Methane time bomb?

Some rather worrying news in the newspapers a week or so ago. Sorry for the delay in posting. This is reports following the significant rise in methane in the atmosphere for the third year in a row. Details can be found in the Daily Telegraph.

Why is it a worry? The theory is that large quantities of methane, a greenhouse gas approximately 23 time more powerful than carbon dioxide, are trapped in the permafrost in the arctic circle. As the world warms and permafrost melts there is the potential for this gas to be released in ever increasing quantities, maybe leading to a positive feedback loop. The scientists are reluctant to confirm the causes for this increase at present but it is something to keep an eye on.