Coral reefs have long suffered from overfishing, water pollution, and land clearing . However, climate change is now the biggest threat . Climate change affects coral reefs in many ways, including more frequent severe storms [4, 8], but the most serious is recurrent “coral bleaching” .
Corals have a close relationship with algae. The algae give the coral sugars, and in return get a safe home in the coral . Under high temperatures, the coral expels the algae, leaving just the white ‘skeleton’ of the coral. This is called coral bleaching .
Bleached corals aren’t necessarily dead. They can survive for a short period, and if the temperature returns to normal, the algae will come back and the corals regain their colour . However, bleached corals are weak and vulnerable to disease , often resulting in their death .
Half of the Great Barrier Reef DIED due to bleaching in 2016 and 2017 [6, 9]. While bleaching is a natural event, climate change makes it happen more often [6, 7]. Damaged reefs can take over 10 years to recover, so bleaching one year after another may make recovery impossible [6, 8].
100% of coral is expected to die with 2°C of warming . This would have much more severe consequences than the loss of the beautiful corals themselves: over 25% of fish species use coral reefs for food or shelter [1,9]. So, when corals die, many other animals die with them. This is called an ‘extinction-cascade’ . It will also have effects on humans: coral reefs currently give protection from flooding and provide food for about 500 million people .
If 2°C warming kills all coral reefs, try to imagine what 3°C or 4°C would do. This is where the Earth is headed if we don’t drastically change .
Join our Newsletter!
Climate Science is registered as a non-profit company limited by guarantee in England and Wales.
Copyright © 2019-2020 Climate Science Ltd. All rights reserved.