For every one degree Celsius increase in global temperature, there's a 10 percent decrease in crop yield.
Crop yields could be down by one-third to one-half by 2100, when the global population is likely to be considerably larger than it is now, said David Battisti, a professor of atmospheric sciences at the University of Washington. Battisti was a speaker at a geoengineering workshop at MIT Friday.
A recent study shows that U.S. crop yields are likely to decrease somewhere between 30 percebt and 82 percent by the end of the century, depending on the pace of global warming.
Battisti said that rising sea levels and increasingly destructive droughts and flooding caused by global warming aren't severe enough problems to convince him to consider drastic measures like geoengineering – deliberately altering the climate to counteract our unintended alterations. The impact of global warming on global food production, however, is another matter. "It's the one thing that scares me," he said.
There's not a lot of unexploited viable cropland left, and we already have a billion people malnourished today, he said.
While today's food security issues probably have more to do with political and economic factors affecting food distribution networks than they do with crop yields, the larger picture Battisti paints is scary. I hope a lot more research focuses on the problem. This also raises the stakes in the biofuel-versus-food debate.
The MIT workshop addressed the questions of whether geoengineering is possible and whether we should attempt it. The consensus was that precious little science has been done on geoengineering, what science is emerging is revealing that geoengineering is highly risky and uncertain, global warming is so bad that we need to consider geoengineering anyway, and we need to get busy with research on the problem. Several scientists expressed concern that we won't be able to reduce the uncertainty in the time we have left.
The issue of the geoengineering moral hazard – whether taking geoengineering seriously leads people to weaken their resolve on emissions reductions – was also discussed at the workshop (see previous post).
Eric Smalley is the editor of Energy Research News. He has written about technology since 1987 and has freelanced for many publications including Discover, Scientific American, Wired News and The Boston Globe on topics ranging from quantum cryptography to global warming.
