If you’re optimistic about the future with regards to global warming, a new study indicates that you don’t have much reason to be. Scientists at the University of Washington believe that there is just a 5 percent change that the Earth will warm by 2 degrees or less through the 21st century, which is the threshold set by scientists as the necessary goal in order to avoid the most catastrophic effects of global warming.

The paper found that a rise of 2 degrees is looking like the best case scenario for our planet at this point, and even to achieve that would take a huge and sustained effort to curb pollution and carbon emissions over the rest of the century, a prospect that looks less and less likely with the United States pulling out of the Paris climate accord and skepticism of global warming still high.

There’s still time to tackle the problem, but as this paper shows, scientists believe we are quickly running out of time.

“Our analysis shows that the goal of 2 degrees is very much a best-case scenario,” said lead author Adrian Raftery, a UW professor of statistics and sociology. “It is achievable, but only with major, sustained effort on all fronts over the next 80 years.”

“Our analysis is compatible with previous estimates, but it finds that the most optimistic projections are unlikely to happen,” Raftery said. “We’re closer to the margin than we think.”