Fears for future of Great Barrier Reef despite new coral growth

Increased coral coverage has been recorded at 36 Great Barrier Reef sites in 2022, as part of a long-term monitoring program.

Northern and central regions of the marine park were found to have the highest amount of coral cover since the Australian Institute of Marine Science (AIMS) began monitoring 36 years ago.

Despite this sliver of good news, scientists remain concerned about climate change driving bleaching at the southern end of the reef.

Left - brown coral at the southern end of the reef. Right - colourful coral at the northern end.
The southern end of the reef (left) has lost more coral than the northern end (right) Source: AIMS

Mass bleaching events occurred in 1998, 2002, 2016, 2017, 2020 and 2022 and were likely fuelled by climate change. The majority of AIMS' data was collected prior to the 2022 event.

Much of the new coral coverage is from the genus acropora, which is fast growing after disturbance but is also vulnerable to extreme weather events and predators, making the overall structure of areas it dominates more sensitive.

What the results reveal:

  • Southern end decrease from 38 per cent in 2021 to 34 per cent.

  • Cooktown region increase from 27 per cent in 2021 to 36 per cent.

  • Central end increase from 26 per cent in 2021 to 33 per cent.

Why the Great Barrier Reef is still in trouble

The report has been released as the Great Barrier Reef's UNESCO World Heritage listing remains under a cloud.

AIMS CEO Dr Paul Hardisty said while the survey shows the reef can recover when free of disturbance, crown of thorns starfish and coral bleaching are continuing to pose a threat.

Graphs comparing coral coverage at the northern and southern ends.
The northern region of the Great Barrier Reef has shown an increase in coral, while the southern end has lost coverage. Source: AIMS

“In our 36 years of monitoring the condition of the Great Barrier Reef we have not seen bleaching events so close together,” he said.

“Every summer the Reef is at risk of temperature stress, bleaching and potentially mortality and our understanding of how the ecosystem responds to that is still developing.”

What rising temperatures mean for coral

This week, Great Barrier Reef Marine Park Authority (GBRMPA) chief scientist Dr David Wachenfeld told Yahoo News Australia he remains concerned about the impact of climate change.

Great Barrier Reef monitoring has been underway for 36 years. Source: AIMS
Great Barrier Reef monitoring has been underway for 36 years. Source: AIMS

With global heating resulting in average temperatures 1.1 degrees warmer than the preindustrial average, marine heatwaves are more severe and they’re being experienced more frequently.

An IPCC prediction suggests heating could rise to 1.5 degrees by the early 2030s, a decade earlier than expected, which Dr Wachenfeld said will “not be good for coral reefs”.

“The concern, of course, is that we haven't stabilised the temperature where we are still increasing, we’re still emitting greenhouse gas emissions, the temperatures are still going up,” he said.

“Even if all the governments in the world meet the commitments that they've made, we are looking at being 2.6 to 2.7 degrees warmer than pre-industrial by the end of the century."

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