The following is from a National Snow & Ice Data Center statement issued March 6, 2018, and available on its Internet site. Its discussion is about sea ice and conditions in the Artic and Antarctic in February this year. The statement focuses on the actuality of sea ice extent rather than possible causes of change.
“As temperatures at the North Pole approached the melting point at the end of February, Arctic sea ice extent tracked at record low levels for this time of year. Extent was low on both the Atlantic and Pacific sides of the Arctic, with open water areas expanding rapidly in the Bering Sea during the latter half of the month. On the other side of the globe, Antarctic sea ice has reached its minimum extent for the year, the second lowest in the satellite record.”
“Winter continues to be mild over the Arctic Ocean. Sea ice extent remained at record low daily levels for the month. Arctic sea ice extent for February 2018 averaged 13.95 million square kilometers (5.39 million square miles). This is the lowest monthly average recorded for February, 1.35 million square kilometers (521,000 square miles) below the 1981 to 2010 average and 160,000 square kilometers (62,000) below the previous record low monthly average in 2017.”
“Extent was especially low in the Bering Sea where sea ice declined during the first three weeks of the month. The eastern part of the Bering Sea was largely ice-free for most of the month; extent was low on the western side, with the ice edge further north than normal. In the Chukchi Sea, extent also retreated during part of February, with open water developing north of the Bering Strait on both the Siberian and Alaskan coasts. As seen all winter, ice extent continued to be below average in the Barents Sea, and at the end of February, a wedge of open water formed north of Svalbard that extended well into the Arctic Ocean.”
“The Arctic Ocean is becoming more accessible for shipping. Most of the increase in commercial shipping traffic has been during summer, primarily through the Northern Sea Route along the coast of Siberia. However, this February a commercial tanker, the Eduard Toll, made the first crossing of the Northern Sea Route in winter. Improvements in ship-building and the development of ice-strengthened hull technology is a major factor in enabling winter access. Previous ice-strengthened ships could only navigate safely through 0.5 meter thick ice, compared to the 1.8 meter thick ice that the Eduard Toll cruised through. A fleet of six ships with similar technology is being constructed by a South Korean shipbuilder.”
“In the Antarctic, sea ice extent reached its daily seasonal minimum, 2.18 million square kilometers (842,000 square miles), on February 20 and 21. This is the second lowest minimum extent in the satellite record, 70,000 square kilometers (27,000 square miles) above the record low, which was set on March 3, 2017. The February average was 2.29 million square kilometers (884,000 square miles), second lowest in the satellite record, and 20,000 square kilometers (7,700 square miles) above the record low February in 2017.”
“Sea ice in the Antarctic is highly variable from year to year—much more so than in the Arctic. This is clearly seen in the February extent values, where low 2011 values were followed by record or near-record highs in 2013, 2014, and 2015. This was then followed by record or near-record lows in 2017 and this year.”
