Slow climate change by cutting other gases
Carbon dioxide remains the undisputed king of recent climate change, but other greenhouse gases measurably contribute to the problem. A new study, conducted by NOAA scientists and published online Friday in Nature, shows that cutting emissions of those other gases could slow changes in climate that are expected in the future.
click image to zoomNOAAThe direct warming influence of all long-lived greenhouse gases in the atmosphere today attributable to human activities. CO2’s warming influence of 1.7 watts/m2 is equivalent to the heat from nearly 9 trillion 100-watt incandescent light bulbs placed across Earth’s surface. The combined influence of the non-CO2 greenhouse gases is equivalent to the heat from about 5 trillion bulbs. The category “other”includes a few very long-lived chemicals that can exert a climate influence for millennia. Discussions with colleagues around the time of the 2009 United Nations’ climate conference in Copenhagen inspired three NOAA scientists – Stephen Montzka, Ed Dlugokencky and James Butler of NOAA’s Earth System Research Laboratory in Boulder, Colo. – to review the sources of non-carbon dioxide (CO2) greenhouse gases and explore the potential climate benefits of cutting their emissions.
Like CO2, other greenhouse gases trap heat in Earth’s atmosphere. Some of these chemicals have shorter lifetimes than CO2 in the atmosphere. Therefore cutting emissions would quickly reduce their direct radiative forcing — a measure of warming influence.
“We know that recent climate change is primarily driven by carbon dioxide emitted during fossil-fuel combustion, and we know that this problem is going to be with us a long-time because carbon dioxide is so persistent in the atmosphere,” Montzka said. “But lowering emissions of greenhouse gases other than carbon dioxide could lead to some rapid changes for the better.”
Scientists know that stabilizing the warming effect of CO2 in the atmosphere would require a decrease of about 80 percent in human-caused CO2 emissions — in part because some of the carbon dioxide emitted today will remain in the atmosphere for thousands of years. In contrast, cutting all long-lived non-CO2 greenhouse gas emissions by 80 percent could diminish their climate warming effect substantially within a couple of decades. Cutting both CO2 and non-CO2 greenhouse gas emissions to this extent could result in a decrease in the total warming effect from these greenhouse gases this century, the new paper shows.