Why is there so much Antarctic sea ice?

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Photograph from a ship traveling through Antarctic sea ice

Even during the Antarctic summer, heavy sea ice conditions are not uncommon. This photograph of sea ice was taken from the British icebreaker, HMS Protector, on its way to assist a Norwegian cruise ship that had become stuck in sea ice in January 2013.
–Credit: Royal Navy Media Archive (http://www.flickr.com/photos/rn_topten/8443836559/in/set-72157632684027667)

In late December 2013, the Russian research vessel, Akademik Shokalskiy, became trapped in thick sea ice off the coast of Antarctica. After several research vessels and icebreakers attempted rescue, the 52 passengers were evacuated. Soon after, one of the rescue ships also became stuck in the ice. However, conditions eased and both icebound ships safely churned out to open water.

Research in polar regions is inherently risky, and these events show how easily weather and ice conditions can disrupt research missions and travel during the already short Antarctic summer. But why was there so much sea ice around Antarctica to begin with, and why was it so thick? Antarctic sea ice is ruled by very different systems than Arctic sea ice. The reasons behind this increase are complex, and several recent studies show that scientists are still trying to understand them. Continue reading

Celebrating 35 years of sea ice satellite data

Image of Arctic sea ice derived from SMMR data

This image is derived from the Scanning Multichannel Microwave Radiometer (SMMR), and shows Arctic Ocean sea ice extent in August 1985. Purple and red show greater ice coverage, while greens and blues indicate less ice. The black circle over the pole indicates no data—SMMR took observations very close to, but not directly over, the pole. Image credit: NSIDC

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

Is an East Antarctic melt probable?

Does melting of the East Antarctic Ice Sheet (EAIS) pose a threat to sea level rise? Studies of the ice melt that fuels sea level rise often focus on the prominent warming and melting of glaciers in Greenland and western Antarctica. The massive East Antarctic Ice Sheet (EAIS) has been largely ignored, until recently. “It’s generally been assumed that it’s so big and so cold that it’s probably immune to some of the warming trends we’ve seen across the planet,” said Chris Stokes, a professor at Durham University. Two recent studies, however, paint a new picture of the world’s thickest, unwavering giant, suggesting the need to look deeper into eastern Antarctica. Continue reading

For sea ice, age matters

Most people picture the Arctic Ocean as miles upon miles of thick sea ice. This icy expanse has become threatened as Arctic sea ice shifts from mainly old ice to much younger, thinner ice. How does this shift impact the Arctic environment? And what is the connection between the average age of ice found in the Arctic and the overall sea ice decline? Continue reading

Are scientists conservative about sea ice?

The U.S. Coast Guard Cutter Healy encountered only small patches of sea ice in the Chukchi Sea when this photograph was taken on July 20, 2011. (Courtesy NASA Goddard Space Flight Center)

The U.S. Coast Guard Cutter Healy encountered only small patches of sea ice in the Chukchi Sea when this photograph was taken on July 20, 2011. (Courtesy NASA Goddard Space Flight Center)

Guest post by Walt Meier, NSIDC Scientist

Arctic sea ice set a record minimum extent in September 2012, far below the previous record low in 2007. Summer extents have been far lower than average for the last decade, with several record or near-record years. Looking at the numbers, one is tempted to think that the Arctic Ocean may reach nearly sea ice-free conditions within just a few years. But most expert analyses indicate that we’re likely at least a couple decades away from seeing a blue Arctic Ocean during the summer.

Continue reading