Relentless heat results in new record low Arctic sea ice max
Monday, March 28, 2016, 7:32 PM - Arctic sea ice reached its winter maximum last week and the news isn't good. Due to a record warm winter, sea ice across the Arctic has reached a new record low extent for the second year in a row.
According to NASA and the US National Snow and Ice Data Center (NSIDC), Arctic sea ice reached its maximum extent on March 24, 2016, at just 14.52 million square kilometres. This is down 13,000 square kilometers from the previous record low, set in 2015, and down roughly a million square kilometres from the 1981-2010 average set for winter maximums.
Arctic sea ice extents for 2006-2016, with 2015 and 2016 maximums inset. Credit: National Snow and Ice Data Center/S. Sutherland
According to records from NOAA, NASA and other agencies, temperatures across the Arctic were exceptionally warm over the 2015-2016 winter season, with the greatest departure from 20th century average on record, and relative to that average, warmer than nearly anywhere else on the planet.
"I've never seen such a warm, crazy winter in the Arctic," Mark Serreze, director of the NSIDC, said in a press release. "The heat was relentless."
Credit: NASA GISS
Sea ice in the Arctic waxes and wanes based on the season, usually reaching a minimum extent sometime in mid-to-late September and then growing to a maximum extent by February or March the next year. Both minimum and maximum extents can vary from year to year, however there is an alarming long-term trend emerging from the data due to the effects of human-enhanced climate change.
"It is likely that we're going to keep seeing smaller wintertime maximums in the future because in addition to a warmer atmosphere, the ocean has also warmed up. That warmer ocean will not let the ice edge expand as far south as it used to," Walt Meier, a sea ice scientist at NASA’s Goddard Space Flight Center, said in a statement. "Although the maximum reach of the sea ice can vary a lot each year depending on winter weather conditions, we’re seeing a significant downward trend, and that's ultimately related to the warming atmosphere and oceans."
Arctic in crisis
"The Arctic is in crisis. Year by year, it's slipping into a new state, and it's hard to see how that won't have an effect on weather throughout the Northern Hemisphere," Ted Scambos, NSIDC's lead scientist, said in a press release on Monday.
Since record keeping began in 1979, every year up to 2000, except 1990, has seen a minimum extent greater than the 1981-2010 average. From 2000 on, every year except 2001 has seen a minimum extent below that 30-year average. In the winter, every year prior to 2000 had a maximum extend above the average, while every year from 2004 onward has had a maximum extent lower than average, with the last two years being the lowest maximums on record.
A record low maximum extent does not necessarily bring about a record low minimum in September. Although 2015 was the lowest maximum on record, it came in fourth lowest on record for the September minimum, behind 2012, 2007 and 2011, all of which were remarkably low record minimums for their time.
At the moment, the 2016 extent as of March 28 is roughly the same as extents recorded at this time of year in 2007, 2011 and 2015. Melt season in the Arctic followed very similar patterns during those years, resulting in very similar September minimums. This could mean that the 2016 extent will track along with them, however, given the tenuous state of sea ice in the Arctic in recent years, it may not take much to push the minimum extent down to a new record low this year.
As the NSIDC said back in 2012, after that year's stunning record minimum extent:
It is likely that the primary reason for the large loss of ice this summer is that the ice cover has continued to thin and become more dominated by seasonal ice. This thinner ice was more prone to be broken up and melted by weather events, such as the strong low pressure system just mentioned. The storm sped up the loss of the thin ice that appears to have been already on the verge of melting completely.
While minimum sea ice extents have been higher since 2012, there is still a majority of seasonal ice - sea ice which has only had one year to grow back since the last melt. The amount of multi-year ice, which is far more resilient to single weather events, is on a generally downward trend in the data record.
Smaller-scale weather events - such as Storm Frank, which blasted past Iceland, Ireland and the UK in late December to usher in an Arctic heat wave - are certainly responsible for smaller time-scale dips and minimums in the record. At the same time, however, the loss of multi-year ice, along with warmer oceans and atmosphere due to climate change, are making the Arctic more susceptible to larger impacts from these smaller events.
Watch below: NASA's Goddard Space Flight Center Scientific Visualization Studio presents a look at the amount of multi-year ice across the Arctic, each year from 1979-2014, showing the alarming downward trend over time.