The maps below show the extent of sea ice in the Northern Hemisphere around the North Pole. Select a month and year from the popup menus to compare two maps side-by-side.
- compare the sea ice in March and September for the same year
- compare the sea ice in March for two different years
- compare the sea ice in September for two different years
- explore sea ice extent in the Southern Hemisphere (around Antarctica)
In the Northern Hemisphere (around the North Pole and the Arctic Ocean) the sea ice reaches its maximum extent in early spring, at the end of the long, cold winter. March is usually the month with the most sea ice.
The ice pack melts and breaks up over the summer. September is usually the month with the least amount of sea ice (in the Northern Hemisphere).
The Northern Hemisphere ice pack is shrinking as a result of climate change. The average rate of decrease in the extent of the ice pack in September between 1979 and 2018 was 12.8% per decade (± 2.3%).
The pink line in the images shows the average (from 1981 to 2010) edge of the ice pack for a particular month.
To extend your learning:
- View three years (2016-2018) of annual changes in sea ice extent in the Northern Hemisphere as an animation.
- Explore predictions that global climate models make about future changes in sea ice extent.
- Go to the NSIDC web site to: