Satellite observations from the University of Maryland are showing strong increases in Arctic methane concentration between August 2011 and August 2012. In our first monthly assessment of these differences, we will analyze their strength as well as the possible implications for Arctic and global warming scenarios.
The atmospheric methane concentration image for August 2012 is:
The methane concentration image for August 2011 is:
And the baseline image established in August of 2003 is:
This sequence shows that average methane levels around the Arctic for the month of August have increased by about 10 parts per billion (ppb) since last year and 20 ppb since the record began in 2008. Values for much of the Arctic in August have ranged between 1840 and 1860 ppb this year as compared to 1830 to 1850 ppb last year and 1820 to 1840 ppb in 2003.
The highest concentrations of methane were found in Siberia and extreme northern Europe with Alaska, Canada, and points in the Arctic Ocean showing elevated levels as well.
As we can see from these satellite observations, the trend since August of 2003 has been for increasing methane concentrations in the Arctic. Methane is much more potent a greenhouse gas than CO2. So this methane increase in the Arctic is adding heating on top of an already increasing CO2 forcing. And though the amount of additional methane for the month of August does not approach the additional forcing of human CO2 emissions, the rate of increase has jumped by an order of magnitude. The result is that the extra methane forcing from 2011 to 2012 in the Arctic environment is equal to about .25 to 1 ppm CO2, adding between 12% and 50% on top of the CO2 increase in the same period. It is worth noting that most of this increase is local to the Arctic environment, so the effect on overall global warming would be less.
But, perhaps, of greatest concern is the fact that the increase in one year — from 2011 to 2012, is equivalent to the entire increase of the eight years spanning 2003-2011. Any similar jump would result in an increase in the methane forcing to possibly exceed the rate of increase in the CO2 forcing. Adding such an effect to loss of reflectivity due to sea ice and snow cover melt would result in greatly increased Arctic heating along with a number of worsening extreme weather and glacial melting effects far exceeding the impacts we see today.
The primary driver of Arctic methane release is a warming climate caused by human greenhouse gas emissions. As ice melts, methane is released from Arctic tundra and soils frozen for thousands, tens of thousands and, sometimes, millions of years. In addition, as seas warm, methane hydrates destabilize and bubble up from the sea bed. Heating is also amplified as the ice sheets retreat, resulting in a loss of albedo, or reflectivity. Dark seas and darker land masses absorb more of the sun’s radiation, causing more warming in turn. The effect returns again to do work liberating more methane and CO2 which again results in more heat.
This is a powerful feedback loop that is enhancing warming in the Arctic while adding more greenhouse gasses to Earth’s atmosphere. The above methane data, provided by the University of Maryland, provides us with one more way of measuring the heat amplification going on in the Arctic.
Learn more about amplifying feedbacks in the Arctic here.