ROBERT SIEGEL, HOST:
Many consumers would love to eat food that is green, that is grown in a way that does the least harm to the environment. But take sugar - about half of our sugar comes from sugar cane, which grows where it's warm and wet and half from sugar beets, which grow where it's colder and drier. Each takes its toll, so how do you decide which is better?
Well, as NPR's Dan Charles reports, economists are now trying to figure it out.
DAN CHARLES, BYLINE: If you go to South Florida to the town of Belle Glade, there's a dramatic yet silent measure of the cost of growing food here. It's a concrete post painted white. Environmental scientist Len Scinto, from Florida International University, is standing beside the pole, and the top of it is above his head.
But in 1924, when researchers put that post here, drove it deep into the soil, the top of that post was level with the surface of the ground. Over the decades since, the land surface has fallen by six feet.
LEN SCINTO: We've lost two thirds of the soil right here.
CHARLES: That's because that soil was no ordinary dirt. It was peat, the remains of long dead vegetation. >>SCINTO: Old, decaying plant fibers and decaying roots, just this decomposing organic matter. It built up over 4 to 5,000 years in the northern Everglades - built up bit by bit.
CHARLES: For those thousands of years, it didn't rot away because the dead plants were submerged in water. But starting a century ago, people drained this area and created the Everglades Agricultural Area, a thousand square miles of fields for farmers like Rick Roth to grow vegetables and sugarcane, especially sugarcane.
RICK ROTH: I would make the argument that this is probably the best place to farm in the United States, if not the entire world.
CHARLES: But when this fertile soil was exposed to air, it started to decompose. It turned into carbon dioxide and vanished. In another 50 or 100 years, so much will be gone, it may not be possible to farm here anymore. There are also other problems with the Everglades Agricultural Area. It prevents water from flowing as it used to from Lake Okeechobee in the north into Everglades National Park in the south.
The water that does make it through picks up fertilizer from the farmland, causing more damage to the park. So environmental advocates and the government have been putting pressure on farmers to limit the damage, to use less fertilizer and keep more of the peat soil immersed in water. Rick Roth says he's is favor of all that. Protecting the environment is important, he says, but it can't be more important than growing food.
ROTH: They're trying to get the land away from the farmers saying that the Everglades is more important than food production, which I think is relatively insane. Cheap food is the number one goal. It should be the number one goal of the world.
CHARLES: This conflict between growing food and protecting the environment is not just playing out in the Everglades. It's everywhere, actually. If you don't get your sugar from here, maybe you get it from sugar beets growing on Bill Markham's farm near the foothills of the Rocky Mountains in Colorado. That meant plowing up grasslands a century ago and bringing in water. You can't grow much in this dry country without it.
BILL MARKHAM: You got water coming out of the mountains. All our water comes out of the Big Thompson River. And they dug all those canals and everything to get water to these farms.
CHARLES: But that takes scarce water away from fish and frogs and riverside vegetation. No matter where food is grown, it has some environmental cost. And increasingly, government officials and economists are trying to put a number on that cost. What's the price tag of soil in the Everglades or river water in Colorado, because that price, that number, might help all of us decide which food comes at a cost we're not willing to pay.
Economist Catherine Kling at Iowa State University says she's working on this.
CATHERINE KLING: In an ideal world, we would include the damages, the costs, in the decision about where to produce and how much to produce.
CHARLES: Kling admits that's not easy, but economists are inventive. They've studied how much farther people are willing to drive to visit a pristine ecosystem versus a polluted one. That's a measure of how much they value it.
KLING: Another way we do it is to straight out ask people.
CHARLES: How much would you pay to restore a wetland and bring back wildlife there? Like all prices, these are based on personal preferences. Kling says people tend to put higher values on ecosystems that seem unique, beautiful.
KLING: Original, natural.
CHARLES: So I'm just guessing they might think that the Everglades because it's unusual is more valuable than, say, the grasslands in Colorado.
KLING: That absolute would be my intuition.
CHARLES: Ecologists aren't always happy about these subjective judgments. They say an ordinary-looking grassland can be just as precious as an alligator-filled swamp. But Kling says there is progress. Policymakers and even consumers are starting to balance the value of food against the environmental cost of producing it. Dan Charles, NPR News.
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