Tuesday, 5 April 2016

Arctic sea ice extent at a record low for the time of the year

Record Arctic Warming

On April 3rd, 2016, Arctic sea ice extent was at a record low for the time of the year, reports the National Snow and Ice Data Center (NSIDC).

4 April, 2016

For more on what constitutes "ice-covered" and what is sea ice extent (versus sea ice area), see this NSIDC 
FAQ page.

Another measure is sea ice area. On April 2nd, 2016, Northern Hemisphere sea ice area was at a record low for the time of the year, reports the 
Cryosphere Today

In 2015, there still was more sea ice area than there is now when it was half a month later (15 days) into the year. In 2012, there still was more sea ice when it was 25 days later in the year. In other words, sea ice area decline is almost one month ahead compared with the situation in 2012.

NSIDC scientist Andrew Slater (see his website) has created the chart below of freezing degree days in 2016 compared to other years at Latitude 80°N.

The Arctic has warmed more than elsewhere on Earth. Surface temperatures over the past 365 days were more than 2.5°C or 4.5°F higher than they were in 1981-2010.

The image below compares sea ice thickness on April 3rd for the years 2012, 2015 and 2016 (respectively the left, center and right panel).

[ click on images to enlarge them ]

This means that the outlook for the sea ice in the Arctic this year is not good. Given that the current El NiƱo is still going strong and given the currently very high ocean temperatures, chances are that the sea ice will be largely gone by September 2016. The image on the right shows sea surface temperature anomalies above Latitude 60°N.

Sea ice acts as a buffer, absorbing heat and keeping the temperature of the water at freezing point. Without such a buffer, further heat will instead make that the temperature of the water will rise rapidly. Furthermore, less sea ice means that less sunlight gets reflected back into space and more sunlight instead gets absorbed by the Arctic Ocean.

These are just some of the many 
feedbacks that accelerate warming in the Arctic. Warm water reaching the seafloor of the Arctic Ocean can penetrate sediments that can contain huge amounts of methane in the form of hydrates and free gas, triggering abrupt release of methane in gigantic quantities, escalating into runaway warming, and subsequent destruction and extinction at massive scale.

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

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