Arctic sea ice has likely reached its maximum extent for the year, at 14.62 million square kilometers (5.64 million square miles) on March 6. The 2023 maximum is the fifth lowest in the 45-year satellite record. NSIDC scientists will present a detailed analysis of the 2022 to 2023 winter sea ice conditions in the regular monthly post in early April.

Overview of conditions

Figure 1. This image shows Arctic sea ice extent on March 7, 2023, which was 14.62 million square kilometers (5.64 million square miles) like the extent on March 6, 2023. The March 7 image is being used because of missing data on the prior day’s map. The orange line shows the 1981 to 2010 average extent for that day. Sea Ice Index data. About the data

Credit: National Snow and Ice Data Center
High-resolution image

On March 6, 2023, Arctic sea ice likely reached its maximum extent for the year, at 14.62 million square kilometers (5.64 million square miles), the fifth lowest extent in the satellite record. This year’s maximum extent is 1.03 million square kilometers (398,000 square miles) below the 1981 to 2010 average maximum of 15.65 million square kilometers (6.04 million square miles) and 210,000 square kilometers (81,000 square miles) above the lowest maximum of 14.41 million square kilometers (5.56 million square miles) set on March 7, 2017.

The date of the maximum this year, March 6, was six days earlier than the 1981 to 2010 average date of March 12.

Conditions in context

Figure 2. The graph above shows Arctic sea ice extent as of March 6, 2023, along with daily ice extent data for four previous years and the record low year. 2022 to 2023 is shown in blue, 2021 to 2022 in green, 2020 to 2021 in orange, 2019 to 2020 in brown, 2018 to 2019 in magenta, and 2011 to 2012 in dashed brown. The 1981 to 2010 median is in dark gray. The gray areas around the median line show the interquartile and interdecile ranges of the data. Sea Ice Index data.

Credit: National Snow and Ice Data Center
High-resolution image

The ice growth season ended with below average sea ice extent in the Bering Sea, Sea of Okhotsk, Barents Sea, and Labrador Sea. Above average extent was in the Greenland Sea. Extent was well below average in the Gulf of St. Lawrence for a second year in row.

Since the maximum on March 6, extent has dropped about 200,000 square kilometers (77,000 square miles), with losses primarily in Labrador Sea, Gulf of St. Lawrence, and the Barents Sea.

Table 1. Ten lowest maximum Arctic sea ice extents (satellite record, 1979 to present)

For the Arctic maximum, which typically occurs in March, the uncertainty range is ~34,000 square kilometers (13,000 square miles), meaning that extents within this range must be considered effectively equal.

Throughout February, Arctic sea ice extent tracked between second and fourth lowest in the satellite record while Antarctic sea ice extent tracked at record low extents. Antarctic sea ice has hit its minimum extent for the year, setting a new record low, and is now expanding.

Overview of conditions

Figure 1a. Arctic sea ice extent for February 2023 was 14.18 million square kilometers (5.47 million square miles). The magenta line shows the 1981 to 2010 average extent for that month. Sea Ice Index data. About the data

Credit: National Snow and Ice Data Center
High-resolution image

Figure 1b. The graph above shows Arctic sea ice extent as of March 1, 2023, along with daily ice extent data for four previous years and the record high year. 2022 to 2023 is shown in blue, 2021 to 2022 in green, 2020 to 2021 in orange, 2019 to 2020 in brown, 2018 to 2019 in magenta, and 2011 to 2012 in dashed brown. The 1981 to 2010 median is in dark gray. The gray areas around the median line show the interquartile and interdecile ranges of the data. Sea Ice Index data.

Credit: National Snow and Ice Data Center
High-resolution image

The February 2023 average Arctic sea ice extent was 14.18 million square kilometers (5.47 million square miles), the third lowest February in the satellite record (Figure 1a). February extent was 1.12 million square kilometers (432,000 square miles) below the 1981 to 2010 average of 15.30 million square kilometers (5.91 million square miles), but 210,000 square kilometers (81,000 square miles) above the record low set in February 2018.

The overall daily rate of increase in extent through the month was near average, but with periods of rapid increase at the start and the middle of the month, followed by periods of little change (Figure 1b). This is not uncommon for this time of year as ice growth slows and the ice edge is vulnerable to winds that either compress or expand the ice cover. Ice expansion slowed the last week of February and while the seasonal maximum does not appear to have been reached, it is likely not far away. The seasonal maximum has occurred as early as February 24 in 1987 and 1996 and as late as April 2 in 2010.

Overall, extent increased 724,000 square kilometers (280,000 square miles) during February 2023, compared to the 1981 to 2010 average February increase of 573,000 square kilometers (221,000 square miles). Regionally, extent remained below average in the Barents Sea, the Sea of Okhotsk, and the Gulf of St. Lawrence. In the Bering Sea, the ice extent was closer to average.

Conditions in context

Figure 2a. This plot shows average sea level pressure in the Arctic in millibars for February 2023. Yellows and reds indicate high air pressure; blues and purples indicate low pressure.

Credit: NSIDC courtesy NOAA Earth System Research Laboratory Physical Sciences Laboratory
High-resolution image

Figure 2b. This plot shows the departure from average air temperature in the Arctic at the 925 hPa level, in degrees Celsius, for February 2023. Yellows and reds indicate higher than average temperatures; blues and purples indicate lower than average temperatures.

Credit: NSIDC courtesy NOAA Earth System Research Laboratory Physical Sciences Laboratory
High-resolution image

During February, the Arctic Oscillation, a large-scale mode of Arctic climate variability, was in a strongly positive phase. When the Arctic Oscillation index is positive, the low sea level pressure over Svalbard strengthens, and the winds circulating around the North Pole are stronger, helping to keep cold air in the Arctic Ocean. The sea level pressure pattern for February featured unusually low sea level pressure over Svalbard coupled with high pressure over the central Arctic Ocean and Siberia (Figure 2a). The Siberian High and Beaufort Sea High are common features of winter, yet this February, the Beaufort Sea High shifted more towards the Pole. The combination of low pressure over Svalbard and high pressure over the central Arctic Ocean helped drive relatively warm air from the south across the North Atlantic and into the Barents Sea, and push cold Arctic air towards the Bering Sea. Cold Arctic air was also drawn westwards into eastern Canada. Air temperatures of up to 6 degrees Celsius (11 degrees Fahrenheit) below average  were also found over Baffin Bay and Hudson Bay (Figure 2b).

Another noteworthy atmospheric event of February was a sudden stratospheric warming (SSW). These occur when atmospheric longwaves propagate into the stratosphere, weakening or even reversing the stratospheric polar vortex. The effects can then propagate downward into the troposphere, enabling cold Arctic air to spill into lower latitudes. Heading into February, it appears that the stratospheric vortex was already in a weakened state because of vertical wave propagation. This made it susceptible to further breakdown about 10 days later when the vortex center shifted from the pole toward Europe. Overall, SSW events generally lead to Arctic sea ice growth, though the exact response varies by region.

February 2023 compared to previous years

Figure 3. Monthly February ice extent for 1979 to 2023 shows a decline of 2.8 percent per decade.

Credit: National Snow and Ice Data Center
High-resolution image

The downward linear trend in February sea ice extent over the 45-year satellite record is 42,300 square kilometers (16,300 square miles) per year, or 2.8 percent per decade relative to the 1981 to 2010 average. Based on the linear trend, since 1979, February extent has lost 1.86 million square kilometers (718,000 square miles) of ice. This is equivalent to about seven times the size of Colorado or about five times the size of Germany.

The role of atmospheric rivers in keeping Arctic winter sea ice extent low

Figure 4. This figure shows November to January averaged trends in atmospheric river (AR) events. The Arctic map (a) shows AR frequency trend from the ERA5 model and two other climate re-analyses. The plot (b) shows a time series of ARs in the Barents and Kara Seas from three different atmospheric reanalysis data sets together with the sea ice area in that region. AR frequency refers to the number of atmospheric river events in the late-fall/early-winter period; ABK (Arctic-Barents-Kara) refers to the area outlined in red in the map, and SIA is sea ice area.

Credit: Zhang et al., 2023
High-resolution image

In recent years, low sea ice extent in the Barents and Kara Seas has driven the overall negative trend in winter Arctic sea ice. Previous studies attributed the low ice cover in this region to increased ocean heat transport from the North Atlantic. A new study is looking at the role of atmospheric rivers as a contributing process. Atmospheric rivers bring in warm moist air from the tropics and subtropics, increasing the downward longwave radiation to the surface. They can also bring heavy rainfall. Both processes can melt sea ice. According to the study, more atmospheric rivers are entering the Eurasian Arctic than previously, leading to reduced ice formation or melting of thin ice in November through January.

The Kivalliq polynya

Figure 5. This NASA Visible Infrared Imaging Radiometer Suite (VIIRS) visible image was taken on February 6, 2023. The darker area on the western half of the Bay is newly formed sea ice where the polynya opened.

Credit: The National Oceanic and Atmospheric Administration Cooperative Institute for Meteorological Satellite Studies (CIMSS) at the University of Wisconsin-Madison Satellite Blog
High-resolution image

Hudson Bay is generally completely ice covered during the Arctic winter. However, as in other places, polynyas, regions of persistent open water, can occur under certain conditions. In western Hudson Bay, openings and closings of what is called the Kivalliq polynya are regular events related to strong winds. This polynya forms in winter as offshore winds push the ice away from the coast. As ice is pushed away, the open water left behind begins to freeze and new ice quickly forms. On average, about 182 cubic kilometers (43.7 cubic miles) of new ice is produced annually in this polynya, equivalent to about 20 percent of the winter ice volume of Hudson Bay, according to colleagues at the University of Manitoba. On January 21, the Kivalliq polynya once again opened and was soon covered by thin ice that was observed in visible and thermal satellite imagery. Synthetic Aperture Radar (SAR) and L-band passive microwave data from the Soil Moisture and Ocean Salinity (SMOS) satellite also captured the opening and closing of the polynya. Interestingly, the ice reflectance and the surface temperature in this region two weeks later was quite uniform, suggesting very uniform ice thickness (Figure 5). Polynyas such as this one not only facilitate ice production, they are also biologically important regions, fostering springtime phytoplankton blooms. They also play a large role in heat and moisture exchanges between the ocean and the colder atmosphere above it. Moreover, they lead to the production of dense, cold, and salty water as the sea ice freezes. Sea ice crystals are fresh ice and the formation of the crystals reject the salt brine, leading to dense descending water.

Antarctic sea ice may be reversing course

Figure 6a. Antarctic sea ice extent for February 2023 was 1.90 million square kilometers (734,000 square miles). The magenta line shows the 1981 to 2010 average extent for that month. Sea Ice Index data. About the data

Credit: National Snow and Ice Data Center
High-resolution image

Figure 6b. Antarctic sea ice concentration for February 2023 was 1.20 million square kilometers (463,000 square miles). The magenta line shows the 1981 to 2010 average extent for that month. Sea Ice Index data. About the data

Credit: National Snow and Ice Data Center
High-resolution image

Antarctic sea ice extent continued to track at record lows for this time of year. By the end of February, extent was 1.83 million square kilometers (707,000 square miles). This is 93,000 square kilometers (35,900 square miles) below the record seasonal minimum that occurred on February 25, 2022. Extent remained particularly low in the Amundsen, Bellingshausen, and Ross Seas (Figure 6a). Most of the sea is ice gone from the Ross Sea, and what little ice remains in the Amundsen/Bellingshausen Seas is very low concentration (Figure 6b). In the Weddell Sea, the ice edge remains near average for this time of year.

Until recently, there was a weak overall upward trend in Antarctic sea ice extent, but with some parts of the Antarctic sea ice exhibiting strong positive trends in extent and other areas exhibiting strong negative trends. According to colleagues at Commonwealth Scientific and Industrial Research Organisation (CSIRO Australia), this pattern is changing. Over the past decade, there is less regional variability. Patterns of sea ice extent variations, high or low, have become more uniform around the continent. This has contributed to the lower Antarctic sea ice extents that have been observed since 2016.

References

Bruneau, J., D. Babb, W. Chan, S. Kirillov, J. Ehn, J. Hanesiak, and D. G. Barber. 2021. The ice factory of Hudson Bay: Spatiotemporal variability of the Kivalliq Polynya. Elementa: Science of the Anthropocene, 9, (1). doi:10.1525/elementa.2020.00168.

Schroeter, S., T. J. O’Kane, and P. A. Sandery. 2023. Antarctic sea ice regime shift associated with decreasing zonal symmetry in the Southern Annular Mode. The Cryosphere, 17, 701–717, doi:10.5194/tc-17-701-2023.

Smith, K. L., L. M. Polvani, and L. B. Tremblay, L. B. 2018. The Impact of Stratospheric Circulation Extremes on Minimum Arctic Sea Ice Extent. Journal of Climate, 31(18), 7169-7183. doi:10.1175/JCLI-D-17-0495.1.

Zhang, P., G. Chen, M. Ting, et al. 2023. More frequent atmospheric rivers slow the seasonal recovery of Arctic sea ice. Nature Climate Change. doi:10.1038/s41558-023-01599-3.

On February 21, Antarctic sea ice likely reached its annual minimum extent of 1.79 million square kilometers (691,000 square miles). This the lowest sea ice extent in the 1979 to 2023 sea ice record, setting a record low for the second straight year.

Please note that this is a preliminary announcement. Changing winds or late-season melt could still reduce the Antarctic ice extent. NSIDC scientists will release a full analysis of the Antarctic and Arctic February conditions in early March.

Overview of conditions

Figure 1. Antarctic sea ice extent for February 21, 2023, was 1.79 million square kilometers (691,000 square miles). The orange line shows the 1981 to 2010 average extent for that day. Sea Ice Index data. About the data

Credit: National Snow and Ice Data Center
High-resolution image

On February 21, 2023, sea ice in the Antarctic reached an annual minimum extent of 1.79 million square kilometers (691,000 square miles), setting a record low in the satellite record that began in 1979. This year’s minimum is 1.05 million square kilometers (405,000 square miles) below the 1981 to 2010 average Antarctic minimum extent. It is 136,000 square kilometers (52,500 square miles) below the previous record low from February 25, 2022. Nearly all of the remaining ice is in the Weddell Sea, with isolated patches along the coasts of Princess Astrid and Princess Ragnild and regions of eastern Wilkes Land and the Pine Island Bay.

The Antarctic minimum extent was reached three days earlier than the 1981 to 2010 median date of February 24. The interquartile range for the date of the Antarctic minimum is February 20 to February 27.

Conditions in context

Figure 2a. The graph above shows Antarctic sea ice extent as of February 21, 2023, along with daily ice extent data for four previous years and the record high year. 2022 to 2023 is shown in blue, 2021 to 2022 in green, 2020 to 2021 in orange, 2019 to 2020 in brown, 2018 to 2019 in magenta, and 2013 to 2014 in dashed brown. The 1981 to 2010 median is in dark gray. The gray areas around the median line show the interquartile and interdecile ranges of the data. Sea Ice Index data.

Credit: National Snow and Ice Data Center
High-resolution image

Figure 2b. This graph shows Antarctic annual sea ice minimum extent, depicted as black diamonds, from 1979 to 2023, based on a 5-day running average of daily extent. The linear trend line is in blue with a 1.0 percent per decade downward trend, which is not statistically significant. A five-year running average is shown in red.

Credit: W. Meier, NSIDC
High-resolution image

This year marks a second consecutive record low in Antarctic sea ice extent (Figure 2a). In recent years, 2017 and 2018 also reached very low extents, third and fourth lowest, respectively. With this series of low years, it is natural to speculate if there is now a downward trend. However, a trend computed over such a short time period is not especially meaningful. Note in this respect that 2013 through 2015 saw near record high minimum extents.

Overall, the downward trend in the annual Antarctic sea ice minimum extent computed over the complete satellite record is 2,800 square kilometers (1,100 square miles) per year, or 1.0 percent per decade relative to the 1981 to 2010 average. This trend is not statistically significant (Figure 2b). This is in stark contrast to the Arctic where the trend in the sea ice minimum is larger in magnitude and has strong statistical significance.

Antarctic sea ice extent appears to have broken the record low set last year. With a couple more weeks likely left in the melt season, the extent is expected to drop further before reaching its annual minimum. Much of the Antarctic coast is ice free, exposing the ice shelves that fringe the ice sheet to wave action and warmer conditions.

Overview of conditions

Figure 1a. This map of Antarctica shows many low areas of sea ice concentration, depicted as darker blues, surrounding the continent, rendering extent likely to decrease in the coming days or weeks. Antarctic sea ice extent for February 13, 2023, was 1.91 million square kilometers (737,000 square miles). The orange line shows the 1981 to 2010 median extent for that day. Sea Ice Index data. About the data

Credit: National Snow and Ice Data Center
High-resolution image

Figure 1b. The graph above shows Antarctic sea ice extent as of February 13, 2023, along with daily ice extent data for four previous years and the record high year. 2022 to 2023 is shown in blue, 2021 to 2022 in green, 2020 to 2021 in orange, 2019 to 2020 in brown, 2018 to 2019 in magenta, and 2013 to 2014 in dashed brown. The 1981 to 2010 median is in dark gray. The gray areas around the median line show the interquartile and interdecile ranges of the data. Sea Ice Index data.

Credit: National Snow and Ice Data Center
High-resolution image

On February 13, 2023, Antarctic sea ice extent fell to 1.91 million square kilometers (737,000 square miles) (Figure 1a). This set a new record low, dropping below the previous record of 1.92 million square kilometers (741,000 square miles) set on February 25, 2022 (Figure 1b). This year represents only the second year that Antarctic extent has fallen below 2 million square kilometers (772,000 square miles). In past years, the annual minimum has occurred between February 18 and March 3, so further decline is expected.

Conditions in context

Figure 2. This graph shows Antarctic annual sea ice minimum extent, depicted as black diamonds, from 1979 to 2023, based on a 5-day running average of daily extent. The grey diamond data point depicts the 2023 minimum, which is still preliminary, with further loss expected. The linear trend line is in blue with a 0.9 percent per decade downward trend, which is not statistically significant. A five-year running average is shown in red. As the Antarctic melt season is still in progress, depicted as a grey downward arrow, the linear trend and running average will change slightly.

Credit: W. Meier, NSIDC
High-resolution image

Extent has tracked well below last year’s melt season levels since mid-December. As noted in our previous post, a positive Southern Annular Mode has led to stronger-than-average westerly winds. Along with a strong Amundsen Sea Low, the weather conditions have brought warm air to the region on both sides of the Antarctic Peninsula. This has largely cleared out the ice cover in the Amundsen and Bellingshausen Seas, and reduced the sea ice extent in the northwestern Weddell Sea. Sea ice is patchy and nearly absent over a long stretch of the Pacific-facing coastline of Antarctica.  Earlier studies have linked low sea ice cover with wave-induced stresses on the floating ice shelves that hem the continent, leading to break up of weaker areas.

Antarctic sea ice extent has been highly variable over the last several years. While 2022 and 2023 have had record low minimum extent, four out of the five highest minimums have occurred since 2008. Overall, the trend in Antarctic minimum extent over 1979 to 2023 is near zero. The current downward linear trend in the Antarctic minimum extent from 1979 to 2023 is 2,400 square kilometers (930 square miles) per year, or 0.9 percent per decade, which is currently not statistically significant. Nevertheless, the sharp decline in sea ice extent since 2016 has fueled research on potential causes and whether sea ice loss in the Southern Hemisphere is developing a significant downward trend.

Arctic sea ice extent rose at a slower than average rate through January, and continued to be below the lower interdecile range. By the end of the month, sea ice reached the second lowest extent in the satellite record. Meanwhile, Antarctic extent remained at record low levels. 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.

Overview of conditions

Figure 1a. Arctic sea ice extent for January 2023 was 13.35 million square kilometers (5.15 million square miles). The magenta line shows the 1981 to 2010 average extent for that month. Sea Ice Index data. About the data

Credit: National Snow and Ice Data Center
High-resolution image

Figure 1b. The graph above shows Arctic sea ice extent as of February 5, 2023, along with daily ice extent data for four previous years and the record low year. 2022 to 2023 is shown in blue, 2021 to 2022 in green, 2020 to 2021 in orange, 2019 to 2020 in brown, 2018 to 2019 in magenta, and 2012 to 2013 in dashed brown. The 1981 to 2010 median is in dark gray. The gray areas around the median line show the interquartile and interdecile ranges of the data. Sea Ice Index data.

Credit: National Snow and Ice Data Center
High-resolution image

The January 2023 average Arctic sea ice extent was 13.35 million square kilometers (5.15 million square miles), the third lowest January in the satellite record (Figure 1a). January extent was 1.07 million square kilometers (413,000 square miles) below the 1981 to 2010 average of 14.42 million square kilometers (5.57 million square miles), but 270,000 square kilometers (104,000 square miles) above the record low set in January 2018.

The daily rate of increase in extent was near average through the first half of the month, but slowed during the second half, and extent slightly declined near the end of the month (Figure 1b). Such short-term declines are not unusual in winter and typically reflect responses to weather patterns. Nevertheless, by the end of the month, the overall daily extent tracked at second lowest in the satellite data record. Overall, extent increased 1.09 million square kilometers (421,000 square miles) during January 2023, compared to the 1981 to 2010 average January increase of 1.33 million square kilometers (514,000 square miles).

Regionally, extent remained particularly low in the Barents Sea, and below average extent was also found in the Sea of Okhotsk, the Bering Sea, and the Gulf of St. Lawrence.

Conditions in context

Figure 2a. This plot shows average sea level pressure in the Arctic in millibars for January 2023. Yellows and reds indicate high air pressure; blues and purples indicate low pressure.

Credit: NSIDC courtesy NOAA Earth System Research Laboratory Physical Sciences Laboratory
High-resolution image

Figure 2b. This plot shows the departure from average air temperature in the Arctic at the 925 hPa level, in degrees Celsius, for January 2023. Yellows and reds indicate higher than average temperatures; blues and purples indicate lower than average temperatures.

Credit: NSIDC courtesy NOAA Earth System Research Laboratory Physical Sciences Laboratory
High-resolution image

The sea level pressure pattern for January featured high pressure over the Pacific sector of the Arctic Ocean (Figure 2a). This feature is known as the Beaufort High and is common in winter and spring. The location of the high varies, but on average it is centered over the Beaufort Sea and drives the Beaufort Gyre, which brings ice from north of Greenland and the Canadian Arctic Archipelago through the Beaufort and into the Chukchi Sea. By contrast, over on the Atlantic side of the Arctic, low pressure dominated in the Barents Sea region. As a result, relatively warm air from the south moved into the Barents Sea region, leading to air temperatures at the 925 millibar level (approximately 2,500 feet above the surface) more than 6 degrees Celsius (11 degrees Fahrenheit) above average near Svalbard (Figure 2b). The lack of sea ice in the Barents Sea likely also contributed to above average air temperatures. Elsewhere, air temperatures were above average over most of the Arctic Ocean, with departures from average ranging from 1 degree Celsius (2 degrees Fahrenheit) to 5 degrees Celsius (9 degrees Fahrenheit).

January 2023 compared to previous years

Figure 3. Monthly January ice extent for 1979 to 2023 shows a decline of 3.0 percent per decade.

Credit: National Snow and Ice Data Center
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The downward linear trend in January sea ice extent over the 44-year satellite record is 42,500 square kilometers (16,400 square miles) per year, or 3.0 percent per decade relative to the 1981 to 2010 average. Based on the linear trend, since 1979, January has lost 1.89 million square kilometers (730,000 square miles). This is equivalent to about seven times the size of Colorado or about twice the size of Germany.

Antarctic sea ice at record lows for January

Figure 4a. Antarctic sea ice extent for January 2023 was 3.23 million square kilometers (1.25 million square miles). The magenta line shows the 1981 to 2010 average extent for that month. Sea Ice Index data. About the data

Credit: National Snow and Ice Data Center
High-resolution image

Figure 4b. This maps shows Antarctic sea ice concentration for January 2023. The magenta line shows the 1981 to 2010 average extent for that month. Sea Ice Index data. About the data

Credit: National Snow and Ice Data Center
High-resolution image

Antarctic sea ice extent maintained record lows for this time of year. On February 1, 2023, the extent was 2.26 million square kilometers (873,000 square miles). This is 270,000 square kilometers (104,000 square miles) below the previous February 1 record low in 2017, and  310,000 square kilometers (120,000 square miles) above the record seasonal minimum in extent that occurred on February 25, 2022. Regionally, extent was particularly low in the Amundsen, Bellingshausen, and Ross Seas (Figure 4a). Typically, sea ice is still present along most of the coastline from the eastern Ross Sea to the Antarctic Peninsula, but this year, most of that coast is largely ice free. Extent is also below average along the Wilkes Land coast in East Antarctica, but near average elsewhere around the continent. Large areas of low concentration sea ice are in the Weddell, Ross, and Amundsen Sea ices (Figure 4b). These areas are likely to melt out before the minimum for 2023 is reached, which is expected to occur late this month or in early March.

Weather conditions around Antarctica have been characterized by stronger-than-average westerly winds (a positive Southern Annular Mode index) and a strong and eastward-positioned Amundsen Sea Low. Air temperatures at the 925 millibar level (about 2,500 feet 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 (Zhang et al., 2022).

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 kilometers) per year or 1.3 percent per decade relative to the 1981 to 2010 average.

Arctic freeze/thaw from above and below

A key component in the seasonal and interannual evolution of Arctic sea ice is the timing of melt onset and freeze up. Surface melt and freeze up can be obtained from satellite passive microwave observations but satellite observations do not provide information about what is happening under the ice. The length of the melt season is much longer underneath sea ice as a result of ocean heat. A recent study evaluated data collected from sea ice mass balance buoys (IMBs) and upward looking sonar (ULS) instruments to gain insights on the seasonality of ice melt and freeze up below the ice. Over the period from 2001 to 2018, Lin and colleagues found that in the Beaufort Sea, the bottom melt onset began 17 days before the surface melt. By contrast, in the central Arctic the timing of the melt onset of the top and bottom of the ice was similar. The freeze up of the bottom of the ice began about three weeks after the surface started to freeze. The researchers also found that bottom melt onset occurred about a week earlier during the 2010 to 2018 period compared to the 2001 to 2009 period, because of rising ocean temperatures. Bottom freeze up began one to two weeks earlier in the later period compared to the earlier period because thinner ice allowed faster heat loss from the ocean.

References

Arctic Sea Ice Melt Data Set

Bliss, A. C., M. Anderson, and S. Drobot. 2022. Snow Melt Onset Over Arctic Sea Ice from SMMR and SSM/I-SSMIS Brightness Temperatures, Version 5 [Data Set]. Boulder, Colorado USA. NASA National Snow and Ice Data Center Distributed Active Archive Center. doi:10.5067/TRGWQ0ONTQG5.

Lin, L., R. Lei, M. Hoppmann, D. K. Perovich, and H. 2022. Changes in the annual sea ice freeze–thaw cycle in the Arctic Ocean from 2001 to 2018. The Cryosphere, 16, 4779–4796, doi:10.5194/tc-16-4779-2022.

Steele, M., A. C. Bliss, G. Peng, W. N. Meier, and S. Dickinson. 2019. Arctic Sea Ice Seasonal Change and Melt/Freeze Climate Indicators from Satellite Data, Version 1 [Data Set]. Boulder, Colorado USA. NASA National Snow and Ice Data Center Distributed Active Archive Center. doi:10.5067/KINANQKEZI4T.

Zhang, L., T. L. Delworth, X. Yang, et al. 2022. The relative role of the subsurface Southern Ocean in driving negative Antarctic Sea ice extent anomalies in 2016–2021. Communications Earth and Environment 3, 302. doi:10.1038/s43247-022-00624-1.

Daily extent of Arctic sea ice for December 2022 remained well below average for the entire month; at the end of the month, extent stood at fourth lowest in the satellite record. The average extent for the month ended up as seventh lowest in the satellite record. Antarctic extent is declining much faster than average as austral summer takes hold and is setting record low daily ice extents for the satellite era as of December 22. As such, global sea ice extent is well below average.

Overview of conditions

Figure 1a. Arctic sea ice extent for December 2022 was 11.92 million square kilometers (4.60 million square miles). The magenta line shows the 1981 to 2010 average extent for that month. Sea Ice Index data. About the data

Credit: National Snow and Ice Data Center
High-resolution image

Figure 1b. The graph above shows Arctic sea ice extent as of January 4, 2023, along with daily ice extent data for four previous years and the record low year. 2022 to 2023 is shown in blue, 2021 to 2022 in green, 2020 to 2021 in orange, 2019 to 2020 in brown, 2018 to 2019 in magenta, and 2012 in dashed brown. The 1981 to 2010 median is in dark gray. The gray areas around the median line show the interquartile and interdecile ranges of the data. Sea Ice Index data.

Credit: National Snow and Ice Data Center
High-resolution image

The average Arctic sea ice extent for December 2022 was 11.92 million square kilometers (4.60 million square miles). This is the seventh lowest in the satellite record for the month (Figure 1a). Extent was 920,000 square kilometers (355,000 square miles) below the 1981 to 2010 average of 12.84 million square kilometers (4.96 million square miles) and 460,000 million square kilometers (178,000 square miles) above the record December low set in 2016 of 11.46 million square kilometers (4.42 square miles).

The rate of ice growth through the month was variable. It was faster than average through the first half of the month, then growth slowed, and then picked up the pace again. Over the last week of the month, ice growth was very slow, and as a result, total extent at the end of December stood at fourth lowest in the satellite record (Figure 1b). Regionally, at month’s end, the ice edge was notably north of its average location in the Barents Sea and on the Russian side of the Bering Sea. Hudson Bay is now almost completely iced over.

Conditions in context

Figure 2a. This plot shows the departure from average air temperature in the Arctic at the 925 hPa level, in degrees Celsius, for December 2022. Yellows and reds indicate higher than average temperatures; blues and purples indicate lower than average temperatures.

Credit: NSIDC courtesy NOAA Earth System Research Laboratory Physical Sciences Laboratory
High-resolution image

Figure 2b. This plot shows average sea level pressure in the Arctic in millibars for December 2022. Yellows and reds indicate high air pressure; blues and purples indicate low pressure.

Credit: NSIDC courtesy NOAA Earth System Research Laboratory Physical Sciences Laboratory
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Average December air temperatures at the 925 hPa level (approximately 2,500 feet above the surface) were above the 1991 to 2020 average over essentially all of the Arctic Ocean, but notably in the area centered over the East Siberian Sea (Figure 2a). The unusually warm conditions in this area, which were 6 to 8 degrees Celsius (11 to 14 degrees Fahrenheit) above average, appear to be related to the large area of below-average sea level pressure over the northern North Pacific Ocean pumping warm air into the East Siberian Sea (Figure 2b). Air temperatures were also above average over the eastern Canadian Arctic and most of Greenland.

December 2022 compared to previous years

Figure 3. Monthly December ice extent for 1978 to 2022 shows a decline of 3.5 percent per decade.

Credit: National Snow and Ice Data Center
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The downward linear trend in December sea ice extent over the 45-year satellite record is 44,400 square kilometers (17,100 square miles) per year, or 3.5 percent per decade relative to the 1981 to 2010 average. Based on the linear trend, since 1978, November has lost 2.28 million square kilometers (880,000 square miles). This is equivalent to about 1.5 times the size of Alaska.

The year in review

Figure 4a. The graph above shows Arctic sea ice extent for 2022 (blue line) and 2012, the record minimum year (dashed red line). The gray line shows the 1981 to 2010 median, the dark gray shaded area shows the interquartile range, and the light gray shaded area shows the interdecile range of the data. Sea Ice Index data.

Credit: National Snow and Ice Data Center
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Figure 4b. This plot shows the departure from average air temperature in the Arctic at the 925 hPa level, in degrees Celsius, for summer 2022 from June 1 to August 31. Yellows and reds indicate higher than average temperatures; blues and purples indicate lower than average temperatures.

Credit: NSIDC courtesy NOAA Earth System Research Laboratory Physical Sciences Laboratory
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Figure 4c. This plot shows average sea level pressure in the Arctic in millibars for summer 2022 from June 1 to August 31. Yellows and reds indicate high air pressure; blues and purples indicate low pressure.

Credit: NSIDC courtesy NOAA Earth System Research Laboratory Physical Sciences Laboratory
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While Arctic sea ice extent was below average over the entire year (Figure 4a), no records were set, and the September average sea ice extent, at 4.87 million square kilometers (1.88 million square miles), tied with 2010 as only the eleventh lowest in the satellite record. The September daily minimum extent, set on September 18 at 4.67 million square kilometers (1.80 million square miles), tied with 2017 and 2018 for tenth lowest in the satellite record. The September minimum extent is strongly dependent on summer weather conditions, and summer average air temperatures, while above climatological averages over most of the Arctic Ocean, were not extreme (Figure 4b), generally from 1.5 to 2.5 degrees Celsius (3 to 4.5 degrees Fahrenheit) above the 1991 to 2020 baseline. The summer average sea level pressure pattern was in turn quite flat, meaning light winds. A pronounced Beaufort Sea High, which generally favors low September sea ice extent, is notably lacking (Figure 4c).

Ice down under

Figure 5a. This map from January 3, 2023, shows a large polynya that now spans the Ross Sea and much of the western Amundsen Sea, as well as polynyas that have appeared in Pine Island Bay and the southeastern Weddell Sea. Sea ice concentration data are from the Japan Aerospace Exploration Agency Advanced Microwave Scanning Radiometer 2 (AMSR2) imagery.

Credit: University of Bremen
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Figure 5b. This plot shows the departure from average air temperature in the Antarctic at the 925 hPa level, in degrees Celsius, for November and December 2022. Yellows and reds indicate higher than average temperatures; blues and purples indicate lower than average temperatures.

Credit: NSIDC courtesy NOAA Earth System Research Laboratory Physical Sciences Laboratory
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Summer is taking hold in the Southern Hemisphere. While the decline in Antarctic Sea ice extent is always steep at this time of year, it has been unusually rapid this year, and at the end of December, Antarctic sea ice extent stood at the lowest in the 45-year satellite record. Sea ice extent was more than 500,000 square kilometers (193,000 square miles) below the previous record year of 2018; four of the five lowest years for the last half of December have occurred since 2016. As is evident in sea ice maps prepared by colleagues at the University of Bremen from the Japan Aerospace Exploration Agency (JAXA) Advanced Microwave Scanning Radiometer 2 (AMSR2) data, an extremely large polynya now spans the Ross Sea and much of the western Amundsen Sea. Polynyas have also appeared in Pine Island Bay and the southeastern Weddell Sea (Figure 5a). There are also extensive areas of low sea ice concentration in the Weddell Sea that are likely ready to melt out.

Weather-related causes for the unusually low sea ice extent seem to stem from a band of above-average  temperatures extending from the Weddell Sea westward to the Ross Sea and eastern Wilkes Land (Figure 5b). Air temperatures at the 925 mb level were more than 1 degree Celsius (2 degrees Fahrenheit) above average over the entire area in November and December, and were more than 2 degrees Celsius (4 degrees Fahrenheit) above average over the Ross Sea. The past two months have seen periods of strong circumpolar winds and below-average air pressure over the continent, leading to strong winds from the west across the Peninsula. This has caused melting along the eastern Peninsula ice, above-average air temperatures over the Weddell Sea, and outflowing winds from the continent, opening the polynyas and hastening ice decline. This wind pattern is summarized by the Southern Annular Mode (SAM) index, a measure of the intensity of the circumpolar winds; this has been in a positive phase for most of 2022 and has been quite strong in the last quarter of the year.

November’s rate of sea ice growth in the Arctic was near average. Several of the peripheral seas have open water areas late into the autumn season. Warm air temperatures persist in the northern North Atlantic and northwestern Europe. In Antarctica, sea ice extent is low, and persistent low air pressure in the Amundsen Sea has created a somewhat unusual sea ice distribution.

Overview of conditions

Figure 1. Arctic sea ice extent for November 2022 was 9.71 million square kilometers (3.75 million square miles). The magenta line shows the 1981 to 2010 average extent for that month. Sea Ice Index data. About the data

Credit: National Snow and Ice Data Center
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The November 2022 average Arctic sea ice extent was 9.71 million square kilometers (3.75 million square miles). This is the eighth lowest in the satellite record for the month (Figure 1a). Extent was 990,000 square kilometers (382,000 square miles) below the 1981 to 2010 average of 10.7 million square kilometers (4.13 million square miles) and 1.05 million square kilometers (405,000 square miles) above the record November low set in 2016 of 8.66 million square kilometers (3.34 square miles).

Overall for the month, ice extent increased at a near-average rate, but with much faster-than-average growth for the first week balanced by slow growth over the remainder of the month.  Open water conditions persisted in part of the Chukchi Sea, approximately two weeks late in the season relative to the 1981 to 2010 average. Similarly, ice extent has remained below average in the Kara and Barents Seas, and in Hudson Bay. Ice in the Bering Sea is limited to Norton Sound and Kotzebue Sound. The coast of Svalbard in the far northern North Atlantic remains ice free at the end of the month.

Conditions in context

Figure 2a. The graph above shows Arctic sea ice extent as of December 4, 2022, along with daily ice extent data for four previous years and the record low year. 2022 is shown in blue, 2021 in green, 2020 in orange, 2019 in brown, 2018 in magenta, and 2012 in dashed brown. The 1981 to 2010 median is in dark gray. The gray areas around the median line show the interquartile and interdecile ranges of the data. Sea Ice Index data.

Credit: National Snow and Ice Data Center
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Figure 2b. This plot shows the departure from average air temperature in the Arctic at the 925 hPa level, in degrees Celsius, for November 2022. Yellows and reds indicate higher than average temperatures; blues and purples indicate lower than average temperatures.

Credit: NSIDC courtesy NOAA Earth System Research Laboratory Physical Sciences Laboratory
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Figure 2c. This plot shows average sea level pressure in the Arctic in millibars for November 2022. Yellows and reds indicate high air pressure; blues and purples indicate low pressure.

Credit: NSIDC courtesy NOAA Earth System Research Laboratory Physical Sciences Laboratory
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Warm conditions prevailed in the northern North Atlantic and over northwestern Europe (Figure 2b). Air temperatures at the 925 mb level (approximately 2,500 feet above the surface) over much of the Greenland Sea (between Norway and Greenland) were 3 to 6 degrees Celsius (5 to 11 degrees Fahrenheit) above average. Temperatures in the northern Yukon and northeastern Alaska regions were about 4 degrees Celsius (7 degrees Fahrenheit) above average. However, the Siberian side of the Arctic experienced temperatures 1 to 3 degrees Celsius (2 to 5 degrees Fahrenheit) below average. The Baffin Bay region had temperatures 3 to 5 degrees Celsius (5 to 9 degrees Fahrenheit) below average.

Atmospheric circulation for the month was characterized by a strong low sea level pressure centered south of Iceland (Figure 2c). The counterclockwise circulation around this low is largely responsible for the widespread warm conditions in the northern North Atlantic and the cooler conditions in Baffin Bay. By contrast, the pressure field over the Arctic Ocean was fairly flat, indicating weak winds overall.

November 2022 compared to previous years

Figure 3. Monthly November ice extent for 1979 to 2022 shows a decline of 4.8 percent per decade.

Credit: National Snow and Ice Data Center
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The downward linear trend in November sea ice extent over the 45-year satellite record is 51,800 square kilometers (20,000 square miles) per year, or 4.8 percent per decade relative to the 1981 to 2010 average. Based on the linear trend, since 1978, November has lost 2.28 million square kilometers (880,000 square miles). This is equivalent to 1.5 times the size of Alaska.

Bloomin’ down under

Figure 4. These conceptual models show how the sun stimulates plankton grown at, near the surface, and on the sea floor. When coastal areas are ice free in early to mid-summer, more light penetrates through the water column to feed a plankton bloom at deeper depths. 

Credit: Shiozaki et al. 2022
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A new study by Shiozaki et al. (2022) reveals that plankton on the seabed in the Arctic Ocean is increasingly in bloom, as longer ice-free periods near the coast allow more light to reach the shallow coastal ocean bottom and stimulate growth (Figure 4). Since this represents an expansion of the area and volume that plankton can thrive, it has implications for bio-productivity in the Arctic food chain and sequestration of carbon by the ocean.

As sunshine returns to the Arctic in spring, it stimulates plankton growth at or near the surface—a typical plankton bloom. However, plankton growth is often limited by the nutrient level in the water column, and in many areas the surface bloom consumes all the nutrients in the top ocean layer. If the shallow coastal areas of the Arctic become ice free in early to mid-summer, more light can penetrate through the water column. This provides energy to plankton that have descended in the water column to depths where there are still abundant nutrients, resulting in a bloom on the sea floor.

The regions where this appears to be occurring are in the Chukchi Sea, but it could potentially occur over wide regions of the Siberian and Alaskan shallow continental shelf.

Antarctica’s spring

Figure 5. Antarctic sea ice extent for November 2022 was 15.06 million square kilometers (5.81 million square miles). The magenta line shows the 1981 to 2010 average extent for that month. Sea Ice Index data. About the data

Credit: National Snow and Ice Data Center
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Antarctic sea ice is declining rapidly now in response to seasonal warming. Sea ice extent is particularly low in the Bellingshausen Sea, where much of the eastern portion adjacent to the Antarctic Peninsula has been ice free for much of November. By sharp contrast, ice extent in the Amundsen Sea just west of the Bellingshausen, has extended much farther to the north than is typical and is the one area of the Antarctic sea ice that has above-average ice extent.

This is explained by the sea level pressure pattern. A strong low over much of the Amundsen Sea and eastern Ross Sea has driven a clockwise air circulation that has brought warm air from the north onto the western Peninsula region, and cold air from the continental ice sheet northward in the Amundsen Sea.

This low-pressure region is a well-known feature of Antarctica’s climate, and its strength is often measured by a climate index called the Antarctic Oscillation (AAO). The AAO index has been strongly positive for the entire month of November, indicating especially strong low pressure in the Amundsen Sea. In fact, the index has been generally positive for the entire year, and has become more positive over the past several decades.

Further reading

Shiozaki, T., A. Fujiwara, K. Sugie, K., S. Nishino, A. Makabe, and N. Harada. 2022. Bottom‐associated phytoplankton bloom and its expansion in the Arctic Ocean. Global Change Biology, 28(24), 7286-7295, doi:10.1111/gcb.16421.

As October drew to a close, freezing progressed rapidly in the Laptev Sea. In the Antarctic, where spring is slowly unfolding, overall ice extent is low, with patterns suggesting a strong persistent low atmospheric pressure in the Amundsen Sea.

Overview of conditions

Figure 1a. Arctic sea ice extent for October 2022 was 6.61 million square kilometers (2.55 million square miles). The magenta line shows the 1981 to 2010 average extent for that month. Sea Ice Index data. About the data

Credit: National Snow and Ice Data Center
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Figure 1b. The graph above shows Arctic sea ice extent as of November 2, 2022, along with daily ice extent data for four previous years and the record low year. 2022 is shown in blue, 2021 in green, 2020 in orange, 2019 in brown, 2018 in magenta, and 2012 in dashed brown. The 1981 to 2010 median is in dark gray. The gray areas around the median line show the interquartile and interdecile ranges of the data. Sea Ice Index data.

Credit: National Snow and Ice Data Center
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The October 2022 average Arctic sea ice extent was 6.61 million square kilometers (2.55 million square miles). This is the eighth lowest in the satellite record (Figure 1a). Extent was 1.74 million square kilometers (672,000 square miles) below the 1981 to 2010 average of 8.35 million square kilometers (3.22 million square miles) and 1.28 million square kilometers (494,000 square miles) above the record minimum set in 2020 of 5.33 million square kilometers (2.06 million square miles).

Ice extent increased at a below average rate at the beginning of the month, and open water persisted for some time in the Laptev Sea, whereas the East Siberian Sea was among the first regions to freeze up. In the last ten days of the month, ice extent rapidly increased (Figure 1b) as the Laptev Sea iced over. The delayed freeze up in the Laptev Sea could be partly a result of ocean heating from the extended period of open water this past spring and summer. However, slow freeze up in this region in recent years is also consistent with observations of eddies within the Arctic Circumpolar Boundary Current that maintain a generally upward ocean heat flux, bringing warm Atlantic water along the eastern Arctic continental slope. The Arctic Circumpolar Boundary Current is a shallow, 200- to 400-meter-deep (660 to 1,300 feet) eastward-flowing current that follows the edge of the continental shelf and carries warm water at 2 to 3 degrees Celsius (36 to 37 degrees Fahrenheit) in shallow depths around the Arctic Ocean. The configuration of the continental shelf in the Russian Arctic brings this water very near the coastal Laptev Sea.

At the end of the month, extent remained below average in the Chukchi Sea on the Pacific side of the Arctic, and also in the Barents and Kara Seas on the Atlantic side.

Conditions in context

Figure 2a. This plot shows the departure from average air temperature in the Arctic at the 925 hPa level, in degrees Celsius, for October 2022. Yellows and reds indicate higher than average temperatures; blues and purples indicate lower than average temperatures.

Credit: NSIDC courtesy NOAA Earth System Research Laboratory Physical Sciences Laboratory
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Figure 2b. This plot shows average sea level pressure in the Arctic in millibars for October 2022. Yellows and reds indicate high air pressure; blues and purples indicate low pressure.

Credit: NSIDC courtesy NOAA Earth System Research Laboratory Physical Sciences Laboratory
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Air temperatures during October at the 925 millibar level (approximately 2,500 feet above the surface) were near to above average over most of the Arctic Ocean (Figure 2a). The largest departures from average for this time of year were over the Kara Sea, where air temperatures averaged for October remained above freezing.

The average atmospheric circulation pattern was dominated by below average sea level pressure over nearly the entire Arctic (Figure 2b). Pressures were as much as 10 to 12 millibars below average over the Chukchi and East Siberian Seas and stretching across the pole. This pattern is reflected in the persistence of positive values of the Arctic Oscillation Index for most of the month. When the Arctic Oscillation is in its positive mode, pressures are below average over the Arctic, but above average over the Northern Hemisphere mid latitudes.

October 2022 compared to previous years

Figure 3. Monthly October ice extent for 1979 to 2022 shows a decline of 9.6 percent per decade.

Credit: National Snow and Ice Data Center
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The downward linear trend in October sea ice extent over the 45-year satellite record is 80,400 square kilometers (31,000 square miles) per year, or 9.6 percent per decade relative to the 1981 to 2010 average. Based on the linear trend, since 1979 October has lost 3.46 million square kilometers (1.34 million square miles). This equivalent to about twice the size of the state of Alaska.

Arctic sea ice loss may make El Niños more common

Figure 4. These plots show histograms of El Niño indices associated with Arctic sea ice loss experiments in climate model runs. The left histogram (a) shows the zonal sea surface temperature (SST) gradient in the equatorial Pacific that is defined as the average SST over the Niño 3.4 region (5S-5N, 170W-120W) minus the Maritime Continent region (5S-5N, 110E-160E). The histogram on the right (b) shows the meridional SST gradient in the eastern equatorial Pacific that is defined as the average SST over 5N-10N, 160W-100W minus 2.5S-2.5N, 160W-100W. The vertical bars denote 20-year periods of constant Arctic sea ice in experiments using the US National Center for Atmospheric Research Community Earth System Model (CESM). Gray is the historical period (1980 to 1999); blue is the future period of moderate ice loss (2020 to 2039); and red is the future period of seasonally ice-free conditions (2080 to 2099). Each bin represents 0.5 standard deviation of the corresponding SST anomalies or gradients. Black dashed lines represent 1.5 (strong El Niño) and 2 (extremely strong El Niño) standard deviations.

Credit: Jiping Liu et al. 2022, adapted by NSIDC
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El Niño is an important departure in ocean temperatures along the equator, linked to weakened trade winds. During an El Niño, the cold upwelled waters along the coast of the Americas and much of the eastern parts of the tropical Pacific are replaced by warmer water. This can have global impacts on weather, ecosystems, and economies around the world by shifting the Pacific jet stream southwards. In North America, this usually results in drier and warmer conditions than usual in the northern areas, and wetter conditions in the south. While episodes of El Niño typically occur every two to seven years and can last several months to more than a year, climate model simulations by colleagues at the University of Albany suggest that the frequency of El Niño events could increase by 35 percent by the end of this century if the Arctic Ocean loses its summer ice cover.

This link was found to result from increased heat transfer from the ocean to the atmosphere in the absence of sea ice, intensifying low-pressure systems in the Bering Sea (in the area of the Aleutian Low). Lower sea level pressure increases wind speeds that may oppose trade winds, bringing warm western Pacific water towards the east. Another possible mechanism is that as the Arctic Ocean warms from losing its sea ice cover, ocean currents weaken from the south that bring warm water from the eastern Pacific toward the Arctic. Analysis with other climate models is necessary to test the robustness of these connections.

The Antarctic

Figure 5. The graph above shows Antarctic sea ice extent as of November 2, 2022, along with daily ice extent data for four previous years and the record high year. 2022 is shown in blue, 2021 in green, 2020 in orange, 2019 in brown, 2018 in magenta, and 2012 in dashed brown. The 1981 to 2010 median is in dark gray. The gray areas around the median line show the interquartile and interdecile ranges of the data. Sea Ice Index data.

Credit: National Snow and Ice Data Center
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The seasonal Southern Ocean sea ice maximum extent was reached on September 16, at 18.19 million square kilometers (7.02 million square miles). This was the fourth lowest sea ice maximum in the satellite record, behind 1986, 2002, and 2017. Low sea ice extent has continued to persist, and the springtime decline in austral ice extent has proceeded at an above average pace. At month’s end, Antarctic sea ice was nearing record-low daily ice extents for the date.

Extent is far below average in the Bellingshausen Sea, and far above average in the Amundsen and eastern Ross Seas, a pattern indicative of a strong Amundsen Sea Low. Sea level pressures in the region have been 8 to 12 millibars below average. However, sea ice extent is also low along the Wilkes Land coast, where air temperatures have been 1 to 4 degrees Celsius (2 to 7 degrees Fahrenheit) above average.

Further reading

Aksenov, Y., V. V. Ivanov, A. G. Nurser, S. Bacon, I. V. Polyakov, A. C. Coward, A. C. Naveira‐Garabato, and A. Beszczynska-Moeller. 2011. The Arctic circumpolar boundary current. Journal of Geophysical Research: Oceans. doi:10.1029/2010JC006637.

Liu, J., M. Song, Z. Zhu, et al. 2022. Arctic sea-ice loss is projected to lead to more frequent strong El Niño events. Nature Communications. doi:10.1038/s41467-022-32705-2.

Pnyushkov, A., I. V. Polyakov, L. Padman, and A. T. Nguyen. 2018. Structure and dynamics of mesoscale eddies over the Laptev Sea continental slope in the Arctic Ocean. Ocean Science. doi:10.5194/os-14-1329-2018.

After reaching the minimum on September 18, Arctic sea ice extent has been steadily increasing. With the passage of the equinox, the sun has set at the North Pole. September average ice extent ended up tying with 2010 for eleventh lowest in the satellite record.

Overview of conditions

Figure 1a. Arctic sea ice extent for September 2022 was 4.87 million square kilometers (1.88 million square miles). The magenta line shows the 1981 to 2010 average extent for that month. Sea Ice Index data. About the data

Credit: National Snow and Ice Data Center
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Figure 1b. The graph above shows Arctic sea ice extent as of October 3, 2022, along with daily ice extent data for four previous years and the record low year. 2022 is shown in blue, 2021 in green, 2020 in orange, 2019 in brown, 2018 in magenta, and 2012 in dashed brown. The 1981 to 2010 median is in dark gray. The gray areas around the median line show the interquartile and interdecile ranges of the data. Sea Ice Index data.

Credit: National Snow and Ice Data Center
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The September 2022 average Arctic sea ice extent was 4.87 million square kilometers (1.88 million square miles), tying with 2010 for eleventh lowest in the satellite record (Figure 1a). Extent was 1.54 million square kilometers (595,000 square miles) below the 1981 to 2010 average and 1.30 million square kilometers (502,000 square miles) above the record minimum set in 2012. The annual minimum extent was reached on September 18 and the autumn freeze-up is now well underway.

Ice extent declined at a faster than average rate from the beginning of the month until the minimum was reached on September 18 (Figure 1b). This resulted in a tie for the tenth lowest minimum daily extent in the satellite record. Extent was below average in all sectors of the Arctic Ocean, apart from the northern shore of the Canadian Arctic Archipelago, where ice is almost invariably pushed up against the coast by winds and ocean currents. A tongue of ice continued to extend southward in the East Siberian Sea, and a portion of ice floes broke away from the main pack ice off the tip of that tongue. An open water passage has nevertheless persisted along the Northern Sea Route. The Northwest Passage has started to freeze up, particularly the northern route through Parry Channel, but much of the Canadian Archipelago remained essentially ice free through the end of the month.

Conditions in context

Figure 2a. This plot shows the departure from average air temperature in the Arctic at the 925 hPa level, in degrees Celsius, for September 2022. Yellows and reds indicate higher than average temperatures; blues and purples indicate lower than average temperatures.

Credit: NSIDC courtesy NOAA Earth System Research Laboratory Physical Sciences Laboratory
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Figure 2b. This plot shows average sea level pressure in the Arctic in millibars for September 2022. Yellows and reds indicate high air pressure; blues and purples indicate low pressure.

Credit: NSIDC courtesy NOAA Earth System Research Laboratory Physical Sciences Laboratory
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Air temperatures during September at the 925 millibar level (approximately 2,500 feet above the surface) were above average over the North American side of the Arctic and near average or below average over most of the Eurasian side (Figure 2a). Averaged sea level pressure for September featured low pressure extending across Eurasia, Alaska, and the Canadian Arctic Archipelago, with high pressure over the central Arctic Ocean, notably north of the Canadian Arctic Archipelago (Figure 2b). The low pressure over Alaska reflects the passage of an extremely strong storm during the middle of the month that caused extensive damage and flooding to the town of Nome and surrounding areas.

September 2022 compared to previous years

Figure 3. Monthly September ice extent for 1979 to 2022 shows a decline of 12.3 percent per decade.

Credit: National Snow and Ice Data Center
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The downward linear trend in September sea ice extent over the 44-year satellite record is 79,100 square kilometers (30,500 square miles) per year, or 12.3 percent per decade relative to the 1981 to 2010 average. Based on the linear trend, since 1979, September has lost 3.59 million square kilometers (1.39 million square miles). This is equivalent to about twice the size of Alaska.

Summer 2022 in review

Figure 4a. This plot shows the departure from average air temperature in the Arctic at the 925 hPa level, in degrees Celsius, from June to August 2022. Yellows and reds indicate higher than average temperatures; blues and purples indicate lower than average temperatures.

Credit: NSIDC courtesy NOAA Earth System Research Laboratory Physical Sciences Laboratory
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Figure 4b. This plot shows average sea level pressure in the Arctic in millibars from June to August 2022. Yellows and reds indicate high air pressure; blues and purples indicate low pressure.

Credit: NSIDC courtesy NOAA Earth System Research Laboratory Physical Sciences Laboratory
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Figure 4c. The upper left map shows ice age distribution toward the end of the melt season for 1985. The upper right map shows the end of the 2022 melt season. The bottom graphs shows sea ice age extent for multiyear ice, as depicted by the black line, and 4+ year-old ice, as depicted by the red line, for the Arctic Ocean region. The inset identifies the region of interest. Note the ice age product does not include ice in the Canadian Archipelago.

Credit: Tschudi et al., 2019
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Figure 4d. This graph shows the annual change of multiyear and 4+ year-old ice over the summer melt season (mid-March to the September minimum) for 1985 to 2022. The black line depicts multiyear ice; the red line depicts 4+ year-old ice.

Credit: Tschudi et al., 2019
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Figure 4e. This graph shows weekly sea ice extent in the Parry Channel, the red highlighted region in inset, based on Canadian Ice Service analyses for last four years, 2019 to 2022, the 2011 record low year, and the 1991 to 2020 average.

Credit: Steve Howell, Environment and Climate Change Canada
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Figure 4f. Clink on this animation to view the 2022 seasonal ice retreat. Images are from sea ice concentration data from NSIDC’s Sea Ice Index. The timeline is not uniform. The animation shows one image per week from May 2 to August 1, and then every other day through August, and every day in September until September 18, the seasonal ice minimum.

Credit: Michon Scott, NSIDC
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The summer 2022 melt season had some noteworthy highlights. Extent loss was less extreme than recent years through much of the summer; for the first time since 2014, extent briefly sat within the 1981 to 2010 lower interdecile range. However, late season ice loss was strong, pushing the September average to eleventh lowest in the passive microwave satellite record. No region of the Arctic was extreme in terms of how far north the ice edge retreated, though compared to average conditions, the ice edge was quite far north in the Laptev and Chukchi Seas. Surface melt onset was also variable, with earlier-than-average melt along the Siberian coast, particularly in the Kara and Barents Seas, but later-than-average melt in much of the central Arctic Ocean.

Air temperatures at the 925 millibar level (about 2,500 feet above sea level) were above average over much of the Arctic Ocean, but not as extreme as in many recent summers. Much of the Arctic Ocean experienced summer (June, July, August) temperatures 1 to 3 degrees Celsius (2 to 5 degrees Fahrenheit) above average (Figure 4a). Only in parts of the Barents Sea did 2022 summer air temperatures reach up to 4 degrees Celsius (7 degrees Fahrenheit) above average. In the southern Chukchi and northern Bering Seas, temperatures were 1 degree Celsius (2 degrees Fahrenheit) below average.

During June through August, average sea level pressure was low over much of the Siberian side of the Arctic, as well as over eastern Canada, and east of Greenland, with a small and weak Beaufort Sea High that primarily manifested itself in June (Figure 4b). Summer-averaged pressure gradients were slack, particularly in July and August, albeit with intermittent stronger gradients caused by passing weather systems. Weak pressure gradients resulted in relatively weak surface winds and sea ice circulation through much of the summer.

Of particular note was the formation of polynyas north of the Kara Sea, at about 87 degrees North latitude. These started to form in early July and were observed intermittently through the end of August. These unusual polynyas likely opened at least in part because of divergent ice motion, but their formation and general persistence is also an indication of thin, young, and uncompacted ice. It is also possible that deep ocean waters were churned toward the surface as currents flowed over the Lomonosov Ridge beneath some of the polynya areas.

The distribution of sea ice age at the end of summer 2022 shows a dominance of first and second-year ice (Figure 4c). Some of this second-year ice extends south into the East Siberian Sea and is one reason why the Northern Sea Route maintained ice until later in the summer. A thin ribbon of old ice (3 to 4 and 4+ years age) extends along the northern shore of the Canadian Arctic Archipelago. The summertime loss of the multiyear ice has generally increased since the mid 1980s, but with large variations from one summer to the next (Figure 4d). The 4+ year-old ice shows less summertime change, especially since 2012, because so little of that ice remains in the Arctic. The most notable feature in both ice age classes is the large spike in loss during the 2007 summer.

The evolution of sea ice concentration during the 2022 melt season is presented in an animation, which begins on May 2 and ends at the sea ice minimum on September 18 (Figure 4f). Rapid early loss is noticeable in the Kara Sea with large retreats also occurring in the Laptev and Beaufort Seas. By August, a tongue of somewhat older and thicker ice is left behind in the East Siberian Sea. Retreat was generally ahead of the average date for ice extent through the summer. Also shown is the unusually persistent low sea ice concentration in the high Arctic north of the Severnaya Zemlaya islands, eventually leading to the opening of two high-latitude polynyas in late August into early September. Melt events are shown as brief drops in concentration, but the regions around the polynyas remained low throughout the second half of the summer.

The Northwest Passage (NWP)—a shortcut between Europe and Asia through the channels of the Canadian Arctic Archipelago—was the dream of explorers and financiers for centuries. The southern NWP route was first navigated by Roald Amundsen over three summers, 1905 to 1908. In recent years, his circuitous route, winding through narrow and shallow channels, has often opened for at least part of the summer. However, even in recent years, the more direct northern route through Parry Channel, with wide and deep channels more suitable for shipping, has remained choked with ice. This is partly because of an influx of thick, multiyear ice into the channel from the Arctic Ocean to the north. This year the northern route largely opened. While operational analysis showed the region with 10 to 80 percent ice cover, high resolution maps of the ice cover, indicated a continuous path through open water starting in late August until mid-September. Overall, the ice area in the northern route reached the fourth lowest in the 55-year record of Canadian Arctic sea ice conditions analyzed by the Canadian Ice Service; the NWP information was provided by Steve Howell of Environment and Climate Change Canada (Figure 4e).

Top ten lowest sea ice extents in northern route of the Northwest Passage

The view down south

Figure 5. The graph above shows Antarctic sea ice extent as of October 3, 2022, along with daily ice extent data for four previous years and the record high year. 2022 is shown in blue, 2021 in green, 2020 in orange, 2019 in brown, 2018 in magenta, and 2014 in dashed brown. The 1981 to 2010 median is in dark gray. The gray areas around the median line show the interquartile and interdecile ranges of the data. Sea Ice Index data.

Credit: National Snow and Ice Data Center
High-resolution image

As the Arctic makes its journey into autumn, Antarctic sea ice extent is nearing its winter maximum. On September 16, extent stood at 18.19 million square kilometers (7.02 million square miles), which may represent the seasonal maximum. However, extent may yet rise above that value. After record and near-record low extent earlier in the year, late ice growth increased the extent within the inter-decile range by mid-September.

Antarctic sea ice extent has exhibited extreme interannual variability with record highs and record lows within the past decade. There is also strong regional variability, with some areas showing long-term trends of ice loss, with others showing gains. One region with a notable downward trend in extent is the Bellingshausen Sea, west of the Antarctic Peninsula. The Peninsula region has also experienced a strong multi-decade warming trend, which has resumed after a decade-long hiatus. One factor in these changes is a strengthening of the Amundsen Low the brings southward winds to the region, which raise air temperatures and compact the ice. A new study by Dalaiden et al. suggests that this Amundsen Low strengthening is caused by an anthropogenic forcing, and a coupling to the general temperature pattern and trends in the Pacific Ocean.

Update

On October 5, 2022, the Arctic Sea Ice News & Analysis team decided to add the animation of sea ice loss through the melt season and corresponding text (Figure 4f).

References

Dalaiden, Q., A. P. Schurer, M. C. Kirchmeier-Young, H. Goosse, and G. C. Hegerl, G. 2022. West Antarctic surface climate changes since the mid-20th century driven by anthropogenic forcing. Geophysical Research Letters, 49, e2022GL099543. doi:10.1029/2022GL099543.

Tschudi, M., W. N. Meier, J. S. Stewart, C. Fowler, and J. Maslanik. 2019. EASE-Grid Sea Ice Age, Version 4 [Data Set]. Boulder, Colorado USA. NASA National Snow and Ice Data Center Distributed Active Archive Center. doi:0.5067/UTAV7490FEPB. Date Accessed 10-04-2022.

Tschudi, M., W. N. Meier, and J. S. Stewart. 2019. Quicklook Arctic Weekly EASE-Grid Sea Ice Age, Version 1 [Data Set]. Boulder, Colorado USA. NASA National Snow and Ice Data Center Distributed Active Archive Center. doi:10.5067/2XXGZY3DUGNQ. Date Accessed 10-04-2022.

On September 18, Arctic sea ice likely reached its annual minimum extent of 4.67 million square kilometers (1.80 million square miles). The 2022 minimum is tied for tenth lowest in the nearly 44-year satellite record, with 2018 and 2017. The last 16 years, from 2007 to 2022, are the lowest 16 sea ice extents in the satellite record.

In the Antarctic, sea ice extent has hit record lows through most of the growth season. Starting in early August, sea ice began expanding rapidly, exemplifying the strong degree of variability in Southern Hemisphere sea ice. As such it is too early to assume that the maximum has been reached as storms may still expand or compact the extended ice edge. The maximum for Antarctic sea ice typically occurs in late September or early October.

Please note that this is a preliminary announcement. Changing winds or late-season melt could still reduce the Arctic ice extent, as happened in 2005 and 2010. NSIDC scientists will release a full analysis of the Arctic melt season, and discuss the Antarctic winter sea ice growth, in early October.

Overview of conditions

Figure 1. Arctic sea ice extent for September 18, 2022, was 4.67 million square kilometers (1.80 million square miles). The orange line shows the 1981 to 2010 average extent for that day. Sea Ice Index data. About the data

Credit: National Snow and Ice Data Center
High-resolution image

On September 18, sea ice reached its annual minimum extent of 4.67 million square kilometers (1.80 million square miles) (Figure 1), tying for tenth lowest with 2018 and 2017. In response to the setting sun and falling temperatures, ice extent has begun expanding and will continue through autumn and winter. However, a shift in wind patterns or a period of late season melt could still push the ice extent lower.

The minimum extent was reached four days later than the 1981 to 2010 median minimum date of September 14. The interquartile range of minimum dates is September 11 to September 19.

Conditions in context

Figure 2. The graph above shows Arctic sea ice extent on September 18, 2022, along with several other recent years and the record minimum set in 2012. 2022 is shown in blue, 2021 in green, 2020 in orange, 2019 in brown, 2018 in magenta, and 2012 in dashed brown. The 1981 to 2010 median is in dark gray. The gray areas around the median line show the interquartile and interdecile ranges of the data. Sea Ice Index data.

Credit: National Snow and Ice Data Center
High-resolution image

This year’s minimum set on September 18 was 1.28 million square kilometers (494,000 square miles) above the satellite-era record minimum extent of 3.39 million square kilometers (1.31 million square miles), which occurred on September 17, 2012 (Figure 2). It is also 1.55 million square kilometers (598,000 square miles) below the 1981 to 2010 average minimum extent, which is equivalent to twice the size of Texas.

In the 44-year-satellite record, 16 of the lowest minimums have all occurred in the last 16 years.

The overall, downward trend in the minimum extent from 1979 to 2022 is 12.6 percent per decade relative to the 1981 to 2010 average. The loss of sea ice is about 78,500 square kilometers (30,300 square miles) per year, equivalent to losing the size of the state of South Carolina or the country of Austria annually.

Sixteen lowest minimum Arctic sea ice extents (satellite record, 1979 to present)

Values within 40,000 square kilometers (15,000 square miles) are considered tied. The 2021 value has changed from 4.72 to 4.77 million square kilometers (1.84 million square miles) when final analysis data updated near-real-time data. 

Further reading

NASA visualization of 2022 Arctic sea ice minimum extent