Last summer, a chunk of ice three times the size of Manhattan broke off Petermann Glacier in Greenland and floated out to sea. The calving left miles of newly open water in the deep Petermann Fjord, which had been capped in a thick layer of glacial ice. New research out this summer confirmed that it was likely the largest calving in the region since observations began in 1876. What does this event tell us about climate change in the Arctic? Continue reading
Arctic sea ice is near its annual low extent for the year. Will it reach a new record low? While many people are watching this year’s ice extent closely, the effect of climate change on ice extent in a single year is different than its effect in the long term. Arctic sea ice has declined more than 30 percent in summer since satellite measurements started in 1979. But from year to year, ice extent jumps up and down quite a lot. Continue reading
If you have been following the topic of Arctic sea ice, you have probably seen a few headlines warning that the Arctic is about to lose its summer ice cover. Although scientists agree that Arctic sea ice is declining, they have published several different estimates of when the last of the sea ice will melt in summer, leaving more ocean surface open to absorb heat and add to global warming. What is behind all these different predictions? Continue reading
Over the 2010 to 2011 winter, news stories suggested a potential connection between a warming climate, low Arctic sea ice extent, and unusually cold weather this winter in the U.S. and Europe. What do scientists know about how sea ice affects the weather?
Scientists have been exploring a possible link, but the question is far from settled. It makes sense that changing sea ice conditions could affect weather in the Arctic and other parts of the world. During the colder months, sea ice insulates the relatively warm ocean from the colder atmosphere. As sea ice declines, more heat can escape to the atmosphere in the fall and winter, affecting wind patterns, temperature, and precipitation. Continue reading
As Arctic sea ice thins and becomes more vulnerable to melting in summer, the data trend indicates that we may eventually see ice-free summers. The question is when. Could it be sooner than we think, because the weakened ice cover has reached a point of no return? A new study suggests that, in fact, there may be no “tipping point.”
Scientists refer to a tipping point as a threshold after which a system changes irreversibly. For sea ice, a tipping point would mean losing so much ice that its heat-reflecting effects are severely diminished, leading to more and more ice loss. With this vicious cycle in place, ice could not recover to its previous summertime levels. After Arctic sea ice hit a record low in 2007, some scientists considered the possibility that sea ice has already passed this tipping point. Continue reading