Trees as a Source of Greenhouse Gases

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We generally think of trees as one of our biggest natural allies in the fight against global warming. And they are — they suck up billions of tons of the greenhouse gas carbon dioxide every year.

But in an interesting new twist, scientists have now found that the army of green might be spewing large quantities of methane into the atmosphere every year. Methane is 25 times more potent as a greenhouse gas than CO2, and the new study, written about here, suggests that trees could be partially to blame for the recent sharp rise in methane concentrations.

According to the study, trees don't produce the methane themselves — so we'll just end all discussion of the "Farting Tree study" now. Instead, soil bacteria are the ones doing the tooting, in microscopic amounts. The trees are merely the conduit, sucking methane out of the soil and depositing it in the air, like chimneys (actually that's a matter of debate — a study a few years ago

suggested that trees do fart. This one makes it look like they don't).

In all, this chimney effect could be responsible for up to 10 percent of the global methane budget. And it may help explain why methane concentrations have been steadily rising faster than scientists expected.

On whole whole, trees are still helping us out, even though our carbon emissions vastly outpace their efforts to bury it. And we'll still need to pay attention to cow farts, rice paddies, and melting methane clathrate, which are much bigger deals than trees. So we shouldn't go chopping them down or anything just because we've found out they're methane-enablers. But it's still good to know.

Image: Flickr

Source: Nature