The great barrier reef is the biggest coral reef system in the world. One can see it from outer space. It is the largest living structure made by living organisms in the world. And it is highly vulnerable. In the past three decades, it has lost half its coral cover, pollution has caused deadly starfish outbreaks, and global warming has produced horrific coral bleaching. Coastal development also looms as a chief threat. Huge coral bleaching events occurred in 1998 and 2002. The reef was hit especially hard in 2016 and 2017 by underwater heat waves that prompted bleaching events. This year, it is suffering a sixth mass bleaching due to heat stress caused by climate change.

But recently, two-thirds of the coral reef showed the highest recovery in the last 36 years. The recovery of the coral in the north and central regions was a sign the reef could recover from disturbances. At the same time, the loss of coral in the south demonstrated how the reef is still vulnerable to continued acute and severe interferences occurring more often and are longer-lasting. The latest results show that the reef can recover during periods free of intense disruption.

Scientists are currently exploring the possibility of making the clouds above the Great Barrier Reef larger and brighter in the hope that this will save it from further coral bleaching. Researchers believe that by manipulating low-lying clouds over the reef to be more reflective, it will have a chance to cool the affected waters by a few degrees, a critical option during any potential El Niño climate warming occurrences.

Though this piece of research is still in its early days, several groups are studying cloud brightening as a potential option for altering the climate. First presented by British scientist John Latham almost 30 years ago, the idea is that fleets of boats could spray minuscule particles of salt that have been generated from seawater into the lower-lying clouds, inducing them to expand and become denser. These thicker white clouds should then be able to reflect more of the incoming heat out into space and away from the Earth’s surface. Lathem led a study in 2012 at the University of Manchester, which found that this approach could offset the resulting heat from double the amount of carbon dioxide in the atmosphere.

Coral reefs are one of our greatest treasures. It is almost shameful how we don’t value our riches. Let us all join hands with those who are working towards protecting it.

Darshini Shah