“The Methane Time Bomb”

By | October 29, 2008

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The scare: On September 23, 2008, The Independent wrote yet another in its series of articles predicting that “global warming” will produce what has become known as a “methane burp” as vast reserves of the gas locked in Northern-Hemisphere permafrost are released by “global warming”.
Methane, in a given concentration, is 23 times more potent as a greenhouse gas than carbon dioxide.

The paper reports that an expedition off Siberia has found methane bubbling from vents on the sea floor, inferentially because permafrost has melted at depth. It concludes that these methane emissions may have been responsible for the recent warming of the Arctic region, and says that millions of tons more methane may yet be released as the permafrost melts, leading by implication to catastrophic “global warming”.

The truth: Each time The Independent – Britain’s second most alarmist newspaper on the “global warming” issue – reports the methane scare, it describes it as a “new” global threat. In 2007 the newspaper devoted an entire front page to an artist’s impression of a tsunami created by an imaginary methane burp 60 years hence. Some caution, therefore, should be exercised when citing this particular newspaper as any kind of authority on “global warming”.

First and foremost, the atmospheric concentration of methane has been falling since 2000. This result appears in the 2007 assessment report of the UN’s climate panel, even though, like The Independent, it tends strongly in an alarmist direction. Two conclusions follow: either the methane reported by the “Arctic scientists” who are the source of the Independent’s latest methane-burp scare is being readily taken up and fixed in the biosphere, or the actually quite small emissions of seabed methane observed by the scientists are being more than matched by reductions in other natural methane emissions. For instance, deforestation reduces the very considerable natural methane emissions from forests.

Secondly, 2008 will turn out to be cooler than 1980, 28 years ago, and there has been a seven-year period of global cooling since late in 2001. Though there has been some warming of the Arctic, that region is 1 or 2 degrees Celsius (2 or 3 F) cooler than it was in the 1930s and early 1940s. And the cause of the Arctic warming, according to a NASA paper last year, was natural: the poleward transport of warm tropical water by ocean currents, notably the current warming phase of the Atlantic Multidecadal Oscillation, accompanied by southerly winds. The other great ocean circulation – the Pacific Decadal Oscillation – transited from its warming phase to its cooling phase early in 2008. Arctic sea ice extent in October 2008 was almost as great as in October 1979, the first year of the satellite record. End of scare.