The Antarctic has changed its mode of existence, and a record low ice thickness has been recorded in the Arctic
Antarctic sea ice is «behaving strangely» and may have entered a «new regime,» the director of the US National Snow and Ice Data Center (NSIDC) told the scientific publication Carbon Brief. After a record low peak in September 2023, sea ice extent in Antarctica has remained near record lows for the past six months. It reached its 2024 minimum extent last month, making it the second-highest Antarctic low in 46 years of satellite records compared to 2022.
NSIDC director Dr Mark Serreze told Carbon Brief that more warm ocean water is reaching the surface to melt the ice and prevent it from forming again. He notes that we «will have to wait and see» whether this is a «temporary effect» or whether Antarctica has entered a «new regime.» Meanwhile, Arctic sea ice reached its largest extent in a year, peaking at 15.01 million square kilometers on March 14. Preliminary NSIDC data shows that this winter peak in 2024, despite tailwinds that contributed to sea ice formation, was at 640 thousand square meters. km is less than the average maximum of 1981–2010. This year's high was the 14th lowest in satellite records.
“In general, the road through Arctic sea ice remains downhill, but it is quite bumpy,” another scientist told Carbon Brief. This relatively high winter peak is «remarkable and a good reminder that we need to communicate and account for this type of weather variability when we talk about climate change in Antarctica.» He adds that while the maximum is high compared to previous years, the ice is still «much thinner» than it was several decades ago. The «broad coverage of this thinner ice» means total sea ice volume in February was the third highest on record.
The extent of sea ice in the Arctic varies throughout the year. It rises each winter before reaching its peak in February or March and then melts in the spring and summer, reaching its annual minimum usually in September. Using satellite data, scientists can track the growth and melting of sea ice, allowing them to determine the size of the winter maximum and summer minimum of the ice sheet.
Dr. Zach Leib, who works at NOAA's Geophysical Fluid Dynamics Laboratory, emphasizes that «while this winter was once again consistent with the long-term trend of a warmer Arctic with less ice, regional weather patterns could still contribute to ice expansion and slower network contraction.» On September 19, Arctic sea ice reached its minimum extent in 2023.
After a yearly low, sea ice growth in the Arctic was «slower than average,» resulting in the fifth-lowest September on record, according to NSIDC. The frost season began with «widespread open water across the Pacific side of the Arctic, with large areas of ice missing north of Alaska,» contributing to «well above average temperatures» in the region. However, during October, sea ice extent increased by 119,800 square kilometers per day — faster than the average for the period 1981-2010. The Arctic freeze has been “particularly rapid” in the seas along the Siberian coast. By late October, ice cover had reached the region, although open water remained in the Beaufort and Chukchi Seas. Temperatures over the Arctic Ocean, about 2,500 feet above surface level, were generally above average in October—especially in and around the Canadian Archipelago, where temperatures were 4 to 5 degrees Celsius above average.
< p>In general, the Arctic winter can be characterized by «unusual warmth in the northern Arctic, but a larger total ice area.» These «counterintuitive» dynamics were caused by atmospheric circulation patterns that resulted in «warmer and wetter air blowing toward the north pole, while northerly winds promote ice expansion in the Greenland and Okhotsk seas,» he said. During November, sea ice extent in the Arctic continued to increase faster than average. However, NSIDC says ice cover «temporarily stalled» for about five days starting November 22 as a series of three tropical cyclones brought warm, moist air into the North Atlantic.
NSIDC said the combination of low pressure in the north and west of Svalbard and a high pressure center in the southeast «has created a strong, persistent southerly flow of relatively warm and moist air from the North Atlantic Ocean towards Svalbard.» This air flow can be seen as “an extension of the atmospheric river into the Arctic,” the report says. It also highlights that strong winds «have helped push the ice edge in the eastern Greenland and Barents Seas northward, limiting the formation of new ice.» NSIDC notes that pauses in Arctic sea ice freezing have occurred before in November, in 2013 and 2016, making such events «rare but not unknown.» According to NSIDC, Arctic sea ice extent continued to increase at a «noticeably faster rate» than normal through December, and «sea ice formation in Hudson Bay occurred unusually late, but ice cover expanded rapidly from west to east in mid-December.»
Overall, December 2023 saw the third-largest monthly increase on record, with sea ice extent increasing by 2.71 million square kilometers over the month. The average Arctic sea ice extent in December 2023 was the ninth smallest on record in satellite records at 12 million square kilometers. As the new year began, Arctic sea ice extent continued to decline in the rankings, despite slower than average ice growth.
NSIDC reports that sea ice extent in the Arctic actually decreased for a few days at the end of the month, although this is «not unusual at this time of year» and is «caused by weather systems that temporarily stop ice growth or push ice north.» The average Arctic sea ice extent in January 2024 was 13.92 million square kilometers—the 20th smallest on record. This relatively large extent of sea ice is “remarkable and a good reminder that we need to communicate and account for this type of weather variability when we talk about climate change in the Arctic,” Dr. Labe told Carbon Brief. Sea ice extent in the Arctic continued to increase throughout February, adding 15.3 million square kilometers over the month. The February 2024 area of 14.61 million square kilometers was 690 thousand square kilometers below the February 1981–2010 average area and tied with 2022 as the 15th lowest on record, according to NSIDC .
Temperatures over the Arctic Ocean are typically «well below freezing» in February 2024, but NSIDC notes that in 2024 they were not as cold as traditionally for this time of year. In the central Arctic Ocean, air temperatures at 2,500 feet above sea level were 10 degrees above average. Labe notes that while sea ice extent was high compared to past years, the ice is still «much thinner» than it was several decades ago: «Total sea ice in the Arctic in February was the third highest on record.» due to the wide coverage of this thinner ice.” Variability and long-term decline in February thickness.
The Antarctic minimum was 850,000 square kilometers less than the 1981–2010 average summer minimum of 2.84 million square kilometers, but 200,000 square kilometers more than the previous record low set on February 21, 2023. This year marks the third consecutive minimum amount of sea ice in Antarctica.
Mark Serreze stated that “summer length in the southern hemisphere has fallen to record lows over the past few years. We've seen all-time highs before this! What changed? The answer appears to lie in the ocean: more warm water rises to the surface to melt the ice or prevent it from forming. Is this a temporary effect or, as many argue, have we entered a “new regime” in which the ocean will continue to greatly influence sea ice? Again, we will have to wait and see.”
Antarctic conditions in 2023 were “truly exceptional” and “completely outside the bounds of normality,” according to experts. Antarctic sea ice melt was «slower than average» in 2023, according to NSIDC. However, Antarctic sea ice extent remained at record lows.
Antarctica welcomed 6.37 million square kilometers of sea ice into the new year, the sixth-highest sea ice extent, according to scientists. in Antarctica on New Year's Eve in all recorded history. The ice melted rapidly throughout the month, and by the end of January, daily sea ice extent in Antarctica reached 2.58 million square kilometers, the second lowest on record.
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