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Bleached coral on Lizard Island, Queensland © WWF-Aus / Alexander Vail

Coral bleaching on the Reef

Australia’s Great Barrier Reef is one of the seven natural wonders on our planet. It’s renowned for its beauty, diversity, spectacular marine wildlife and vibrant corals. The dazzling display attracts millions of tourists who travel all over the world to witness this magnificent and unique reef system.

But rising sea temperatures due to climate change threatens all of that. It’s estimated that half of the world’s coral reefs have been lost to coral bleaching over the last 30 years.

 

  • What is coral bleaching?

    The vibrant colours of corals come from algae that live inside their tissues. It gives corals energy, allowing them to grow and flourish.


    When water temperatures are are too hot for too long, corals expel the algae which causes them to turn white.

     

    Though they can recover from bleaching, if bleached corals are exposed to warmer water for eight weeks or more, they become vulnerable to diseases and begin to die.

     

  • Causes of coral bleaching

    Coral bleaching is the ghostly face of climate change. Corals are paying the price for our reliance on mining and burning fossil fuels like coal and gas.

    As carbon pollution is emitted into Earth’s atmosphere, it traps heat and causes temperatures to rise. The ocean then becomes warmer, resulting in heatwaves that cause stress to corals.

     

    Ocean heatwaves can destroy entire reef ecosystems and the marine life that depend on healthy, thriving corals.

     

  • How can we stop it?

    Back-to-back mass bleaching events in 2016 and 2017 wiped out half of the shallow corals on the Great Barrier Reef.


    If carbon pollution isn’t reduced, climate change is expected to cause more frequent and severe coral bleaching on the Reef.

    Coral reefs are incredibly resilient but their full recovery can take decades.

    That’s why it’s important to take action and make a rapid shift towards renewable energy before it’s too late.

 

 

  • For the first time researchers recorded severe coral bleaching events on coral reefs in every region of the world, with 16% of corals killed around the world.

    Half the reefs on the Great Barrier Reef were impacted.

  • The Great Barrier Reef suffers another mass bleaching event.

    As coral bleaching became an issue of world concern, universities and research institutes strived to learn more.

  • The second global mass coral bleaching event hit the world’s reefs. Luckily, the Great Barrier Reef avoided extensive damage.

  • As ocean temperatures continue to rise, experts declared the third global bleaching event was underway and that it had started in mid-2014.

  • The largest die-off of corals ever recorded on the Great Barrier Reef, with an area roughly 1,100 km long affected.

    By February 2016
    The National Oceanic and Atmospheric Administration (NOAA) confirmed we were experiencing the longest global coral bleaching event ever observed.

  • The Reef suffered mass coral bleaching for a shocking second year in a row. The fragile corals were then hit by devastating winds caused by Tropical Cyclone Debbie and polluted floodwaters.

    In just two years, an estimated two-thirds of the Reef’s corals were damaged.

  • © naturepl.com / Doug Perrine / WWF; © Troy Mayne; © WWF / James Morgan; © Shutterstock / Andrey Nosik / WWF; © Shutterstock / Debra James / WWF

Bleached coral on Lizard Island, QLD, in February 2016 © WWF-Aus / Alexander Vail

Coral bleaching in Lizard Island © WWF-Aus / Alexander Vail

2019 and beyond...


Surveys showed that in the past two decades, 91% of corals were found to have been bleached at least once.

So what does the future look like for the Great Barrier Reef?

Though corals have a good capacity to bounce back from bleaching, it can take decades for them to fully recover after severe bleaching events.

As Earth’s climate continues to rise and severe weather events occur more frequently, carbon emissions must be curbed if we’re to ensure protection for the Great Barrier Reef.
Large export vessels are loaded with coal and other cargo at the Gladstone Port. Queensland, Australia.

Large export vessels are loaded with coal at Gladstone Port in Queensland, Australia © WWF / James Morgan

Coral, coal and climate change


Australia’s energy needs are largely met by fossil fuels, including coal, oil and gas. But our reliance on these energy sources is placing the Great Barrier Reef in danger of extinction.

The mining and burning of fossil fuels contributes to our warming climate, trapping heat within our atmosphere and causing ocean temperatures to increase and corals to bleach.

With coal accounting for 75% of the country’s energy production, more needs to be done to shift our country towards renewable energy sources.
Solar panels and wind turbines generating electricity in solar power station © Shutterstock / Soonthorn Wongsaita / WWF

Wind and solar power © Shutterstock / Soonthorn Wongsaita / WWF

100% renewable electricity by 2035


Maintaining a healthy, rich and vibrant Reef is possible if we make a rapid shift towards clean, renewable energy, like solar and wind power. This involves setting a target of 100% renewable energy by 2035 and putting an end to fossil fuel subsidies.

WWF-Australia is campaigning for improved climate policies and urges countries globally to embrace a future powered by renewable energy.

Take action on climate change today - send a message to key politicians and urge them to do more to meet and exceed Australia’s commitment to the Paris Climate Agreement.
A worker injects a crown of thorns starfish in Cairns, Australia.

A crown of thorns starfish being injected by a worker with a toxin developed at the James Cook University © WWF / James Morgan

What is WWF doing to improve water quality?


Coral bleaching isn’t the only issue for the Great Barrier Reef. Chemical run-off from poor farming practices is impacting the Reef’s water quality.

This nitrogen filled pollution smothers corals, blocking them from sunlight and fueling algal blooms, which drives outbreaks of the coral-eating crown of thorns starfish.


Beyond addressing global warming, WWF-Australia is dedicated to helping repair land surrounding the Great Barrier Reef, advocating for laws to reduce pollution, working with Queensland farmers to adopt sustainable farming practices and proper fisheries management.

Reef crest dominated by robust branching corals and coralline algae, Great Barrief Reef © WWF / James Morgan
 

© Darren Jew

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