Dramatic rise in methane levels since end July 2013

There has been a dramatic rise in methane levels since end July 2013. The image below pictures methane levels above 1950 ppb on the Northern Hemisphere from 12 p.m. August 9, 2013, to 12 a.m. August 10, 2013.

[ click on image to enlarge ]

Quite suddenly, readings above 1950 ppb have become commonplace since July 31, 2013.

The chart below illustrates the dramatic jump in methane levels that occurred since July 31, 2013. The chart shows the area (square km) with methane readings over 1950 ppb for selected layers, over the period from July 24, 2013, to August 9, 2013. The chart further below shows that peak methane levels have increased dramatically.

Particularly worrying are high levels of methane over the Arctic Ocean, such as on the image below showing methane levels over 1950 ppb in yellow for selected layers on August 5, 2013 (a.m.).

[ click on image to enlarge ]

Methane levels are also very high on the Southern Hemisphere, as illustrated by the image below on the right. High readings have featured over the heights of Antarctica for quite some time, but the high levels of methane over the oceans on the Southern Hemisphere have only shown up recently. They could be caused by one or more methane hydrates getting destabilized in the ocean between Antarctica and South America.

[ click on image to enlarge ]

Peter Carter sent the image below, edited from NOAA Earth System Research Laboratory, showing high (and rising) methane levels in Pallas Sammaltunturi (north Scandinavia), measured with surface flasks.

Peter also added the image below, pointing at high methane levels in Lac La Biche, Northern Alberta, Canada. “What to make of it?”, Peter adds, “It is not far from the Tar Sands - that does have a methane problem, but it is basically wetland peat region vicinity which is why I checked it.”

Methane levels keep rising rapidly

Global methane levels keep rising rapidly. Earlier this month, the post Methane as high as 2303 ppb quickly became outdated and was updated with the post Methane as high as 2349 ppb. Meanwhile, though, the most recent data show that the highest level reached on August 5, 2013, was 2442 ppb.

This recent peak level is only slightly below the highest peak level this year, which was a level of 2475 ppb reached on April 26, 2013, which at the time was considered a one-off local peak.

These recent high peak levels do seem to be more than just local peaks, given that high levels of methane are suddenly recorded over much of the globe, as described in the earlier post Methane as high as 2349 ppb.

The image on the right (added later, editor) also shows that not only have peak levels greater than 2300 ppb appeared since late June 2013, but also have the highest daily mean methane levels suddenly increased by about 20 ppb recently.

The image below shows over how many square kilometers methane was present at over 1950 ppb globally over the past few days.

The numbers also feature in the image on the left and they illustrate the huge jump that took place somewhere between July 31 and August 1, 2013.

It may be that there has indeed been a huge sudden increase in methane.

On the other hand, it could also be that EuMetSat implemented a re-calibration on July 31. After all, EuMetSat announced recently that IASI Level 2 products from Metop-B had been declared operational and would be available on GTS from 31 July.

Such a re-calibration (if it did indeed take place) does appear to make sense, given the discrepancy between IASI's mean methane levels and the levels recorded at stations. Below are measurements taken at Mauna Loa, Hawaii, which given the station's location close to the equator are often taken as global averages (flasks on the left, and hourly average in situ measurements on the right).

[ click on image to enlarge ]
from: http://www.esrl.noaa.gov/gmd/dv/iadv/index.php

Mauna Loa methane levels are often quoted to be about 1830 ppb, whereas the highest IASI mean levels did barely cross the 1800 ppb mark earlier this year. Since the jump, the highest IASI mean levels have suddenly been significantly higher (20 ppb more, at around 1820 ppb).

Even so, the current situation is very worrying. High levels of methane are present not only on the Northern Hemisphere, but also on Antarctica and over the oceans on the Southern Hemisphere, as shown in a recent post. And of course, the situation remains most threatening in the East Siberian Arctic Shelf (ESAS), as described at the Methane-hydrates blog and and at Arctic Methane FAQ.