A shocking new study claims that the melting of sea ice will cause an astonishing one third of the 25,000 polar bears in the world to disappear in the next few decades. The study, performed by research scientists from the United States, Canada and Norway, found that the loss of Arctic sea ice due to climate change and global warming is the main threat polar bears face.

To come to their conclusions, the scientists looked at four polar bear eco-regions and 19 subpopulations, and then analyzed sea ice data between 1979 and 2014. They found that there was the potential for huge declines in the polar bear population because of sea ice loss.

By the middle of the century, scientists worry that the bears will have an extra seven weeks when there is absolutely no ice for them to utilize. Because the bears rely on this ice to hunt seals from, that’s a big problem. Later in the century, the polar bear population could dwindle to as low as 9,000.

A recent University of Washington study used funding and satellite data from NASA to discover just how sea ice melting was negatively affecting polar bear populations. It was published Sept. 14 in The Cryosphere.

“This study shows declining sea ice for all subpopulations of polar bears,” co-author Harry Stern, a researcher with the UW’s Polar Science Center, said in a statement from the university. “We have used the same metric across all of the polar bear subpopulations in the Arctic so we can compare and contrast, for example, the Hudson Bay region with the Baffin Bay region using the same metric.”

“Sea ice really is their platform for life,” said co-author Kristin Laidre, a researcher at the UW’s Polar Science Center. “They are capable of existing on land for part of the year, but the sea ice is where they obtain their main prey.”