"Climate Change Stunts Growth of Global Crop Yields"

The other day, I posted a graph showing delining crop yields from Michael Roberts and wondered what is behind the growth slowdown. Here's one answer (also discussed by Michael Roberts in a follow-up post):

Cereal Killer: Climate Change Stunts Growth of Global Crop Yields, by David Biello, Scientific American: The people of the world get 75 percent of their sustenance—either directly, or indirectly as meat—from four crops: maize (corn), wheat, rice and soybeans. The world's rising population—now predicted by the United Nations to reach 10.1 billion by century's end—has been fed thanks to rising yields of all four of these crops during the past century. Humanity's predilection for burning fossil fuels, however, is now contributing to the slowing of such rising yields, cutting harvests of wheat 5.5 percent and maize 3.8 percent from what they could have been since 1980, according to a new analysis of yields.

"On a global scale, we can see pretty clearly significant changes in the weather for most places where we grow crops," explains agricultural scientist David Lobell of Stanford University's Woods Institute for the Environment, who led the analysis published in the May 6 issue of Science. "Those changes are big enough to sum up to pretty big losses for wheat and corn." ...

More troubling, further climate change is already locked in.... That means areas that have not been affected to date, such as the "corn belt" of the U.S., may soon see the same or worse impacts. ...