The age of Arctic sea ice can be a rough indicator for ice thickness. Paler colors indicate older ice, with light blue indicating 4-year ice, to white indicating very old ice. In the 1980s, 26% of the Arctic winter ice pack consisted of old ice. [No narration] After 2007, older ice diminishes rapidly and is replaced by younger ice. Starting in 2011, very old ice remains only along the Canadian coast. At the end of winter 2014, only 10% of the ice pack was old ice, less than half the amount in the early 1980s, and very old ice has become more rare.