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.

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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.

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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 :)

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Or it's possible that you were responding to something I didn't write?

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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.

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-- 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,...)


--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

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> 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?

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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.

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Jan 30·edited Jan 30

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, 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.

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Jan 30·edited Jan 30

“ 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.

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Jan 29·edited Jan 29

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.

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