Last year, many scientists blamed the winter storms that blasted the Northeastern United States and Europe on the negative mode of a weather pattern called the Arctic Oscillation. This winter, the Arctic Oscillation started out in the opposite mode, which scientists connect to the warmer-than-average temperatures and unusually low snowfall over much of the U.S. The swings of the Arctic Oscillation also help control how sea ice moves in the Arctic Ocean, which is of great interest to climate scientists. Readers often write in to ask us about this powerful but mysterious climate phenomenon, and how it affects weather where they live. What is the Arctic Oscillation, and how does it affect Arctic sea ice and the rest of the Northern Hemisphere? Continue reading
The Arctic Ocean is not the only place with sea ice. The ocean surrounding the continent of Antarctica also freezes over each winter. But we don’t hear much about sea ice on the bottom of the planet. What’s happening to Antarctic sea ice and why does it matter?
One reason that we hear less about Antarctic sea ice than Arctic sea ice is that it varies more from year to year and season to season than its northern counterpart. And while Arctic ice has declined precipitously over the past thirty years of the satellite record, average Antarctic sea ice extent has stayed the same or even grown slightly. Continue reading
On November 8 and 9, a strong storm hit the Western Alaska coast, bringing blizzard conditions, storm surge of up to 10 feet and wind gusts as fast as 93 miles per hour. Along the Western Alaskan coastline, towns and villages prepared for the worst. “Up here, cities are much more sparse, but a storm like this still impacts the people that live there,” said Kathleen Cole, an ice forecaster at the National Weather Service. Damage reports after the storm indicated extensive flooding, wind damage to buildings, as well as power outages, which led to many evacuations to higher ground and to shelters with generator power. Some reports referred to the storm as a “blizzicane,” or an Arctic hurricane. What was unusual about this storm—and was there any connection to changes in the Arctic climate? Continue reading
Did Arctic sea ice reach an all-time record low this year—or not? Scientists at University of Bremen in Germany thought it was a new record, while data from NSIDC showed the sea ice at its second-lowest level. The two groups were examining data from two different satellite sensors. Why did the data differ—and if data can vary, does a record low really matter? Continue reading
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