To stabilize the climate and avoid catastrophe (such as sea level rise, shrinkage of Arctic Ocean ice and global heat waves), we will need to cut carbon emissions by a minimum of 70 percent, according to a recent study by scientists at the National Center for Atmospheric Research in Boulder, Colorado. That level of reduction would stabilize atmospheric concentrations of CO2 at about 450 parts per million — roughly 17 percent higher than current levels.

Their study, which will be published in the journal Geophysical Research Letters, states that "we can no longer avoid significant warming during this century," but implies that we do still have the opportunity to control it. By the end of this century, the research says, a 70 percent reduction in CO2 emissions could hold temperature increases to roughly 1 degree F above current levels. But we know that 450 parts per million is not where we need to be. An overwhelming majority of scientists, including NASA scientist James Hansen, state that where we need to be looks a lot more like 350 ppm, if we are to stay in the Holocene. The way we see it, what this study is inadvertently saying is that we need zero, now, before the world becomes a much different, much less inhabitable place.

Via: Worldchanging