The Great Barrier Reef is expected to experience widespread death this summer, which could imperil the massive structure’s long-term viability, according to a forecast by the US National Oceanographic and Atmospheric Administration.
NOAA found that there’s a 60% chance the entire reef will undergo a bleaching event in response to extremely hot water temperatures between November and February. If that happens, it would be the most thorough bleaching event to date. Up to this point, only sections of the reef have bleached.
It would also accelerate the reef’s overall decline, displacing thousands of marine species and undermining local economies in the process.
“This is really the first warning bells going off that we are heading for an extraordinarily warm summer and there’s a very good chance that we’ll lose parts of the reef that we didn’t lose in the past couple of years,” marine biologist Ove Hoegh-Guldberg told the Guardian. “These are not good predictions and this is a wake-up call.”
The news is especially alarming because bleaching generally occurs in March, when water temperatures are higher than preceding months. As a result, multiple bleaching events could strike the reef this summer.
Bleaching happens when marine heat waves shock coral and cause it to expel the symbiotic organisms that give it color and nutrients, turning the organism bone white.
Coral reefs need several years to recover from bleaching events, and if they happen successively a reef can end up permanently dying.
The Great Barrier Reef is already half dead due to extreme bleaching events over the past two years.
Earlier in the year, the Australian Government pledged $379 million in critical reef interventions, such as improving water quality by the Great Barrier Reef and developing hardier coral in laboratories.
Their efforts may just be delaying the inevitable, however. By 2050, scientists predict that all coral reef could die because of climate change.
In addition to bleaching, coral reefs are threatened by industrial pollution, invasive species, overfishing, plastic pollution, and ocean acidification, which is when the oceans absorb too much carbon dioxide from fossil fuel emissions and acidify.
Losing coral reefs would have significant ripple effects throughout the world, according to UNESCO. Reefs foster vast ecosystems, providing food, shelter, and breeding grounds for thousands of marine creatures.
They protect coastal communities by preventing waves from destroying shorelines. The many types of fish and other species depending on reefs, meanwhile, provide food to humans.
Reefs also generate billions of dollars in tourism revenue annually for neighboring countries.
“[Coral reefs] are facing existential threats, and their loss would be devastating ecologically and economically,” Dr. Mechtild Rossler, director of the World Heritage Center, said in a statement. “These rainforests of the sea protect coastal communities from flooding and erosion, sustain fishing and tourism businesses, and host a stunning array of marine life.”