On the effect of international human migration on nations' abilities to attain CO2 emission-reduction targets.

I merge publicly available data on CO2 emissions, with patterns of human movement, to analyze the anticipated effects of human migration on the abilities of nations to attain 2030 UNFCCC CO2 emission targets. I do so at both global (175 countries) and national (Canada and the USA) scales. The analyses reveal that mean per capita CO2 emissions are nearly three times higher in countries with net immigration than in countries with net emigration. Those differences project a cumulative migration-induced annual increase in global emissions of approximately 1.7 billion tonnes. For Canada and the United States, the projected total emissions attributable to migration from 2021 to 2030 vary between 0.7 and 0.9 billion tonnes. Although staggering, the annual and total emissions represent a small fraction of current global emissions totalling 36 billion tonnes per annum. Even so, the projected decadal immigration of nearly 4 million humans to Canada, and 10 million to the USA, represent significant additional challenges in reducing CO2 emissions. The challenges pale in comparison with poor nations that are minor contributors to climate change. Such nations face the incomprehensible burden of improving the quality of their citizens' lives without increasing global CO2 emissions. National and international strategies aimed at lowering emissions must thus acknowledge, and cooperatively address, consumptive inequities and expected increases in human population size and migration.