Over the past few days, I've been trying to pull together some data on how airplane travel affects global warming, as part of a broader project on transportation and climate change. My stunningly obvious conclusion: it's complicated. Worse, different calculation methods yield wildly different results. Take, for instance, this brilliant chart (below) from the Stockholm Environment Institute, comparing many of the major online emissions calculators. Emissions are represented by the light blue lines. As you can see, the online calculators find that a Boston-D.C. round trip has the impact of somewhere between 0.19 tons and 0.48 tons of CO2 emissions, …

A new study by researchers at a British Columbia cancer agency stands as a stark reminder that, when it comes to pollution, an ounce of pollution prevention is worth a pound of cure: Researchers found people with the highest levels of a certain type of insecticide in their blood had 2.7 times the risk of developing non-Hodgkin lymphoma as those with the lowest amounts ... People with PCBs in their blood, meanwhile, had twice the risk of developing the disease as those with the lowest exposures. That's about the same level of increased risk as having a family history of …

France is supercharging vehicle efficiency -- not by doling out big R&D subsidies for cars that never make it to market, but by instituting a system of efficiency feebates. In a nutshell: the French ministry of ecology has announced a program that would require purchasers of new gas guzzlers (luxury Mercedes, for example) to pay an extra fee for the privilege. That money is rebated to people who buy super-efficient cars. If it's done right, the system doesn't really involve taxpayers, since the rebates balance out the fees. And it gives huge incentives for sales of the most gas-miserly vehicles. …

Can anyone out there help me out? Doing some fact-checking for a book, I ran across a question I didn't know the answer to: How much power is consumed by lighting in the U.S.? I spent a bit of time Googling for an answer, but at risk of looking like a dim bulb, I have to confess -- I just couldn't figure it out! The Green Home Guide says that lighting uses 5 to 10 percent of household electricity. That lines up pretty closely with figures from the U.S. Energy Information Administration (part of the U.S. Department of Energy), which …

The headline says it all: "PacifiCorp labels coal a no-go for new plants." PacifiCorp has backed away from plans to build any new coal plants within the next 10 years, conceding that coal no longer can overcome tightening regulations and environmental opposition. This seems like a big deal, since -- in my opinion at least -- the gravest long-term climate threat from our part of the world is coal-fired power. Nationwide, coal power plants represent America's largest source of greenhouse-gas emissions; and there's still an awful lot of coal in the ground in the American West. Until recently, coal's abundance, …

At least someone gets it: All three of the leading Democratic candidates have proposed cap-and-trade plans that auction 100% of their CO2 permits. This is, economically speaking, the same thing as a carbon tax. The context: New York Times columnist Tom Friedman is complaining that no major presidential candidate has proposed a carbon tax -- which he takes as evidence that nobody has had the guts to take a stand in favor of policies that would "trigger a truly transformational shift in America away from fossil fuels." But as uber-blogger Kevin Drum points out, this is simply rubbish. There are …

A couple of years ago, I ran some numbers trying to figure out which was the better buy for the planet -- a biodiesel Jetta or a hybrid Prius. And I came to the tentative, but perhaps counterintuitive, conclusion that the best buy was ... wait for it ... a Toyota Corolla. The Corolla, you see, was thousands of dollars cheaper than the Prius (the runner-up), even after I accounted for all the savings on gas from driving a fuel-miser. And if you were a green-minded consumer -- someone whose top priority was reducing climate-warming emissions, say -- you could …

The Washington Post ran an interesting op-ed in its Think Tank Town section last week, arguing for a carbon tax. The nut graph: The only effective way to begin reducing greenhouse gas emissions and slow global climate change is to make it more expensive to emit carbon dioxide. Unless businesses and consumers pay a price for carbon dioxide, neither will make the investments in technology and changes in energy use needed to dramatically reduce emissions. Rock on, Think Tankers. But that's just the start of the goodness. The authors -- two researchers from RAND Corporation -- also put forth a …

From an awesomely meaty article on cap-and-trade from The San Francisco Chronicle comes this pearl of wisdom (in bold at the bottom of the quote): [T]he lesson of the acid rain program is to keep the plan simple and easy for all parties to understand. "If it starts to employ a lot of special provisions to take care of every party's special needs ... and if it starts to look like the Chicago phone book, then throw it out," [RFF economist Dallas Burtraw] said. "A poorly designed market is worse than no market at all." I'm not sure I'd go …

On the heels of the year's biggest travel week, some interesting news: Consumers purchased an average 9.32 million barrels of gasoline a day in the week ended Nov. 23, down 1.7 percent from the same week last year ... It was the fifth consecutive week that demand at the pump dropped compared with a year earlier. The price [of gas] was 38 percent higher than a year earlier. That's right, population rose, but gas consumption fell, year-over-year. Measured per person, that's a decline of about 3 percent -- not huge, but still noteworthy. So does this mean that higher prices …