Intergovernmental Panel on Climate Change

The short but interesting (and climate-clobbering) life of methane, that *other* greenhouse gas

rm iwest mugRichard Harris' NPR piece today on methane's climate-clobbering effects jolted me to remember a post I planned but that went by the wayside when I got so busy editing our coverage of last month's big climate conference in Copenhagen.

During the big UNFCCC negotiations, an op-ed of huge import came out but didn't get as much attention as you might think, considering it was co-authored by Robert Watson, former chair of the Intergovernmental Panel on Climate Change, and Mohamed El-Ashray, a senior fellow at the United Nations Foundation. Reducing carbon dioxide emissions is important, they acknowledged, but a big focus in the next few years should be methane, because it traps heat in the Earth's atmosphere much more efficiently than CO2. And methane converts to carbon dioxide after 10 or 12 years -- compared to CO2's residence time in the atmosphere that's measured in hundreds of years.

Methane's quite a bit easier to control, too (for now -- more on that shortly). So, to buy time to invent better ways to reduce CO2 emissions,  focus on methane, Watson and El-Ashray argue:

If we need to suppress temperature quickly in order to preserve glaciers, reducing methane can make an immediate impact. Compared to the massive requirements necessary to reduce CO2, cutting methane requires only modest investment. Where we stop methane emissions, cooling follows within a decade, not centuries. That could make the difference for many fragile systems on the brink.

Both Harris' piece and the op-ed point out that controlling methane also helps fight ground-level ozone, a public health threat.