Please select your home edition
Edition
Pantaenius 2022 - SAIL & POWER 2 LEADERBOARD ROW

Global warming is transforming Great Barrier Reef

by coralcoe.org.au 5 May 2018 06:27 UTC
A severely bleached acroporid colony amongst the minimally bleached Porites colonies © ARC Centre of Excellence for Coral Reef Studies / Gergely Torda

A new study published online today in Nature shows that corals on the northern Great Barrier Reef experienced a catastrophic die-off following the extended marine heatwave of 2016.

"When corals bleach from a heatwave, they can either survive and regain their colour slowly as the temperature drops, or they can die. Averaged across the whole Great Barrier Reef, we lost 30 per cent of the corals in the nine month period between March and November 2016," said Prof Terry Hughes, Director of the ARC Centre of Excellence for Coral Reef Studies (Coral CoE).

The scientists mapped the geographical pattern of heat exposure from satellites, and measured coral survival along the 2,300-km length of the Great Barrier Reef following the extreme marine heatwave of 2016.

The amount of coral death they measured was closely linked to the amount of bleaching and level of heat exposure, with the northern third of the Great Barrier Reef being the most severely affected. The study found that 29 per cent of the 3,863 reefs comprising the world's largest reef system lost two-thirds or more of their corals, transforming the ability of these reefs to sustain full ecological functioning.

"The coral die-off has caused radical changes in the mix of coral species on hundreds of individual reefs, where mature and diverse reef communities are being transformed into more degraded systems, with just a few tough species remaining," said co-author Prof Andrew Baird of Coral CoE at James Cook University.

"As part of a global heat and coral bleaching event spanning 2014-2017, the Great Barrier Reef experienced severe heat stress and bleaching again in 2017, this time affecting the central region of the Great Barrier Reef," said co-author Dr Mark Eakin of the U.S. National Oceanic and Atmospheric Administration.

"We're now at a point where we've lost close to half of the corals in shallow-water habitats across the northern two-thirds of the Great Barrier Reef due to back-to-back bleaching over two consecutive years," said Prof Sean Connolly of Coral CoE at James Cook University.

"But, that still leaves a billion or so corals alive, and on average, they are tougher than the ones that died. We need to focus urgently on protecting the glass that's still half full, by helping these survivors to recover," said Prof Hughes.

The scientists say these findings reinforce the need for assessing the risk of a wide-scale collapse of reef ecosystems, especially if global action on climate change fails to limit warming to 1.5?2 degreesC above pre-industrial levels.

The study is unique because it tests the emerging framework for the International Union for Conservation of Nature (IUCN) Red List of Ecosystems, which seeks to classify vulnerable ecosystems as 'safe,' 'threatened' or 'endangered.'

"The Great Barrier Reef is certainly threatened by climate change, but it is not doomed if we deal very quickly with greenhouse gas emissions. Our study shows that coral reefs are already shifting radically in response to unprecedented heatwaves," said Prof Hughes.

The researchers warn that failure to curb climate change, causing global temperatures to rise far above 2 degreesC, will radically alter tropical reef ecosystems and undermine the benefits they provide to hundreds of millions of people, mostly in poor, rapidly-developing countries."

Related Articles

DNA reveals the past and future of coral reefs
New DNA techniques are being used to understand how coral reacted to the end of the last ice age New DNA techniques are being used to understand how coral reacted to the end of the last ice age in order to better predict how they will cope with current changes to the climate. Posted on 22 Oct 2022
The double burden of climate change
A new study on the effects of climate change in five tropical countries A new study on the effects of climate change in five tropical countries has found fisheries are in more trouble than agriculture, and poor people are in the most danger. Posted on 9 Jul 2022
Fade to grey
Fish communities become duller as coral reefs die James Cook University researchers have found brightly coloured fish are becoming increasingly rare as coral declines, with the phenomenon likely to get worse in the future. Posted on 26 Mar 2022
Concerns as development threatens reefs
A stark warning about the impacts of urban growth on the world's coral reefs A new study has delivered a stark warning about the impacts of urban growth on the world's coral reefs. Posted on 10 Mar 2022
New data shows coral everywhere face catastrophe
The refuges will provide almost no escape Alarming new research shows global warming of 1.5 degreesC relative to pre-industrial levels will be catastrophic for almost all coral reefs - including those once thought of as refuges. Posted on 4 Feb 2022
Coral identity crisis
A new way to distinguish and identify coral species Researchers have found a new way to distinguish and identify coral species—providing crucial information to help manage coral reefs in a warming world. Posted on 30 Nov 2021
Corals roll with the punches
Corals may be able to cope with climate change in the coming decades A new study suggests corals may be able to cope with climate change in the coming decades better than previously thought- but will still struggle with ever-faster rates of climate change. Posted on 8 Sep 2021
Measuring conservation in a way that counts
The term 'save' in conservation needs to be better defined A new study raises questions on whether current conservation science and policy for protected areas could be saving more biodiversity—with political and economic expediency often having taken precedence in the past. Posted on 30 Jul 2021
More 'fairness' needed in conservation
A new approach is needed if protected areas are to be effective New research shows what is often assumed to be 'fair' in conservation practice may not be considered so by the very people most affected by it—and a new approach is needed if protected areas are to be effective. Posted on 12 Jun 2021
Time running out to save coral reefs
A window of opportunity to save the world's coral reefs - but time is running out New research on the growth rates of coral reefs shows there is still a window of opportunity to save the world's coral reefs - but time is running out. Posted on 13 May 2021
Cure Marine - Cure 55 - FooterCrewsaver 2021 Safetyline FOOTERSelden 2020 - FOOTER