Alaska May Not Have Rising Methane Levels from Melting Permafrost

It turns out that we may not have to worry about as much methane being released as previously thought. Scientists have discovered that despite large temperature increases in Alaska, methane is not being released from Alaskan soils and into the atmosphere at high rates.

Methane is the third most common greenhouse gas in the atmosphere, after water vapor and carbon dioxide. Although there is much less of it in the air, though, it's 33 times more effective at trapping heat in the atmosphere than carbon dioxide.

High concentrations of methane have been measured in the atmosphere at individual Arctic sites, especially in Siberia. This, in particular, has added to the concern that methane releases could drastically impact future warming.

In order to better understand by how much methane levels are increasing, scientists analyzed methane measurements made over Alaska from May through September 2012. They then estimated emission rates for the winter months, during most of which no methane was released due to frozen soil.

So what did they find? It turns out that annual emissions in 2012 equaled about one percent of total global methane emissions. This means that the Alaskan rate was very close to the global average rate.

"That's good news, because it means there isn't a large amount of methane coming out of the ground yet," said Rachel Chang, the lead author of the new study, in a news release.

That said, more methane could be released in the future. Vast amounts of carbon are stored in undecayed organic matter in Arctic permafrost and peat. As this thaws, the methane releases. This means that rising temperatures in the future could mean an increase in methane release. For now, though, it seems as if conditions aren't as bad as once thought.

The findings are published in the journal Proceedings of the National Academy of Sciences.