Methane, one of the gases implicated in climate change, accounts for about 18 to 20 percent of greenhouse gases, and contributes to nearly as much warming as all of the other non-CO2 greenhouse gases (carbon monoxide, nitrous oxide, etc.) combined.
While concentrations of carbon dioxide (CO2) in the atmosphere have risen by about 25 percent since 1750, methane has risen nearly 250 percent, from 700 to nearly 1,800 parts-per-billion in 2008. And while human activities account for only about 3 percent of CO2, these activities have contributed 150 percent to methane levels.
The Ny-Aalesund Arctic research station, at the northwestern tip of the Svalbard archipelago, is - like the Arctic in general - a hotspot for global warming, which only makes this report more concerning. A warming Arctic leads to thawing of frozen lakes, tundra and permafrost, where much of the planet's methane has been trapped since the last interstitial warming period.
Permafrost is that layer of permanently frozen ground beneath a typically 3-to-6 foot surface layer that is frozen only for part of the year, and can extend from 6 to more than 50 feet into the earth, with the highest amounts of methane trapped in deeper layers.
The Arctic has been warming precipitously for the last decade, but nowhere is this more evident than in measurements of atmospheric methane. The 2008 rise documented in Norway matches the 2007 rise, but both topped previous rises, which had remained stable at about 0.34 percent during the last decade. The two-year deviation likely indicates that some natural regulatory mechanism has faltered.
If methane is coming from this Arctic melt, the resurgence of plant life that results from a warmer climate will forestall much of the release (because plants absorb methane). However, absorption levels will decrease over time, as the concentration of methane overwhelms plant's absorption capacity. Somewhere between 15 and 50 years from now, when plants are "tapped out" in terms of absorption capacity, methane will begin rising even more rapidly and will potentially tip the balance in favor of runaway global warming.
This is what the Norway report suggests is happening, but chief research scientist at the Australian Commonwealth Scientific and Research Organization, Paul Fraser, has his doubts.
Fraser suspects the additional methane is coming from wetter wetlands in the tropics and in the north. Both 2007 and 2008 were record years for moisture in the tropics, breaking a 25-year cycle of dryness. Wetland ecosystems, particularly in the tundra, taiga and boreal forests of the north, tend - when very damp - to cause excessive microbial activity or rotting, which releases methane. In drier periods, the methane trapped in plants remains stable.
Frazer completely dismisses melting permafrost, on the grounds that two years is too short a time to thaw permafrost and account for such a surprising increase. Others are unconvinced by his arguments. In fact, no one knows yet where the extra methane is coming from. Some suspect newly developed natural gas and coal resources in Russian Siberia. Others suggest a change in global wind patterns. One source cites flaring from the StatoilHydro Alve gas field in the Norwegian Sea.
The UN has already indicted farming and forestry in more than 30 percent of methane releases, and much of that comes from livestock belching, passing intestinal gas or defecating. Another source of methane is the 600 active and 7,582 abandoned U.S. coal mines, which - together with coal mines around the world - contribute 500 billion cubic feet of methane every year.
Still, abrupt shifts in methane emissions are nothing new in geologic terms. Reports in Science Magazine show that abrupt shifts, from 50 to 300 parts-per-billion, were common in most of the interstadial (Dansgaard-Oeschger) warming events based on ice-core sampling. There have been 23 such events in the last 110,000 years, indicating that it's far too soon to break out the Apocalypse party hats.
This article was contributed to Celsias by Jeanne Roberts
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