The Arctic just finished its warmest winter on record. And sea ice hit record lows for this time of year, with plenty of open water where ocean water normally freezes into thick sheets of ice, new U.S. weather data revealed.
In February, Arctic temperatures soared more than 45 degrees above normal. Temperature stations closest to the North Pole measured temperatures at the highest on record for the month of February. February also saw the greatest loss of Arctic sea ice in the past 1,500 years. Record-low levels of sea ice in the Bering Sea and the Arctic are shattering all known records.
In a shocking melting event, half of the ice in the Bering Sea disappeared during a two-week period in February. Brian Brettschneider, a climatologist based in Alaska, posted “overall sea ice extent on Feb. 20 was the lowest on record.”
An alarming heatwave in the sunless winter Arctic is causing blizzards in Europe and forcing scientists to reconsider even their most pessimistic forecasts of climate change.
While the Eastern United States experienced its warmest February weather ever recorded in history, the Arctic is also simmering in temperatures more than 45 degrees above normal. This latest huge temperature spike in the Arctic is another striking indicator of its rapidly transforming climate.
Temperatures over the entire Arctic north of 80 degrees latitude have averaged about 10 degrees (6 Celsius) above normal since the beginning of the calendar year. These kinds of temperature anomalies in the Arctic have become commonplace in winter in the past few years.
The cause and significance of this sharp uptick are now under scrutiny. Temperatures often fluctuate in the Arctic due to the strength or weakness of the polar vortex, the circle of winds – including the jetstream – that help to deflect warmer air masses and keep the region cool. As this natural force field fluctuates, there have been many previous temperature spikes, which make historical charts of Arctic winter weather resemble an electrocardiogram.
But the heat peaks are becoming more frequent and lasting longer – never more so than this year.
The new research out Tuesay suggests that the polar vortex has been disrupted by the warming of the globe. Warming temperatures have weakened the low pressure system’s flow, argue climate scientists, causing it to drift southward from the polar region—and to bring cold Arctic air along with it.
Last month, the northernmost weather station in the world, Cape Morris Jesup at the northern tip of Greenland, experienced more than 60 hours of temperatures above freezing according to the Danish Meteorological Institute. These recent temperatures have been, at times, warmer than London and Zurich, which are thousands of miles to the south. Before this year, scientists had seen the temperature there rise above freezing in February only twice before, and then extremely briefly. Last month’s record-high temperatures have been more like those typical of May, said Ruth Mottram, a climate scientist at the Danish Meteorological Institute.
Although it could yet prove to be a freak event, the primary concern is that global warming is eroding the polar vortex, the powerful winds that once insulated the frozen north.
The North Pole receives no sunlight until March, but an influx of warm air has pushed temperatures in Siberia up by as much as 35°C above historical averages in February. Greenland has already experienced 61 hours above freezing in 2018 – more than three times as many hours as in any previous year.
In February, Arctic sea ice covered 5.4 million square miles, about 62,000 square miles smaller than last year’s record low, the ice data center said Tuesday. The difference is an area about the size of the state of Georgia. Sea ice coverage in February also was 521,000 square miles below the 30-year normal — an area nearly twice the size of Texas.
The record-setting temperatures and lack of ice is exactly what scientists have projected over the Arctic for years and it’s fundamentally changing the landscape.
“Arctic shows no sign of returning to reliably frozen region of recent past decades,” NOAA concluded in its Arctic Report Card, published in December.