Arctic sea ice this year is the smallest in winter since satellite records began in 1979, in a new sign of long-term climate change, U.S. data showed on Thursday.
Every year, Arctic sea ice — ice that forms and floats in Arctic waters — grows during the winter and typically reaches its peak in March before receding with the spring thaw. A new report from the National Snow & Ice Data Center (NSIDC), however, reveals this year’s Arctic sea ice reached its maximum extent earlier than expected, on Feb. 25. At this peak, sea ice covered just 5.61 million square miles (14.54 million square kilometers) — the lowest maximum extent since satellite record keeping began in 1979.
“This year’s maximum ice extent was the lowest in the satellite record, with below-average ice conditions everywhere except in the Labrador Sea and Davis Strait,” the U.S. National Snow and Ice Data Center (NSIDC) said in a statement.
Researchers have seen fluctuations in the date of the sea ice’s peak, with it occurring as early as Feb. 24 in 1996 and as late as April 2 in 2010. Still, this year’s maximum extent occurred 15 days earlier than the March 12 average calculated from 1981 to 2010.
The Arctic ice cap grows and shrinks with the seasons, and changes in the region’s ice cover are largely dictated by variations in sunlight, temperature and weather conditions. This year’s maximum extent was 425,000 square miles (1.10 million square km) below the average from 1981 to 2010 of 6.04 million miles (15.64 million square km). This year’s ice cover was also 50,200 square miles (130,000 square km) lower than the previous record low set in 2011.
NASA made this amazing video that shows the ice creep across the Arctic waters, and then stop short:
Ice growth this winter lagged behind last year’s progress, partly due to unusual patterns in the jet stream in February that created warm pockets over the Bering Sea and the Sea of Okhotsk, in the western Pacific Ocean, according to the NSIDC. Warmer seas, combined with milder temperatures, made for “exceptionally” poor conditions for this year’s freeze, scientists said.
The report did note that a late season surge in ice was still possible, though unlikely. “Over the next two to three weeks, periods of increase are still possible,” the scientists wrote. “However, it now appears unlikely that there could be sufficient growth to surpass the extent reached on February 25.”
The U.N. panel of climate scientists links the long-term shrinkage of the ice, by 3.8 percent a decade since 1979, to global warming and says Arctic summertime sea ice could vanish in the second half of the century. Patterns of warming on land and sea show no sign of slowing: numerous data sources have confirmed that 2014 was the hottest year since records began in the 19th century.
The new findings come on the heels of a study published earlier this month in the journal Cryosphere, which concluded that Arctic sea ice is vanishing far more rapidly than was previously thought. Combining a variety of measurements, both historical and modern, the researchers discovered that annual average sea ice thickness over the entire Arctic basin was decreasing about 18 inches per decade since 2000. Since 1975, the annual average thickness in just the central part of the basin had dropped from about 11 feet to 4 feet — a decline of 65 percent. That was nearly double the 36 percent decline that a previous study calculated over the period from 1975-2000.
The decline of Arctic ice is already having a dramatic impact on the ecosystem and wildlife, from walruses to polar bears, and has forced Indigenous peoples to alter their hunting strategies, leading to more dangerous conditions. The loss of ice in the Arctic also has serious implications for the climate. Without ice cover to reflect sunlight back into space, the summer Arctic has begun to absorb solar energy at a significantly higher rate. Additionally, the melting Arctic permafrost is releasing large amounts of methane into the atmosphere and creating a feedback loop that scientists say is “certain to trigger additional warming.”
Ted Scambos, senior research scientist for the NSIDC, told the Guardian that “[The record low extent] is significant, in that it shows that the Arctic is being seriously impacted by our warming climate.”