Sea ice is the vast space a polar bear calls home–––and that home is rapidly melting. This visualization by NASA - National Aeronautics and Space Administration shows the age of the Arctic sea ice between 1984 and 2016. Younger sea ice, or first-year ice, is shown in a dark shade of blue while the ice that is four years old or older is shown as white. A bar graph displayed in the lower right corner quantifies the area in square kilometers covered by each age category of perennial sea ice. | Pola