The winter ice pack in the Arctic was once dominated by multi-year*, thick ice. Today, very little old ice remains. This animation shows maps of sea ice age ...
Since 1988, Arctic sea ice is getting younger, and young ice is not a good thing. In 1988, ice that was at least 4 years old accounted 26 percent of the Arctic’s sea ice. By 2013, ice that age was only 7 percent of all Arctic sea ice.
The vanishing act is occurring because climate change is helping warm the ocean waters in parts of the Arctic. Those warmer temperatures are whittling away at older sea ice during the summer melt season.
Replacing this thicker, harder old ice with young ice, which is generally thinner and melts more easily, is also contributing to the steep decline in summer sea ice extent and could trigger a feedback loop. That’s because less ice means more dark ocean water is exposed to the sun, which absorbs more of the incoming sunlight than white ice. That means warmer waters, which could in turn mean even less old ice and ice cover with each passing year.
Via Bert Guevara