Mexican Immigration May Rise As Warming Reduces Crop Yields, Study Says

Rising temperatures and reduced crop yields in Mexico could force as many as 6.7 million Mexicans to emigrate to the United States over the next 70 years, according to a new study. Researchers from Princeton University, led by atmospheric scientist Michael Oppenheimer, made that projection after studying historical patterns of emigration, climate change, and crop yields in Mexico between 1995 and 2005. Oppenheimer and his colleagues concluded that for every 10 percent reduction in crop yield, an additional 2 percent of Mexicans aged 15 to 65 could emigrate to the United States. Their research, published in the Proceedings of the National Academy of Sciences, projected that 1.4 million to 6.7 million Mexicans could migrate to the U.S., depending on how high temperatures rise and how much damage is done to staple crops, such as corn. The U.S. National Research Council has estimated that every degree Celsius of warming could mean a 5 to 15 percent drop in yield, particularly for corn. But Oppenheimer and scientists not connected with his research noted that other factors, such as U.S. border and immigration policy, will also determine how many Mexicans may emigrate as temperatures rise in the coming decades.