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Scientists believe that low-lying clouds could reflect the sun's heat back out to space, allowing the waters around the dying reef to cool down.

Scientists believe that low-lying clouds could reflect the sun’s heat back out to space, allowing the waters around the dying reef to cool down. Photo: Coralreefs.net


The Inertia

A recent study of Australia’s Great Barrier Reef revealed something alarming: over two-thirds of it has been devastated by coral bleaching. Australian marine scientists think they might have a way to save the reef, and it’s a pretty weird idea.

Researchers doing an aerial survey of the UNESCO World Heritage Site found that nearly a thousand miles of the reef had been severely damaged by warming waters.  “We didn’t expect to see this level of destruction to the Great Barrier Reef for another 30 years,” said Terry P. Hughes, lead author of the cover article of the journal Nature. “In the north, I saw hundreds of reefs — literally two-thirds of the reefs were dying and are now dead.”

It’s been rough few years for the GBR–record setting bleaching events driven by climate change, exacerbated by last year’s El Niño events, have dealt more than a few crippling blows.

So what’s this weird idea? Well, researchers want to make low-lying clouds off Australia’s northeastern coast. They’re hoping that by making the area more reflective, the water around the world’s biggest coral reef system will have a chance to cool down.

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Scientists at Sydney Institute of Marine Science and the University of Sydney School of Geosciences have been meeting up for the last six months, trying to figure out if their idea is feasible.

“Cloud brightening is the only thing we’ve identified that’s scalable, sensible, and relatively environmentally benign,” says Daniel Harrison, a postdoctoral research associate with the Ocean Technology Group at the University of Sydney.

According to MIT’s Technology Review, cloud brightening isn’t a brand new idea. Thirty years ago, a British scientist named John Latham introduced the idea as a way of controlling global warming. His theory was published in Nature, and involved ships spraying “tiny salt particles, generated from sea water, toward the low-lying marine clouds that hug the coasts of several continents.” He believed the additional water droplets would increase the surface area of the clouds, and the more of the sun’s heat would be reflected back into space.

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Of course, when it comes to large-scale geoengineering projects, researchers are a little leery. The University of Harvard is in the early stages of launching the world’s biggest geoengineering projects right now, and they’re not taking it lightly. While the Australian marine scientists are concerned only with the sky above the Great Barrier Reef, the Harvard study is looking at controlling the global climate. There are three main ways of doing that. The first, which would be used over the Great Barrier Reef, is called Albedo Enhancement. The second uses space reflectors, and the third, which is what Harvard is looking at using, uses stratospheric aerosols–sending small, reflective particles into the upper atmosphere to reflect some sunlight before it reaches the surface of the Earth.

Not everyone thinks it’s going to work, though. “I just don’t think there are enough clouds of the right type there that would be susceptible to marine cloud brightening,” Ken Caldeira, a climate scientist at Carnegie told Technology Review. “Below a certain geographic footprint, probably around 10,000 square miles, it might be difficult to produce a big enough change in cloud density to add up to much of a difference.”

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