Earth Equity News

Methane Levels May See 'Runaway' Rise. By Michael McCarthy, The Independent, February 22, 2010. "Atmospheric levels of methane, the greenhouse gas which is much more powerful than carbon dioxide, have risen significantly for the last three years running... leading to fears that a major global-warming 'feedback' is beginning to kick in. For some time there has been concern that the vast amounts of methane, or 'natural gas', locked up in the frozen tundra of the Arctic could be released as the permafrost is melted by global warming. This would give a huge further impetus to climate change, an effect sometimes referred to as 'the methane time bomb'. This is because methane (CH4) is even more effective at retaining the Sun's heat in the atmosphere than CO2... Over a relatively short period, such as 20 years, CH4 has a global warming potential more than 60 times as powerful as CO2, although it decays more quickly.

"Now comes the first news that levels of methane in the atmosphere, which began rising in 2007 when an unprecedented heatwave in the Arctic caused a record shrinking of the sea ice, have continued to rise significantly through 2008 and 2009... There is a fear that rising temperatures may have started to activate the positive feedback mechanism. This would see higher atmospheric levels of the gas producing more warming, which in turn would release more methane, which would produce even further warming, and so on into an uncontrollable 'runaway' warming effect. This is believed to have happened at the end of the last Ice Age, causing a very rapid temperature rise in a matter of decades... The new figures were revealed at a major two-day conference [7/22-23] on greenhouse gases in the atmosphere, at the Royal Society in London. They were disclosed in a presentation by Professor Euan Nisbet, of Royal Holloway College of the University of London, and Dr Ed Dlugokencky of NOAA's Earth System Research Laboratory in Boulder, Colorado… Many climate scientists think that frozen Arctic tundra, like this at Sermermiut in Greenland, is a ticking time bomb in terms of global warming, because it holds vast amounts of methane, an immensely potent greenhouse gas. Over thousands of years the methane has accumulated under the ground at northern latitudes all around the world, and has effectively been taken out of circulation by the permafrost acting as an impermeable lid. But as the permafrost begins to melt in rising temperatures, the lid may open -- with potentially catastrophic results."