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

Richard 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. And there's also the side benefit that once collected, methane can be burned to provide energy. (In fact, it's the main ingredient in natural gas.)

Now, here's the bad news: We've written before about the prospect of hitting a "tipping point" when greenhouse gases go out of control because of the melting tundra and permafrost of the northern regions. Well, Harris' piece points out that methane's concentration in the atmosphere kept going up in concert with the Industrial Revolution. Then -- and no one's really sure why -- atmospheric methane levels stopped increasing in the 1990s. But as of 2007, methane levels started rising again.

Now, here's the really troubling part: One of the biggest potential sources of methane is melting permafrost and tundra. The question is whether what we're seeing is the beginning of a vicious cycle: the more methane escapes from the tundra and permafrost, the more the atmosphere is warmed... which thaws more tundra and permafrost (not to mention melting glaciers and the arctic ice caps)... which causes more tundra and permafrost to thaw, and so on.

One of the two scientists quoted in Harris' NPR piece is Drew Shindell of the NASA Goddard Institute for Space Studies, who I was lucky enough to meet at The New York Times Institute on the Environment last spring. He laid on the assembled journalists one of the easier-to-understand explanations of many facets of global warming I've heard, including this sobering fact: If we stopped emitting all greenhouse gases tomorrow, the effects of global warming that we've already felt since the beginning of the Industrial Revolution would double before things started to return to normal again.

We are headed toward a period of drought in the West even more intense than the one that drove the Anasazi from their cliff dwellings, Shindell said. And as for methane?

Methane, if it escapes from the Arctic, would dwarf all the warming we have seen to date.

Methane comes from a variety of sources. Some -- like cow farts -- are hard to control. But others -- like methane escaping from cow dung -- are pretty darn easy to capture if the poop is composted where the methane can be gathered and used as energy. Other easy fixes would capture methane from landfills, coal mines and gas-drilling operations.

For a mere $200 million, the scientists argue, the world could start taking a big bite out of global warming right now -- and provide ourselves with energy and better health at the same time.

The op-ed concludes: