Did you know that sea ice has an age? In this dataset, colors show the age of sea ice floating in the Arctic Ocean. The darkest blue areas on the map show seasonal or first-year ice, which formed during the most recent winter. White areas show where ice is more than four years old. Since the late 1900s, Arctic sea ice has thinned, and less sea ice has persisted in the Arctic over multiple melt seasons. The trend toward younger, thinner sea ice over time reflects warming temperatures in the Arcti