Aussie researchers have hatched a bright idea to turn clouds into giant sun shades to protect the Great Barrier Reef from climate change.
It might sound far-fetched, but scientists are refining a technique that could make clouds more reflective to help stop heat from cooking sensitive corals.
University of Sydney researcher, Dr Daniel Harrison, admits it's an "out there" idea, but if it works, there could one day be a network of "cloud-brightening stations" across the Great Barrier Reef.
The technique would see minute sea-salt molecules, harvested from sea water, sprayed into the air.
Air currents would sweep the particles into low-level cloud, increasing the amount of sunlight those clouds bounce back towards the sun.
"One cloud-brightening station would be blowing billions of these nano-sized salt crystals, so small you couldn't even see them, out, and the atmospheric mixing will take them quite quickly up to the level of the low clouds that you want to influence," Dr Harrison told AAP on Tuesday.
"It's one of the few options that is scalable up to the whole reef, and can buy us some time."
The researchers are presenting their idea at symposium in Cairns about ways to help preserve one of Australia's iconic attractions.
Nozzles that could disperse the sea-salt molecules are already being developed, alongside a study to test the concept's feasibility.
Dr Harrison said the world would need a wide range of tools to save reef ecosystems, but ongoing action to tackle climate change was paramount.
"We can help buy the reef time, but obviously it's treating the symptoms, not the cause or the problem."
The cloud-brightening idea is one of many innovative approaches being outlined at the symposium.
Another team is investigating whether an ultra-thin, biodegradable film, made from light-reflecting materials already found in the marine environment, can be applied to the sea surface to shade corals and limit bleaching.
