How often do you get to save the planet, reduce America's dependence on foreign oil and create an economic boom for Minnesota corn farmers -- all at the same time?

It's easy. Join our governor and Legislature as they peddle ethanol -- this three-in-one miracle cure -- to the state and nation.

But what if the miracle cure turns out to be snake oil?

What if ethanol and similar biofuels actually damage the environment more than the fossil fuels they replace?

That's the conclusion of David Tilman, Regents professor of ecology at the University of Minnesota. In a recent study, according to a Star Tribune report, he and his co-authors point out that as farmers around the world rush to meet rising demand -- actually, rising mandates -- for ethanol by clearing forests and grasslands, they are releasing far more carbon dioxide than is saved by biofuels' lower emissions.

In fact, the study estimates that the process could release hundreds of times more carbon than it saves by replacing fossil fuels.

Here in the Midwest, farmers are rapidly returning to cultivation lands that the government has paid them to set aside for conservation.

The study calculates that "it will take 93 years for the carbon losses from plowing one acre of healthy grassland to equal the carbon savings from corn-based ethanol produced on that land," according to the Star Tribune article.

Ethanol production also threatens our aquifers, according to another Star Tribune story, which are vital for both municipal and agricultural water use. The industry is slurping up about 2 billion gallons of groundwater every year, according to state estimates, and the figure may quadruple by 2011.

In a particularly troubling development, ethanol production is contributing to a steep rise in global food prices. Last year, Jean Ziegler, a U.N. food expert, called the practice of using crop land for biofuel production a "crime against humanity," according to the Associated Press. The soaring price of corn and wheat and the hunger that results, he said, is "a growing catastrophe" for the world's poor.

So much for ethanol as a tool for saving the planet. But at least by adding it to our gasoline, we are reducing our dependence on fossil fuels, right? Wrong. Ethanol production is highly energy intensive. It takes lots of fuel to run biofuel plants, and lots of natural gas to make the nitrogen fertilizer that corn craves. Though estimates vary, ethanol production consumes nearly as much energy as it produces.

Is ethanol the solution to our dependence on foreign oil? Nope. James Eaves and Stephen Eaves, writing in Regulation quarterly, observe that "if we devoted 100 percent of all corn grown in the United States to producing ethanol, we could displace only about 3.5 percent of current gasoline consumption." That's "only slightly more than we could displace by making sure drivers' tires are inflated properly," they add.

A boon for farmers

Ethanol has one big advantage, though. It's is an economic boon for corn farmers and ethanol producers. Minnesota now has 17 ethanol plants; another six are being built and 10 more are on the drawing board. A 2005 law requires that by 2013 ethanol must make up 20 percent of state gasoline, up from 10 percent today.

But a heavily subsidized business is not the same as a healthy business.

Big Ethanol's problem is that ethanol is more costly and inefficient than petroleum-based fuel, and so has a tough time attracting consumers in a free market. As a result, special interests have pressured government to create an industry by passing laws to compel demand and subsidize ethanol production.

From 1987 to 1998, the Minnesota Legislature even appropriated about $100,000 a year in part to "educate" the rest of us about ethanol's supposed benefits. You'd expect Republicans, traditionally devoted to free market principles, to raise a ruckus about this.

Sen. David Hann, R-Eden Prairie, has tried. Several years ago, he introduced a bill to compel ethanol producers to account for the role that public subsidy plays in their business. The bill went nowhere.

"Ethanol is bad science, bad environmental policy and bad economic policy," said Hann. "But Republicans are reluctant to acknowledge that, because they don't want to go against their friends in the agricultural sector, and because it's hard to resist the popular conception that renewable fuels will somehow solve our energy problems."

Any way you cut it, it's time to close up shop on this boondoggle.

Katherine Kersten • kkersten@startribune.com Join the conversation at my blog, Think Again, which can be found at www.startribune.com/thinkagain.