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Since 2016, Half of All Coral In the Great Barrier Reef Has Died (theatlantic.com)
A new paper, published Wednesday in the journal Nature, reports that the Great Barrier Reef has lost more than half of its corals since 2016. The authors inspected every one of its reefs, surveying them on an almost species-by-species basis, and found the damage to be widespread across the entire ecosystem. "Two of its most recognizable creatures -- the amber-colored staghorn corals, and the flat, fanlike tabular corals -- suffered the worst casualties," reports The Atlantic. From the report: "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."
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.
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.
they only look at temperature. Why were there not any chemical samples taken? pollutant studies?
Pollutants are measured in areas where they are a concern, such as where mine tailings flow into the sea. But the GBR is 2300 km (1400 miles) long, and it is implausible that chemical waste or effluent could have so much effect across such a vast area.
ph level measurement?
Rising CO2 causes ocean ph to drop. This is happening worldwide. It is unlikely that falling ph (rising acidity) is the root problem, because acidity is rising everywhere and reefs are surviving and sometimes even expanding in places like Papahanaumokuakea in the Northwestern Hawaiian Islands, or the Sea of Japan, where temperatures are relatively cool.
I wouldn't get too focused on it being dead or not, we can do coral reintroduction, and the healthiest and most biodiverse reefs in the world sit just north of Australia in places like Indonesia, so if we can restore things to the point at which they can sustain reef life, there's a reasonable chance it can recover.
There's this kind of mystique around reefs when we see claims about how incredibly biodiverse they are, and how they're home to millions of unique species. That's true, but the diversity doesn't change drastically across large regions - sure different areas do have unique species, but the common species that build the reefs are continent wide, or even global.
I've recently participated in a coral conservation programme in the Caribbean helping to restore the exact same staghorn spoken about in the article. It's a species of coral that's struggling globally, but the good news is that it's also pretty damn easy to repopulate it, because you can just cut bits off, and grow them for a bit in ocean based nurseries, then just plant them with marine grade putty and similar things and within a few years they'll restore an area to it's natural state. The same is true of many corals.
As someone whose dived globally, one thing you start to realise is that for all those millions of species, there are certain ones you see time and time again - from Florida all the way down the chain of Caribbean islands to Curacao and all the way back up the mainland past Costa Rica, Yucatan and Mexico and back to Florida, you'll see the same species time and time again - the same fish, the same turtles, the same morays, the barracudas, the sharks, the puffers, the rays. Cozumel has it's distinct splendid toadfish, St Lucia has "the thing" and so on, but ultimately, it's clear that there are key species that prop up the reefs and sit widespread. If you go over to Asia the same applies, places like Lembeh like to tout their access to things like the Blue Ringed Octopus, and their nudibranchs and stuff, but you can see these all across tropical Asia - Thailand, the Philipines, Indonesia, Australia Some of those species are common all the way up through the Indian ocean into Egypt and Jordan's Red Sea reefs. Even in the colder regions, you see the same species along Norway's coastline as you do around the UK, and around Greenland and Iceland and to North America's northern coasts.
So even if we can't save say, the barrier reef in time to solve the warming problem, if we can at least keep some reefs going we can restore others to productivity. We will lose some localised distinctive species, which may mean we lose unique treatments for cancers and so forth, so it's not cost free for us as a species, but it needn't also be catastrophic for the oceans, because if we do lose the reefs, with lose the hatcheries and nurseries, and if we lose them, we lose 20%+ of the world's global food supply.
Ideally therefore, we want to limit the impact as fast as we can to protect food supplies, and to protect unique species that have led to groundbreaking medical research and other scientific advancement, but if we can't, there's still at least some hope. As with everything though - your backup plan should be just that, your backup plan, because if you don't even bother to try your primary plan, and fall straight through to the backup, then what happens if that fails? The harder we try for plan A - saving the reefs as they are, the easier and more likely it'll be we can succeed with plan B, if we absolutely end up having to fall back on it, so giving up because we might fail most definitely should not be an option we even begin to consider.