When Ros Gleadow opened the airlock to the greenhouse at The Australian National University, she stepped into the atmosphere of the future. The air was thick with carbon dioxide—700 parts per million, to be precise—which matches the concentration predicted 90 years from now. While evaluating the responses of crops to the altered atmosphere in the summer of 2008, she found that the cotton, sorghum, soybean and cassava plants she’d planted 9 months earlier grew higher, a little woodier, and with more stems and smaller leaves than normal—all of which she’d expected. But when she dug the cassavas out of their pots, the tubers, which usually grow as large as yams, looked like stunted fingers.
Her cassavas of the future had produced 80 percent less food. “It came completely unexpectedly because plants normally grow bigger under higher CO2,” says Gleadow, a plant physiologist at Monash University in Melbourne. Her immediate thought ...
