Temperature rise will be ‘catastrophic’ for coral reefs

Limiting temperature rise to 1.5°C above pre-industrial levels will still be catastrophic for coral reefs, new research suggests. 

The new research, led by the University of Leeds, suggests that the future of coral is even worse than predicted by the Intergovernmental Panel on Climate Change (IPCC), which reported in 2018 that 1.5 degrees of warming would cause 70-90% of coral reefs to decline. 

In the past few decades, 84% of the world’s tropical coral reefs have had enough time to recover between heat waves that cause bleaching mortality.

But the research team, which included colleagues from Australia and the United States, has found that even at 1.5°C, only 0.2% of reefs will have sufficient recovery time between heat events and 90.6% of reefs will suffer intolerable thermal stress.

Heat stress causes the decline of all reef species and reduces food and livelihood opportunities for people.

The authors state that coral reef survival will require significant and urgent action globally to reduce greenhouse gas emissions. 

Lead author Adele Dixon, a PhD researcher in the School of Biology, said: ‘Our finding reinforces the stark reality that there is no safe limit of global warming for coral reefs. Following COP26 in Glasgow in which some progress was made towards the 1.5°C target, our finding shows that 1.5°C is still a substantial amount of warming for the ecosystems on the frontline of climate change.’

There are ‘hope sites’ that have high variability in temperatures, such as in the Eastern Pacific. These areas may be better able to cope with temperature extremes.

Scott Heron, Associate Professor in Physics at the ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, Australia, added: ‘This analysis confirms that significant action on greenhouse gas emissions is urgent, with significant action needed this decade, but we also need to ramp up local management actions to help reefs survive through predicted impacts.’