Everyone's always talking about how an aging population, with more retirees, is going to wreak havoc on Social Security and the federal budget. Here's my question: What impact will that have on the planet? After all, my grandparents don't seem to care much about global warming, their refrigerator is from the 1970s, and they use an awful lot of air conditioning at home. Give it to me straight: Are Grandma and Grandpa bad for the environment? "Do it for the kids" has always been one of the most popular arguments in favor of environmentalism: Older people need to get their...