A new report shows just how much climate change is killing the world's coral reefs

Rachel Treisman

October 05, 2021 / 9:20 am

caption: Aerial view of a coral reef area at Playa Blanca, in Portobelo, Colon province, Panama, on April 16, 2021. A massive new report shows that the world's coral reefs are under stress, but could recover if greenhouse gas emissions are significantly reduced.

Rising ocean temperatures killed about 14% of the world's coral reefs in just under a decade, according to a new analysis from the Global Coral Reef Monitoring Network.

Put another way: The amount of coral lost between 2008 and 2019 is equivalent to more than all of the living coral in Australia.

The report — the first of its kind since 2008 — found that warming caused by climate change, overfishing, coastal development and declining water quality has placed coral reefs around the world under "relentless stress."

But it also found signs of hope, noting that many of these reefs are resilient and may be able to recover if immediate action is taken to stabilize emissions and fight future warming.

"People around the world depend on healthy coral reefs and the services they provide for food, income, recreation, and protection from storms," said Jennifer Koss, director of the National Oceanic and Atmospheric Administration's Coral Reef Conservation Program. "It is possible to turn the tide on the losses we are seeing, but doing so relies on us as a global community making more environmentally conscious decisions in our everyday lives."

NOAA calls this the largest global analysis of coral reef health ever undertaken: "The analysis used data from nearly two million observations from more than 12,000 collection sites in 73 countries over a time span of 40 years (1978 to 2019), representing the work over over 300 scientists."

The study covers 10 coral reef-bearing regions around the world, and identifies "coral bleaching events caused by elevated sea surface temperatures" as the biggest driver of coral loss. Researchers looked at levels of both algae and live hard coral cover, a scientifically based indicator of reef health.

They also observed some recovery in 2019, with coral reefs regaining 2% of their coral cover.

"This indicates that coral reefs are still resilient and if pressures on these critical ecosystems ease, then they have the capacity to recover, potentially within a decade, to the healthy, flourishing reefs that were prevalent pre-1998," reads a GCRMN release.

On the flip side, continued warming could take an even greater toll.

Sharp declines in coral cover corresponded with increases in sea surface temperature, which experts say shows coral's vulnerability to spikes — a phenomenon they say is likely to happen more frequently as the planet continues to warm.

Read more from NPR's climate team about why coral reefs are so crucial, and exactly how much of a reduction in greenhouse gas emissions is needed to preserve them.