The central and southwestern portions of the United States have experienced drought for the past several years. This photograph was taken in mid-February, 2010. By that point in winter, these rows would normally have been fully covered in snow. Photograph credit: Kristy Johnson (http://www.flickr.com/photos/kayaker1204/4359744393/)
In spite of the massive blizzards that have slammed parts of the northeastern United States, much of the country is experiencing a pronounced lack of snow. And where there is snow, it is less than usual. It follows a very low snow year from the previous season, causing people to worry if low snowfall is the new normal.
A previous Icelights post, Arctic sea ice and U.S. weather, discussed possible causes behind the changes in winter weather, trying to see if there are correlations to larger climate changes. Researchers like Jennifer Francis of Rutgers University are exploring the possibility that declining sea ice in the Arctic is altering atmospheric temperatures and weakening the jet stream. This change may shift the Northern Hemisphere storm track, leaving some places unusually snowy, or leaving normally snowy locations dry. Can a few good blizzards help reverse the snow drought across parts of the United States? Or is this string of dry winters yet another symptom of climate change? Continue reading
During the short austral summer, much of the sea ice surrounding Antarctica melts, often leaving only the large, tabular icebergs. Credit: NSIDC courtesy Andi Pfaffling
September 2012 was a record-setting month for both of Earth’s poles, but for different reasons: sea ice in the Arctic fell to a record low minimum extent after a summer of melting while Antarctic sea ice froze to a record high extent during the South Pole winter. Is record Antarctic sea ice canceling out the losses in Arctic ice? And does the record in the south mean that Antarctica is not warming? Continue reading
Sea ice extent reached a new record low on August 27, 2012 and continued to decline. The last six years have seen minimum sea ice extents below the two standard deviation range of the data. The graph above shows Arctic sea ice extent as of August 13, 2012, along with daily ice extent data for the previous five years. 2012 is shown in blue, 2011 in orange, 2010 in pink, 2009 in navy, 2008 in purple, and 2007 in green. The gray area around the average line shows the two standard deviation range of the data.
Satellite observations since 1979 show that sea ice melted to its lowest extent in the satellite record, during August 2012 . As of this post date, the ice continues to melt, with two to three weeks left before the days shorten enough for the ice extent to begin to expand through the winter. Readers often write to us asking what such records really mean. How far from normal is this year’s record low, and how do scientists decide what is normal? Continue reading
Bubbling methane melted a hole in the ice of this otherwise frozen lake in the Brooks Range, Alaska, in April 2011. Credit: Katey Walter Anthony
As people watch the decline of Arctic sea ice, the most obvious sign of climate warming in that region, scientists are noting other signs of change, like methane seeping out of the ground as permafrost thaws and glaciers melt across the Arctic. Scientists suspected these methane seeps existed, but no one had measured how much methane was escaping—until recently. Continue reading
On July 20, 2011, the U.S. Coast Guard Cutter Healy traveled through a break in the sea ice and melt ponds in the Arctic Ocean, during the NASA Impacts of Climate on Ecosystems and Chemistry of the Arctic Pacific Environment (ICESCAPE) mission, a field survey aimed at understanding the ecology of the Arctic Ocean. Credit: NASA/Kathryn Hansen
In summer months, icebreaking ships head north into the Arctic Ocean, tearing through the sea ice and leaving trails of open water in their wakes. Readers occasionally write in to ask us whether the trails left by these ships contribute to the melting of sea ice. Continue reading