Sunday, May 14, 2017

Earthquake east of Greenland triggers methane releases

An earthquake with a magnitude of M 4.5 on the Richter scale hit the seafloor 204 km East of Nord, Greenland, on May 8, 2017 at 04:48:53 (UTC). Location: 81.684°N 5.076°W. Depth: 10.0 km.

The inset shows that methane levels over 1950 ppb (magenta color) were recorded on the morning of May 8, 2017, by two satellites.

This is a reminder that earthquakes can destabilize methane hydrates, which can hold huge amounts of methane in sediments at the seafloor of the Arctic Ocean. As temperatures keep rising, snow and ice on Greenland and Svalbard keeps melting, taking away weight from the surface, making that isostatic rebound can increasingly trigger earthquakes on the faultline that crosses the Arctic Ocean.

Methane releases have followed earthquakes in the Arctic before, e.g. see this 2016 post, illustrating the danger of potentially huge methane releases in case of larger earthquakes in the Arctic.

Why is methane so important again? Below follow some images from the methane page

Over a 10-year timescale, methane emissions cause more warming than carbon dioxide emissions, as illustrated by the graph in the left-hand panel of above image.

Methane levels fluctuate with the time of year, higher mean levels are typically reached in September.

On September 14, 2016, methane levels at 367 mb were as high as 2697 ppb (locally), while global mean methane level was as high as 1865 ppb (above image).

On May 13, 2017, am, global mean methane levels were as high as 1844 ppb at altitudes corresponding to 383mb to 469 mb (MetOp-1 satellite), while local levels as high as 2485 ppb were recorded.

Methane levels have risen 256% from 1750 to 2015, as illustrated by the image on the right.

Growth in methane levels has been accelerating recently. Contained in existing data is a trend indicating that methane levels could increase by a third by 2030 and could almost double by 2040, as illustrated by the image below. 

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


• Climate Plan

• High Methane Levels Follow Earthquake in Arctic Ocean

• Methane

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