August extent just half of the average levels recorded in the 1980s and 1990s
By Summit Voice
SUMMIT VOICE — For the first time in the modern satellite record, Arctic sea ice extent has dropped below 4 million square kilometers, marking a 45 percent reduction from the levels recorded in the 1980s and 1990s.
The National Snow and Ice Data Center said the ice extent may shrink for another week or so before the Arctic region starts to cool off, leading to a renewed cycle of freezing.
During most of August, the ice extent remained well below the levels of 2007, when the previous record low was set. The only place where sea ice remained near its average long-term extent was along the east coast of Greenland.
According to the NSIDC, the five-day running average dropped below the previous record low daily extent on August 26, more than two weeks earlier than the record low set on Sept. 18, 2007.
The rate of ice loss in August was by far the fastest that’s been observed, shrinking by about 91,700 square kilometers (35,400 square miles) per day. That’s almost double the average daily rate of ice loss that’s been recorded during the satellite observation era (about 55,100 square kilometers per day.
In August 2007, ice was lost at a rate of 66,000 square kilometers (25,400 square miles) per day, and in 2008, the year with the previous highest August ice loss, the rate was 80,600 square kilometers (31,100 square miles) per day.
This year’s rapid pace of ice loss was dominated by large losses in the East Siberian and the Chukchi seas, likely caused in part by the strong cyclone that entered the region earlier in the month and helped to break up the ice.But even after the cyclone had dissipated, ice loss continued at a rate of 77,800 square kilometers (30,000 square miles) per day.
Other recent measurements also show that the volume of ice, based on thickness, as well as extent, has been decreasing steadily. More and more studies are suggesting that the diminishing ice pack is affecting mid-latitude climate and weather.
As compared to the bright ice, the darker colored open water absorbs and holds more heat. That has affected the air pressure gradient between the high latitudes and the mid-latitudes, slowing the jet stream and increasing the amplitude of high and low pressure areas.
Those ridges and dips in the jet stream appear to be slowing down and even getting stuck at times, leading to sustained periods of more extreme weather, like this summer’s brutal months-long heatwave in North America.