Climate change deniers often claim that ice in the Arctic is nothing to worry about because it is actually expanding in area. While it may be true that the expanse of the ice cover is growing, the ice itself is thinner, younger, and less likely to persist. A new paper published in The Cryosphere describes work completed by researchers from the University of Washington about how ice in the Arctic Ocean has been thinning at a breakneck pace over the last few decades.

“The ice is thinning dramatically,” lead author Ron Lindsay said in a press release. “We knew the ice was thinning, but we now have additional confirmation on how fast, and we can see that it’s not slowing down.”

The study utilized measurements of Arctic ice taken each year between 1975 and 2012. Overall, the researchers found that the ice thinned by about 62% during this time. The most staggering result came from data in September each year, when ice cover is thinnest. During the time covered by the study, September ice had decreased by an astonishing 85%.

The data were collected primarily via submarine until 1990, when aerial measurements via satellite became more common. This study is the first to combine several data sets collected from disparate studies and make a unified conclusion about the future outlook of Arctic ice.

“A number of researchers were lamenting the fact that there were many thickness observations of sea ice, but they were scattered in different databases and were in many different formats,” Lindsay continued.

Unfortunately, these measurements exceed the rate of ice loss that had been predicted through various computer modeling, which does not bode well for the future of certain regions of the Arctic.

“At least for the central Arctic basin, even our most drastic thinning estimate was slower than measured by these observations,” senior author Axel Schweiger added.

Though the modeling might have been slower than anticipated, these results do show that they were correct in the drastic thinning of the ice. The results build an important foundation for future research. Reliable measurements will be added to this database, creating an important historical record to refine models regarding climate and ice cover.

The researchers do note there has been a slight uptick in thickness of ice since 2012, which occurred after the study’s time frame and was therefore not included, but they do not believe it negates their findings.

“What we see now is a little above the trend, but it’s not inconsistent with it in any way,” Lindsay concluded. “It’s well within the natural variability around the long-term trend.”