Will Climate Change Push Mexicans North to the US?

The potential demographic consequences of climate change have been difficult to assess, but a new study published in the Proceedings of the National Academy of Sciences (PNAS) suggests that climate change could force residents of Mexico to go north in search of jobs. Shuaizhang Feng, Alan B. Krueger, and Michael Oppenheimer, all of Princeton University, have generated a model that simulates the drop in crop yield associated with projected global warming, and then projects the number of Mexicans working in agriculture who would be forced out of the country if crop yields dropped:

Depending on the warming scenarios used and adaptation levels assumed, with other factors held constant, by approximately the year 2080, climate change is estimated to induce 1.4 to 6.7 million adult Mexicans (or 2% to 10% of the current population aged 15–65 y) to emigrate as a result of declines in agricultural productivity alone.

The model is very complex and incorporates a great many assumptions with which you might or might not agree. Indeed, an initial reaction to the publicity about this study was alarm on the part of some people in the US who want to cut off immigration from Mexico, rather than absorb new immigrants. But there is a great deal of food for thought in this analysis and it deserves our careful analysis.