According to research released on Tuesday, global warming has killed 14 percent of the world's coral reefs in the last decade, and more will be wiped out if ocean temperatures continue to rise.
Coral reefs the size of 11,700 square kilometers — 2.5 times the area of Grand Canyon National Park — were lost between 2009 and 2018, according to a report by the Global Coral Reef Monitoring Network (GCRMN).
In a statement released by the United Nations, co-author Paul Hardisty, CEO of the Australian Institute of Marine Science, said, "Climate change is the biggest threat to the world's reefs,"
"There are clearly unsettling trends toward coral loss, and we can expect these to continue as warming persists," he warned.
The report, produced by the United Nations-supported worldwide data network, is the largest ever survey of coral health, encompassing data from 73 countries and 12,000 locations over 40 years.
The research also mentions dynamite fishing and pollution. Still, global warming is cited as the leading cause of coral reef degradation, which has resulted in swaths of bleached bones in place of dynamic ecosystems.
Much of the loss is due to coral bleaching.
South Asia, Australia, the Pacific, East Asia, the Western Indian Ocean, the Gulf, and the Gulf of Oman were among the worst-affected corals.
According to the analysis, coral bleaching was responsible for a large portion of the loss.
Coral bleaching occurs when corals, under the influence of warmer water, expel the colorful algae inside their tissues, rendering them white.
According to the study, a single bleaching event in 1998 was responsible for losing 8% of the world's corals.
"Since 2009 we have lost more coral worldwide than all the living coral in Australia," UNEP executive director Inger Anderson said.
"We can reverse the losses, but we have to act now."
Some reefs can 'bounce back.'
During the research, scientists discovered that coral reefs recovered by roughly 2% in 2019, demonstrating that they can be resilient when given a break from the factors acting against them.
"Some reefs have demonstrated a remarkable ability to bounce back," Hardisty added, "offering some hope for the future recovery of degraded reefs."
Coral reefs cover less than 1% of the ocean floor yet are home to more than 25% of all marine species.
According to the analysis, the reefs generate nearly $2.7 trillion (€2.3 trillion) in goods and services annually, including tourism.
