Farmworkers pull weeds from a field of lettuce near Gonzales, Calif. Salinas Valley farms like this one rely on wells, which haven't been affected much by the drought. George Rose/Getty Images hide caption

itoggle caption George Rose/Getty Images

A fully formed coffee berry, left, is shown next to a damaged coffee berry due to drought, at a coffee farm in Santo Antonio do Jardim, Brazil on Feb. 6. Paulo Whitaker/Reuters/Landov hide caption

itoggle caption Paulo Whitaker/Reuters/Landov

Wheat fields like this one could yield wheat with less zinc and iron in the future if they are exposed to higher levels of CO2, according to the journal Nature. Zaharov Evgeniy/iStockphoto.com hide caption

itoggle caption Zaharov Evgeniy/iStockphoto.com

Wal-Mart is promising to drive down the prices of organic food by bringing in a new company, WildOats, to deliver a whole range of additional products. Wal-Mart/Flickr hide caption

itoggle caption Wal-Mart/Flickr

Backers of the new Open Source Seed Initiative will pass out 29 new varieties of 14 different crops, including broccoli, carrots and kale, on Thursday. J. Scott Applewhite/AP hide caption

itoggle caption J. Scott Applewhite/AP

Farmers participate in a CGIAR climate training workshop on how to interpret seasonal rainfall forecasts in Kaffrine, Senegal. Courtesy of J. Hansen/CGIAR Climate hide caption

itoggle caption Courtesy of J. Hansen/CGIAR Climate

Customers order food from a McDonald's restaurant in Des Plaines, Ill. The company has promised to start buying "verified sustainable beef" in 2016. Scott Olson/Getty Images hide caption

itoggle caption Scott Olson/Getty Images

The world is increasingly relying on a few dozen megacrops, like wheat and potatoes, for survival. Above, a wheat field in Arkansas. Danny Johnston/AP hide caption

itoggle caption Danny Johnston/AP