America's vast stretches of farmland are a big resource in the fight against global warming because their soil traps carbon. But not all farmers believe changing their ways to help in that fight would be profitable.
The global warming bill the House passed last summer gives farmers incentives to manage their soil to trap carbon, one of the main factors in global warming.
"The less we can have a carbon footprint, I think the better we are," says Carmen Fernholz, an organic farmer in western Minnesota.
Fernholz does things a little differently from most other farmers. For instance, he plants radishes in the late summer after his main crop harvest, but the radishes will never be harvested for food. Instead, he leaves them in the ground all winter long.
"In the spring as the temperatures warm up, the radishes start decaying and disappearing," Fernholz says. "And in this decay process, it's slowly releasing the nutrients that it scavenged the previous fall."
Those nutrients will help fertilize next year's crop. But the radishes also help fight global warming. Through photosynthesis, the radishes convert carbon dioxide, a greenhouse gas, into organic plant matter.
When the radishes die and decompose, the carbon in the plant also remains stored in the soil. Fernholz says the nutrient benefits are his main objective in planting the radishes, but he also likes knowing they help reduce greenhouse gases.
"The less we can have a carbon footprint, I think the better we are," Fernholz says. "So yes, there's no question that's where I'm looking at, in those directions."
If the U.S. House has its way, there could be a lot more farms like Fernholz's in the future. The House passed a bill last summer aimed at reducing global warming, and the Senate will take up the legislation soon.
The House bill would pay farmers to manage their land to store carbon — the carbon is "sequestered," in agricultural parlance. Fernholz says the legislation signals a change in the world of farming.
"I think the fact that it did pass is definitely a positive," Fernholz says.
Some farmers worry the bill will raise the cost of agriculture and possibly put them out of business. Others, like James Dontje, say the House bill doesn't go far enough.
"It was really an attempt to limit how much agriculture had to change," Dontje says. "It conveys the message of, 'Leave us alone, we don't want to change.'"
Dontje manages the Johnson Center for Environmental Innovation at Gustavus Adolphus College in St. Peter, Minn., and is part owner of a farm just across the Minnesota border in northern Iowa. Dontje says a big part of the "leave us alone" message in the legislation concerned protective measures for ethanol made from corn.
"Outside of farm country, the ethanol industry is seen as a political pork barrel project," Dontje says.
But for many farm-state House members, including their leader, U.S. Rep. Collin Peterson, D-Minn., ethanol is a success story. Although supporters say that ethanol helps reduce greenhouse gases, Dontje says it may actually contribute to global warming.
He says that's because the fuel helped boost corn prices, causing farmers in other parts of the world to plow up virgin land to grow the suddenly very profitable grain. That land breaking releases significant amounts of greenhouse gases.
The House bill prohibits using the land issue in calculating ethanol's carbon footprint. Dontje says those sorts of protective measure are the wrong position for farmers to take.
"Carbon sequestration will have some value and that becomes an income stream," Dontje says. "By adopting an oppositional, 'keep your hands off approach,' agriculture might miss some of the opportunities."
He says those opportunities include expanding production of farm-based energy, ones that are more efficient than corn ethanol. He says that includes biofuels made from grasses and other farm produce. The grasses store carbon in the soil, and the fuel would help reduce gasoline use, a major source of greenhouse emissions.
Dontje says another opportunity is to use gas collectors which capture livestock methane emissions, a contributor to global warming. Dontje also says more wind energy production should be built, reducing the nation's reliance on coal-based electricity.
"Carbon legislation can really affect that," Dontje says. "Because those kinds of efforts will become very valuable if we truly account for the cost of carbon in the system."
But many farmers say the proposed climate legislation will increase their cost of doing business. Among them is southern Minnesota farmer Lawrence Sukalski.
Sukalski checked on the corn he has stored in one of his bins, to make sure there's no mold growing on it. Sukalski keeps close track of the corn because it's one of his major moneymakers. He's worried the global warming legislation could change that.
"If it passes, we're going to have Europe-style food prices and Europe-style fuel prices," Sukalski says. "Everything will be so high you won't be able to do anything."
Including making a profit on the farm. Sukalski says the climate bill will force petroleum refiners, the electricity industry and others to spend money on reducing greenhouse gas emissions. He says those costs will be passed on to consumers, including farmers, in the form of higher energy prices.
Sukalski doubts that farmers will be able to offset those higher costs with money made from sequestering carbon on their land.
"I am not sold that this will make money for the farmers later on down the road," Sukalski says. "There's just too many things to it; it's too complex."
Recent research shows just how uncertain the economics of carbon sequestering are. Many people think no-till will trap large amounts of carbon in the soil. The theory is the practice reduces the amount of soil-based carbon escaping into the air compared to conventional plowing.
Deborah Allan, a soil scientist at the University of Minnesota, says her research fails to show that's true.
"I feel pretty confident that for Minnesota, it's not going to be a net gain in carbon in a no-till situation," Allan says.
But even if no-till does not pay off, Allan says there are plenty of other ways farmers can hold carbon. Planting trees or perennial crops, like alfalfa, or Carmen Fernholz's tillage radishes, could be additional components to reduce carbon and prevent the consequences of a too-warm plant.
"It's on my mind all the time," Fernholz says. "It's just sometimes you feel a little bit frustrated that you can't do more."
That frustration is something both sides of the farm debate over global warming are feeling. For some, like Fernholz, the fight against global warming is moving too slowly. For others, the pace is too rapid, and they fear it will do long-term damage to the job of producing food.