The amount of sea ice in the Arctic Ocean likely reached its lowest winter level on record last month, according to scientists at the National Snow and Ice Data Center (NSIDC). Arctic sea ice typically reaches a high point around February or March, as it expands with colder temperatures. According to the latest figures from the NSIDC, this year's maximum point is the lowest since satellite observations began in 1979.
Arctic sea ice appears to have reached a maximum on February 25th of this year, when it covered 5.61 million square miles — 50,200 square miles lower than the previous lowest winter maximum in 2011. The NSIDC acknowledges the difficulty in identifying the exact high point, due to variability in seasonal trends, though there was "a clear downward trend" in ice coverage for several days following February 25th. "Over the next two to three weeks, periods of increase are still possible," the NSIDC said in a report published Thursday. "However, it now appears unlikely that there could be sufficient growth to surpass the extent reached on February 25."
Overall, Arctic sea ice grew by 3.83 million square miles this winter, which is significantly lower than last year. Sea ice levels reached a record low in 2012, and the NSIDC says this year's low maximum is likely due to unusual wind patterns that led to warmer conditions over the Pacific side of the Arctic. Once sea ice reaches a maximum, it begins melting during the warmer spring and summer months, typically reaching a minimum around September. Declining levels of arctic sea ice could have a range of environmental and social implications, as Vox explains in greater detail.
The NSIDC will release a comprehensive analysis of 2014-2015 winter ice coverage in April, after data for March has been collected.