Friday, 5 February 2016

Increasing winter methane levels in Arctic

Dramatic increase in methane in the Arctic in January 2013

1 February, 2016

Below a combination of images produced by Dr. Leonid Yurganov, showing methane levels January 1-10, 2013 (below left), January 11-20, 2013 (below center) and January 21-31, 2013 (below right).

Click on image to enlarge

Above image shows dramatic increases of methane levels above the Arctic Ocean in the course of January 2013 in a large area north of Norway.

Why are these high levels of methane showing up there? To further examine this, let's have a look at where the highest sea ice concentrations are. The image below shows sea ice concentrations for January 2013, from the 
National Snow and Ice data Center (NSIDC).

Overlaying methane measurements with sea ice concentrations shows that the highest levels of methane coincide with areas in the Arctic Ocean without sea ice. This is shown on the animation below, which is a 1.84 MB file that may take some time to fully load.

Strong correlation between Methane and Ocean/Land/Sea ice

Where methane levels above the Arctic Ocean are relatively low, there still may be very high levels of methane underneath the sea ice that are still broken down by bacteria, as discussed in the postFurther feedbacks of sea ice decline in the Arctic. As that post concludes, much of this methane is likely to enter the atmosphere without getting broken down by bacteria as the sea ice retreats further. Sea ice is declining at exponential pace. The big danger is that a huge rise of temperatures in the Arctic will destabilize huge amounts of methane currently held in the seabed. Comprehensive and effective action is needed now to avoid catastrophe.

Dr. Malcolm Light kindly provided the following comments on the image at the top of this post:
The first image clearly shows that the westerly Svalbard branch of the Gulf stream must be destabilizing methane hydrates between Norway and Svalbard. The effects of the eastern Yermack branch of the Gulf stream which enters the Barents Sea is clearly seen in the third figure and methane hydrates in the whole Barents Sea region are clearly being destabilized by the heat it is bringing in. All this extra heating of the Gulf Stream causing increased evaporation is the reason for the giant flooding that has been seen in Europe and the water clouds are preventing the ocean from losing its heat efficiently so the Yermack and Svalbard branches can still destabilize the methane hydrates even in the dead of winter.
Little correlation between Methane
and Depth of the Arctic Ocean
As said, there appears to be a strong relationship between the location of the high levels of methane and the contours of land and sea ice, as illustrated by the above animation. There appears to be little relationship between methane levels and depth of the sea, as illustrated by the animation on the right. For a larger-scale version of the bathymetry map by Martin Jakobsson, see the earlier post on Arctic temperature anomalies.

The animation further below shows selected NOAA images at different altitudes on January 23, 2013. The lowest altitude is ~111 meters (~364 feet) above sea level. At this altitude, high methane levels (up to ~2000 ppb) show up over the Arctic Ocean, against a global mean of 1793 ppb. Much of the land remains colored grey at this altitude, since no values are registered where the land is higher than this altitude.

At all higher altitudes up to ~8 km (~26250 ft) peak values in the Arctic remain visible that are higher than 2000 ppb, up to a staggering 2241 ppb, while global mean methane levels range from 1768 to 1795 ppb.

At even higher altitudes, centrifugal forces move the methane toward locations over the equator. At an altitude of ~16 km (~52000 ft), levels of up to 1880 are recorded over the equator, against mean global levels of ~1700 ppb. All this compares with 
pre-industrial methane levels of ~715 ppb.

Proportionally, distribution of the methane on that day remains roughly the same geographically, i.e. relatively high methane levels consistently show up in the same spots in the Arctic. Comparison with other days furthermore shows that values for each location often do not change much from day to day. This indicates that methane tends to rise up in the air and will remain in the same location unless there are winds strong enough to spread the methane geographically.

Methane on January 23, 2013 - this is a 2.42 MB animation that may take some time to fully load 

Below a combination of images showing methane levels over five years (2009 on the left, to 2013 on the right), each time for the same period (January 21-31) - images by Dr. Leonid Yurganov.

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