Coral bleaching in the Great Barrier Reef off Queensland, Australia
Nature Picture Library/Alamy
Efforts to protect Australia’s Great Barrier Reef from the damaging effects of rising temperatures have become increasingly urgent, according to a recent study. Scientists have found that changes in shipping fuels have heightened the risk of coral bleaching in the region.
In recent years, the Great Barrier Reef has experienced extensive bleaching due to the warming of sea temperatures caused by climate change.
Research conducted by Robert Ryan from the University of Melbourne indicates that alterations in shipping fuel regulations in 2020 have exacerbated the situation. While these changes aimed to reduce sulphur dioxide emissions, a harmful pollutant, they inadvertently eliminated aerosols that play a crucial role in enhancing the cooling effect of marine clouds above the reef.
Using computer models, Ryan and his team simulated the impact of these fuel changes on cloud cover and solar radiation over the Great Barrier Reef in February 2022. Their findings suggest that the reduction of sulphate aerosols from shipping emissions has led to a significant increase in sea surface temperature, making coral bleaching events more likely.
“The decrease in shipping sulphate aerosols has contributed to conditions that favor coral bleaching events at the Great Barrier Reef,” explains Ryan.
Bjørn Samset from the Center for International Climate Research in Oslo acknowledges the study’s significance in highlighting the impact of aerosol reduction on local environments. He emphasizes the need for further research to understand the role of aerosols in marine heatwaves.
As a response to these findings, Ryan and his team are exploring the concept of marine cloud brightening (MCB) as a potential solution to cool the reef artificially. This technique involves dispersing sea salt particles into the air to enhance the cooling effect of marine clouds.
Daniel Harrison, a researcher at Southern Cross University, believes that MCB could effectively mitigate the effects of coral bleaching on the reef, especially considering the cooling impact of shipping emissions. He has secured funding for a project to trial MCB at the Great Barrier Reef over the next five years.
However, not all experts are convinced of the feasibility of MCB as a solution. Terry Hughes from James Cook University remains skeptical, citing previous unsuccessful attempts to reduce sea temperatures through MCB trials. Despite differing opinions, the urgency to protect the Great Barrier Reef remains a top priority.
