You might find this hard to believe, but the federal government’s push to boost ethanol production has led to unanticipated results no one would have supported. Even the Associated Press recognizes the problem.

The hills of southern Iowa bear the scars of America’s push for green energy: The brown gashes where rain has washed away the soil. The polluted streams that dump fertilizer into the water supply.

Even the cemetery that disappeared like an apparition into a cornfield.

It wasn’t supposed to be this way.

With the Iowa political caucuses on the horizon in 2007, presidential candidate Barack Obama made homegrown corn a centerpiece of his plan to slow global warming. And when President George W. Bush signed a law that year requiring oil companies to add billions of gallons of ethanol to their gasoline each year, Bush predicted it would make the country “stronger, cleaner and more secure.”

But the ethanol era has proven far more damaging to the environment than politicians promised and much worse than the government admits today.

As farmers rushed to find new places to plant corn, they wiped out millions of acres of conservation land, destroyed habitat and polluted water supplies, an Associated Press investigation found.

Five million acres of land set aside for conservation — more than Yellowstone, Everglades and Yosemite National Parks combined — have vanished on Obama’s watch.

Landowners filled in wetlands. They plowed into pristine prairies, releasing carbon dioxide that had been locked in the soil.

Sprayers pumped out billions of pounds of fertilizer, some of which seeped into drinking water, contaminated rivers and worsened the huge dead zone in the Gulf of Mexico where marine life can’t survive.

The consequences are so severe that environmentalists and many scientists have now rejected corn-based ethanol as bad environmental policy. But the Obama administration stands by it, highlighting its benefits to the farming industry rather than any negative impact.