What if climate change kills the coral reefs?

 By Amanda Saint

A new documentary just released on Netflix, Chasing Coral, documents the effects of climate change on coral reefs around the world. Unfortunately, the story is not currently a happy one, but the overarching message is one of hope if rising sea temperatures can be halted…

Coral reefs are an essential part of the earth’s delicate ecosystem and also play a big part in its economic system. Statistics from the U.S. Department of Commerce National Oceanic and Atmospheric Administration show that although they only populate a tiny fraction of the ocean they provide habitats for approximately 4,000 species of fish and 800 hard corals.
They provide billions of dollars in revenue from tourism, fishing and other commerce, and are used in medical research for cures to diseases such as cancer and arthritis and also in the fight against bacterial and viral infections.
Reefs form crucial barriers protecting coastlines from the full force of storms. The impact of losing the majority of reefs will be huge and will affect the food supply chain, the atmosphere, world economies and human health.
Marine scientists report that in the past 30 years 50 percent of them have died and many predict that by 2050 only 10 per cent will remain, even if the climate goals set in the Paris agreement are achieved.

Bleaching and recovery

UNESCO has awarded 29 coral reefs World Heritage. In a report it released in June 2017 — the first global scientific assessment of climate change impacts on World Heritage coral reefs — the findings are alarming.
Rising sea temperatures in the past three years, which have been the highest ever recorded, mean that 21 of these World Heritage reefs have been under severe and/or repeated heat stress. World famous coral reefs such as the Great Barrier Reef in Australia, and the Aldabra Atoll in the Seychelles, have seen the most severe bleaching events since records began.
But coral reefs can recover from bleaching events if the conditions are right. Reef Resilience, a network of coral reef ecosystem experts from around the world, reports that if the sea temperature fluctuations remain relatively stable, complete coral mortality from the bleaching event is low, and the reef is in overall good health before the bleaching, then it can completely recover in as little as 10 years but more likely between 15 and 25 years.

Coral bleaching in the Gulf of Thailand (Petchrung Sukpong, Flickr)

But the signs are that the conditions are not going to be right, and the analysis in the UNESCO report predicts that all 29 World Heritage coral reefs will no longer be functioning coral reef ecosystems by the end of this century if global greenhouse gas emissions are not reduced significantly, and quickly.
The potential impacts of this are huge. UNESCO estimates that the social, cultural and economic value of coral reefs is $1 trillion and that climate-related loss of reef ecosystem services will total $500 billion per year or more by 2100. Most of these losses will be felt the hardest by the communities living by and depending on coral reefs for their food and income. But it will affect us all as coral reefs also put some of the oxygen in the air that we breathe.
So can this catastrophic loss be prevented?

Reef conservation

There are many scientists and organizations working hard to help the world’s coral reefs survive. One of these is 50 Reefs, a conservation project led by The Ocean Agency and the University of Queensland‘s Global Change Institute, working with the Wildlife Conservation Society.
Rather than pin its hopes on saving them all, 50 Reefs focuses resources and conservation efforts on those reefs that are least vulnerable to climate change and have the greatest capacity to repopulate other reefs over time.
It’s starting the work with a comprehensive study led by The Centre of Excellence in Environmental Decisions at The Global Change Institute, to identify the reefs with the best chance of survival, the greatest biodiversity and the best connectivity to other reefs.
The Coral Reef Alliance started in 1994 as a small, grassroots alliance working with local communities to help them protect their reefs. It has now grown into a global organization providing comprehensive reef management plans and models that can be replicated the world over with minor adaptations to suit local environments. It has also worked hard to develop sustainable tourism practices that allow people to experience the reefs without causing lasting damage.
The annual Coral Reef Alliance Conservation Prize works to raise the profile of the people leading the way in protecting reefs and highlight the urgent need for it in people’s minds.
There is no doubt that there is an urgent need to turn things around for the coral reefs —their loss will affect the air that we breathe, the food supply chain, world economies and human health.

READ MORE: Can clouds save the Great Barrier Reef? by Chris Dalby

about the author
Amanda Saint
Journalist and content writer, specialised in engineering and technology with a focus on environmental sustainability, urbanisation and biotechnology.