Let's start with two thought-provoking questions: 1. If we stop greenhouse gas emissions, won't the climate naturally go back to the way it was before? 2. Isn't there "warming in the pipeline" that will continue to heat up the planet no matter what we do? The correct answer to both questions is "no". This subject was examined in a recent peer reviewed science paper that you can read about here : http://skepticalscience.com/global-warming-not-reversible-but-stoppable.... The paper referred to does not make one obvious point clear : it is the CO2 from fossil fuels that matters, CO2 from natural sources ( like what we breathe out or from a wood fire ) has no effect on the total CO2 level because the carbon in it was recently removed from the air, passed through the food chain, and is just returning to the air. Fossil fuels, on the other hand, were formed many millions of years ago when slow geological processes sequestered carbon from trees or leaves or plankton. Burning fossil fuels (which amounts to humankind's harvesting of ancient solar energy) thus dumps large quantities of ancient carbon into the global system. It has been suggested that we could counteract this with large-scale modern carbon sequestration, by making charcoal from trees or crop residue, and plowing it into farmers fields. This would enrich the soil, but it is likely to be much more expensive than a concerted effort to drastically reduce the use of fossil fuels. Remember, what we do now DOES matter (see the answer to question 2 above). If you have heard arguments against global warming -- and some of those arguments do sound plausible at first hearing -- please take the time to read the specific replies here : http://skepticalscience.com/argument.php?f=taxonomy Phil
