This whole idea of the human niche is bullshit in my opinion. Humans have occupied essentially the entire vegetated surface of the earth for tens of thousands of years. Now, there may be greater risks of catastrophe, previously productive crops may fail, and coastal areas in particular may actually become uninhabitable due to inundation. So there will be problems, maybe very serious problems—but this will be true in the north as well. I don’t buy that literally the entire population of the south will need to be resettled. There’s just nothing in the science to suggest this at projected levels of warming.
Building a model from the current distribution of humans and assuming that distribution is going to stay the same with respect to the climate ignores human ability to adapt which is demonstrably huge.
People have lived pretty much everywhere, but at very very different population densities, and those differences in density, are to a large extent, driven by climate
This misattributes historical patterns of human population growth to some fundamental limit to human population which is totally unsupported by any evidence, and in fact is obviously disproven by looking at the current distribution of humans across the world. By focusing on relative population growth, the authors are able to obscure huge increases in tropical and subtropical population and agricultural productivity that have taken place in the modern era. By the way, I live in one of the most agriculturally productive parts of the entire planet and it already exists outside of this supposed human niche.
It also ignores the rise of new technologies that eliminate the need for human labor in agriculture—in fact there is no need for the majority of humans to move to places of high agricultural productivity unless global trade breaks down in some kind of cultural or social catastrophe. While this is possible, it is far from fated to happen and I think is far less likely than many people assume.
It is certainly true that humans have found it more difficult to live in some biomes—mainly polar climates, deserts, and rainforests. A more interesting analysis might look at how these various biomes might shrink or expand in populated areas. But on the tropical end, these biomes are largely defined by precipitation, which is not expected to change as dramatically as temperature. Even if migration is necessary in some areas, it will not necessitate the depopulation of entire countries. Many tropical and subtropical areas with moderate precipitation are already heavily populated and likely will be in the future as well.
Yeah, I think yours is proably the more correct take. Carrying capacity exists in nature because other animals can’t ship produce around by truck. That said, there’s still an economic carrying capacity, so to speak, where the forces of desirability and affordability meet, that will dictate the population size of an area. Climate pressure will decrease affordability of many regions driving more and more people to move or face poverty.
Yes, these changes will pose large challenges in many areas, and it is possible or maybe even likely that some countries may struggle to adapt for various reasons. But collectively I think we already have to tools to tackle them and we will develop more as time goes on. I expect climate migration will look more like an extreme version of today where some governments break down due to various stressors, while others in the same climates and regions continue to thrive.
If we could figure out better and more equitable ways to produce and distribute resources globally it is entirely possible that our future world could be more stable and prosperous than today, but that may be overly optimistic in the face of these challenges and powerful forces that seek to maintain our current exploitative economic system.
