Sea Ice Extent was Lowest on Record in January
The combined sea ice extent of the Arctic and Antarctic was the lowest for the month of January on record, according to new reports.
Sea ice extent for the Antarctic was the lowest on record for January, and for the Arctic the third lowest, according to Europe’s Copernicus Climate Change Service and the US National Snow and Ice Data Center (NSIDC).
“Combined, the two hemispheres set a record low for total global sea ice extent, yet this does not signify a trend necessarily and may be caused by weather-related variability,” said NSIDC.
Sea ice extent is one of the climate indicators used by WMO in its State of the Global Climate reports.
Temperature is another indicator, and the past eight years have been the warmest on record. It was the 7th warmest January on record, according to Copernicus Climate.
Copernicus Climate Change Service, which is implemented by the European Centre for Medium Range Weather Forecasts. It was the third warmest January for Europe, which witnessed unusually mild temperatures on New Year’s Day.
The Arctic is warming more than twice as fast as the global average. As a result, Arctic sea ice has retreated dramatically over the 44-year satellite record.
Based on the linear trend, since 1979, January has lost 1.89 million square kilometers (730,000 square miles), about twice the size of Germany, according to NSIDC.
Regionally, sea ice extent remained particularly low in the Barents Sea, and it was also below average in the Sea of Okhotsk, the Bering Sea, and the Gulf of St. Lawrence.
Arctic sea ice usually reaches its annual maximum extent in late February or early March, when Antarctic sea ice reaches its minimum extent. On 1st February 2022, Antarctic sea ice maximum extent was the lowest on record (2.26 million square kilometers or 873,000 square miles).
The January 2023 average Antarctic extent of 3.23 million square kilometers (1.25 million square miles) is the lowest January extent in the satellite record, below the previous January record low of 3.78 million square kilometers (1.46 million square miles) set in 2017.
The downward linear trend in January sea ice extent is 6,400 square kilometers (2,500 square miles) per year or 1.3 percent per decade, according to NSIDC.
Every year, at this time, summer eats away at the sea ice around Antarctica.
But this year, West Antarctica in particular has been warmer than usual, and this, combined with strong winds and large waves, has helped to create huge ice-free areas in the area from the Weddell Sea, and west towards the Ross Sea, via the Antarctic Peninsula.
This is a huge area where sea ice is far below normal, and this brings the total extent of sea ice around Antarctica to a record low distribution for the month of January.
Since 2017, the area from the Weddell Sea westwards towards the Ross Sea in the southernmost part of the Pacific Ocean has marked itself with a more or less constant low extent of sea ice.
Gorm Dybkjær, Sea Ice Researcher, Danish National Centre for Climate Research, Danish Meteorological Institute said: "Throughout last year, the extent of sea ice was generally low in Antarctica, and this is leaving its mark as the new sea ice that forms over the winter becomes more fragile and has an easier time breaking up and melting.
"It quickly turns into a vicious circle where the sea ice will have difficulty recovering – just as we see in the Arctic Ocean.
"It is too early to conclude whether sea ice continues to shrink in Antarctica or whether there are just long-term natural fluctuations in the weather, here we need a stronger statistical basis before we can assess whether the changes are due to climate change.
"However, we can say that the lower extent of sea ice in Antarctica fits into our expectation of what happens when the global temperature rises. In any case, it is certain that we will follow this closely in the coming years, together with the sea ice around the Arctic."
Air temperatures at the 925 hPa level (about 2,500 feet or 760 meters above sea level) have been 1 to 2 degrees Celsius (2 to 4 degrees Fahrenheit) above average since November in a broad area of the coast stretching clockwise from the eastern Wilkes Land through the Ross and Amundsen Sea, and over most of the Weddell Sea.
However, warm ocean waters just below the surface layer are also thought to be playing a role in the general downward trend of Antarctic sea ice since 2016, according to NSIDC.