In a single decade, climate change has helped kill 14% of the world’s coral reefs, according to a new study.
In its first global report since 2008, the Global Coral Reef Monitoring Network (GCRMN) found that rising ocean temperatures due to climate change have resulted in a succession of “large-scale bleaching events” that have resulted in the decline of coral reefs around the world. Although the report lists other causes such as pollution, overfishing and construction, bleaching caused by warming ocean waters has been by far the biggest contributor to coral deaths.
“Large-scale coral bleaching events caused by high sea surface temperatures (SST) are the biggest disturbance to coral reefs in the world,” the report said.
Coral reefs are home to more than 25 percent of all marine life on the planet, but only cover 0.2 percent of the ocean floor. The death of the reefs would trigger the collapse of an entire ecosystem, scientists have long warned.
The GCRMN report, which drew its conclusions on the basis of data compiled over 40 years in 73 countries, found a marked increase in the amount of algae on the world’s coral reefs in just a decade.
“There was 20% more algae on the world’s coral reefs in 2019 than in 2010. The increase in the amount of algae, a globally recognized indicator of stress on coral reefs, has been associated with a decrease in the amount of hard corals, ”the report said. .
Still, the report notes that following a mass bleaching event in 1998, coral reefs were able to rebound to some extent, especially in places where pollution and overfishing were kept at bay.
“While the report’s findings are sobering, there are examples of the ability of coral reefs to recover in the absence of major disturbance,” said Margaret Johnson, managing director of the Great Barrier Reef Marine Park Authority in Australia. , in a press release accompanying the report. . “This reinforces our conviction that we must step up and accelerate efforts at all levels to address the main threats and step up global action at all levels to reduce the extent of the impacts of climate change.”
Despite the fact that they can rebound from individual bleaching events, coral reef systems remain at risk as the oceans absorb the vast majority of the heat caused by climate change. Last year, the oceans reached their hottest temperature on record, and five of the hottest years on record have all occurred since 2015.
“Most of the excess atmospheric heat is returned to the ocean. As a result, the heat content of the upper ocean has increased dramatically in recent decades,” the National Oceanic and Atmospheric Association said on his website.
Coral reefs, which require sunlight, are found in shallow water, where the impact of the increase in temperature has been profound.
“We are running out of time: we can reverse the losses, but we must act now,” said Inger Andersen, head of the United Nations Environment Program, in a statement regarding the report’s findings.
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