Scientists have long predicted that — eventually — temperatures and altered rainfall caused by global climate change will take a toll on four of the most important crops in the world: rice, wheat, soy and corn.
Now, as world grain prices hover near record highs, a new study finds that the effects are already starting to be felt.
"For two crops, maize [corn] and wheat, there has actually been a decline in yields, if you account for the trend in climate — especially the warming trend that we've observed over the last 30 years," says Wolfram Schlenker, who teaches environmental economics at Columbia University. He's a co-author of the study, along with David Lobell and Justin Costa-Roberts at Stanford University.
The scientists looked specifically at places where there are warming trends, and sure enough, they found these staple crops weren't doing quite as well.
For rice and soy, declines in some places were offset by productivity boosts elsewhere in the world, so there was no overall change. But they did see a change for wheat and corn.
The losses caused by warming thus far are still smaller than the gains made though improved agriculture.
http://www.npr.org/2011/05/07/135952277/worlds-farmers-feel-the-effects-of-a-hotter-planet
