Senin, 02 Juli 2012

Arctic waters are heating up

The post Fires are raging again across Russia featured the image below, showing how much sea waters in the Arctic were already warming up on June 15, 2012.

Satellite image June 15, 2012 from DMI - http://ocean.dmi.dk/arctic/satellite/index.uk.php


The animated image below shows warming of Arctic waters for the period June 13 up to July 1, 2012.



Note: This file is a 1.7MB animation that may take some time to fully load. 

Sea water temperatures in the Arctic are likely to warm up even further, as the summer sun warms up the ocean currents and the rivers, and as less sunlight gets reflected by sea ice and is instead warming up ever larger areas of water. The image below shows the extent to which waters did warm up in September 2011.



As described in the post Abrupt Local Warming, sea surface anomalies of over 5 degrees Celsius were recorded in August 2007 (NOAA image right). 

Strong polynya activity caused more summertime open water in the Laptev Sea, in turn causing more vertical mixing of the water column during storms in late 2007, according to one study, and bottom water temperatures on the mid-shelf increased by more than 3 degrees Celsius compared to the long-term mean.

Indeed, the danger is that heat will warm up sediments under the sea, containing methane in hydrates and as free gas, causing large amounts of this methane to escape rather abruptly into the atmosphere. 

The image on the right, from a study by Hovland et al., shows that hydrates can exist at the end of conduits in the sediment, formed when methane did escape from such hydrates in the past. 

Heat can travel down such conduits relatively fast, warming up the hydrates and destabilizing them in the process, which can result in huge abrupt releases of methane.

Since waters can be very shallow in the Arctic, much of the methane can rise up through these waters without getting oxidized. 

As the methane causes further warming in the atmosphere, this will contribute to the danger of even further methane escaping, further accelerating local warming, in a vicious cycle that can lead to catastrophic conditions well beyond the Arctic.

Finally, remember the image that Professor Peter Wadhams added in his supplementary evidence to the EAC. Below is an annotated version, from Arcus.org

Figure 6. Composite satellite measurements of sea surface temperature (SST) and real-
color land and sea ice images for the end of the summer 2011 season in the Pacific Arctic.
Note extreme temperature maximums of 5-8 °C and that multiple ice, atmosphere and
ocean processes help reinforce albedo feedbacks (after Wood et al., submitted).

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