A brave new world for coral reefs

Scientists say that the reefs we know today are changing rapidly as they struggle to cope with the combined impacts of global warming, overfishing and pollution. “The reefs of the future will be radically different from today or 30 years ago,” says Professor Terry Hughes, Director of the ARC Centre of Excellence for Coral Reef Studies (Coral CoE). He led the study on reef futures and their capacity for rapid shifts. “But, if we take the right steps immediately, we can - and must - secure a future for reefs, recognising that the possibility of restoring them to their former condition is no longer possible.”

“Current approaches to protecting coral reefs are failing because too often we ignore the real reasons for their decline,” says co-author Professor Josh Cinner, also from the Coral CoE. “We need to understand why they are declining, and encourage changes in human behaviour to sustain reefs for the future.”

“It’s death by a thousand cuts,” remarked co-author Professor Jeremy Jackson, from the Smithsonian Tropical Research Institute. “Reefs suffer simultaneously from dredging, overharvesting, pollution, sewage, sediments, and steadily increasing temperatures.”

These combined elements are transforming reefs into new configurations, where the mix of species is rapidly changing. According to the scientists, navigating this transition will require radical shifts in the science, management and governance of reefs worldwide.

“We can’t save every species or turn back history,” Prof. Hughes explained. “The challenge now is to steer reefs into the future, to ensure that they remain fully functional, and to retain their ability to support the livelihoods and wellbeing of the 100s of millions of people who depend on them.”

Professor Steve Palumbi, Director of Stanford University’s Hopkins Marine Station, adds, “Coral species themselves are changing, evolving, adapting at a huge scale.” “Their ability to change rapidly is an asset for us – the corals that live on warmer reefs now may be better prepared for future conditions. And every asset we have is important to use,” he said.

“The window of opportunity to save reefs remains open, but it is closing rapidly,” the scientists say. “One degree of average global warming has already caused three global coral bleaching events, so +1.5 or +2C will radically change reefs for centuries to come.”

The scientists base their future vision on the COP21 Paris agreement. Reefs will run the gauntlet of climate change over coming decades as ocean temperatures continue to climb. However, some areas will warm less than others, and under the COP21 Paris Agreement, the most extreme future temperature rises and severe impacts of ocean acidification will be avoided.

Prof. Hughes is emphatic about the importance of COP21 to reefs: “They’ll be different, but recognisable as coral reefs. However, if COP21 fails badly, coral reefs as we know them today will be destroyed.”

These findings are presented in a major article published in an Insight on Biodiversity in this week’s Nature.

Text: Wageningen University & Research
Photos: Holobionics, Wikimedia Commons, CC BY-SA 4.0; Richard Ling, Wikimedia Commons, CC BY-SA 3.0