from an article on the same study
Quote
Open-air field trials involving five major food crops grown under carbon-dioxide levels projected for the future are yielding signifcantly less than those raised in earlier enclosed test conditions. Scientists at the University of Illinois at Urbana-Champaign warn that global food supplies could be at risk without changes in production strategies.

sure, you can talk to god, but if you don't listen then what's the use? so, onward through the fog!