vrijdag 10 maart 2017

Low sea ice extent contributes to high methane levels

SATURDAY, MARCH 4, 2017

Low sea ice extent contributes to high methane levels at both poles

[ click on images to enlarge ]
On March 2, 2017, Antarctic sea ice extent was at a record low since satellite readings started.

As the image on the right shows, sea ice extent in 2017 (light blue) around Antarctica has been more than 1 million km² lower than the 1981-2010 median.

At the same time, Arctic sea ice extent was at a record low for the time of the year since 1979.

As the image underneath on the right shows, Arctic sea ice extent in 2017 has also been more than than 1 million km² lower than the 1981-2010 median.

[ click on images to enlarge ]
For about half a year now, global sea ice extent has been more than 2 million km² lower than it used to be, not too long ago, as illustrated by the image below, by Wipneus.

This means that a lot of sunlight that was previously reflected back into space, has been absorbed instead by Earth, contributing to global warming, especially at the poles.

Greater warming at the poles has also caused more extreme weather, resulting in stronger winds and waves and in wild weather swings, further accelerating the decline of the sea ice.

The combination of rising ocean heat and stronger winds looks set to devastate the sea ice around Antarctica. Ocean heat is increasing particularly in the top layer (see image on the right).

Warming water is increasingly reaching the coast of Antarctica. The image below illustrates how much sea ice melt has occurred close to the coast of Antarctic over the past few months, while much sea ice has drifted away from the coast due to strong currents and wind.


As said, less sea ice means that a lot of sunlight is no longer reflected back into space, but is instead further warming up the poles. As a result, methane levels can be very high at both poles. The combination image below shows methane levels as high as 2560 ppb on March 1, 2017. The image in the panel on the left shows high methane levels over Antarctica in an area with much grey, indicating that it was hard to get a good reading there. On the image in the panel on the right, high methane levels do show up clearly in that area.

[ click on images to enlarge ]
As discussed before, methane hydrates can be present both on Greenland and on Antarcticaunderneath thick layers of snow and ice. Due to global warming, wild weather swings are now common at the poles, as illustrated by the image below. This can cause sequences of rapid and extreme expansion, compacting and fracturing of snow and ice, resulting in destabilization of methane hydrates contained in the permafrost.


The image below shows methane levels as high as 2562 ppb, with solid magenta-colored areas showing up over the Laptev Sea on March 4, 2017.

The image below shows that sea surface temperatures in the Arctic Ocean were as high as 12.7°C or 54.9°F on March 3, 2017 (at the location marked by the green circle), i.e. 12°C or 21.6°F warmer than in 1981-2011.


The danger is that self-reinforcing feedback loops such as albedo decline and methane releases will further accelerate warming and will, in combination with further warming elements, cause a temperature rise as high as 10°C or 18°F by the year 2026, as described at the extinction page.

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


Links

• Climate Plan
http://arctic-news.blogspot.com/p/climateplan.html

• Extinction
http://arctic-news.blogspot.com/p/extinction.html

• Methane hydrates
http://methane-hydrates.blogspot.com/2013/04/methane-hydrates.html

• Earthquakes in the Arctic Ocean
http://arctic-news.blogspot.com/2014/04/earthquakes-in-the-arctic-ocean.html


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