It's been a long slog to get to this election day. We all know the campaigns spent millions to get their messages across. But Bob Grant at The Scientist wondered about the environmental cost (log-in required)—specifically how much the campaigns of Sens. Barack Obama and John McCain contributed to global warming. Based on total campaign expenditures—including flying, driving, and printing materials—Grant (with help from consultant Standard Carbon) estimates  that the Obama camp emitted nearly 78,000 tons of climate-change inducing carbon dioxide (CO2) and the McCain campaign roughly 59,000 tons of CO2.

Standard Carbon suggests planting 18 square miles of new trees to offset that climate change pollution—the growing trees would theoretically soak up an equivalent amount of CO2—but such carbon offsets don't address the core of the problem: burning fossil fuels.

Of course, fossil fuels have been a big campaign issue. McCain supports offshore drilling while Obama argues that oil companies that now have rights to drill should do so to keep pump prices sliding. McCain is unsympathetic to the plight of grizzly bears and Palin would like to shoo away fruit fly research. Here's a complete rundown of the candidate's environmental positions.

But both presidential candidates consider global warming to be a critical problem (although McCain has seemed to edge away from his own legislative efforts over the course of the campaign) and believe something needs to be done to reverse it, such as legislation requiring curbs on CO2 emissions across the board in the form of a carbon tax or a cap-and-trade regime.

And if you're wondering why anyone would care how much CO2 the candidates' campaign jets have spewed into the atmosphere, check out this video on carbon and what to do about greenhouse gas pollution.

Credit: U.S. Air Force