Balancing the World's Carbon Budget
The recent meeting in Paris on climate change ended with a challenge to all the countries of the world: do not settle for a global warming of 2°C, but aim for a much more ambitious goal of 1.5°C. Scenarios based on either target require taking carbon dioxide already emitted back from the environment and dispose of it safely and permanently in order to create net negative carbon dioxide emissions. This calls for technologies that can remove carbon dioxide from air and a storage capacity for spent fossil carbon that is sufficient to cope with an amount of carbon dioxide comparable to last century's emissions. I will argue that negative emissions are technically feasible and outline approaches that have the potential for cost effective implementations and could operate at the scale necessary to significantly reduce carbon dioxide concentrations in the air and the ocean. If the good intentions of Paris are to be realized, the release of carbon dioxide to the atmosphere must be outlawed, just like the dumping of raw sewage into rivers and lakes is outlawed in most nations.