Guest essay by Eric Worrall
Reef scientists claim to be worried coral bleaching will destroy the reef. But they neglect to mention a few key facts.
Rescuing the Great Barrier Reef: how much can be saved, and how can we do it?
As global heating makes coral bleaching a regular event, scientists are urgently seeking ways to help the world’s biggest reef survive.
When coral scientist Zoe Richards left the Great Barrier Reef’s Lizard Island in late January, she was feeling optimistic.
Richards is a taxonomist. Since 2011 she has recorded and monitored 245 coral species at 14 locations around the island’s research station, about 270km north of Cairns.
In 2017 she saw “mass destruction of the reef”. Back-to-back mass bleaching in 2016 and 2017, and cyclones in 2014 and 2015, had wreaked havoc.
But in January, she saw thousands of new colonies of fast-growing Acropora corals that had “claimed the space” left by dead and degraded corals. In a three-year window without spiralling heat or churning cyclones, some corals were in an adolescent bloom – not mature enough to spawn, but getting close.
“It was an incredible recovery,” says Richards, of Curtin University. “But I knew if it was hit again, it would be trouble – and that’s exactly what happened.”
The “incredible recovery” is the clue. Corals are highly mobile, highly adaptable and resilient organisms. The larval form of Coral is a free swimming organism, which can actively seek a location to settle. Reef coral has repeated demonstrated its resilience, by surviving multiple mass extinctions including the event which killed the dinosaurs.
The Great Barrier Reef is only 6-8000 years old. 6-8000 years ago, the age of the Holocene Optimum, sea levels were 2m higher than today. Since the Holocene Optimum sea levels have dropped as the polar ice sheets expanded, yet the reef endured, continuously shifting to more favourable sites, as it has always done in response to changed circumstances.
Even if global warming does eventually kill off part of the Great Barrier Reef, this die off will be balanced by an expansion of the colder Southern end of the Great Barrier Reef, as warm water corals successfully invade cooler waters made habitable by global warming.
The reef does not need “rescuing”, any more than the weeds in your garden need rescuing.