Researcher wants to brighten clouds to rescue reef
Within days, oceanographer Daniel Harrison will become a father for the first time. Worried that his son may never experience the kaleidoscopic marvels of the Great Barrier Reef, he has devised an ingenious plan to help save it.
Harrison is developing a technology known as ‘‘cloud brightening’’ – encouraging clouds over the reef to deflect more of the sun’s rays back into space, which would hopefully curb rising sea temperatures that cause coral bleaching.
The reality is dawning that even swift global action on climate change is unlikely to save the Great Barrier Reef, because several decades of elevated global temperatures are already locked in.
Scientists fear swift action on climate change will not be enough to save the reef and are looking for short-term ways to restore it.
Scientific solutions are needed to buy the reef time and prevent catastrophic damage in the near future. Experts from Australia and around the world will meet at a symposium in Cairns this week to discuss the most promising and cost-effective techniques for intervention.
Harrison’s proposal is similar to that of a snow-making machine or cloud-seeding to increase rainfall for hydro power. Except in this case, the water would stay in the clouds.
Sea water would be pumped through a filter and sprayed out of small nozzles that produce minuscule water droplets.
A fan would propel the droplets into the atmosphere. The water would evaporate, leaving behind a tiny particle of salt to which other water droplets would condense, brightening existing clouds.
Aside from shading the reef, the clouds would also deflect solar radiation, potentially cooling surface water temperatures by about half a degree Celsius.
‘‘That one droplet creates an aerosol particle that then grows 15 million times in size into a cloud droplet,’’ said Harrison, a University of Sydney researcher.
Corals bleach due to a combination of higher temperatures and sunlight, so the effect of the cloud ‘‘might be very powerful in mitigating the bleaching,’’ he said.
The units would need to operate over weeks or months when coral was at most risk of bleaching. The research is at an early stage and has not yet been trialled.
Harrison said impending fatherhood had given his work new impetus.
‘‘My first child is due on Tuesday . . . I really hope the reef will be around for him to enjoy when he gets older,’’ he said.
‘‘[Losing the reef] isn’t something that’s going to happen in future generations, it’s right now in this generation if we don’t act now. It’s truly scary.’’
The project is part of the Reef Restoration and Adaptation Programme, led by the Australian Institute of Marine Science, which brings together experts to create new, targeted measures to preserve and restore the reef.
The programme’s director, David Mead, said while aggressive action on climate change was critical, scientists were asking ‘‘what else can we do?’’
‘‘We are trying as broadly as possible to assess what some of the other options might be. [We’re taking] a no-stone-unturned approach,’’ he said. – Fairfax