Two Ice Caps That Grow and Shrink Every Year
Every winter the seas around the poles freeze, and every summer much of that ice melts again. In the Arctic, sea ice usually peaks in late February or March and reaches its smallest extent in September. In the Antarctic the seasons are reversed: the ice is smallest in February or early March and largest in September. Satellites have measured this cycle continuously since late 1978.
This map shows both ice caps at their extremes in every year from 1979 to 2026, as two polar discs side by side: the Arctic on the left, the Antarctic on the right. Each frame is one year, with that year's winter maximum and, inside it, the summer minimum. Watching the frames in sequence shows two very different histories: a steady decline in the north, and decades of stability in the south followed by a sudden drop.
The Arctic: A Shrinking Summer
The clearest change on the map is the Arctic summer ice. Its September minimum averaged 7.0 million km² in 1979–1988 and 4.5 million km² in 2017–2026. The decline came with a run of new records: 6.04 million km² in 1990, 5.76 in 1999, 5.64 in 2002 and 5.32 in 2005. In 2007 the minimum fell to 4.15 million km², more than a million km² below the previous record, and on 17 September 2012 it reached 3.39 million km², the lowest in the satellite record and a record that still stands. In 2026 the minimum, on 12 September, was about 4.6 million km².
The winter maximum has fallen less, from an average of 16.2 million km² in 1979–1988 to 14.7 million km² in 2017–2026. Even so, it set new record lows ten times between 1989 and 2025. The most recent was 14.31 million km² on 22 March 2025.
Antarctica: Decades of Stability, Then a Sharp Drop
Antarctic sea ice behaved very differently. For decades it held steady, and its winter maximum even set new record highs: 19.22 million km² in 1998, then 2005, 2006, 2012 and 2013, and finally 20.16 million km² on 21 September 2014, the largest extent in the satellite record.
Since then it has dropped sharply. The summer minimum set record lows of 2.11 million km² in 2017, 1.98 million km² in 2022 and 1.85 million km² on 21 February 2023. In September 2023 the winter maximum reached only 17.07 million km², breaking the record low of 17.96 million km² that had stood since 1986. Within nine years the Antarctic went from its largest maximum on record to its smallest.
September: Opposite Seasons Side by Side
September is when both poles reach an extreme at the same time: the Arctic its minimum and the Antarctic its maximum. A bar at the top of the map compares those two numbers year by year. In 1979 the Arctic minimum was about 6.9 million km² and the Antarctic maximum about 18.3 million km²; in 2026 they were about 4.6 and 17.6 million km².
How to Read the Map
Each disc is a polar stereographic map centred on a pole, reaching 40°N for the Arctic and 50°S for the Antarctic. Blue shows the winter maximum and white, inside it, the summer minimum, each on its own date. The blue band between them is the seasonal ice that forms and melts every year; the white is the ice that survived the summer. Pins mark each new record from 1985 on. Large pins are records that still stand; smaller pins are records that were later broken.
Both shades show sea ice extent: every 25 km grid cell where satellites measure at least 15% ice cover. Maxima and minima are dated on a five-day mean, the convention used by the National Snow and Ice Data Center (NSIDC). The ice edge is smoothed and simplified to about 10 km, and floes smaller than about 1,500 km² are left out.
How the Map Was Made
The map is built from NSIDC's Sea Ice Index, Version 4 (G02135): its daily extent maps for the outlines and its daily extent series for the numbers. For each year and each pole the dates of the maximum and minimum were found from the five-day mean, and the ice outline of that day was drawn. Until August 1987 the satellites measured every other day, and NSIDC counts the small area around the North Pole that older satellites could not see as ice. Land and Antarctic ice shelves come from Natural Earth. Values for 2026 are near-real-time and may still be revised slightly.
Chronological Timeline
- 1979 — First full year of the map; Arctic September minimum about 6.9 million km²
- 1986 — Record low Antarctic maximum (17.96 million km²), unbroken until 2023
- 1990 — Arctic minimum record low of 6.04 million km²
- 1998 — Antarctic maximum record high of 19.22 million km²
- 2005 — Records on both sides: Arctic maximum and minimum lows, Antarctic maximum high
- 2007 — Arctic minimum falls to 4.15 million km²
- 2012 — Arctic minimum reaches 3.39 million km² (17 September), still the record low
- 2014 — Antarctic maximum reaches 20.16 million km² (21 September), still the record high
- 2017 — Record low Antarctic minimum (2.11 million km²) and Arctic maximum (14.41 million km²)
- 2022 — Antarctic minimum record low of 1.98 million km²
- 2023 — Antarctic minimum (1.85 million km², 21 February) and maximum (17.07 million km², 9 September) both at record lows
- 2025 — Arctic maximum record low of 14.31 million km² (22 March)
- 2026 — Arctic minimum about 4.6 million km² (12 September)
Play the interactive map to watch 48 years of polar ice, pause on any year, click a pin for the record it marks, or embed the map on your own site. You can also export it as an animated GIF for lessons, talks and social media.
Explore the full interactive map →