This visualization shows the age of the sea ice in the Arctic between 1984 and 2019. A graph in the upper left corner quantifies the change over time by showing the area covered by sea ice that is 4 years old or older in millions of square kilometers. The video shows seasonal variability of the ice, as well as changes from year to year. Younger sea ice, or first-year ice, is shown in a dark shade of blue while the ice that is over four years old is shown as white. A color scale identifies the age of the intermediary years.