Great Barrier Reef Bleaching Years

This graph shows the years in which the Australian Great Barrier Reef has experienced mass bleaching.

• Before 1998, we had not recorded mass bleaching; the bleaching was infrequent and localised.
• We have had mass bleaching in 1998, 1998, 2002, 2006, 2016, 2017, 2020, 2022, 2024, and 2025.
• We have had bleaching in consecutive years on two occasions: 2016/17 and 2024/25.
• In the last 11 years, we have had 6 bleachings, i.e. 55% of the years.
• The increased intensity and frequency of mass bleaching are due to human-induced climate change.

 
(The Great Barrier Reef Foundation website provides current information about bleaching on the reef.)

(The fifth mass bleaching in eight summers: Prof Terry Hughes: The Conversation: 9 March 2024.)

We Risk Losing the Great Barrier Reef

• The single largest living marine structure on Earth
• Extends 2,300 km along the Australian coast
• Extraordinary biodiversity
• A key part of the regional ecosystem.
• Protection of the Queensland coast from the full force of the Pacific Ocean.
• A contribution of about $6.4 billion per year to the Australian economy
• About 64,000 jobs, many in tourism.

Bleaching Maps in 2016 and 2017

Here are two maps of the Australian Great Barrier Reef showing the bleached areas in 2016 and 2017.

No evident political impact

It seems that this terrible occurrence is making no ripples in our major parties, the ALP and the Coalition, and the expansion of fossil fuel activities is continuing.

The dangers of inaction

Mass coral reef bleaching is now common worldwide.

This damage is occurring with the current 1°C rise in average global air temperatures above pre-industrial levels. Governments are reacting very slowly, with some negotiating about a 2°C rise. A 2°C rise would almost certainly mean the collapse of warm-water tropical reefs around the world.

The Great Barrier Reef and other reefs worldwide will not survive unless there are rapid, deep cuts in greenhouse gas levels in the atmosphere.

Other Threats to the Reef

As well as bleaching, the reef also suffers from:

• Cyclones: The waves break the corals
• Ocean acidification, which is caused by the build-up of carbon dioxide in the atmosphere, has reduced the rates at which some corals are now building their skeletons; these rates have declined since 1990.
• Pollution, and
• Crown-of-thorns starfish.

Sources

Coral Bleaching Events
Australian Institute of Marine Science

Lethal Consequences: Climate Change Impacts of the Great Barrier
The Climate Council 2018

Reef Health: Summer 2018 – 2019
Australian Government: Great Barrier Reef Marine Park Authority

Loaded January 2019. Updated 28 July 2026.