Scientists are tracking record low sea ice extent in the Southern Hemisphere as well, where it is currently summer. On February 5, the Amundsen Sea was nearly ice-free, with only a scattering of ice patches, whereas in the Weddell Sea, the extent is only slightly below average.
Sea ice has been expected to decline at both poles as the Earth continues to heat up due to a buildup of greenhouse gasses in the atmosphere. This is seen most clearly in the Arctic, where sea ice is at half the area it was at this time in the early 1970s.
Antarctic sea ice extent
In the Antarctic, sea ice levels are more variable as we have seen over the last several years. The sea ice usually reaches a minimum extent in the Southern Hemisphere’s late summer (February or March). Up until early September 2016, Antarctic sea ice extent was near average.
But the sea ice extent began a rapid decline through the end of the year. Looking at the average for the entire year, the Antarctic sea ice extent was 4.2 percent below average, the second smallest on record. But we all know that sea ice extent in the Antarctic has varied greatly over the past few years, approaching record low levels in 2011 and record high levels in 2013. And as Live Science is reporting, “Scientists are still unraveling the processes that affect it from year to year.”
An unusual winter in the Northern Hemisphere
The large decline in Arctic sea ice has created a cyclic warming that is creating havoc with our weather. With little ice, the polar seas absorb more radiation from the sun, heating the surface waters, in turn, exacerbating warming in the polar region.
This also means there are more instances of waves from storms beating on the Arctic’s coastlines, increasing erosion and driving Indigenous communities from their homes. And the warming of the Arctic region has led to an increase in shipping and tourist ship excursions into an already frail environment.
The repeated spikes in warm temperatures can be explained by the number of storms moving up from the Atlantic Ocean bringing warm air with them. “This has been a most unusual winter,” Julienne Stroeve, of the National Snow and Ice Data Center, which tracks sea ice levels, said in an email to Live Science.
Overall, the chances are good that the Arctic will set a record low end-of-winter peak, which usually occurs in mid-March, and if so, it will be the third year in a row that this occurs. Stroeve says that the significant loss of summer sea ice means that the sea ice loss will start to show up in other seasons, especially now that fall is starting later and later, not giving ice much time to accumulate.
