It is unlikely that corals can adapt to climate change

Nov 29. () –

Corals’ adaptation to warming oceans and marine heat waves will likely be outpaced if global greenhouse gas emissions are not rapidly reduced.

A new study, led by Dr Liam Lachs from Newcastle University, reveals that corals’ adaptation to heat tolerance through natural selection could keep pace with ocean warming, but only if the commitments of the Paris Agreement are metwhich limit global warming to two degrees Celsius.

“The reality is that marine heatwaves are triggering mass coral bleaching mortality events in the world’s shallow tropical reef ecosystems, and the increasing frequency and intensity of these events will increase due to climate change,” said Dr . in a statement.

“While emerging experimental research indicates that there is room for adaptation in the ability of corals to tolerate and survive thermal stress, a fundamental question remains for corals: can adaptation through natural selection keep pace with the global warming? Our study shows that the adaptation window is likely to be exceeded by moderate to high levels of warming”

The international team of scientists studied Palau corals in the western Pacific Ocean and developed an eco-evolutionary simulation model of coral populations.

This model incorporates data on the thermal and evolutionary biology of common but heat-sensitive corals, as well as their ecology. Published in Science magazinethe study simulates the consequences of alternative futures of global development and fossil fuel use created by the Intergovernmental Panel on Climate Change.

Professor Peter Mumby, co-author of the study from the University of Queensland, explains that “our world is expected to warm between 3 and 5 degrees by the end of this century if we do not meet the commitments of the Paris Agreement. At these levels of warming , “Natural selection may be insufficient to ensure the survival of some of the most sensitive but important coral species.”

“We can still have fairly healthy corals in the future, but this requires more aggressive reductions in global emissions and strategic approaches to coral reef management.”

Dr. Lachs explains that “with current climate policies, we are on track for an intermediate emissions scenario, leading to around 3°C of warming, in which natural selection for heat tolerance could determine whether some coral populations survive.”

“From modeling this current emissions scenario, we expect to see profound reductions in reef health and an elevated risk of local extinction for heat-sensitive coral species. We also recognize that there remains considerable uncertainty in the ‘ evolutionary capacity’ of coral populations”.

Dr James Guest, co-author of the study and director of the Coralassist Laboratory, says there is an urgent need to understand how to design smart management options for coral reefs.

“We need management actions that can maximize the natural capacity for genetic adaptation, and at the same time explore whether it will be possible to increase the probability of adaptation in wild populations.”

“One such option, which is still in experimental stages to date, would be the use of targeted assisted evolution interventions that could, for example, improve heat tolerance through selective breeding,” said Dr. Guest, referring to an independent article recently published by the Coralassist Laboratory.

Coral reefs are remarkably diverse and critically important marine ecosystems. “Taken together,” says Dr. Lachs, “our modeling results suggest that genetic adaptation could offset some of the projected loss of coral reef functioning and biodiversity during the 21st century. whether rapid climate action can be achieved“.