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Animated map showing annual variation of sea ice extent in the Arctic Ocean on a monthly basis from January 2016 through December 2018.

Animated map showing annual variation of sea ice extent in the Arctic Ocean on a monthly basis from January 2016 through December 2018.

Credit: UCAR Center for Science Education (Randy Russell) using maps and data from the NSIDC.

This animation shows the annual variation of sea ice extent in the Northern Hemisphere. Throughout the winter, the cold temperatures freeze more and more of the water in the Arctic Ocean and surrounding bodies of water. As this water freezes, it gradually builds a layer of ice on the surface that covers millions of square kilometers. The ice pack generally reaches its maximum extent around March.

As warmer temperatures arrive in the Arctic in the springtime, the ice begins to melt, and much of the ice pack breaks up. This melting continues throughout the summer, so the extent of the ice pack is usually at its minimum around September.  After that it begins growing again, repeating the annual cycle.

This animation shows three years of this cycle, from January 2016 through December 2018.

The maps used in this video are from the National Snow and Ice Data Center (NSIDC). If you want to see more videos and pictures of sea ice, go to the NSIDC web site to: