Things don’t look good—in either scenario. A climate-changed Australia will be a more sweltering, less biodiverse place. Toasty waters off its shores will evict the continent’s marine ecosystems, while, on land, summers that would once have broken records will become routine.

The study is important to researchers even beyond the land down under. Since the adoption of the Paris Agreement last year, the world’s nations have aspired to keep global temperatures from rising by more than 1.5 degrees Celsius.

It’s a nice idea—and a really tough goal to meet. The actual stated commitments of the Paris Agreement put the world on track for 3.4 degrees Celsius of warming. To have a good shot at avoiding 1.5 degrees of warming, the world would have to halt all carbon emissions by 2021, according to the U.K.-based think tank Carbon Brief. (Without the halt, we won’t actually reach the 1.5 degree threshold for a couple more decades, but by 2021 there will be enough carbon in the atmosphere to lock us in for that warming.)

In Australia, both 1.5 degrees and 2 degrees of warming will cause more heat waves and coral calamities. Take the risk of another 2016-level event in the Coral Sea, for instance. The paper finds that—in a two-degree world—there’s an 87-percent chance that 2016-levels of warmth will strike the Great Barrier Reef in any individual year.

“At two degrees Celsius of warming, last year’s event would actually be a bit cooler than average,” said Andrew King, a climate scientist at the University of Melbourne and one of the authors of the paper, in an email. “This poses a major problem for the survival of most of the Great Barrier Reef.”

Its prognosis barely improves on a slightly-less-warm planet. In a 1.5-degree world, there’s still about a two-thirds chance that any summer would bring 2016-level heat to the Great Barrier Reef. And even in the coolest, kindest of the scenarios—the “gentlest” version of a 1.5-degree world—the odds of 2016-level heat are just over 50 percent. The reef would bleach every other year.

“By the time we’re seeing bleaching temperatures there every year, there probably will not be a reef anymore. There’s only five or six times bleaching can happen before a reef is essentially dead,” said Ruth Gates, a coral biologist at the University of Hawaii and the president of the International Society for Reef Studies. She was not connected to the paper.

She said that in the few back-to-back bleaching events that scientists have observed in the wild—like the one in Kāne’ohe Bay, next to her lab, in 2014 and 2015—they find that the second year is even “more profound” in its consequences than the first. “It will be a magnification each time a coral bleaches,” she said. “You will lose a portion of the reef each time, and there comes a point where it’s no longer functionally a reef. ”

The authors also found ominous results when they modeled land temperatures. In 2013, Australia experienced a broiling, weeks-long series of heat waves dubbed the “Angry Summer.” Power systems buckled, wildfires ignited across the country, and the Bureau of Meteorology had to put a new color on weather maps to describe temperatures above 125 degrees Fahrenheit (52 degrees Celsius).