of the orthodoxy is: climate is not weather, so few degrees of global warming will not result in experience of "everything is some degrees warmer, crop yields are improved". Along these lines, IPCC AR 6 makes many specific claims concerning food and water systems and adaptation options. It would more convincing if these IPCC claims were tackled head-on, point-by-point.
Referring to IPCC claims has an added benefit for a lay reader like me, who has a great difficulty judging how seriously to take any particular random cited study or Fermi estimates based o "maps showing yield of various crops can be found online" as you put in a presented pdf. IPCC presumably is both the presumed authority and their report present the major arguments in favor of the orthodoxy. Referring to their materials, can argue that their material is correct but the orthodoxy draws wrong conclusions or overstates them; or refer material they cite and point out where their assumptions go wrong.
Sea level rise argument appears most convincing: urban habitation and assets are slowly rebuilt and thus easily move in any case, thus adaptation does not appear impossible or prohibitively expensive. However, it would be good to refer IPCC estimates, such as AR6 Cross-Chapter Paper 2.
Changes to agriculture appear most significant to me. For instance, AR6 Chapter 4 section 4.5.1 outlines drought driven yield loss estimates for various crops, which appear significant even if RCP8.5 is discounted; Section 5.4.3 and Figure 5.3 present negative crop yield estimates for most crops including C02 fertilization effects); quickly scanning, only soybeans and potatoes (root crops) are projected to benefit anywhere. This seems at odds with the claim " Is there any significant amount of land that is too hot to grow crops? So far as I can tell, there is not." in the same pdf of yours. (Cross-Chapter Paper 3 discusses desertification, but I didn't attempt to read any part of it for this comment).
Adaptation by cultivar changes is discussed in Section 5.4.4.1, which is surprisingly non-committal section; cost of global adaptation is cited at only tens of billions which to me sounds super cheap (considering that US GDP alone is counted in trillions). More careful analysis of the references cited therein would be interesting, and make claims of increased crop yields in extreme latitudes to offset losses more credible.
Why it is odd? Please tell! I wrote a long-ish commit longing for more engagement with the claims made by the current orthodoxy and why and when it could be dismissed. More one-liners don't really help here.
Look I was all about climate and science generally from say 1990-2005 or so. But I am also a skeptic and have a brain.
You only need to listen to so many hundreds of interviews and so many hundreds of articles before you develop a pretty good model of the dysfunctions in this field. And the dysfunction is that it is a religion/ideology to a significant fraction of these people and they simply are not conducting fact lead research and are instead taking an unrelated thesis "climate change is going to be catastrophic" and beating whatever pegs they find, round, square, triangular into a round whole to fit it.
And an IPCC report no matter how well intentioned built out of those raw materials is bound to be compromised.
Here is my experience with the "science" (yes this includes talking to say people at climate think tanks with Phds and frontline researchers).
Scientist 1: OMG in 2075 there will be no more sea ice and polar bears will go extinct. The world is dying! (and yes you will see "the world is dying" rhetoric coming out of scientists mouths regularly).
"While that is regrettable and I don't want that, and am willing to do my part, how is that evidence the world is dying, what are the actual impacts on humans beyond no polar bears?"
Oh the world is a fragile delicate ecosystem we barely understand and with no polar bears eating seals the seals will eat to much fish and the fish population will collapse and the whole artic food web will collapse.
"That seems like an awfully specific prediction from someone who claims we barely understand how this works."
Well it could happen!
"Ok, but that isn't the level of contingency you convey in your article...couldn't it also be helpful to the food web?"
No because I define the 'health' of the food web, by how much it looks like the food web when I was an undergraduate.
"But didn't we already have a lot of human impacts and climate change by then? Why is that the target? Besides the main thing impacting the food web of the oceans is not climate change or the presence or absence of polar bears, but overfishing"
You just hate polar bears! Look at this guy he hates polar bears.
Scientist 2: Changes in the temperature have changed the range of the Northeastern Iowa Maple Fungus and now it is ravaging the trees of southeastern Minnesota. The forests of Southeastern Minnesota are being destroyed!
"Ok that isn't good, how is it spreading?"
It is spreading as the trees from northeast Iowa migrate north into northeast Minnesota, we have already seen 25 miles of migration since 1900, and by 2100 the forest mix may have moved 50 miles northward.
"Ok so the forests in southern Minnesota will have the mix that the ones in northern Iowa had 50 years ago, and the one in northern Iowa will have the mix the ones in southern Iowa had. That sounds not ideal, and people don't like change, but are the forests really going to be 'destroyed'? It sounds like there will still be forests, jsut the percentages of various trees will be different.
Well but the tree mix impacts albedo and that has all sorts of chaotic impacts on the local climate and microclimates and who knows what might happen! This is an important farming area and rainfall could down.
"Oh that great that area has a lot of problems with flooding and ample water for irrigation."
No no no, didn't you hear me say we don't know what would happen, rainfall could go way up too, and then there could be lots more flooding you don't want that right?
"More flooding would be bad, but it kind of sounds like you are determined to make this bad, no matter what the data is."
SCIENTIST 3: Yes I know it is very bad! OMG with all this AGW there is going to be widespread drought and famine everywhere, crop yields will crash, people will starve.
"Isn't climate change going to lead to more rain, why will there be an increase in drought? Also haven't we already seen significant warming, and yet yields are only up over that period?"
But that is because farmers have been benefiting from a period of extra glacier melt from all the warming. Extra warm summers have lead to extra melt from glaciers and much needed extra water in the dry season. And farmers need that extra melt water to survive, and it will all be gone if the glaciers melt away.
"But not everywhere has a wet winter and dry summer. Also if we stop global warming, then there won't be that extra melt water either, just the 'normal' amount. it seems like you are jsut taking the worst possible interpretation of every potential impact"
Also the rain is only going to fall in places that don't want rain, and then the increased heat will lead to more evaporation and drought from the places that do want more rain.
"That seems awfully convenient for your argument, also wasn't SCIENTIST 2 just telling me that this whole process is chaotic and that the climate models have very little actual likelihood of predicting specifics accurately?"
Oh no no on, we have the most accurate, up-to date-models, and while there is a lot of uncertainty generally, we can confidentially predict that whatever thing you don't want to happen, will happen.
"That seems very unlikely, almost like the model has been trained to provide outputs you want."
Well of course if it isn't providing the outputs we want how would we know it was working?
"..."
Now I am being uncharitable for the purposes of brevity, and making a point. But that is my general read on all this. I am actually pretty pro immediate action on climate change. If I was global dictator we would have a carbon tax tomorrow.
But I feel the scientists have done a piss poor, and at times actively deceptive job of controlling for their biases and desires. Yes to Dr. Franklin Kearns who studied anteaters in the jungle for 15 years, the extinction of anteaters is a global catastrophe. To humans generally it is not.
Now I am not arguing climate change won't have all sorts of multi-billion dollar negative impacts. It absolutely will! It will cost trillions. But there will also be a lot of benefits, and that is mostly not looked into with even 5% of the interest as the costs. And the IPCC report both isn't as dispassionate as people claim, and can only work with the raw materials scientists produce, and the raw materials are highly ideological.
This is probably my favourite substack post of all time, I really hope other people read it and criticize it, especially people who are very epistemically rigorous. I have been reading your blog for quite a long time now and have kept a mental synthesis of all of your posts on climate change, so to see it all come together is amazing.
I do have some minor nit-picks that mostly come down to stylistic choices, the most obvious is neglecting to explicitly mention that when attempting to calculate the optimum quantity of people or CO2 what matters is the net externality of the marginal unit of people or CO2. I fear that whilst not explicitly mentioning it (and also not talking about how P=MC=MB in your sketch of price theory) and other things makes this post more accessible, it opens you up to weak but "smart" sounding criticism one of my favourite examples on a different but related topic being Greg Mankiw's "David Friedman's Slippery Slope".
I have also read a lot of criticism of you on a variety of topics and it seems that lots of the "smart" sounding criticism could easily be avoided if you marginally increase the degree to which you use technical language, the reason being people knowledgeable enough to understand the language probably realize the argument your making is more subtle or intelligent than other people making similar sounding but weaker arguments, and people who don't understand the language would hopefully read up on the surrounding literature to avoid sounding stupid or uninformed and hopefully learn something (they could also accuse you of using superfluous language to make a bad argument sound better, but this would have the effect of people who are familiar with the language discounting those critics which is probably good).
On a similar note it probably makes sense to include a lot more hyperlinks to other work, such that people who read something that sounds wrong can read up on it and conclude you are right as opposed to dismissing you based on something that probably isn't even relevant to the argument your making.
I think Steven Landsburg also has made very similar overall arguments to the ones you have made, in particular emphasising the point that in a market economy resource consumption is a private cost not a cost imposed on others, which is contrary to the way people usually think about population, where people just see a fixed number of resources and then see how increasing the number of people decreases the resources per person and makes everyone poorer (this is obvious, but wrong and shows people even supposedly smart people lack a good model of how a market economy works). Your 1972 article is very similar to Landsburg's style of thinking. Although I think you undersell your argument, that is it seems to me that one can with a reasonable degree of belief say almost a prior that both overpopulation is not a problem and that even under Laissez-faire there is a underproduction of people due to the positive externality of ideas (scientific innovation etc.) seeming massive (compared to negative externalities) and of course not being properly accounted for either by parents or their children. There is also utilitarian arguments that make this underproduction of people seem even more dire than what economic efficiency suggests, but that's quite a long argument to properly grasp the problem. I also think you undersell your arguments with respects to the benefits of climate change put that's also a very long and complicated argument, and in the eyes of most people harder to defend.
I considered including the point about resource conservation, which I like to put as "a baby is not born with a deed to a per capita share of the Earth's resources clutched in his fist," but I thought it distracted from this essay, where the population argument serves mostly as a lead in to the climate argument. I have pointed it out elsewhere.
Of course, a legitimate response is that we don't live in a world with a guarantee of secure property rights, and a baby is born, at least in many countries, with an invisible deed to a vote when he grows up.
Part of the problem with AGW hysteria is that the benefits of fossil fuels are ignored and the costs of solar and wind generation are ignored. The real world always gives you choices with costs and benefits, and all you can do is trade-off between the choices. If you aren't counting the other side of the scale, then you will NEVER arrive at a good trade-off. NEVER.
Very nice, thank you. I assume you've read "Unsettled" by Koonin. I wonder if you have found any good references for the chances of glaciation in the absence of AGW. The references I find to this are now all in the vein of, "Well the next glacier is at least 10k years away, so no threat and so shouldn't be part of our calculation." They all seem to be suffering from motivated reasoning... AGW bad.
I think there is moderately good evidence that that problem has already been solved by anthropogenic warming, starting seven or eight thousand years ago with the invention of agriculture resulting in a massive increase in human population and large scale deforestation. That's the Early Anthropogenic Hypothesis, which I discussed some time back on my blog.
https://daviddfriedman.blogspot.com/2021/10/how-humans-held-back-glaciers.html
But if one is listing consequences that are very unlikely but have very large consequences, I think it should be included.
Thank you, So man has already had a positive effect on the climate by pushing back the next ice age. We all should get some credit for that... to counterbalance all the crappy things we've done.
“ the U.S. Atlantic coast shifts in by about a hundred feet for every foot of sea level rise. ”. That seems very wrong to me. An extra foot in many places wouldn’t breach a beach at high tide.
I found that figure in a book but have not been able to find the book again, which is why I didn't cite it.
you're missing a major dynamic of climate change: mass migration and the social problems created by people of different cultures moving into new places. any analysis like this must also consider the social impact.
What is the reason to expect change on the order of a tenth of degree a decade, possibly two tenths, to produce mass migration? Observed migration seems due now, as it was a century or two ago, primarily to people moving to countries where they could make a better living than where they were.
Surely increasing the amount of habitable land comes at the cost of some other land becoming uninhabitable. The net cost is substantial as people have to move from uninhabitable land around the equator and develop new land at the poles. Likewise, that only a small amount of coastal land is lost to sea-level rise ignores the fact that almost all major human settlements are built on coastal land.
More generally, we only have one earth. There are strong reasons to suspect the existence of climate change tipping points, going beyond which would result in irreversible and unpredictable things happening. You also seem overly ready to gloss over the total loss of biodiversity on Earth. We may be reliant on nature in ways that we don't fully understand.
The core assumption here seems to be that humans can adapt to any change in climate or surroundings, which is true, but the cost of such adaptation is massive. It seems better to make some effort to stop climate change now rather than continuing to blindly wonder towards the edge of a cliff. In the case of population growth, that is a fixable problem. If the population gets too high, it will likely be reduced through people dying. The climate is not self-balancing like this, but self-destructive (e.g. through the release of methane trapped in permafrost).
"Surely increasing the amount of habitable land comes at the cost of some other land becoming uninhabitable."
Why "surely"? Try superimposing a map of population density on a map of average temperature. You discover that some of the hottest regions are densely populated, the coldest empty. A little land will be lost to sea level rise, but not very much, orders of magnitude less than is gained. Take a look at the calculations in https://daviddfriedman.substack.com/p/land-gained-and-lost.
"There are strong reasons to suspect the existence of climate change tipping points"
Take a look at a graph of temperature over geological time — there is one covering the past five hundred million years at the end of https://daviddfriedman.substack.com/p/does-climate-catastrophe-pass-the. Current global temperature is high in terms of the recent past, low in the longer term, some fifteen degrees below the high of the past hundred million years. If that did not cause a tipping point, why do you expect this to?
Projected warming by the end of the century gets Minnesota to about the temperature of Michigan. Do you think the cost of adapting to a change of that size, with most of a century to do it in, is "massive"?
"Try superimposing a map of population density on a map of average temperature"
I notice that the hot and cold regions are quite far apart. So it will be quite costly to move all the people in the hot areas to the cold ones. As you point out, most human settlements are in the areas most effected by climate change, moving all of them elsewhere will likely cost quite a lot. The cost I talk about is in building new houses in the unsettled cold regions, rather than the potential value of new habitable land.
"If that did not cause a tipping point"
It seems to have caused a tipping point. Notice that the graph is dominated by sudden changes rather than smooth curves. I'm not a climate scientist, but this is a graph which seems highly consistent with the theory of tipping points, where temperature is stable until a certain threshold is reached then begins to suddenly change. Climate scientists seem to agree that such tipping points exist and that the changes in that graph are examples of them. Even supposing your interpretation, a change of 1 degree every million years might have a different effect than a change of one 1 degree every few decades. I am inclined to trust the climate researchers on this matter because they seem to have done more research on it than you. You are at your most persuasive when you take those results from research and attempt to show a minimal economic impact, rather than when you dispute the science directly.
"Projected warming by the end of the century gets Minnesota to about the temperature of Michigan"
This is disingenuous. A rise of just a few degrees in climate can lead to vastly different weather. In my own country of the England, many houses now need air conditioning as they were designed for colder climates. Say everyone finds an AC unit for as cheap as $40 across 25 million homes, that's still a billion dollars in costs for one very simple thing in a country that isn't much effected . Floods in Africa and Fires in Australia due to disruptions in the Indian ocean dipole are likely to cause much more severe damage than can be solved with air conditioning. Some of the most productive land on the planet around California is experiencing a clear and consistent increase in the size of wildfires.
It's quite difficult to know the exact cost of these things when compared with a green transition but I (and most world governments) think it is best to play things on the safe side. Meanwhile you suggest that everyone being forced to move away from the most densely populated areas on the planet is a net positive because there will be a new habitable land in undeveloped areas while downplaying the cost needed to re-develop infrastructure in those places. Even the outlook you present seems very costly when properly examined.
I am not disputing the accepted views of climate science — on the contrary, I base most of my calculations on IPCC projections. You are confusing the wildly exaggerated view of climate change in the media with the actual view of serious scientists.
I am not suggesting moving people from hot areas to cold areas. I am pointing out that some of the hottest regions of the world are densely populated, that there is no region which is depopulated due to its current temperature. There are regions which are empty because they are both hot and dry, such as the Sahara, but hotter regions that are densely populated. So what is your reason to believe that if the summer temperature of hot regions went up by a degree or two — greenhouse gas warming is greatest in cold regions and seasons, least in hot — suddenly vast numbers would have to move?
Do you think that a rise of two degrees in average temperature, less than that in summer temperature, means that lots of people have to get air conditioning?
Try actually reading the IPCC report for numbers, to get a feel for the scale of the effects, which is wildly exaggerated in the sort of catastrophist literature you are taking seriously.
I don't know if you are old enough to remember the similar scare over population in the the sixties and seventies. You had the same pattern of lots of high status media insisting that there was a terrible threat that had do be dealt with, and quite a lot of people in India were sterilized as a result. Population in poor countries continued to rise and instead of their getting poorer and hungrier they got richer and less hungry.
Ehrlich's prediction of mass famine in the 1970's, with hundreds of millions dying, was taken seriously by the same sort of authorities that take seriously the idea that places where people manage to live fine now will somehow become uninhabitable if average temperature goes up by two degrees.
"Notice that the graph is dominated by sudden changes rather than smooth curves."
You are being misled by the scale. What you see as a sudden change on that graph is taking something like a million years.
Simple test you can apply to yourself. My post lists a bunch of positive effects some, such as CO2 fertilization, large. Before you read it how many of them were you aware of? If the answer us few or none, that is evidence that you have been exposed to a very biased selection of the relevant facts.
"I am not disputing the accepted views of climate science"
You can say that, but you did just dispute the widely held scientific belief of climate tipping points based on your personal interpretation of a graph.
"I am not suggesting moving people from hot areas to cold areas."
But you are saying that people live in these areas, and we know they will become substantial less habitable. So, what happens to those people? Wet bulb temperatures are set to rise above 35° in some inhabited regions and that means you die if you go outside. This phenomenon used to be rare but is increasingly common.
"that there is no region which is depopulated due to its current temperature"
Well this isn't true, but I'll interpret it charitably. While humans to live in very hot places, they tend to be poorer. So if more places became hot, it is likely they also would become poorer.
"Try actually reading the IPCC reports"
Have you? The IPCC target of 1.5° is chosen specifically because it reduces the risk of climate change tipping points, which you are denying exist.
"So what is your reason to believe that if the summer temperature of hot regions went up by a degree or two suddenly vast numbers would have to move?"
Primarily economic reasons. We already see large numbers of economic migrants moving away from these areas. The effect of climate change will be to increase the cost of food and decrease the productivity of these areas, as well as making them less enjoyably places to live. If you are dirt poor and there are days of the year where going outside kills you, you'll probably want to move somewhere else.
"Do you think that a rise of two degrees in average temperature, less than that in summer temperature, means that lots of people have to get air conditioning?"
Yes, because I have experienced it. An increase in average temperatures means that high temperatures can be vastly higher, the result is people buying AC. Also, this is factually inaccurate. According to the IPCC, climate change is accelerated at about 3 times the temperate regions of the world. So 2° average increase is 6° in Europe.
"Population in poor countries continued to rise and instead of their getting poorer and hungrier they got richer and less hungry."
And how do you think that crisis was averted? The answer is that advances in technology improved agricultural output. Would it not then be reasonable to invest in climate mitigating technology to avoid the climate crisis as investments in agricultural technology avoided the population crisis?
"where people manage to live fine now will somehow become uninhabitable if average temperature goes up by two degrees"
The people in these places aren't exactly fine. The heat is already a present threat in their lives, which will become much aggravated by climate change. There are periods of time when going outside is dangerous, and these are set to greatly increase due to climate change. A lot of important economic activities happen outside, so not being able to go there is a big problem.
"You are being misled by the scale."
No, I appreciate that the "suddenness" of these changes is in fact millions of years, but they are sudden relative to the periods of consistent temperatures surrounding them. I am confident of this because I didn't personally interpret that graph. I looked it up and found some papers by climate scientist which said that the changes in that graph were proof of climate tipping points.
"Before you read it how many of them were you aware of? If the answer us few or none, that is evidence that you have been exposed to a very biased selection of the relevant facts."
I was aware of a number of the points you mentioned. Perhaps their omission from climate discourse (including from those IPCC reports you mention) is evidence that you miscalculating their benefits. For instance CO2 fertilisation seems good, but it also decreases the nutritional value of crops. Combined with losses due to flooding and increased temperature variation, the result is a net loss. It simply doesn't make sense talking about a factor that increases crop yield if the overall effect is decreased crop yield. Every moneyed interest in this area wants to downplay the risks of climate change, so if these effect are relevant I think they would be overall more prominent.
Read this https://www.ipcc.ch/sr15/chapter/chapter-3/
You frequently talk about "one or two degrees" as if that is a small amount. But here the IPCC devotes an entire document to the massive damages that would result from just 0.5° difference in climate change. 7-10% of all livestock being lost between those numbers is not a small difference. 420 million extra people being exposed to extreme heatwaves is not a small difference. That would result in a massive loss of productivity. And yet you try to downplay changes because the absolute number in degrees is small. The increased flooding and fires is something we can already see happening and is very damaging.
When I wrote "I am not disputing the accepted views of climate science" I was referring to the views of climate science on climate, such as future temperature, not to their view on the consequences of climate change, which involves a variety of other fields, including mine (economics).
I am not competent to critique the climate part of the literature, beyond very simple things such as comparing IPCC projections to what happened thereafter. But I have critiqued, in some detail, work in the climate literature that is about consequences. From doing so I have concluded that most of the literature is biased and some of it, including respectable sources such as an article in _Nature_, is dishonest. Given that, I don't take "a published article says climate change will have consequence X" as a reason to believe it unless I have actually gone over the analysis pretty carefully. I accept the climate predictions because I have no better options, but not with much confidence given what I have observed of parts of the literature I was able to critique.
Obviously that is not a reason for you to refuse to believe published articles in respectable sources unless and until you have made similar observations. Elsewhere in the thread I have offered links to, I think, three examples of work that is either fraudulent or irresponsibly incompetent, along with the evidence to support that conclusion. One is an article in _Nature_ which the EPA says it is considering as a possible basis for regulation:
https://daviddfriedman.substack.com/p/critique-of-comprehensive-evidence.
One is a college textbook now in its third edition, whose author is active in climate controversy.
https://daviddfriedman.substack.com/p/a-climate-science-textbook
One is a very widely quoted factoid about the controversy which claims to be based on evidence.
https://daviddfriedman.substack.com/p/a-climate-falsehood-you-can-check
If you are curious about the basis for my skepticism of sources of information you trust those three should show part of my reason. For more of my work along these lines, see:
http://www.daviddfriedman.com/Sorted_Posts.html#Climate
Responses to a few of your points:
Where in the IPCC report does it make your claim about likely tipping points?
So far as the graph, you agree that your "tipping point" involves a change occurring over a million or more years — longer than our species has existed, a hundred times longer than our history. Given how fast human civilization has changed over the past thousand years, do you think it makes sense to base present policies on projections about effects a million years off?
When people in the climate debate talk about tipping points, do you think they mean, and intend their hearers to think they mean, changes occurring over a million years or more?
"According to the IPCC, climate change is accelerated at about 3 times the temperate regions of the world. So 2° average increase is 6° in Europe."
Can you link to a quote from the report supporting that? It doesn't fit the maps of projected temperature I have seen.
I responded to the claim about reduced nutrition here in
https://daviddfriedman.substack.com/p/climate-change-and-food-supply
under the subhead And Nutrition (it's a long post).
Were you aware that what was meant by reduced nutrition was a reduction in (some) nutrients per calorie, due to an increase in yield of calories, not a reduction in nutrient yield per acre? The implicit assumption, explicit in other work by some of the same authors, is that when yield goes up poor people continue to eat the same number of calories as before.
"Where in the IPCC report does it make your claim about likely tipping points?"
The nature of some tipping points is discussed in sections 3.5.2.5 and 3.5.5. Additionally its worth noting that high-risk large-scale tipping points are referred to as "large-scale singular events" and constitute one of the five primary "Reasons For Concern" laid out in the document.
"do you think it makes sense to base present policies on projections about effects a million years off?"
I lack expertise on the matter, but climate scientists think tipping points are relevant.
"Can you link to a quote from the report supporting that?"
"Temperature means and extremes are also projected to be higher at 2°C compared to 1.5°C in most land regions, with increases being 2–3 times greater than the increase in GMST projected for some regions (high confidence)."
"The strongest warming of hot extremes is projected to occur in central and eastern North America, central and southern Europe, the Mediterranean region (including southern Europe, northern Africa and the Near East), western and central Asia, and southern Africa (medium confidence)."
"Were you aware that what was meant by reduced nutrition was a reduction in (some) nutrients per calorie"
I had assumed that more food was growing faster, but it was less nutritious as a result. Though as for the part about increased yields, the IPCC report I linked has some interesting views on the matter:
"observations of trends in actual crop yields indicate that reductions as a result of climate change remain more common than crop yield increases, despite increased atmospheric CO2 concentrations (Porter et al., 2014). For instance, McGrath and Lobell (2013) indicated that production stimulation at increased atmospheric CO2 concentrations was mostly driven by differences in climate and crop species, whilst yield variability due to elevated CO2 was only about 50–70% of the variability due to climate. Importantly, the faster growth rates induced by elevated CO2 have been found to coincide with lower protein content in several important C3 cereal grains (Myers et al., 2014), although this may not always be the case for C4 grains, such as sorghum, under drought conditions (De Souza et al., 2015). Elevated CO2 concentrations of 568–590 ppm (a range that corresponds approximately to RCP6 in the 2080s and hence a warming of 2.3°C–3.3°C (van Vuuren et al., 2011a, AR5 WGI Table 12.2 ) alone reduced the protein, micronutrient and B vitamin content of the 18 rice cultivars grown most widely in Southeast Asia, where it is a staple food source, by an amount sufficient to create nutrition-related health risks for 600 million people (Zhu et al., 2018). Overall, the effects of increased CO2 concentrations alone during the 21st century are therefore expected to have a negative impact on global food security (medium confidence)."
As for what should be done, I think it's reasonable to avoid climate change even if the effects on food supply were completely ambiguous. We presently have enough food, and I think we should avoid upsetting that situation even if there's a chance we get more. We don't need more, but less would be a big problem. It's just not a smart bet to make.
(Edit) and if you're going to try that whole guilt by association thing on people concerned about climate change, the people who aren't concerned about climate change are generally much more suspect and separated from the facts. Three of four inaccuracies on the side of climate concern are pretty much dwarfed by the volume of blatant disinformation surrounding climate denial.
Welcome to Substack.
About the population costs and benefits: I wonder whether you included the benefit *to the newly-created people* of getting to live, which is probably the biggest potential benefit.
I did not. The context of my piece was not a dispute among utilitarians over the optimal size of population — I have a different article relevant to that, a chapter in one of Julian Simon's books. It was the widely believed claim that population increase made existing people worse off.
You appear to be taking for granted the total utility version of utilitarianism. As I expect you know, both that and the average utility version have problems. I tried to offer a version that avoided those problems in the chapter I wrote (http://www.daviddfriedman.com/Academic/What%20Does%20Optimum%20Population%20Mean.pdf).
Are the predicted mass third-world migrations resulting from climate change likely?
If so, this is a negative externality that will absolutely dwarf any conceivable positive ones. Europe and the US will be at risk of societal collapse if hundreds of millions of unselected third-world people move to thse places.
To anyone who thinks this is sensationalist: Sub-saharan africa is a mess because of the people living there, its not something intrinsically wrong with the climate or resources of these places, it's the people. We know for a fact that unselected immigrant populations from these countries do not rapidly assimilate into developed countries, and we should expect doing so to be much much easier under current relatively lower immigration rates than potential future higher immigration rates. Which is to say: We don't know how to assimilate unselected third world migrants at the moment, and these migrants have impose a huge per capita cost on developed countries in the form of fiscal impact and crime. There's absolutely no reason to think this will become less the case with radically more immigration, so even if it doesn't get worse the costs these additional immigrants will impose on developed countries will already be staggeringly large (and this says nothing of the political, cultural and institutional externalities of these people), though in reality the per capita cost will be dramtically higher.
Americans and especially euopeans demonstrate self-destructive levels of compassion and tolerance towards these kinds of people, but under such conditions it should be expected that enough of them will rightfully object to their way of life and their societies being completely upended in these ways, and this will have enormous political and social consequences.
Thanks for your advice regarding linking substack. No good deed goes unpunished, so naturally I will be reading anything you write.
That said, I sincerely enjoyed this. We need more humility and the ability to say, I do not know. You'd actually probably enjoy my latest post - it's even somewhat relevant :)
Or it's possible that you were responding to something I didn't write?
Good post.
AMOUNT:
-- Current trajectory puts us on track for between 2.1 °C and 3.9 °C
**uncertainty is skewed towards a stronger climate response
**does NOT factor in long-term carbon cycle feedbacks
--permafrost thawing, forest fires, etc...
**does NOT factor in worst-case climate responses
**some simulations suggest stratocumulus decks may abruptly be lost
-- if this happens, there could be additional ∼8 °C global warming
**IPCC projections have been conservative (emissions trajectories, sea level rise, attribution,...)
CROPS:
--benefits of CO2 fertilization are limited:
**excess CO2 produces no benefit for C4 plants
**C3 plants need RuBisCo activase to benefit
--RuBisCo activase is sensitive to heat
--other effects will be much more significant
**growing temperatures
**extreme drought
**invasive species benefit most from CO2
-- weeds show strongest responses
-- and resist herbicides
"**IPCC projections have been conservative (emissions trajectories, sea level rise, attribution,...)"
I have heard both that claim and the opposite, so some years ago I tested it by reading the first few IPCC reports and comparing the prediction you got from each report to what happened to temperature thereafter. The first report predicted high — actual warming was below it predicted range. Since then there has been no clear pattern of high or low.
https://daviddfriedman.substack.com/p/testing-ipcc-projections-against
Did you do a similar calculation? If not, what is your reason for believing that the IPCC projections have been conservative
"CROPS:
--benefits of CO2 fertilization are limited:
**excess CO2 produces no benefit for C4 plants"
That is not correct. It produces little or no benefit for C4 plants that have adequate water but reduces water requirements for both C3 and C4 plants — they don't have to pass as much air through their leaves to get the carbon they need, so lose less water. For water stressed C4 plants increased CO2 increases yield.
You cite skeptical science.com. That site is run by John Cook. I believe I have shown, with publicly available evidence you can check, that he has lied in print about his own work.
https://daviddfriedman.substack.com/p/a-climate-falsehood-you-can-check
If you do not find my argument convincing by all means let me know what is wrong with it. If you do, you will know that he is not to be trusted.
re "Did you do a similar calculation?"
I agree with your characterization of IPCC prediction error for surface warming (with the caveat that, if you control for short-term influences like ENSO, the projections match the observed trend). My comment referred to IPCC projections about emissions, sea level rise, and attribution. Additionally, I could have referenced their projections about sea ice decline. If their track record is 'accurate,' 'conservative,' 'conservative,' 'conservative,' and 'conservative,' I think it is reasonable to infer that their institutional bias is more conservative than alarmist.
re 'That is not correct.'
When I said 'excess CO2 produces no benefit,' I had in mind the direct effect on photosynthesis. You're right that elevated CO2 can reduce water requirements, but causing plants to reduce their stomatal conductance is more of a mixed bag than you let on. Ironically, by impairing thermoregulation, it makes plants more susceptible to heat stress. More importantly, there is the issue of the competitive dynamics.
re 'You cite skeptical science'
The article is (a) not written by Cook, (b) cites sources for the relevant claims (make sure you to click on the 'advanced' tab rather than the 'basic' tab). None of the sources that it cites are written by Cook either.
Re Cook and Skeptical Science, did you read my piece? If so and you agree with my conclusion, you should be careful of trusting a site he controls. As before, the question is whether the article is convincing if you don't assume it is written by an honest author, which requires you to actually read the sources it cites.
I only checked the IPCC temperature predictions. Is there a webbed equivalent to what I did for SLR? At some point I may try to do it.
Cook 2013 is deeply flawed for a number of reasons. While I find your specific criticism/his response less conclusive than you do, there are other reasons to question the integrity of the authors. For instance, there are reports that the authors were marketing their results before they began conducting their research and changed their operational definitions in the middle of conducting their research. Additionally, I have a general attitude of skepticism towards Cook because his 'expertise' is in advocacy rather than science.
Thanks.
What is wrong with my specific criticism? Do you agree that his 97% was for Categories 1-3? That only Category 1 is humans as the main cause, and a tiny fraction of the total? That in the second piece he claims that 97% is for humans as the main cause?
The fact that Cook lies in print does not tell us much about the climate literature in general, but the fact that his lie is widely repeated by reputable sources and almost nobody points it out does.
I'm not saying there is anything wrong with your criticism. My point is just that if I were to find out that someone like you made a similar misstatement and then doubled-down or deflected, I would find motivated reasoning/stubbornness more plausible than willful deception. It would not appreciably decrease my confidence in anyone who ever approvingly cited unrelated work of yours. I would be unlikely to become so suspicious of you that I would bring up the incident whenever someone cited a website affiliated with you.
Rest of my comment got cut-off... not going to rewrite but happy to dialogue. Here are some helpful references for the parts of comment that were preserved:
1)https://www.pnas.org/doi/10.1073/pnas.2108146119#:~:text=UN%20Secretary%2DGeneral%20Ant%C3%B3nio%20Guterres,global%20catastrophe%E2%80%9D%20(9).
2) https://skepticalscience.com/co2-plant-food-advanced.htm
Regardless of the theoretical benefit of CO2 fertilization, more plants are growing bigger and faster.
First, your empirical claim is grossly misleading. Agricultural productivity growth has declined to its lowest level in sixty years. Evidence suggests that climate change is an important (perhaps the primary) driver of that decline.
Second, your implicit methodology is wrongheaded. In assessing the expected value of a climate response, evidence about physical processes should often trump the observed relationship between variables for two reasons:
--The relationship between variables is often non-linear (and even non-monotonic). The present example (relationship between temperature anomaly and yields) is a case in point. Observations are either confined to a narrow range of values of a parameter or rely on a dubious paleoclimate record.
--The climate is a complex dynamical system. Observed relationships will be confounded by at least dozens (most likely, hundreds) of other significant inputs. Further, in the case of a dependent variable like agricultural yields, many of the most important inputs are exogenous to the climate system.
"Evidence suggests that climate change is an important (perhaps the primary) driver of that decline. "
Can you offer a link to that evidence?
According to the IPCC report, the Earth is greening and the likely explanation is CO2 fertilization. That is many facts from the report that did not make it into the Summary for Policy Makers, which is the most reporters read.
re 'Can you offer a link to that evidence'
https://www.nature.com/articles/s41558-021-01000-1
re 'the Earth is greening'?
Why is that relevant? My comment was about agricultural productivity, not the extent of green vegetation.
Thanks for the link; I haven't yet read it. Have you gone over the article carefully enough to be reasonably confident that the conclusion is correct or are you merely assuming that an article in _Nature_ can be trusted?
I ask because I did a very careful critique of a different _Nature_ article on a related topic and concluded that it could not be. Its calculation of the cost of carbon included the implicit assumption of no medical progress in the next three centuries and the implicit assumption that a ten-fold increase in per capita income would have no effect on people's vulnerability to temperature. That part of the argument was responsible for about half the total calculated cost.
My critique is: https://daviddfriedman.substack.com/p/critique-of-comprehensive-evidence
It is one of the things that convinced me that the field is sufficiently corrupt so you have to go over the analysis of a published article carefully before you have any reason to trust it. If you read my critique you can decide for yourself whether that is a justified conclusion.
This post was my first, and I have made many more on that topic (and others, of course) since. You can find links to all of them at: http://www.daviddfriedman.com/Sorted_Posts.html#Climate. I believe they provide additional support for the conclusion. Another that does is:
https://daviddfriedman.substack.com/p/a-climate-science-textbook
Of course, the fact that I say something is also not an adequate reason to believe it. That is why I try, as in my piece on John Cook and the 97% claim, to provide my reader with evidence he can check for himself. That policy limits how sophisticated my analysis can be; it has to be something that an intelligent layman willing to take some trouble can check for himself. In my piece on increased usable land I include links to published articles that do a much more sophisticated job of looking into the question. The advantage of my cruder analysis is that the reader can check it.
That is the cost of professional scientists being willing to do dishonest work if it produces the right result. It is part of the reason that my overall conclusion is that we simply do not know whether climate change will make us better or worse off.
I am not convinced that you are responding to what I said.
> That is in a model in which per capita consumption roughly triples by then. So the difference between the world without climate change and the world with climate change is, by his model, the difference between an increase in per capita income by 2100 of 300% and an increase of 292.5%.
A tripling would be an increase by 200%, no?
It's a grift. Think of all the sinecures it produces! The people who profess to care with no skin in the game are just the useful idiots getting mulcted.
And, pleasure to see you are on Substack, I'm a great fan.
Impressions: mixed.
Common version of the orthodoxy is: climate is not weather, so few degrees of global warming will not result in experience of "everything is some degrees warmer, crop yields are improved". Along these lines, IPCC AR 6 makes many specific claims concerning food and water systems and adaptation options. It would more convincing if these IPCC claims were tackled head-on, point-by-point.
Referring to IPCC claims has an added benefit for a lay reader like me, who has a great difficulty judging how seriously to take any particular random cited study or Fermi estimates based o "maps showing yield of various crops can be found online" as you put in a presented pdf. IPCC presumably is both the presumed authority and their report present the major arguments in favor of the orthodoxy. Referring to their materials, can argue that their material is correct but the orthodoxy draws wrong conclusions or overstates them; or refer material they cite and point out where their assumptions go wrong.
Sea level rise argument appears most convincing: urban habitation and assets are slowly rebuilt and thus easily move in any case, thus adaptation does not appear impossible or prohibitively expensive. However, it would be good to refer IPCC estimates, such as AR6 Cross-Chapter Paper 2.
Changes to agriculture appear most significant to me. For instance, AR6 Chapter 4 section 4.5.1 outlines drought driven yield loss estimates for various crops, which appear significant even if RCP8.5 is discounted; Section 5.4.3 and Figure 5.3 present negative crop yield estimates for most crops including C02 fertilization effects); quickly scanning, only soybeans and potatoes (root crops) are projected to benefit anywhere. This seems at odds with the claim " Is there any significant amount of land that is too hot to grow crops? So far as I can tell, there is not." in the same pdf of yours. (Cross-Chapter Paper 3 discusses desertification, but I didn't attempt to read any part of it for this comment).
Adaptation by cultivar changes is discussed in Section 5.4.4.1, which is surprisingly non-committal section; cost of global adaptation is cited at only tens of billions which to me sounds super cheap (considering that US GDP alone is counted in trillions). More careful analysis of the references cited therein would be interesting, and make claims of increased crop yields in extreme latitudes to offset losses more credible.
I will bet you any amount of money you care to wager that yields per acre and total yields will be higher in 2050, 2075, 2100, then today.
Seems odd to worry about desertification in an overall environment with more precipitation.
Why it is odd? Please tell! I wrote a long-ish commit longing for more engagement with the claims made by the current orthodoxy and why and when it could be dismissed. More one-liners don't really help here.
Look I was all about climate and science generally from say 1990-2005 or so. But I am also a skeptic and have a brain.
You only need to listen to so many hundreds of interviews and so many hundreds of articles before you develop a pretty good model of the dysfunctions in this field. And the dysfunction is that it is a religion/ideology to a significant fraction of these people and they simply are not conducting fact lead research and are instead taking an unrelated thesis "climate change is going to be catastrophic" and beating whatever pegs they find, round, square, triangular into a round whole to fit it.
And an IPCC report no matter how well intentioned built out of those raw materials is bound to be compromised.
Here is my experience with the "science" (yes this includes talking to say people at climate think tanks with Phds and frontline researchers).
Scientist 1: OMG in 2075 there will be no more sea ice and polar bears will go extinct. The world is dying! (and yes you will see "the world is dying" rhetoric coming out of scientists mouths regularly).
"While that is regrettable and I don't want that, and am willing to do my part, how is that evidence the world is dying, what are the actual impacts on humans beyond no polar bears?"
Oh the world is a fragile delicate ecosystem we barely understand and with no polar bears eating seals the seals will eat to much fish and the fish population will collapse and the whole artic food web will collapse.
"That seems like an awfully specific prediction from someone who claims we barely understand how this works."
Well it could happen!
"Ok, but that isn't the level of contingency you convey in your article...couldn't it also be helpful to the food web?"
No because I define the 'health' of the food web, by how much it looks like the food web when I was an undergraduate.
"But didn't we already have a lot of human impacts and climate change by then? Why is that the target? Besides the main thing impacting the food web of the oceans is not climate change or the presence or absence of polar bears, but overfishing"
You just hate polar bears! Look at this guy he hates polar bears.
Scientist 2: Changes in the temperature have changed the range of the Northeastern Iowa Maple Fungus and now it is ravaging the trees of southeastern Minnesota. The forests of Southeastern Minnesota are being destroyed!
"Ok that isn't good, how is it spreading?"
It is spreading as the trees from northeast Iowa migrate north into northeast Minnesota, we have already seen 25 miles of migration since 1900, and by 2100 the forest mix may have moved 50 miles northward.
"Ok so the forests in southern Minnesota will have the mix that the ones in northern Iowa had 50 years ago, and the one in northern Iowa will have the mix the ones in southern Iowa had. That sounds not ideal, and people don't like change, but are the forests really going to be 'destroyed'? It sounds like there will still be forests, jsut the percentages of various trees will be different.
Well but the tree mix impacts albedo and that has all sorts of chaotic impacts on the local climate and microclimates and who knows what might happen! This is an important farming area and rainfall could down.
"Oh that great that area has a lot of problems with flooding and ample water for irrigation."
No no no, didn't you hear me say we don't know what would happen, rainfall could go way up too, and then there could be lots more flooding you don't want that right?
"More flooding would be bad, but it kind of sounds like you are determined to make this bad, no matter what the data is."
SCIENTIST 3: Yes I know it is very bad! OMG with all this AGW there is going to be widespread drought and famine everywhere, crop yields will crash, people will starve.
"Isn't climate change going to lead to more rain, why will there be an increase in drought? Also haven't we already seen significant warming, and yet yields are only up over that period?"
But that is because farmers have been benefiting from a period of extra glacier melt from all the warming. Extra warm summers have lead to extra melt from glaciers and much needed extra water in the dry season. And farmers need that extra melt water to survive, and it will all be gone if the glaciers melt away.
"But not everywhere has a wet winter and dry summer. Also if we stop global warming, then there won't be that extra melt water either, just the 'normal' amount. it seems like you are jsut taking the worst possible interpretation of every potential impact"
Also the rain is only going to fall in places that don't want rain, and then the increased heat will lead to more evaporation and drought from the places that do want more rain.
"That seems awfully convenient for your argument, also wasn't SCIENTIST 2 just telling me that this whole process is chaotic and that the climate models have very little actual likelihood of predicting specifics accurately?"
Oh no no on, we have the most accurate, up-to date-models, and while there is a lot of uncertainty generally, we can confidentially predict that whatever thing you don't want to happen, will happen.
"That seems very unlikely, almost like the model has been trained to provide outputs you want."
Well of course if it isn't providing the outputs we want how would we know it was working?
"..."
Now I am being uncharitable for the purposes of brevity, and making a point. But that is my general read on all this. I am actually pretty pro immediate action on climate change. If I was global dictator we would have a carbon tax tomorrow.
But I feel the scientists have done a piss poor, and at times actively deceptive job of controlling for their biases and desires. Yes to Dr. Franklin Kearns who studied anteaters in the jungle for 15 years, the extinction of anteaters is a global catastrophe. To humans generally it is not.
Now I am not arguing climate change won't have all sorts of multi-billion dollar negative impacts. It absolutely will! It will cost trillions. But there will also be a lot of benefits, and that is mostly not looked into with even 5% of the interest as the costs. And the IPCC report both isn't as dispassionate as people claim, and can only work with the raw materials scientists produce, and the raw materials are highly ideological.
This is probably my favourite substack post of all time, I really hope other people read it and criticize it, especially people who are very epistemically rigorous. I have been reading your blog for quite a long time now and have kept a mental synthesis of all of your posts on climate change, so to see it all come together is amazing.
I do have some minor nit-picks that mostly come down to stylistic choices, the most obvious is neglecting to explicitly mention that when attempting to calculate the optimum quantity of people or CO2 what matters is the net externality of the marginal unit of people or CO2. I fear that whilst not explicitly mentioning it (and also not talking about how P=MC=MB in your sketch of price theory) and other things makes this post more accessible, it opens you up to weak but "smart" sounding criticism one of my favourite examples on a different but related topic being Greg Mankiw's "David Friedman's Slippery Slope".
I have also read a lot of criticism of you on a variety of topics and it seems that lots of the "smart" sounding criticism could easily be avoided if you marginally increase the degree to which you use technical language, the reason being people knowledgeable enough to understand the language probably realize the argument your making is more subtle or intelligent than other people making similar sounding but weaker arguments, and people who don't understand the language would hopefully read up on the surrounding literature to avoid sounding stupid or uninformed and hopefully learn something (they could also accuse you of using superfluous language to make a bad argument sound better, but this would have the effect of people who are familiar with the language discounting those critics which is probably good).
On a similar note it probably makes sense to include a lot more hyperlinks to other work, such that people who read something that sounds wrong can read up on it and conclude you are right as opposed to dismissing you based on something that probably isn't even relevant to the argument your making.
I think Steven Landsburg also has made very similar overall arguments to the ones you have made, in particular emphasising the point that in a market economy resource consumption is a private cost not a cost imposed on others, which is contrary to the way people usually think about population, where people just see a fixed number of resources and then see how increasing the number of people decreases the resources per person and makes everyone poorer (this is obvious, but wrong and shows people even supposedly smart people lack a good model of how a market economy works). Your 1972 article is very similar to Landsburg's style of thinking. Although I think you undersell your argument, that is it seems to me that one can with a reasonable degree of belief say almost a prior that both overpopulation is not a problem and that even under Laissez-faire there is a underproduction of people due to the positive externality of ideas (scientific innovation etc.) seeming massive (compared to negative externalities) and of course not being properly accounted for either by parents or their children. There is also utilitarian arguments that make this underproduction of people seem even more dire than what economic efficiency suggests, but that's quite a long argument to properly grasp the problem. I also think you undersell your arguments with respects to the benefits of climate change put that's also a very long and complicated argument, and in the eyes of most people harder to defend.
I considered including the point about resource conservation, which I like to put as "a baby is not born with a deed to a per capita share of the Earth's resources clutched in his fist," but I thought it distracted from this essay, where the population argument serves mostly as a lead in to the climate argument. I have pointed it out elsewhere.
Of course, a legitimate response is that we don't live in a world with a guarantee of secure property rights, and a baby is born, at least in many countries, with an invisible deed to a vote when he grows up.