Coral Reefs Unlikely To Survive Warming; Hitting Paris Targets Means GBR Bleaching Every Other Year

EDIT

Other parts of the world have so far avoided this blight. More than half of the reefs near Australia and in the Indian Ocean have bleached three times since 1980. But reefs in Australia seem to be getting worst fastest. “The sense that everyone had, that, wow, this is a very different world than it was 30 years ago, was a correct impression,” said Lasker. “The nice thing about an analysis like this is it makes clear to people who make policy that this isn’t an impression, it’s actually occurring. It is important to do this.” “Now, the impact it has on those officials ... that’s another issue,” he added.

Perhaps most worryingly, the study argues that soon it will not take a global heat wave—such as an El Niño event in the Pacific Ocean—to kill corals. “As global warming progresses, average tropical sea-surface temperatures are warmer today under La Niña conditions than they were under El Niño events only three decades ago,” says the paper. “We are already approaching a scenario in which every hot summer, with or without an El Niño event, has the potential to cause bleaching and mortality at a regional scale.”

This isn’t unexpected. Last year, a study conducted by Australian government scientists and published in Nature Climate Change found that even if the world warms by an average of only 1.5 degrees Celsius—the “reach” goal of the Paris Agreement—the Great Barrier Reef could suffer a major bleaching event 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,” Ruth Gates told me at the time. Gates is a coral biologist at the University of Hawaii and the president of the International Society for Reef Studies; she wasn’t connected to either study. “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.”

EDIT

https://www.theatlantic.com/science/archive/2018/01/the-global-scourge-on-coral-reefs/549713/