Methane Causes Vicious Cycle In Global Warming Carbon dioxide usually gets most of the blame for global warming, but a dramatic increase in methane gas emissions is worrying scientists. Global warming is causing the world's wetlands to produce more methane gas — which in turn is causing more global warming.
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Methane Causes Vicious Cycle In Global Warming

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Methane Causes Vicious Cycle In Global Warming

Methane Causes Vicious Cycle In Global Warming

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Yesterday on MORNING EDITION, we heard how a possible solution to urban smog could end up contributing to increased global warming. Today, we'll report on methane, which also plays an important role in global warming. It appears it's on the rise in the atmosphere. NPR's Richard Harris reports on why efforts to control methane are faltering.

RICHARD HARRIS: Methane gas comes from all sorts of sources - wetlands, rice paddies, cow tummies, coal mines, leaking natural gas pipes, garbage dumps, even termites. Drew Shindell at NASA's Goddard Institute in New York says it's built up dramatically in the atmosphere.

DREW SHINDELL: It's gone up by 150 percent since the pre-industrial period. So, that's an enormous increase. CO2, by contrast, has only gone up by about 30 percent.

HARRIS: Molecule for molecule, methane is much more effective at trapping heat in the atmosphere than carbon dioxide, and that's just part of the trouble.

SHINDELL: 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.

HARRIS: For example, methane in the atmosphere also creates ground-level ozone. And ozone isn't only bad for human health, it also contributes to global warming. Shindell recently totaled up all the effects of methane emissions and realized that the heating effect a not-too-distant second to carbon dioxide.

SHINDELL: So, that tells you that methane is actually a pretty big player.

HARRIS: A study published 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.

PAUL PALMER: The higher the temperature, the more efficient they are at producing methane.

HARRIS: So, global warming is causing these wetlands to produce more methane, and the methane is causing more global warming.

PALMER: This really does emphasize the fact that we are having this vicious cycle in the climate system. And we're seeing it now.

HARRIS: 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 Drew Shindell says, remember, methane contributes to ozone, which costs society real money because of its human health effects, and because ozone also damages crops.

SHINDELL: So, if you account for all the economics, all the gains that you get through the benefits of controlling methane that are not even related to climate, you find that many of the reductions you could make actually pay for themselves.

HARRIS: So, why is there relatively little effort now to control methane? Mohamed El-Ashry at the United Nations Foundation says part of the reason has been a fear by governments and advocates that attacking methane would be a dangerous distraction.

MOHAMED EL: People are worried about diverting the attention away from carbon dioxide. And it shouldn't really be the case at all.

HARRIS: El-Ashry is part of a group advocating for a new $200 million fund to help jump-start these methane programs again.

SHINDELL: Here is an opportunity to have some immediate effects in terms of impacts, particularly on the Arctic, as well as even secondary impacts, like on health.

HARRIS: Richard Harris, NPR News.

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