Many green-minded people give lip service to the idea of local produce, but how many of us eat local all winter long? An organic gardener in Vermont is pioneering a new type of greenhouse that might make winter growing more feasible for aspiring locavores by using heated soil.

In its spring issue, Vermont’s Local Banquet magazine pays a visit to Carol Stedman’s greenhouse, where in January “the air temperature inside was only slightly higher than outside … but a thermometer stuck deep in the dirt read a balmy 60 degrees.” Stedman uses tubes to circulate warm water through the soil, a system she calls “radiant dirt heating.” Her can-do attitude and experimental spirit might just get you started on planning and designing your own “cool greenhouse” for next winter.

The “cap-and-trade” strategy for reducing greenhouse gases isn’t a new idea. But that doesn’t mean it’s easy to understand. Even after reading numerous articles on it, the concept of an emissions market where companies can trade shares of pollution still makes my head spin. But in “The (Very Profitable) Economics of Emissions” in the Jan.-Feb. issue of Mental Floss (article not available online), writer Sam Kean makes sense of an abstract idea:

Instead of looking for ways to dump pollution, companies “own” their emissions output and can trade it like a commodity. For instance, if a business has 25,000 permits but only needs 20,000, then it can sell the extra shares for cash. Or, if a company unexpectedly exceeds its pollution limit, it can buy extra permits to cover itself.

The result is a “cap-and-trade” market, which allows the government to screw down maximum emissions levels and lessen pollution by taking shares out of circulation. When shares disappear, the supply goes down, and the remaining shares become more expensive. Eventually, it costs companies too much to simply buy extra permits and prompts them to invest in cleaner technology.

—Sarah Pumroy

Would Sen. John McCain be a good environmental president? Don’t bet the planet on it. Joseph Romm at Salon writes that although the Republican nominee-to-be is the only GOP candidate who believes in the science of global warming and who has proposed legislation to reduce greenhouse gas emissions, his green credentials are shaky at best.

“While McCain may understand the scale of the climate problem, he does not appear to understand the scale of the solution,” writes Romm. Unless a President McCain appointed judges and agency heads who would not gut efforts to address climate change—something he’d be unlikely to do—he wouldn’t make much headway. Romm also points out that McCain has backed huge subsidies for nuclear power, yet he “remarkably” told Grist in an interview last October that wind and solar need no such help.

Over at Huffington Post, Arianna Huffington also calls out McCain on his environmental wishy-washiness in “End of a Romance: Why the Media and Independent Voters Need to Break Up With John McCain”:

“The old John McCain talked about trying to do something about global warming and encourage renewable energy. The new John McCain didn’t show up for a vote last week on a bill that included tax incentives for clean energy, even though he was in D.C. And then his staff misled environmentalists who called to protest by telling them that he had voted for it.”

McCain is still getting mileage out of the “maverick” label that no longer applies, Huffington claims. But perhaps he’s still a maverick when compared to green voters: He’s got almost nothing in common with them.

—Keith Goetzman

Image by  Geoffrey Chandler , licensed under Creative Commons.