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

Does dusty snow mean less water in the Rockies?

Have you been skiing in the Western U.S. and been surprised by brown snow? We recently talked to a research team that studies these coats of dirt. The dust storms that cause dusty snow appear to be getting bigger, thanks to climate warming drying out this region. Worse, dust on snow may increase flooding and slowly smother water supplies in the southwestern U.S. How bad is this situation and who will be affected by it? Can anything be done? 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.

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What is the Arctic’s new normal?

Although Arctic sea ice extent as of June 2013 falls within the normal range, sea ice overall is still declining compared to the average. This photograph was taken in August 2009, when sea ice extent nears its lowest annual extent before refreezing for the winter. (Courtesy Patrick Kelley, United States Coast Guard)

Although Arctic sea ice extent as of June 2013 falls within the normal range, sea ice overall is still declining compared to the average. This photograph was taken in August 2009, when sea ice extent nears its lowest annual extent before refreezing for the winter. (Courtesy Patrick Kelley, United States Coast Guard)

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

Modeling the Arctic climate

In February, polar climate researchers gathered at the National Center for Atmospheric Research in Boulder, Colorado to discuss the newest updates to models of the Earth’s climate system. The researchers are working together to create better models of the Arctic and Antarctic climates, which will feed into larger models of the whole Earth that help scientists understand how climate will change in the future. What goes into a climate model, and what can scientists learn from models that they cannot learn from observations?

This image shows several aspects of climate, including sea ice, surface winds, and sea surface temperature. This image came from data simulated from NCAR’s Community Earth System Model. Credit: ©UCAR, image courtesy Gary Strand, NCAR

What’s in a model?
Computer climate models are based on scientists’ understanding of Earth’s climate. The models use mathematical relationships to try to quantify the relationships between parts of the climate system. If you tweak one factor in climate, how does the simulated climate system respond? Models that bring many factors together help scientists learn how the climate system works, and let them run simulations on Earth’s climate. They also allow scientists to assess how climate may be affected by present and future changes in greenhouse gases and solar forcing, and how much of a role natural variability plays. Continue reading