The Uncertain Future of the Great Barrier Reef

The Great Barrier Reef is undoubtedly the jewel in the crown of coral reefs worldwide. But like all coral reefs today, it faces a very uncertain future, primarily because of the impacts of climate change.

This has been highlighted in the recently released Federal Government’s National Climate Risk Assessment report. The report noted that the world is moving too slowly to reduce carbon emissions, the main driver of climate change. Currently, we are on track to reach a 2.7 degree increase in temperature by 2100, far above the 1.5 degree increase which is needed to keep coral reefs alive.

The impacts of climate change on the Reef have become very clear over the past two decades. Best known would be coral bleaching which is caused by marine heatwaves. The Reef has suffered through 5 mass bleaching events over the past 8 years.

The Australian Institute of Marine Science (AIMS) reported the most recent bleaching event (2024) was responsible for the largest ever loss of coral across the Reef. Compared to the 2024 levels, coral cover in the northern region dropped by a quarter (from 39.8% to 30%), the central region by 13.9% (from 33.2% to 28.6%), and the southern region by almost one-third (from 38.9% to 26.9%).

Another serious, but more subtle impact of climate change is ocean acidification. The ocean absorbs carbon dioxide from the atmosphere. The more carbon dioxide we pump into the atmosphere, the more the ocean absorbs. This causes the ocean to become more acidic.

Many marine animals, including corals, build their skeletons from calcium carbonate. A more acidic environment slows down the building of skeletons as well as weakens the skeleton. This makes animals more prone to damage by severe weather events like cyclones.

Speaking of cyclones, climate change will not necessarily increase the number of cyclones each year, but will likely increase the intensity of cyclones; more category 4’s and 5’s which will lead to more reef destruction.

Another well-known impact of climate change is sea level rise. This is not good news for our low-lying seaside communities. But sea level rise will also impact our intertidal environment, mangrove forests and seagrass meadows, which are very important nursery grounds for many fish species. Mangrove forests also help stabilise and protect our coastline from storm damage.

The future of our Great Barrier Reef does look bleak. But the Reef’s destiny is not written in stone. At least not yet. To give the Reef a fighting chance, we must rapidly reduce our carbon emissions.

Our Federal Government has just released their new carbon reduction target of 62-70% by 2035 (compared to 2005 levels). This is an improvement from the previous target of 43%, but considered timid and will not save the Reef. We need to continue pushing for more.

Most scientists agree that nett zero by 2035 is the only way to give the Reef a fighting chance to survive.

The Great Barrier Reef is worth fighting for.

Contributed with thanks to Whitsunday Conservation Council.

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Photo supplied.

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