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MARK AUSTIN THOMAS: An environmental think tank says the government has vastly underestimated the demand for corn by the ethanol industry. It says that could lead to higher prices at the grocery store. From the Marketplace Sustainability Desk, Sam Eaton reports.

SAM EATON: The Earth Policy Institute says U.S. ethanol plants, which turn corn into fuel, will consume half of the nation’s harvest next year.

That’s more than double the government’s projections.

The Institute’s president Lester Brown says that disparity could trigger everything from higher supermarket bills at home to political instability abroad.

LESTER BROWN: What this means is that there just won’t be enough corn to go around. And this is not going to just affect this country, it’s going to affect the entire world.

Corn is the world’s largest grain crop. Most of it is grown in the U.S. but Brown says more ethanol plants here mean less of that corn is exported, driving up food costs as far away as China.

I’m Sam Eaton for Marketplace.