Satellites have continuously monitored Arctic sea ice since 1979. Over the course of a year, the area covered by the ice changes. The ice melts down to its minimum every summer and builds back up again during the winter. During the last three decades, scientists have seen a decline per decade of the minimum area and thickness of the sea ice.
This image shows the extent of Arctic sea ice on September 11, 2015. The ice covers an area of 4.4 million square kilometers (1.7 million square miles), the fourth lowest recorded extent. The gold line shows the average minimum extent from 1981 to 2010.
The image was created using data collected by the Japan Aerospace Exploration Agency’s "SHIZUKU" (GCOM-W1) satellite.