Have we passed a Tipping Point? Methane, Permafrost, & the Beaufort Sea
Tipping Points are the thresholds where a slight rise in temperature starts a climate change or event which then triggers a greater increase in temperature, which then accelerates the inital change or event in a chain reaction which would trigger a catastrophic rise in temperature.
The primary focus of world concern is on the CO2 tipping point, but Methane is 21 times more powerful at warming the atmosphere than CO2, while it does have a much shorter atmospheric lifetime of about 8 to 12 years, versus CO2’s lifetime of 50-200 years.
Methane concentrations rose dramatically before leveling off in the 1990’s and have remained at a steady state of 1751 ppb between 1999 and 2002.
Ice core samples taken at sites in Greenland and Antarctica show that atmospheric concentrations of Methane before about 1750 A.D. ranged from 676 to 716 ppb; after about 1750 A.D. concentrations began to increase to their present value of more than 1700 ppb.
Until recently, Methane appeared to be under control.
Now reports from around the world show that the permafrost is melting and retreating at a rate similar to the world’s glaciers.
Acknowledging the seriousness of this problem, scientists have established 263 Permafrost monitoring stations around the world to measure this phenomena.
Late last year, a report was issued that documented “soaring” emissions of Methane in Northern Siberia, as methane which previously had been trapped in sediment at the bottom of frozen lakes was now bubbling to the surface. Here is a photo of methane bubbles trapped in lake ice.
This summer scientists will be back to re-investigate bubbles of methane which are seeping out of more than 300 volcano-shaped hills (first discovered in the 1940s) on the bottom of the Beaufort Sea, which can be up to 30 meters high and up to a kilometer in width.
A recent German study concludes that fears of massive methane releases are unsupported; based on ice-core analyses previously made by other scientists, which indicate minimal release of methane during warm periods occurring during the last 9,000 years.
Unfortunately, another scientific report indicates that more than 500 billion tons of carbon dioxide is also trapped in the melting permafrost, which would almost double the amount currently in the atmosphere.
Methane bubbles have also been documented in the Timor Sea, Northwest of Australia.
It is impossible to make any conclusion at this time, but it is clear that Methane poses a greater risk than previously thought, and that it has the potential to become a bigger problem than CO2.
Posted: June 8th, 2007 under
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