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Barrier Reef report reveals first mass bleaching in a La Nina cycle

Melissa Iaria, May 11, 2022 7:00PM Kids News

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Aerial surveys found 91 per cent of 719 reefs assessed showed some bleaching, according to the Reef Snapshot: Summer 2021-22 report. Pictured is coral bleaching on Stanley Reef, Great Barrier Reef, as at 23 March, 2022. Picture: Harriet Spark media_cameraAerial surveys found 91 per cent of 719 reefs assessed showed some bleaching, according to the Reef Snapshot: Summer 2021-22 report. Pictured is coral bleaching on Stanley Reef, Great Barrier Reef, as at 23 March, 2022. Picture: Harriet Spark

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Above average water temperatures led to a mass coral bleaching* of the Great Barrier Reef over summer, as the Aussie icon was impacted by “escalating*” climate change, a new report has revealed.

The Great Barrier Reef Marine Park Authority (GBRM) in March confirmed a sixth mass bleaching event on the Great Barrier Reef – the fourth such event since 2016.

Unusually, it was the first mass bleaching event to occur under La Nina conditions, which are typically cooler.

Aerial surveys found 91 per cent of 719 reefs assessed showed some bleaching, according to the long-awaited Reef Snapshot: Summer 2021-22 report released late on Tuesday.

Bleaching media_cameraLast summer marked the first time a mass bleaching event has occurred on the reef during a La Nina weather cycle, which generally brings cooler temperatures. Picture: Harriet Spark

The report is a joint initiative of the Australian Government’s lead management and science agencies for the Great Barrier Reef: the Great Barrier Reef Marine Park Authority, the Australian Institute of Marine Science and CSIRO.

The release of the report, which reveals how the reef fared over the past summer, was delayed and published late on Tuesday amid calls for its release before the May 21 federal election.

The snapshot said a “marine heatwave” was the one major pressure affecting the Great Barrier Reef compared with previous summers.

Waters warmed early in December 2021, exceeding historical summer maximums that typically occurred in the hottest summer months.

Ocean temperatures continued to accumulate heat throughout the summer until early April 2022, with three distinct heatwaves increasing thermal* stress throughout the reef’s central and northern parts.

Bleaching media_cameraWarmer waters in December 2021 continued until early April 2022, increasing thermal stress on the reef. Picture: Harriet Spark

“This prolonged* heat exposure led to a mass bleaching of coral across the Great Barrier Reef; the fourth to occur in seven years,” the report said.

Bleached corals are still living but stressed. Low or moderately bleached corals have a higher chance of recovering if there are minimal impacts in following years.

Severely bleached corals have higher mortality* rates.

The report said climate change remained the reef’s greatest threat.

“It influences weather patterns and the ocean’s temperature, pH level and currents as well as intensifying the effects of other threats,” it said.

“Climate change is escalating, and the reef is already experiencing the consequences of this.

“Unfortunately, the events that cause disturbances on the reef are becoming more frequent, leaving less time for coral recovery.”

media_cameraThe report said that disturbances on the reef are becoming more frequent, leaving less time for coral recovery.” Picture: Glenn Nicholls/AFP

The aerial surveys by the GBRM and the Australian Institute of Marine Science in late March analysed a sample of 719 reefs between the Torres Strait and the Capricorn Bunker Group in the Great Barrier Reef Marine Park.

A total of 654, or 91 per cent, showed some bleaching, with the impact minor to severe.

The report said underwater surveys would be critical to understanding the fate of bleached coral.

Climate Council director of research Dr Simon Bradshaw said the report confirmed that the reef was “in serious trouble”.

“The reef’s very survival, and all the jobs and industries that depend on it, requires a major step up on climate action now and during this next term of government, starting with a credible plan to rapidly reduce Australia’s greenhouse gas emissions – not 30 years from now, this decade,” Dr Bradshaw said.

“Climate change is front of mind for voters this election. They are counting on our next Federal Government to show true leadership. Australians deserve a government that will work hard to give our reef a fighting chance.”

media_cameraClimate Council director of research Dr Simon Bradshaw said a credible plan to reduce Australia’s greenhouse emissions was needed “not 30 years from now, this decade.” Picture: supplied

Australian Marine Conservation* Society Great Barrier Reef campaign manager Dr Lissa Schindler said although the ALP had a better emissions* reduction target than the Coalition, both major political parties’ climate goals fell short when it came to the reef.

“They are not enough for the 64,000 people working in reef tourism and connected industries, not for the millions from around the world who have visited or want to visit the reef,” she said. “This is an Australian icon that we must do everything within our power to protect.

“By taking the action required and embracing the huge opportunities of the renewable* energy revolution in Australia, we can help protect tens of thousands of reef jobs and create thousands more in clean energy.”

Additional reporting by David Mills

GLOSSARY

  • coral bleaching: whitening due to stresses like changes in temperature, light, or nutrients
  • thermal: relating to heat and temperature
  • prolonged: continuing for a long time
  • mortality: death, condition of being mortal
  • conservation: protecting Earth’s natural resources for current and future generations
  • emissions: substances released into the air like gas, heat and light
  • renewable: clean energy from natural sources or processes that are constantly replenished

EXTRA READING

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Reef avoids ‘in danger’ listing for now

QUICK QUIZ

  1. How many bleaching events have occurred since 2016?
  2. Of 719 assessed reefs, what percentage showed signs of some bleaching?
  3. According to the report, what remains the reef’s biggest threat
  4. Approximately how many people work in reef tourism and connected industries?
  5. The aerial surveys of 719 reefs stretched from the Torres Strait to where?

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CLASSROOM ACTIVITIES
1. Create a diagram
Create a diagram that will help younger kids understand the most important information about the problems caused by climate change for the Great Barrier Reef

Time: allow 30 minutes to complete this activity
Curriculum Links: English; Science; Geography

2. Extension
If you could speak to the candidates in the federal election about what needs to be done to save the Great Barrier Reef and why it’s so important, what would you say? Write the speech that you would give.

Time: allow 25 minutes to complete this activity
Curriculum Links: English; Civics and Citizenship; Science

VCOP ACTIVITY
Down-level it
When you up-level a sentence, you do things to it to improve it: make it more interesting, or more complex.

But sometimes when we read something, it can be too complex and we don’t understand it very well. If you ask someone to explain it to you and they do it in a simpler way, you might think, “Well, why didn’t they just say that?”

Go through the article and find a sentence or two that is complex or hard to read.

Ask an adult what it means, or try and look up some of the words in the glossary.

Once you know what the sentence means, see if you can rewrite it in a simpler, down-level way, but make sure you don’t change the meaning of the sentence in any way.

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