4. Green myth: It's better to drive to your vacation destination than to fly. Fact: Not if your car is an SUV, station wagon, minivan, or truck. That may be mitigated, though, if you have the entire family in the car, or drive a car that's fuel-efficient.
5. Green myth: Compact fluorescent lights (CFLs) result in mercury emissions; incandescents don't. Fact: "CFLs generally result in less mercury emissions than conventional incandescents, since coal-based electricity generation is the single largest source of anthropogenic mercury emissions and CFLs save a considerable amount of electricity," says Hausfather. While much has been made of the mercury dangers of broken CFLs, he notes that most of the bulb's mercury is bound to the glass.
6. Green myth: Given a choice between paper bags and plastic bags, go with paper. Fact: From a standpoint of carbon emissions, they're equally bad. Plastic is worst from a solid waste perspective. (But plastic is a littering problem in many places.) Most environmentally friendly of all, as you already know, is bringing your own reusable bags (which is, admittedly, easier if you aren't buying groceries for a family of four).
7. Green myth: An electric car is best for the environment. Fact: If you live in a state where most of your electricity is generated by coal, that's not so. In those areas, electric cars can emit more carbon than high-efficient hybrids. Unless the electricity for the car is generated solely by renewable energy, electric vehicles are "far from zero emissions."
8. Green myth: If you want to help alleviate global warming, plant trees. Fact: Once again, it depends on where you live. In areas with cold winters, "the additional sunlight absorbed by the dark-colored trees just about offsets any cooling from carbon reduced." In high-latitude regions, "planting trees can actually heat up the earth," Hausfather says. However, in urban areas and the tropics, planting trees is good from a global-warming perspective. (Remember, this is talking only about benefits to the climate, not to trees or other ecosystem effects.)