The Arctic sea ice melt - 08/21/2015

Ocean Heat Invades Arctic Ocean

Arctic News,

21 August, 2015

On land, it now is about 1°C (1.8°F) warmer than the 20th century average. July 2015 was the warmest month ever recorded for the globe. The combined average temperature over global land and ocean surfaces for July was the all-time highest monthly temperature in the 1880-2015 record – it was 16.61°C (61.86°F), i.e. 0.81°C (1.46°F) above the 20th century average. 

Sea surfaces were very warm as well. The July globally-averaged sea surface temperature was the highest temperature for any month in the 1880-2015 record. In July 2015, the sea surface on the Northern Hemisphere was 0.87°C (1.57°F) warmer than it was in the 20th century, as shown on the graph below. 

As the image below shows, the July data for sea surface temperature anomalies on the Northern Hemisphere contain a trendline pointing at a rise of 2°C (3.6°F) before the year 2030. In other words, if this trend continues, the sea surface will be 2°C (3.6°F) warmer in less than 15 years time from now.

[ click on image to enlarge ]

Such a temperature rise would be a catastrophe, as there are huge amounts of methane contained in the form of hydrates and free gas in sediments under the Arctic Ocean seafloor. A relatively small temperature rise of part of these sediments could cause a huge abrupt methane eruption, which could in turn trigger further eruptions of methane.

On the image below, the green circle at the top of each globe indicates a location where sea surface temperature was 17°C (62.6°F) on August 21, 2015, an anomaly of 11.9°C (21.4°F). This is where warm water is entering the Arctic Ocean from the Atlantic Ocean. At the same time, warm water is entering the Arctic ocean through the Bering Strait from the Pacific Ocean.

[ click on image to enlarge ]

There still are a few weeks to go before sea ice can be expected to reach its minimum, at around half September 2015, while sea currents will continue to carry warmer water into the Arctic Ocean for months to come.

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