Western scientists are turning their attention to methane yet again, saying it contributes as much as carbon dioxide to global warming, perhaps even more.
The warning comes in the backdrop of studies showing that the methane in atmosphere has begun to increase after a brief pause in the nineties.
What is of particular concern is that the methane production phenomenon could actually be setting off a vicious cycle.
It is like this. Methane is traced to all sorts of sources including wetlands, rice paddies, coal mines, garbage dumps, termites, even kangaroo farts!
The naturally occurring bacteria in wetlands that churn out methane become even more efficient in producing the gas as the temperature rises. Hence the concern over the recent trends.
Methane in the atmosphere had leveled off in the 1990s, so it seemed that efforts to control industrial emissions were keeping this problem gas in check. But since 2007, methane levels have been on the rise again, Richard Harris reported for the National People's Radio.
A study published last week in Science
magazine suggests that at least part of this increase is coming from the vast wetlands in Canada, Russia and the Arctic. The methane in wetlands comes from naturally occurring bacteria. But study author Paul Palmer at the University of Edinburgh says the bacteria are producing more methane because the temperature is rising.
"This really does demonstrate the fact that we are having this vicious cycle in the climate system. And we're seeing it now."
It's not yet to the stage where it's a runaway warming effect, Palmer says. But climate scientists are worried that we could hit that tipping point.
Molecule for molecule, methane is much more effective than carbon dioxide at trapping heat in the atmosphere, it is pointed out. And that's just part of the trouble.
Drew Shindell, at NASA's Goddard Institute in New York, told NPR, "Methane is much more complicated once it gets into the atmosphere than something like carbon dioxide is, and that's because it reacts with a lot of different important chemicals."
He recently totaled up all the effects of methane emissions and realized that the heating effect is more than 60 percent that of carbon dioxide's.
"So that tells you that methane is a pretty big player."
Also methane in the atmosphere has gone up by 150 percent since the pre-industrial period. So that's an enormous increase. CO2, by contrast, has gone up by something like 30 percent."
There's no obvious way to control methane from natural wetlands other than to keep them from overheating. But at least half of methane emissions are from human activities, ranging from cattle-rearing and natural gas exploration to coal mining.
Since methane is the main ingredient of natural gas, efforts to capture it can actually pay for themselves. You use the gas for energy. And Shindell says there are other benefits of controlling methane. Methane contributes to ozone, which costs society real money because of its human health effects, and ozone also damages crops.
"So if you account for all the economics, all the gains that you get through the benefits of controlling methane that aren't even related to climate, you find that many of the reductions you could make actually pay for themselves," Shindell says.
But third world environmentalists could cry foul. When carbon dioxide is held up as the arch villain, the ostentatious lifestyle of the rich nations could be lambasted to heart's content, whereas moving to cut down on methane could hurt whatever sustenance is available for the poor.
Mohamed El-Ashry at the United Nations Foundation notes that governments and advocates fear that attacking methane would be a dangerous distraction.
"People are worried about diverting attention away from carbon dioxide," he says. "But that shouldn't really be the case at all."
Both problems need to be solved sooner or later, he feels. Only more research is needed for the purpose, he argues.
El-Ashry is part of a group advocating for a new $200 million fund to help jump-start the methane research programs that have ground to a halt for sometime now.
The good thing about methane is that it stays in the air for only about a decade, so if you can reduce emissions, you can see quick results, it is felt.