Potentially Extreme Population Displacement and Concentration in the Tropics Under Non-Extreme Warming.
Evidence increasingly suggests that as climate warms, some plant, animal, and human populations may move to preserve their environmental temperature. The distances they must travel to do this depends on how much cooler nearby surfaces temperatures are. Because large-scale atmospheric dynamics constrain surface temperatures to be nearly uniform near the equator, these displacements can grow to extreme distances in the tropics, even under relatively mild warming scenarios. Here we show that in order to preserve their annual mean temperatures, tropical populations would have to travel distances greater than 1000 km over less than a century if global mean temperature rises by 2 °C over the same period. The disproportionately rapid evacuation of the tropics under such a scenario would cause migrants to concentrate in tropical margins and the subtropics, where population densities would increase 300% or more. These results may have critical consequences for ecosystem and human wellbeing in tropical contexts where alternatives to geographic displacement are limited.
Goldman School of Public Policy, University of California, Berkeley, USA.|National Bureau of Economic Research, Cambridge, Massachusetts, USA.
Solomon M
SM
Hsiang
Department of Earth and Environmental Science, Columbia University, USA.|Department of Applied Physics and Applied Mathematics, Columbia University, USA.|Lamont-Doherty Earth Observatory, Columbia University, USA.
Adam H
AH
Sobel
D000222:Adaptation, Physiological; D000465:Algorithms; D000818:Animals; D057231:Climate Change; D017753:Ecosystem; D057232:Global Warming; D006801:Humans; D008954:Models, Biological; D011156:Population Density; D011157:Population Dynamics; D013696:Temperature; D014329:Tropical Climate