The image below compares the Arctic sea ice thickness on July 14, 2012 (left panel) and on July 14, 2015 (right panel), using Naval Research Laboratory images.
The Naval Research Laboratory's 30-day animation below shows how this situation developed, ending with a forecast for July 17, 2015, run on July 9, 2015.
The dramatic decline of the sea ice, especially north of North America, is the result of a combination of factors, including:
- very high levels of greenhouse gases over the Arctic Ocean
- very high levels of ocean heat
- heatwaves over North America and Siberia extending high air temperatures over the Arctic Ocean
- wildfires triggered by these heatwaves resulting in darkening compounds settling on snow and ice
- very warm river water running into the Arctic Ocean, as illustrated by the image below.
With still two months of melting to go before the sea ice can be expected to reach its minimum for 2015, the threat of sea ice collapse is ominous. The Arctic-News Blog has been warning for years about the growing chance of a collapse of the sea ice, in which case huge amounts of sunlight that previously were reflected back into space, as well as heat that previously went into melting the ice, will then instead have to be absorbed by the water, resulting in a dramatic rise of sea surface temperatures.
The image below shows the already very high sea surface temperature anomalies as at July 10, 2015.
More open water will then come with an increased chance of storms that can cause high sea surface temperatures to be mixed down all the way to seafloor of the Arctic Ocean, which in many cases is less than 50 m (164 ft) deep.
Meanwhile, ocean heat is accumulating off the coast of North America, as illustrated by the image below showing sea surface temperature as high as 31.8°C (89.24°F) on July 8-9, 2015.
Massive amounts of ocean heat will be carried by the Gulf Stream into the Arctic Ocean over the next few months. The combined result of high sea surface temperatures being mixed down to the seafloor and the ocean heat entering the Arctic Ocean from the Atlantic and Pacific Oceans can be expected to result in dramatic methane eruptions from the Arctic Ocean seafloor by October 2015.
Currently, methane levels are high, especially north of Greenland, as illustrated by the image below showing that on July 10, 2015 (am), levels as high as 2416 parts per billion were recorded at 6,041 m (19,820 ft) altitude, while mean methane levels also reached 1831 parts per billion at this altitude.
The situation is dire and calls for comprehensive and effective action, as discussed at the Climate Plan.