Flask measurements continue to be available and the five most recent measurements show levels well over 2000 ppb.
The image below shows methane levels over a period of three years, from August 1, 2008, to August 1, 2011.
The image below shows methane levels over a period of a more recent year, from August 1, 2011, to August 1, 2012. There is a marked increase of methane at higher latitudes, compared to the earlier three years.
The image below shows methane levels in August 2012, with high levels showing up at many places.
The image below shows the most recent methane level measurements available, from September 1, 2012, to September 7, 2012. High levels of methane show up at even more places, such as in the Arctic to the north of North America.
Dr. Leonid Yurganov from IASA data. Note that the scales are slightly different. The images confirm the presence of high levels of methane in the Arctic Ocean north of Siberia. Further below a combination picture showing the significant rise of methane levels in that area between October 2008 and October 2011.
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The images highlight a number of concerns:
- Methane levels are rising over the years;
- Methane levels are particularly high in the Arctic;
- Very high levels of methane are recorded in the Arctic in the months September and October, the very period when Arctic sea ice is at its lowest;
- Incidental measurements, such as at Barrow, add to concerns that levels can rise abruptly with significant amounts.
The big danger is that ferocious warming in the Arctic will trigger methane releases from hydrates and from free gas in sediments, which will further accelerate warming in the Arctic and further trigger methane releases, in a vicious circle set to spiral into runaway global warming unless action is taken to reduce the danger.