How Much Carbon Must We Remove?

Scott K. Johnson spotlights a recent study by Andrew MacDougall on what is would take to return to a pre-industrial climate:

Because warming causes additional carbon to be released into the atmosphere, such as is the case with thawing permafrost, we’ll actually have to remove significantly more CO₂ from the atmosphere than we put there by burning fossil fuels. In fact, we’d have to remove roughly 40 percent more in the model simulations. … The study concludes, “These results suggest that even with monumental effort to remove CO₂ from the atmosphere, humanity will be living with the consequences of fossil fuel emissions for a very long time.” Solutions that limit the amount of CO₂ we end up emitting this century are investments. Not only do they obviously pay off in terms of warming avoided, but they also lessen the burden on future generations should they try to clean up the atmosphere they inherit.