Many people, when they learn that compact fluorescent bulbs contain mercury vapor, get skeptical about the much talked-about benefits of these and assume that traditional incandescent light bulbs are less damaging to the environment despite requiring more power and having shorter lives. After all, mercury is really bad stuff, right? "A toxic metal known to cause brain, spinal cord, kidney and liver damage in humans—does not break down easily and, once airborne, often finds its way into groundwater, rivers and the sea, where it can cause a host of contamination issues for wildlife and people alike." But as often is the case, the truth can be a bit counter-intuitive.
Ironically, compact fluorescent bulbs are responsible for less mercury contamination than the incandescent bulbs they replaced, even though incandescents don't contain any mercury. The highest source of mercury in America’s air and water results from the burning of fossil fuels, such as coal, at utilities that supply electricity. Since a compact fluorescent bulb uses 75 percent less energy than an incandescent bulb, and lasts at least six times longer, it is responsible for far less mercury pollution in the long run. A coal-burning power plant will emit four times more mercury to produce the electricity for an incandescent bulb than for a compact fluorescent.
Not to mention that it will save you money with a lower electricity bill.
Of course, the quote above is true for the US where coal is widely used to make electricity. It would be less true in France, although in that country a lower demand for electricity would lead to less nuclear power plants being built and so on... We also have to factor in that fluorescents can be recycled (even if right now only about 10% of them are recycled in North-America – that number is higher elsewhere in the world) and that when they are the mercury problem is avoided.
::Dear EarthTalk (thanks to B.K. DeLong for letting us know this link was pointing to a page that didn't exist anymore and helping us fix it.)