Climate change could destroy almost all of the Earth's coral reef habitats by 2100, according to new research.
About 70 to 90% of all existing coral reefs are expected to disappear in the next 20 years due to ocean warming, acidic water and pollution, said scientists at the University of Hawaii Manoa, who presented their findings on Monday in an ocean sciences conference.
"Until 2100, it looks pretty bleak," said Renee Setter, one of the researchers at the University of Hawaii in Manoa, in a press release.
Some environmental activists and coral reef researchers have been working on coral restoration – growing live corals in a laboratory and then placing them back in marine environments to try to revive the dying reefs. But that may not be enough to save Earth's reefs, the researchers warned.
The new study mapped areas of the ocean best suited to this type of coral restoration, taking into account factors such as acidity, water temperature, human population density and fishing frequency.
After examining the world's oceans, they came to a bleak conclusion: "By 2100, few to zero suitable coral habitats will remain."
Most of the ocean where coral reefs live today will not be adequate until 2045 – and the health and condition of these environments will only worsen until 2100, according to the team's simulations.
"Honestly, most of the sites are gone," Setter said in the press release. There may only be a few viable sites for coral reef restoration by 2100, such as portions of Baja California and the Red Sea – but even these are not ideal reef habitats because they are close to rivers.
The researchers warned that climate change was the big killer – human pollution, while a problem, is only a small part of the bigger threat.
"Trying to clean the beaches is great and trying to fight pollution is fantastic. We need to continue these efforts," said Setter in the statement. "But in the end, it is really necessary to fight climate change to protect corals and avoid compound stressors."
Coral reefs die
Scientists have warned for years that the world's reefs are moving towards "massive death" and a "planetary catastrophe" as warming and acidifying the oceans kill entire strips of reefs.
The 2,300 kilometers of extension Great Barrier Reef it is the best known example – it has suffered several large-scale "bleaching" events caused by above-average water temperatures in the past two decades.
Then, consecutive marine heat waves in 2016 and 2017 killed about half of the corals in the Great Barrier Reef, along with many others around the world.
One of the natural wonders of the world, the Great Barrier Reef is approximately the length of Italy – and provides a habitat for a wide range of marine life. Up to a third of all marine species everywhere depend on coral reefs, which means that the extinction of a reef could cause an ecological collapse, experts warn.
And these devastating effects will spread to human societies – nearly a billion people worldwide rely on reefs as a source of food protein, according to Mark Eakin, coordinator of the Coral Reef Watch of the US National Oceanic and Atmospheric Administration. Coral reefs also protect coastlines and infrastructure – which means that their death can threaten the safety and sustainability of coastal societies.
In recent years, activists have struggled to find ways to save the reefs; environmental entrepreneurs opened coral farms, which increases and accelerates restoration efforts.
Other scientists have also tried to use underwater speakers replicating the sounds of healthy reefs in an attempt to lure fish back to dead reefs to help them recover.
These attempts have been successful – and potentially buy the world's reefs a little longer – but all the scientists and entrepreneurs involved have warned that it is not enough to save them all. Almost nothing will be, they say – unless we take drastic measures on climate change.