Half of the world’s coral reefs may face unsuitable conditions by 2035

There is more bad news for planet Earth if climate change continues unabated. New research published October 11 in the open access journal PLOS Biology Researchers from the University of Hawai’i in Mānoa, United States, show that, at worst, half of the world’s coral reef ecosystems will be permanently exposed to unsuitable conditions in just 12 years.

The ability of ecosystems to adapt to changes in their environment largely depends on the type and impact of their specific environmental stressors. Coral reefs are especially sensitive to these unsuitable environmental conditions. However, the timetable for environmental suitability has been questioned.

Using CMIP5, an experimental framework designed to calculate global models designed to improve knowledge about climate change, researchers looked at global projections of five environmental stressors, from historical scenarios to projections for the year 2100. These stressors included more sea surface temperature, ocean acidification, tropical storm, land use and human population projections.

“While the negative effects of climate change on coral reefs are well known, this research shows that they are actually worse than expected due to a broad combination of climate change-induced stressors,” said lead author Renee Setter, a doctoral student at the university. from Hawaii in Manoa. “It was also enlightening to discover that coral would face multiple stressors — posing an even greater hurdle and challenge that would have to be overcome to increase its chance of survival.”

Setter and colleagues found that, in the business-as-usual scenario, 2050 is the median year when environmental conditions are expected to become unsuitable for the world’s coral reefs when looking at a single stressor. When multiple stressors are considered, the date falls to 2035. In addition, by 2055 it is projected that the majority of the world’s coral reefs (99%) will experience unsuitable conditions based on at least one of the five stressors studied. By 2100, 93% of global reefs are expected to be threatened by two or more of the stressors identified by the researchers.

“We know that corals are vulnerable to rising sea temperatures and marine heat waves due to climate change. But it is important to include the full anthropogenic impact and numerous stressors to which coral reefs are exposed to better understand the overall risks to these ecosystems,” added co-author Erik Franklin, Associate Research Professor at the University of Hawai’i at Mānoa. “This has major implications for our local Hawaiian reefs that are essential to local biodiversity, culture, fisheries and tourism.”

The research team is now preparing for the next phase of their work. They will take a closer look at how climate change is expected to affect individual coral species. By identifying which species are more likely to survive inappropriate conditions and which are more vulnerable, the team hopes to better understand which species may be more at risk from future stressors.