The issue that the sea ice in the Arctic is melting is nothing new. What is new though is that researchers have now determined how long the ice has been thinning and how much has been lost for how long.

In a study published in the journal The Cryosphere, researchers from the University of Washington compiled historic and modern data to provide a clearer idea of how the Arctic sea ice melt is progressing. According to the results of the study, by 2012, the sea ice has thinned down to 65 percent of its size from 1975. Ice thickness during September, the time of the year ice cover is thinnest, is also 85 percent thinner for the same period.

Ron Lindsay, a climatologist from UW's Applied physics Laboratory and the lead author for the study, said it was evident ice was thinning but now they have information on just how fast the melt is happening.

"We can see that it's not slowing down," he added.

With this kind of information, the study aids in gauging how much change the climate has undergone in the last few decades, helping as well to better predict the state of the Arctic Ocean in the future. It is also the first to bring together all available data on observations about sea ice thickness in the Arctic, helping climate researchers today by providing data from the past.

All the observations reported in the study have been gathered in the Unified Sea Ice Thickness Climate Data Record, which now includes about 50,000 standardized measurements every month. The archive is housed at the U.S. National Snow and Ice Data Center and is being managed by the UW Applied Physics Laboratory.

According to Axel Schweiger, an Applied Physics Laboratory polar scientist and co-author for the study, bringing together different observations collected over a period of time has allowed the researchers to verify the trend that has previously come up in a model created in the last 13 years. Researchers, however, admitted that their estimates about the Arctic sea ice melt have been slower than what data from previous decades indicate.

Data gathered for the study reaches only up to 2012, when sea ice level was at record low during summer. The amount of Arctic sea ice has risen but the researchers put it as just a little spike in the trend. Despite going beyond the average, this does not make the results of the study inconsistent.

The study received some funding support from NASA and the National Science Foundation.

Photo: U.S. Geological Survey | Flickr