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“We are very quickly about to lose the Arctic summer sea-ice cover, basically independent of what we are doing,” Dirk Notz, a climate scientist at the University of Hamburg in Germany tells the New York Times’ Raymond Zhong. “We’ve been waiting too long now to do something about climate change to still protect the remaining ice.” An ice-free summer, also called a “blue ocean event,” will happen when the sea ice drops below one million square kilometers (386,102 square miles), writes Jonathan Bamber, a professor of physical geography at the University of Bristol, in the Conversation. This equates to just 15 percent of the Arctic’s seasonal minimum ice cover of the late 1970s, per the Times.

Previous assessments using models have estimated an ice-free summer under high and intermediate emissions scenarios by 2050. But researchers noticed differences between what climate models predicted about what would happen to sea ice and what they’ve actually seen through observations, according to Bob Weber of the Canadian Press. “The models, on average, underestimate sea ice decline compared with observations,” says Nathan Gillett, an environment and climate change Canada scientist, to Weber.

Now, in a new study published in Nature Communications, Notz, Gillett and their colleagues tweaked these models to more closely fit satellite data collected over the past 40 years. Using these modified models, the researchers projected ice changes under different possible levels of greenhouse gas emissions. Their paper suggests that regardless of emissions scenario, “we may experience an unprecedented ice-free Arctic climate in the next decade or two.” Under a high emissions scenario, the Arctic could see a sustained loss of sea ice from August until as late as October before the 2080s, lead author Seung-Ki Min, a climate scientist at Pohang University of Science and Technology in South Korea, tells CNN’s Rachel Ramirez.