Last year was declared the hottest year in recorded history by NASA and NOAA. “This is the latest in a series of warm years, in a series of warm decades,” Gavin Schmidt, director of NASA’s Goddard Institute for Space Studies, told Joby Warrick and Chris Mooney of The Washington Post. The joint announcement was based on weather records dating back more than 130 years, and concluded that much of the increase in temperature was driven by warming oceans.
Every winter, sea ice expands to fill almost the entire Arctic Ocean basin. Each summer, it shrinks, but the ice that survives becomes thicker — and more likely to survive future summers. The amount of this perennial ice in the Arctic has declined since the 1980s.
The video below, released on Tuesday by NOAA, shows the relative amount of ice from 1987 through November 2014. The animation depicts the oldest ice, more than nine years old, as white and the youngest, first-year ice, as dark blue.
So what does this mean? NOAA explained: “In September 2012, Arctic sea ice melt broke all previous records. …While perennial ice increased between 2013 and 2014, the long-term trend continues to be downward.”