– And why would a rise in Methane levels be important?:
“Methane is the second most important gas causing man-made climate change. Each molecule causes about 25 times more warming than a molecule of CO2, but it survives for shorter times in the atmosphere before being broken down.”
 – As the world’s temperature rises, vast amounts of Methane trapped in the permafrost will be released as the permafrost melts.  In addition, there are vast amounts of Methane trapped in deep ocean sediments as Methane Clathrates and scientists fear that given sufficient warming of the oceans, these will be released into the atmosphere as well.  More warming, more releases, more releases, more warming.  It’s not a pretty picture.
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Levels of the greenhouse gas methane in the atmosphere seem to be rising having remained stable for nearly 10 years.
Data from the National Oceanographic and Atmospheric Administration (Noaa) in the US suggest concentrations rose by about 0.5% between 2006 and 2007.
The rise could reflect melting of permafrost, increased industrialisation in Asia or drying of tropical wetlands.
The rise in carbon dioxide levels was significantly higher than the average annual increase for the last 30 years.
Noaa figures show CO2 concentrations rising by 2.4 parts per million (ppm) from 2006 to 2007. By comparison, the average annual increase between 1979 and 2007 was 1.65ppm.
Concentrations now stand at 384 ppm, compared to about 280 ppm before the era of human industrialisation began
Upwards curve?
The rise in CO2 is not exceptional compared with the previous few years, but does add more evidence that concentrations are rising faster than they were a decade or so ago.
The methane figure is more interesting, and potentially of more concern.
Concentrations have been more or less stable since about 1999 following years of rapid increases. Industrial reform in the former Soviet bloc, changes to rice farming methods and the capture of methane from landfill sites all contributed to the levelling off.
But the 2007 figure indicates that levels may be on the rise again.
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