Coral reefs are a thing of wonder, both organism and underwater infrastructure that houses thousands of species of fish. They are also, as you might already know, in grave danger. Climate change is contributing to massive waves of coral bleaching around the world, from the Great Barrier Reef to the ocean off of Florida, where an extreme oceanic heat wave this year turned mile after mile of reef a ghostly white.
We’ve known about coral bleaching for years, but a new report out Wednesday draws fresh attention to corals’ plight, including reefs — along with ice sheets, rainforests, and ocean currents, among others — on a list of imminent climate “tipping points.” And if they go over the brink, the consequences could reach far beyond the ocean floor.
According to the report, about a billion people, or 13% of the world’s population, are estimated to live within 100 kilometers of a coral reef. Together, those reefs provide $9.9 trillion of economic value each year. Reefs are sources of both nutrition and income; in Australia, the Great Barrier Reef is estimated to create 68,000 jobs and 5.7 billion Australian dollars of revenue each year, mostly from tourism. This means the risk to coral is a risk to humans, as well.
There’s still a lot we don’t know — “There are numerous pathways by which coral reef degradation may cascade into social and economic tipping points,” the authors write — starting with how exactly coral loss affects fish. Some studies have found that species like butterfly fish and parrot fish were negatively affected when their local coral bleached; other studies have shown fish communities getting on just fine.
But those bleaching events were limited. The authors of the “Global Tipping Points” report — led by Tim Lenton at the University of Exeter’s Global Systems Institute, in collaboration with a couple hundred researchers from around the world and received funding from the Bezos Earth Fund — suggest that coral could soon suffer something catastrophic and nearly irreversible on a worldwide scale.
“Documented impacts of coral cover declines include a loss of fish species, reductions in overall fish biomass and productivity, and potential destabilization of the food web,” the authors write. “If reefs are forced by climate change into low-productivity states, and if these states in turn force fish communities across a tipping point into a less diverse and less productive state, many coastal human communities will be forced to modify their lifestyles in significant ways.”
It’s yet another example of the sort of compounding disaster that climate change tends to bring, and a reminder of the interconnectedness of the ecosystems we live in and rely on, even if we can’t always see them. As Benji Jones writes in Vox, scientists are doing their best to find ways to save coral reefs; soon, however, their jobs could turn entirely to resurrection.
