Climate change is the greatest threat to the Great Barrier Reef and coral reefs worldwide.

The Great Barrier Reef is already experiencing the consequences of climate change — most notably, two consecutive years of coral bleaching in 2016 and 2017.

Coral bleaching, and a severe tropical cyclone that occurred in 2017, impacted 80 per cent of the Reef over the last two years.The effects are likely to have far-reaching consequences for the ecosystem and its marine life, as well as its outstanding universal value as a world heritage area.

Impacts

The potential impacts of climate change are outlined in both our 2009 and 2014 Outlook Reports, as well as our strategic assessment.

The Intergovernmental Panel on Climate Change found that climate change is significantly affecting species and ecosystems around the world and this is projected to continue.

It also warned the Great Barrier Reef’s coral reef systems could be eliminated by mid-to late-century under current rates of ocean warming and acidification.

Climate change can affect many aspects of the marine environment, including:

It also presents serious implications for the communities and industries that depend on a healthy Reef for recreation and their livelihoods.

Building the resilience of the Reef is central to ensuring it can withstand threats — this is central to our work.

Changes to the climate

Earth’s climate has always been changing, from the end of ice ages to sea levels changing over millions of years. However, it is now certain the climate is changing at a rate unprecedented over decades to millennia.

The dominant cause is an increase in greenhouse gas emissions, driven by human activities that involve the burning of fossil fuels (coal, oil and natural gas), agriculture and land clearing.

Atmospheric carbon dioxide is at a concentration unprecedented within the last 800,000 years.

The rapid increase in emissions of carbon dioxide and other greenhouse gases since pre-industrial times has amplified their natural role in retaining heat in the Earth’s atmosphere.

Higher concentrations of these gases in the atmosphere, particularly carbon dioxide, trap more heat and increase Earth’s temperature.