September 16, 2015 | The National Snow and Ice Data Center announced yesterday that sea ice in the Arctic had dwindled to the fourth lowest extent since satellites began capturing images of the area in 1979. All nine of the lowest sea ice extents have occurred in the last nine years, according to the NSIDC.

News of another lean year for end-of-summer sea ice has people wondering anew just how long we have left before Arctic Septembers become ice free. 

NCAR climate modelers Marika Holland and David Bailey took a crack at answering that question a few years ago, and their results are illustrated in the animation above. Created by Tim Scheitlin of NCAR's Visualization Lab, the video shows that all the ice could disappear in some Septembers as early as mid-century if human-caused climate change continues unabated.

The degree to which sea ice melts during any particular sun-filled Arctic summer depends on a range of factors, from the temperature of the ocean surface to how many storms hit the region to how much ice accumulated during the preceding winter.

Regardless of how much melt eventually occurs, the process typically wraps up in mid-to-late September, just as the Sun prepares to set on the North Pole for the first time since rising the previous March. With the return of darkness the ice begins to regrow.

In the last several decades, global climate models have becoming increasingly sophisticated in the way they handle these changes in ice from season to season and year to year. The NCAR-based Community Climate System Model (now the Community Earth System Model, or CESM) was one of the first to take the varying nature of ice thickness into account as well as the way sea ice moves across the ocean surface, for example. And though it is now recognized as one of the best in the world for simulating sea ice, NCAR scientists and their collaborators are continuing to refine the model by adding additional detail, such as how pools of melt water or layers of snow on the ice surface may affect the rate of melting.

Global climate models, like CESM, are typically used to show trends over multiple decades, as in the visualization above. But researchers at NCAR and elsewhere are now working to see if the models can be used to make shorter-term decadal predictions of sea ice changes, a timeline that is important to policy makers, residents of the region, and others.

More about NCAR's sea ice research

• Arctic ice melt could pause in near future, then resume again
• Study may answer longstanding questions about little ice age
• Arctic ice more vulnerable to sunny weather, new study shows
• Permafrost threatened by rapid retreat of Arctic sea ice, NCAR study finds
  

Writer/Contact
Laura Snider

See all News