Tuesday, August 18, 2009
Methane Found Bubbling Up from Arctic Seabed
One of the great fears of climate scientists is "runaway global warming." This is point of no return climate change where manmade warming reaches the point that it triggers natural processes beyond our control that discharge masses of greenhouse gases into the atmosphere. These are often referred to as "tipping points" which if you've spent much time in a canoe you'll readily understand.
From BBC News:
Scientists say they have evidence that the powerful greenhouse gas methane is escaping from the Arctic sea bed.
Researchers say this could be evidence of a predicted positive feedback effect of climate change.
As temperatures rise, the sea bed grows warmer and frozen water crystals in the sediment break down, allowing methane trapped inside them to escape.
The research team found that more than 250 plumes of methane bubbles are rising from the sea bed off Norway.
...The gas is normally trapped as "methane hydrate" in sediment under the ocean floor.
"Methane hydrate" is an ice-like substance composed of water and methane which is stable under conditions of high pressure and low temperature.
As temperatures rise, the hydrate breaks down. So this new evidence shows that methane is stable at water depths greater than 400m off Spitsbergen.
The image above is an acoustic image of one of these methane plumes. Below is a clip of Alaskan scientists who are monitoring the emission of methane from melting tundra on frozen lake bottoms. They have trouble lighting it at first because there is too much pressure.