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Climate change is the greatest threat to the world’s coral reefs. Most coral reefs have already declined and are facing irreversible change. The action we take today will determine the Great Barrier Reef we know tomorrow. 

Every increment of global warming is compromising the Reef’s unique biodiversity, significant cultural heritage, social benefits, and the ecosystem services it provides. Urgent global action is critical to deliver on international commitments to limit temperatures to 1.5°C of warming, or as close as possible.

This will deliver the best possible future for the Great Barrier Reef and the livelihoods that depend on it.

The Threat

Human activities, principally through emissions of greenhouse gases, have indisputably caused global
warming, with 2011-2020 average global surface temperatures measured at 1.1°C above the preindustrial
(1850–1900) baseline.

Larger increases have been recorded over land (1.59°C), than over the ocean (0.88°C) (IPCC AR6 WG1 2021).

By 2021, average sea surface temperatures in the Australian region had warmed by 1.05°C since 1900, with eight of the 10 warmest years on record during 2013-2020 (CSIRO and BoM 2022).

The average sea surface temperature for the Great Barrier Reef has warmed by 0.94°C since 1900 (BoM 2023). 

Global warming of 1.5°C relative to 1850-1900 is likely to be reached by 2035 without deep and rapid reductions in emissions (Diffenbaugh & Barnes 2023).

Coral reefs are projected to decline by 70 to 90 per cent at 1.5°C of global warming and by 99 per cent at 2°C of global warming (above pre-industrial levels). 

The impacts of climate change are degrading the world’s coral reefs and significantly impacting biodiversity, primarily through ocean warming and acidification. 

All ecosystems within the Great Barrier Reef are vulnerable to the impacts of climate change (see Outlook 2019 figure).

More extreme weather events such as heatwaves, tropical cyclones, and flood events, are accelerating the degradation of coral reefs, seagrass meadows and mangrove forests.

Figure 1 - Atmospheric carbon dioxide concentration - in parts per million
Groups of species
Habitats

Marine heatwaves triggered four mass coral bleaching events on the Reef between 2016 and 2022 which is unprecedented since records began.

Extreme temperatures in 2016 killed approximately 30 per cent of the Reef’s shallow-water corals (Hughes et al 2018).

More frequent disturbances are leading to inadequate recovery windows and the loss of potential ecosystem refuges (Hughes et al 2021; Dixon et al 2022). 

The Reef will be transformed as coral reef habitats are lost over time.

Reef degradation has significant flow-on effects for Reef-dependent activities such as tourism, fishing, recreational and traditional use. Without urgent action to reduce greenhouse gas emissions, the Reef will continue to degrade, with continuing consequences for its heritage values.

The persistence of the Reef and its provision of goods and services hinges on the health and diversity of reef-building coral species, which have limited capacity to adapt.

Limiting global warming to as close to 1.5°C as possible is critical to minimising significant environmental and societal costs due to loss of Reef habitats (IPCC 2018; McWhorter et al 2022).

Reef resilience jeopardised by a rapidly changing climate

While recent recovery demonstrates that the Great Barrier Reef is still resilient, its capacity to tolerate and recover is jeopardised by a rapidly changing climate.

The relatively moderate heat stress in the bleaching events in 2020 and 2022 coupled with few other disturbances since 2018 allowed coral cover to increase from some of the lowest levels ever observed in 2017 to the highest.

This demonstrates the Reef’s resilience; its inherent capacity to tolerate and recover from disturbances. Recovery during disturbance-free periods is vital, however, it does not guarantee future stability.

Recent recovery has been dominated by fast-growing Acropora corals that are vulnerable to disturbances, evident in the Reef wide recovery “pause” reported by AIMS in 2023.

The increasing frequency and severity of climate driven disturbances means that while recent gains are most welcome, they are precarious.

This is the critical decade for climate action. To limit the impacts of climate change on the Reef, we need to see substantially less greenhouse gases released into the atmosphere, and far more being removed. We also need to strengthen actions to build resilience.

This is the critical decade for climate action. To limit the impacts of climate change on the Reef, we need to see substantially less greenhouse gases released into the atmosphere, and far more being removed. We also need to strengthen actions to build resilience.

What we’re doing to address the impacts of climate change

Strong management has protected the Reef’s capacity to tolerate and recover from impacts. This management began, and has been continued, by First Nations peoples over millennia.

As Australia’s lead management agency for the Great Barrier Reef, we are best-placed to understand what the Reef needs. We can – and will – protect the Reef by mitigating threats within our control and building Reef resilience, improving its capacity to tolerate and recover from climate-related impacts.

This will require more than business-as-usual. We will build on 45 years of adaptive management that has responded to all emerging threats to the Reef to deliver innovative, agile, and resilience-based actions.

First Nations peoples have an intrinsic connection to the Reef and we acknowledge their inherent rights and interests in the amplification of their voices in relation to climate change.

The Great Barrier Reef Blueprint for Climate Resilience and Adaptation (Blueprint 2030) will drive how we adapt our management and help us innovate and evolve how we protect the Reef’s resilience and set the gold standard for Marine Park management.

Blueprint 2030 focuses on the entire Reef ecosystem – beyond corals and coral reefs (the focus of Blueprint 2017). It includes five goals that will help us buy time for the Reef, while we encourage and advocate for greater action to mitigate and remove carbon from the atmosphere.

  • We will:
  • Protect the Reef’s resilience
  • Enhance the Reef Authority’s capability
  • Co-manage Sea Country with Traditional Owners
  • Empower others to protect and manage the Reef
  • Do our part to reduce emissions

What needs to be done

In 2015, 195 countries committed to the Paris Agreement to hold the increase in the global average temperature to well below 2°C above pre-industrial levels and pursue efforts to limit the temperature increase to 1.5°C above
pre-industrial levels.

Despite this, global greenhouse gas emissions have continued to rise and exceed record levels.

The adverse impacts and related damage from climate change will escalate with every increment of global warming.

Every bit of warming prevented is critical and may prevent irreversible damage and provide a better possible future for the Reef.

  • You can take action today to protect the Reef for tomorrow:
  • All emissions matter. Your actions count.
  • Learn about what contributes to climate change and what can be done about it.
  • Talk about climate change, what you’re doing and what else can be done with people you know.
  • Reduce your emissions through daily choices such as using renewable energy sources, eating fewer animal products, and choosing low or zero emission transportation.
  • Be a conscious consumer – prioritise sustainability when purchasing or investing.
  • Abide by rules put into place to protect natural environments.
  • Get involved in conservation actions in your local area.

The future of the Reef will be better if we all act together.

The legacy we leave for future generations is in our hands and the time to act is now.
Created
Updated 11 Feb 2024
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