Mike Tidwell comments -A market approach to reducing greenhouse emissions is gaining in popularity. The idea being that industries which are releasing carbon into the atmosphere could get a credit or an offset from someone who was sequestering carbon, by, for example, planting trees. The backers hope that these schemes will become a market-based solution, that will allow our society to avoid climate change. It is important to keep in mind that these efforts can only be successful to the extent to which they prevent deep-earth carbon—methane, oil, and coal—from entering our atmosphere. This is because such carbon increases the all important above-ground reservoir of carbon that controls climate. It is foolhardy to believe that we can continue to pull these carbon molecules from below ground, release them above ground, and then hope that we can somehow offset these emissions by planting trees, trading credits, and so forth. Don’t be fooled. Watch the below-ground carbon numbers, they are the only legitimate measure of success in our fight to avert catastrophe.