I have a colleague who cares passionately about the environment. She worries about global warming, supports policy to reduce carbon emissions, and is militant about keeping the heat down and maintaining the proper tire pressure in her car. Yet her car is an SUV that gets shameful (her words) gas mileage. She lives in a large house — even by American standards — and recently purchased a second home in the mountains. Another colleague badgers his teenagers to take shorter showers and fishes even the tiniest scrap of plastic out of the garbage — but several times this fall, he rode his motorcycle hundreds of miles through the back roads of New Hampshire and Vermont to enjoy the foliage. He readily admits to feeling conflicted.