Commentary: The Great Barrier Reef is dying and that’s the tipping point of global warming – CNA
Zooks benefit corals by giving them energy and colour, and in return the coral gives them a home in the coral tissue. Under stress, such as in too-hot water, the algae produce toxins instead of nutrition, and the coral ejects them.
Without the algae, the corals begin to starve. They lose their vibrant colours, revealing the bright white limestone skeleton through the coral tissue. If stress conditions abate, the algae can return and coral can recover over months. But if stress persists, the corals can die – the skeletons begin to crumble, removing vital habitat for other species.
WE HAD HOPED FOR A REPRIEVE
Scientists and managers had hoped for a reprieve this year. Much of the Great Barrier Reef was in the early stages of recovery following the 2016, 2017, and 2020 bleaching events.
In the tropical paradise of northern Queensland, we’ve been wishing for cloudy days and cooler temperatures, hoping for rain and even storms (but not big ones). These conditions typically come with La Niña – a natural climate phenomenon associated with cooler, wetter weather, which has now happened two years in a row.
But despite these effects of La Niña, climate change meant 2021 was one of the hottest years on record. Now, at the tail end of Australia’s summer, the reef is experiencing another marine heatwave and is tipping over the bleaching threshold.