Monday, 30 June 2014

The melting Arctic

High temperatures in the Arctic

29 June, 2014

The NOAA map below shows sea surface temperature anomalies above 8 degrees Celsius in the Arctic Ocean.

These anomalies are very high, considering that it is now June and the melting season has only just begun.

Partly causing these high temperatures in the Arctic Ocean is water flowing into the Arctic Ocean from rivers. As the map below shows, a number of large rivers flowing through Siberia end in the Arctic Ocean.

map from:
The Naval Research Laboratory image below shows waters with very low salinity levels (top white rectangles) where warm water from rivers in Siberia enters the Arctic Ocean.

Accelerated warming of the Arctic warms is changing the Jet Streams, increasing the occurence of heat waves that cause huge amounts of warm water to flow into the Arctic Ocean.

Another spot to watch, indicated on above map with the bottom white rectangle, is where the Mackenzie River flows into the Beaufort Sea. In this area, sea surface temperatures up to ~17°C (63°F) were recorded in the Beaufort Sea from June 26 to 28, 2014, as illustrated by the image below.

As the map below shows, similarly high sea surface temperatures were recorded in the Bering Strait.

High temperatures over North America are making the situation worse. On June 28, 2014, temperatures as high as 27°C (81°F) were recorded in the north of Canada and temperatures as high as 23°C (74°F) were recorded in Alaska, as the map below illustrates.

[ click on image to enlarge ]
The 15-hour forecast below, run on June 29, 2014, shows temperatures in the north of North America of up to ~30°C (86°F) in many areas.

As long as the soil is frozen and covered with snow and ice, much of the sunlight is reflected back into space, while much of the sunlight that gets absorbed goes into melting the snow and ice. Once the snow and ice has melted, that energy goes into heating up the soil. The energy required to melt a volume of ice can raise the temperature of the same volume of rock by
150º C.

In Greenland, meltwater percolation is causing latent heat transport into the firn, making it warm up by as much as +5.7°C at midlevel elevations (1400–2500 m), according to a recent study by Polashenski et al.

The situation is particularly dire for the Arctic Ocean, due to the very warm water on the Northern Hemisphere, currently featuring a sea surface temperature anomaly above 1.5º C, as illustrated by above image.

The prospect of an El Niño event striking this year now is 90%, according to predictions by the European Centre for Medium-range Weather Forecasts.

Arctic sea ice volume minimum is typically reached around halfway into September.

This is still months away, and the number of days the Arctic Ocean is covered by sea ice has fallen dramatically over the years, as illustrated by the image on the right, from arecent study by Claire Parkinson.

The danger is that heat will penetrate sediments underneath the Arctic Ocean that contain huge amounts of methane in the form of hydrates and free gas, resulting in huge eruptions of methane from the seafloor of the Arctic ocean, as described at the methane-hydrates blog.

This risk is intolerable and calls for comprehensive and effective action, as discussed at the Climate Plan blog.

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