Climate – related migration is easier to conjecture than to document. One 2019 article from Brookings wrestles with the speculative nature of the subject. Last month, in August 2022, Nomad Century was published, possibly the first trade book on climate change migration.
Most of climate change migration will appear as internal migration. The dominant pattern, I expect, will be gradual, not sudden, change in location within country guided by work opportunity, family and community chains, and governmental aid. I doubt there will be no such thing as large scale formal international climate refugee programs. Wholesale movements of communities over short periods of time will be rare.
The following is from the World Bank, on climate-related migration, which will be mostly internal within countries. This is from a 2018 forecast.
By 2050 as many as 216 million people could be internal climate migrants in major world regions; this represents almost 3% of these regions’ total projected population. Sub-Saharan Africa could see as many as 85.7 million internal climate migrants or 4.2% of the total population. East Asia and the Pacific: 48.4 million or 2.5% of the total population. South Asia: 40.5 million or 1.8% of the total population. North Africa: 19.3 million or 9% of the total population. Latin America: 17.1 million or 2.6% of the total population. Eastern Europe and Central Asia: 15.1 million or 2.3%
They will migrate from areas with lower water availability and crop productivity and from areas affected by sea-level rise and storm surges. Hotspots of internal climate migration could emerge as early as 2030 and continue to spread and intensify by 2050. The reports also finds that rapid and concerted action to reduce global emissions, and support green, inclusive, and resilient development, could significantly reduce the scale of internal climate migration. The World Bank. Here and here.