This post is by ClimateProgress guest blogger Bill Becker, executive director of the Presidential Climate Action Project.

All that glitters is not gold. And all that grows is not green.

fieldThat is the belated realization about grain ethanol — in fact, about any ethanol whose feedstock is grown on cropland. Joe Romm has done a good job posting on this issue, including his report on the recent studies featured in Science magazine. I’d like to weigh in with a few additional points.

The folly of grain ethanol moved this week from Science magazine to Time in a cover article titled “The Clean Energy Scam.” Time traces the carbon-rich life cycle of fuel from grain. As food and fuel compete for corn, the price of the crop rises. As the price rises, farmers have more incentive to grow it. To grow it, they use energy-intensive fertilizers and fuels.

To create more corn, farmers are turning prairies into cropland, releasing carbon that was stored by grasses and undisturbed soils. That unfortunate trend is well underway. As USA Today reports, landowners throughout the Farm Belt are growing crops on land that has not been cultivated for decades — or, in some cases, centuries. Last year, farmers pulled 2.5 million environmentally sensitive acres out of the federal Conservation Reserve Program. Another 5 million acres now preserved under CRP are scheduled to become available for planting over the next two years, as farmers’ conservation contracts expire.

It’s likely that carbon sequestration was not among the CRP’s objectives when the program was created in 1985. Its purpose was to protect wetlands and wildlife habitat. Now, wildlife, ecosystems, and the atmosphere all will miss the program’s benefits as America’s thirst for grain alcohol fuels the drive for more cropland.

The damage extends beyond the U.S.

The rapid push for grain ethanol creates a ripple effect that results in deforestation in Brazil, according to Time. One-fifth of the U.S. corn crop is being diverted to ethanol. Chasing profits, farmers who grow soybeans have switched to corn, which has reduced world soybean supplies. To meet global demand for soybeans, farmers in Brazil are turning pastures into cropland. To replace their lost grazing land, ranchers are clearing rain forest in the Amazon and contributing to deforestation, which accounts for one-fifth of global carbon emissions.

And believe it or not, some of the nation’s ethanol plants burn coal.

So, is grain ethanol a clean fuel? You do the math. Congress certainly didn’t. Nor did the White House. It’s not that they’re incapable. It’s that ethanol appeared to be a way to please the environmental lobby, the farm lobby, and industrial giants like Archer Daniels Midland all at the same time, while addressing energy independence and climate change. The carbon-intensive life cycle of grain ethanol was utterly predictable, had it been given thought.

“The lesson behind the math,” concludes Time, “is that on a warming planet, land is an incredibly precious commodity, and every acre used to generate fuel is an acre that can’t be used to generate the food needed to feed us or the carbon storage needed to save us.”

There is some good news in this story. The rapid increase in ethanol production has demonstrated how quickly the nation can mobilize to produce new energy resources. With the right policies — such as a stable production tax credit — we might mobilize the economy just as quickly to create and sustain a boom in wind energy, solar energy, geothermal energy, low-impact hydro, and bioenergy from feedstocks that have positive net carbon and energy benefits. Among them are cellulosic materials grown on degraded and untillable land, organic municipal and agricultural wastes, and algae.

Despite the misadventure, ethanol has given rural America a taste of the prosperity it can achieve by becoming America’s renewable energy supplier. Now that the Rural Utilities Service at the U.S. Department of Agriculture has stopped making low-interest loans for new coal plants, it should turn its attention to investments in rural wind and solar farms, locally owned bio-refineries that use true-green feedstocks, waste-to-methane projects, and transmission extensions to stranded renewable resources. We should develop robust and lucrative markets for farmers to earn new income from climate-friendly land and forest management.

But back to the lesson. Given the urgency of climate change, the world cannot afford false starts, let alone policies that accelerate global warming and create potentially tragic trade-offs between hunger and environment.

We should apply the lesson of the unused calculator to all public energy subsidies. Consider our large investment in carbon capture and sequestration for “clean coal” combustion, another subsidy backed by the lobbying power of big industries. Does it make sense to invest so much hope and treasure in a technology that is not certain, that won’t be ready for a decade or more, if ever, and that may result in electricity prices that can’t compete with wind, geothermal, and even solar electric generation? With continued research and economies of manufacturing scale as they come into wider use, renewable generation technologies will become less expensive over the next few years while the cost of electricity from “clean coal” goes up, as much as 90 percent by one estimate.

Sound analysis might show that we’re better off investing in other things, such as new technologies to store wind and solar power — compressed air and plug-in hybrids, for example — to solve the intermittency problem.

To be fair, our false start on grain ethanol isn’t only Washington’s fault. A number of environmental and renewable energy groups have advocated ethanol without adequate distinctions between what is green and what is not.

Now the lesson should be clear for all of us: Before we institutionalize any new policy or public investment to solve our energy and climate problems, we need to do the math.

This post was created for, a project of the Center for American Progress Action Fund.