Via The Atlantic:
Once upon a time, there was a city so dazzling and kaleidoscopic, so braided and water-rimmed, that it was often compared to a single living body. It clustered around a glimmering emerald spine, which astronauts could glimpse from orbit. It hid warm nooks and crannies, each a nursery for new life. It opened into radiant, iris-colored avenues, which tourists crossed oceans to see. The city was, the experts declared, the planet’s largest living structure.
Then, all at once, a kind of invisible wildfire overran the city. It consumed its avenues and neighborhoods, swallowed its canyons and branches. It expelled an uncountable number of dwellers from their homes. It was merciless: Even those who escaped the initial ravishment perished in the famine that followed.
Many people had loved the city, but none of them could protect it. No firefighters, no chemicals, no intervention of any kind could stop the destruction. As the heat plundered the city of its wealth, the experts could only respond with careful, mournful observation.
All of this recently happened, more or less, off the east coast of Australia. The Great Barrier Reef—which, at 1,400 miles long, is the longest and largest coral reef in the world—was blanketed by dangerously hot water in the summer of 2016. This heat strangled and starved the corals, causing what has been called “an unprecedented bleaching event.”
Though that bleaching event was reported at the time, scientists are just starting to understand how catastrophically transformative it was. A new paper, published Wednesday in the journal Nature, serves as a kind of autopsy report for the debacle.After inspecting every one of its reefs, and surveying them on an almost species-by-species basis, the paper reports that vast swaths of the Great Barrier Reef were permanently transformed in the summer of 2016. The reef’s northern third, previously its most pristine section, lost more than half of its corals. Two of its most recognizable creatures—the amber-colored staghorn corals, and the flat, fanlike tabular corals—suffered the worst casualties.
But damage was widespread out across the entire ecosystem.
“On average, across the Great Barrier Reef, one in three corals died in nine months,” said Terry Hughes, an author of the paper and the director of the ARC Center of Excellence for Coral Reef Studies, the Australian government’s federal research program devoted to corals.
“You could say [the ecosystem] has collapsed. You could say it has degraded. I wouldn’t say that’s wrong,” Hughes said. “A more neutral way of putting it is that it has transformed into a completely new system that looks differently, and behaves differently, and functions differently, than how it was three years ago.”
“It’s a confirmation of our worst fears,” said John Bruno, a marine biologist at the University of North Carolina who was not involved in the study.
Yet it was not the end of troubles for the Great Barrier Reef. In the summer months of 2017, warm waters again struck the reef and triggered another bleaching event. This time, the heat hit the reef’s middle third. Hughes and his team have not published a peer-reviewed paper on that event, but he shared early survey results with me.Combined, he said, the back-to-back bleaching events killed one in every two corals in the Great Barrier Reef. It is a fact almost beyond comprehension: In the summer of 2015, more than 2 billion corals lived in the Great Barrier Reef. Half of them are now dead.
What caused the devastation? Hughes was clear: human-caused global warming. The accumulation of heat-trapping pollution in the atmosphere has raised the world’s average temperature, making the oceans hotter and less hospitable to fragile tropical corals.
“People often ask me, ‘Will we have a Great Barrier Reef in 50 years, or 100 years?’ And my answer is, yes, I certainly hope so—but it’s completely contingent on the near-future trajectory of greenhouse-gas emissions,” Hughes said.
…The new paper also advances its own idea of what the future of the Great Barrier Reef will look like. In short, it is highly unlikely that the Great Barrier Reef—the northern reef, especially—will resemble its old self in the lifetime of any living person.
“It’s like clear-cutting a redwood forest,” said Bruno, the marine biologist. “In 10 years, you’re going to have a lot of stuff on the ground, but you’re not going to have the old-growth forest back. Some of these corals were 10, 30 years old, but a lot of them were centuries old. In 100 years—if there is no more warming—they could return. But it’s a long time.”
“The most likely scenario,” write the authors of the paper, “is that coral reefs throughout the tropics will continue to degrade over the current century until climate change stabilizes, allowing remnant populations to reorganize into novel, heat-tolerant reef assemblages.”“Novel, heat-tolerant reef assemblages”: That doesn’t exactly evoke the dazzling rainbow vistas familiar to viewers of Blue Planet or even Finding Nemo.
“I regret that I agree with the disturbing prognosis,” said Rebecca Vega Thurber, a coral scientist at Oregon State University who was not connected to the paper, in an email. “Unless we see evidence that these mass thermal anomalies are becoming less frequent or severe (which is counter to the evidence at hand), it is likely that the Great Barrier Reef (and reefs worldwide) will continue to degrade.”
…Hughes said that the news will continue to get worse until governments and their citizens focus on the “root cause” of the problem. The Great Barrier Reef will continue to collapse and die until humanity stabilizes the amount of greenhouse-gas pollution in the air. But fixing that problem will require remaking the energy system, moving away from oil and gas and to solar, wind, and other renewable sources.
“But the federal government of Australia, like the federal government of the United States, still very much favors the continued development of the fossil-fuel industry,” Hughes sighed. “And that, to me, is a complete policy failure for the Great Barrier Reef.”
Go Adani.
