Methane “time bomb” continues to tick away
February 22nd, 2010At the Royal Society in London, scientists at a conference on greenhouse gases report that levels of methane in the atmosphere, after a decade of near-zero growth, began rising in 2007 when an unprecedented heat wave in the Arctic caused a record shrinking of the sea ice and have continued to rise significantly through 2008 and 2009.
An article in the U.K. Independent includes a quotation from the presentation, titled Global atmospheric methane in 2010: budget, changes and dangers:
[G]lobally averaged atmospheric methane increased by [approximately] 7ppb (parts per billion) per year during 2007 and 2008. . . . During the first half of 2009, globally averaged atmospheric CH4 was [approximately] 7ppb greater than it was in 2008, suggesting that the increase will continue in 2009. There is the potential for increased CH4 emissions from strong positive climate feedbacks in the Arctic where there are unstable stores of carbon in permafrost . . . so the causes of these recent increases must be understood.
Global atmospheric levels of the gas now stand at about 1,790 parts per billion. They began to be measured in 1984, when they stood at about 1,630ppb.
The Independent also quotes Euan Nisbet, one of the study’s authors:
“It may just be a couple of years of high growth, and it may drop back to what it was. But there is a concern that things are beginning to change towards renewed growth from feedbacks.
Over a relatively short period, such as 20 years, methane (CH4) has a global warming potential more than 60 times as powerful as CO2, although it decays more quickly.
Many climate scientists fear that frozen Arctic tundra, like this at Sermermiut in Greenland, could be a ticking time bomb. Over thousands of years the methane has accumulated under the ground at northern latitudes all around the world. But as temperatures rise and the permafrost begins to melt, that methane could be released – with potentially catastrophic results.