Jon Sumby
This is an old concern that I’ve been tracking.
In short, carbon dioxide is the major greenhouse gas released by industrial society; we release far less methane.
However, methane is a more potent greenhouse gas. Millions upon millions of tonnes of methane are stored in the permafrost bogs across the Arctic, in Siberia and elsewhere.
The concern is that warming caused by carbon dioxide would melt this permafrost and begin the release of methane, which would increase warming and so more melting and more methane; a positive feedback that anything we do cannot change. Along with methane the permafrost regions also store large amounts of carbon from plants laid down over 40,000 years ago.
Recent research published in ‘Nature’ (7th Sept 2006) indicates that in the areas of permafrost studied, methane is being released at a rate that is five times faster than what was expected. In the last ten years, the temperature inside permafrost has risen four times as fast as it did over the last century.
The general idea is that if the permafrost started warming, the methane and carbon dioxide released by that warming would increase the rate of permafrost melting; creating a positive feedback, a self-sustaining greenhouse gas ‘pump’, and a process we cannot slow, stop, or change. The paper below, and others, indicate that this pump is starting sooner rather than later.
Methane bubbling from Siberian thaw lakes as a positive feedback to climate warming:
(Nature 443; 71-75 (7th September 2006)) http://www.nature.com/nature/journal/v443/n7107/abs/nature05040.html
