If your goal is keeping the earth’s temperature rise below 2°C, the only thing you have left is hope. Hope that the climate sensitivity—how much the global temperature rises from an increase in greenhouse gas concentrations—is far beneath what the climate models calculate it to be. When it comes to trying to use emissions cuts to achieve the 2°C goal, the cat is already out of the bag—maybe not in terms of emissions-to-date, but almost certainly so for emissions-to-come.
Such is the conclusion implicit in the recent analysis by Joeri Rogelj and colleagues published in a recent issue of Nature magazine.
Rogelj et al. did yeoman’s work in collecting all the varied (non-binding) efforts pledged by all of the various countries of the world to reduce their greenhouse gas emissions under the Copenhagen Accord that came out of last December’s big United Nations Climate Conference.…
Air quality from America’s coal plants have been improving for decades, even before Congress passed the Clean Air Act of 1970. And since 1970, the six so-called criteria pollutants have declined significantly overall and in the generation of electricity, even though coal-fired generation has increased by more than 180 percent.[i] (The “criteria pollutants”—those for which the EPA has set criteria for permissable levels—are carbon monoxide, lead, sulfur dioxide [SO2], nitrogen oxides [NOx], ground-level ozone, and particulate matter [PM]).
…Specifically, total SO2 emissions from coal-fired plants were reduced by about 40 percent between 1970 and 2006, and NOx emissions were reduced by almost 50 percent between 1980 and 2006. On an output basis, the percent reduction is even greater, with SO2 emissions (in pounds per megawatt-hour) almost 80 percent lower, and NOx emissions 70 percent lower.