Methane levels as high as 2845ppb

Methane levels as high as 2845 parts per billion (ppb) were recorded on April 25, 2015, as illustrated by the image below.

This is an extremely high peak. The average daily peak in 2015 until May 1 was 2371 ppb, while the highest daily mean ranged from 1807 ppb (January 10) to 1829 ppb (April 22). Daily peaks and daily highest mean levels in 2015 are shown on the image below.

These peaks are much higher than they were in previous years, as illustrated by the image below, from an earlier post and showing the average highest peak readings in 2013 and 2014 at selected altitudes..

Peak readings in above image are averages over April 2013 and April 2014. On specific days, peak readings could be much higher, e.g. on April 28, 2014, methane levels were recorded as high as 2551 ppb at 469 mb. As said, methane levels as high as 2845 ppb were recorded on April 25, 2015, while the average peak for the first four months of 2015 was 2371 ppb, and this average was calculated from peaks across altitudes.

The table below shows the altitude equivalents in mb (millibar) and feet.

56,925 ft	44,689 ft	36,850 ft	30,569 ft	25,543 ft	19,819 ft	14,383 ft	8,367 ft	1,916 ft
74 mb	147 mb	218 mb	293 mb	367 mb	469 mb	586 mb	742 mb	945 mb

Peak levels in April appear to be rising strongly each year, following higher peak readings during previous months, especially at higher altitudes, i.e. especially the Arctic Ocean. It appears that much of the additional methane originating from the higher latitudes of the Northern Hemisphere has moved closer to the equator over the past few months, and is now accumulating at higher altitudes over the continents on the Northern Hemisphere, i.e. Asia, Europe, North America and north Africa.

Further analysis of the rise in global mean methane levels appears to confirm the above. The image below shows methane levels on April 22, over three years. While there appears to be little or no rise in mean methane levels at low altitudes, the rise is quite profound at higher altitudes.  

[ click on image to enlarge ]

Things look set to get worse. As shown by the image below, from an earlier post, global methane levels have risen sharply from a low of 723 ppb in 1755. Mean methane levels were as high as 1839 ppb in 2014. That's a rise of more than 254%.

As that post concluded a year ago, it appears that the rise of methane in the atmosphere is accelerating. What can we expect? As temperatures can be expected to continue to rise and as feedbacks start to kick in, this may well constitute a non-linear trend. The image below shows a polynomial trend that is contained in IPCC AR5 data from 1955 to 2011, pointing at methane reaching mean global levels higher than 3000 ppb by the year 2030. If methane starts to erupt in large quantities from clathrates underneath the seafloor of the Arctic Ocean, this may well be where we are heading. 

The situation is dire and calls for comprehensive and effective action, as discussed at the Climate Plan.

The 2845 ppb recorded on April 25, 2015, is an extremely high peak. The average daily peak in 2015 until now was 2372...
Posted by Sam Carana on Monday, April 27, 2015