Acceleration of drought in Mexico accelerating illegal immigration?

a new study published in the prestigious Proceedings of the National Academy of Sciences appears to establish a coming (and possibly a present) link between global warming and illegal immigration from Mexico,..the study led by atmospheric science Prof. Michael Oppenheimer of Princeton University and co-written by scientists from China’s Shanghai University and the U.S. Treasury Department, the more global warming dries out farms and water supplies in Mexico, the more Mexicans will head to this country.

The Oppenheimer study predicts anywhere between 1.4 million and 6.7 million current Mexican farmers and farmworkers will emigrate north between now and 2080 solely because their farmlands become too parched to produce.

Here's the study: Linkages among climate change, crop yields, and Mexico US cross-border migration