The kind of volatile weather anticipated in the National Climate Assessment is already being seen in the corn belt, agronomist Hatfield says. In 2010, Iowa endured its wettest summer on record and its warmest nighttime temperatures, he says. Corn went from pollination to maturity in 35 days instead of 50, which was bad news for farmers as stressed-out crops yielded a poor harvest. In 2012, Iowa was gripped by the worst drought since 1934 only to experience river flooding in March, topped off with a sudden dry spell.
“This is outside our normal thinking in terms of what our climate looks like,” says Hatfield, the laboratory director of the National Laboratory for Agriculture and the Environment in Ames, Iowa, which is part of the USDA.
Hatfield is developing ways for farmers to adapt. An upbeat man with salt-and-pepper hair, he notes that in the broader discussion of climate, soil is often forgotten. But it’s one element we can actually manage, he says. “We’re never going to make it rain, but what we can do is capture every drop of water and make it available to the plant.”
Hatfield has urged farmers to stop plowing before they plant and instead blanket the soil with corn husks, leaves and other leftovers from last year’s harvest. Microbes feed on this organic matter and enrich the crops with nutrients. Soil cultivated in this manner loses less moisture through evaporation.
Hatfield has found corn plants can send roots 2.2 meters (7.2 feet) into the earth instead of 1.2 meters, tapping deeper groundwater. For every 2 to 3 percent increase of organic matter in the soil, its capacity to hold water jumps 25 percent, Hatfield says, and that boosts yields, even in dry years. About 20 percent of the growers in Iowa have adopted Hatfield’s water- conscious method of tillage.
Going to be Surprised
Forecasting exactly how much of an impact the warming will have on the $300 billion-a-year U.S. agriculture industry is a challenging exercise, says John Reilly, an economics professor at the Massachusetts Institute of Technology. The problem is that most climate models are too generalized to predict how changes in rainfall will affect particular crops in specific areas or how rising temperatures will affect the spread of pests and insects.
“Everyone is trying to put together a quantification of what this all means, but our tools lack the precision we need,” Reilly says. “All the modeling we do tends to smooth out the fact that there’s a high probability that we’re going to be surprised.”
That’s the problem the Risky Business study will have to solve if it’s to be at all effective. Yet Paulson says he has a far bigger worry. “The biggest problem we’re dealing with is a sense of hopelessness,” he says. “But I’m saying we’re the first generation with the knowledge and the ability to do something: We don’t need new science, and we have great technology. We need the will to act now so we don’t leave our children and grandchildren with a catastrophic burden.”
Along with Steyer and Bloomberg, Paulson is betting that as climate change, once a distant possibility, becomes altogether real, our economic self-interest will be the thing that finally provokes a popular call for action. That will almost certainly have to be making carbon dioxide emissions expensive by either taxing or regulating the gas on a global basis, Steyer says.