There's still time to save the Great Barrier Reef

New research published today in the scientific journal Global Change Biology shows that adopting best management practices can help the Great Barrier Reef in a time of climate change. The study models a range of predicted outcomes for the Reef out to 2050 under different scenarios of future climate change and local management action.

“There is significant potential for coral recovery in the coming decades,” said Dr Nick Wolff, Climate Change Scientist at The Nature Conservancy. “But under a scenario of unmitigated greenhouse gas emissions and business-as-usual management of local threats, we predict that after this recovery, average coral cover on the Reef is likely to rapidly decline by 2050.

The research involved scientists from The Nature Conservancy; The University of Queensland; James Cook University; the UK’s Centre for Environment, Fisheries and Aquaculture; and the Australian Institute of Marine Science (AIMS). It modelled changes to corals that make up the Great Barrier Reef in the presence of a range of threats including cyclones, Crown-of-Thorns Starfish, nutrient runoff from rivers and warming events that drive mass coral bleaching.

The study provides much-needed clarity around how conventional management actions can support the resilience of the world’s largest coral reef ecosystem.

“If we can remove pollution and prevent outbreaks of coral-eating Crown-of-Thorns Starfish, then some areas on the Great Barrier Reef would be able to sustain their coral cover for at least the medium term,” said Dr Wolff.

The $60M package announced recently by the Federal Government including $10.4M for Crown-of-Thorns Starfish control and $36.6M for measures to reduce river pollution is a positive step. “This could buy us some critical time,” said Dr Wolff.

The Queensland and Federal Governments have the right strategy in pursuing ambitious targets for water pollution reduction by 2025. Further large-scale investments from both the private and public sectors should now be mobilised to expand and accelerate a range of innovative and tailored solutions to ensure targets are met.

Importantly though, the positive signs for the future shown in the research also depend strongly on whether the world meets the ambitious carbon emission targets of the Paris Climate Agreement.

“If global warming exceeds 1.5°C relative to preindustrial levels, then the capacity for conventional management to protect the Great Barrier Reef will diminish”, said Dr Ken Anthony from AIMS.

The study shows that in a world of unmitigated carbon emissions, the increased frequency and severity of coral bleaching events will overwhelm the capacity of corals to recover and the benefits of good management practices could then be lost.

“Our study demonstrates that the recipe for protecting coral reefs is one of urgent action on climate change AND intensified management” said Dr Wolff. “It’s not enough to implement global OR local solutions – both have to be aligned”.

The study’s results also come with an important warning: not all coral reefs can be protected by good management under climate change, even if global warming can be kept below 1.5°C.

“Global warming will continue while the world transitions to a low-emissions future”, said Dr Anthony. “This means that corals on the Great Barrier Reef could experience up to 0.4°C warmer waters in the coming decades, even under the best-case climate change scenario. This could be too much for some coral species”.

“To protect the most climate sensitive species in the hardest-hit places, we would need to consider additional and unconventional management interventions beyond carbon mitigation AND intensified management. A new innovative R&D program to develop such interventions, including ways to boost the spread of warm-adapted corals to naturally cooler parts of the Great Barrier Reef, is included in the Australian Government’s recent $60M announcement. It’s a big step in the right direction,” concluded Dr Anthony.