We’ve all heard it: Arctic sea ice is melting. Sea ice is thinner year to year and there is less of it. In 2007, scientists observed a nearly 50 percent loss of summer ice as compared to 1980. With such a dramatic shift, what else is taking place in the Arctic Ocean? Scientists are discovering some of the negative affects, but are there any positive influences as well? Continue reading
Polar scientists are celebrating an anniversary of sorts. Thirty-five years ago, sea ice research took a great leap forward. On October 26, 1978, the Scanning Multichannel Microwave Radiometer (SMMR) beamed its first data records back down to Earth. The instrument, pronounced simmer, was capable of mapping global sea ice concentration and extent, giving scientists a more comprehensive look at Arctic and Antarctic sea ice. Thanks to SMMR and its successor remote sensing instruments, scientists now have a long and detailed record of sea ice that helps them understand how sea ice works, and how it is changing. Continue reading
NSIDC recently switched the baseline against which we analyze Arctic sea ice extent. Previously, we relied on a baseline that coincided with the beginning of the satellite period and stretched 20 years, from 1979 to 2000. The new baseline runs from 1981 to 2010, covering 30 years. Why did we make such a change?
Switching to a 30-year baseline allows us to be consistent with other climate monitoring agencies, which commonly use a 30-year time period for conducting analyses. This new baseline also helps account for the wider variations observed in Arctic sea ice extent. Continue reading
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
Readers sometimes ask us, “What are the reasons behind Arctic sea ice decline?” In summer months, ice extent has declined by more than 30 percent since the start of satellite observations in 1979. But is climate change really the culprit, or could other factors be contributing? Continue reading