High ocean temperatures are harming tropical corals almost five times more often than in the 1980s, undermining reefs' ability to survive marine heat waves caused by man-made climate change, scientists have revealed. Newslook
A new report confirms coral reefs and acidic ocean water don't mix.
Increasingly acidic oceans — caused by climate change — will severely harm coral reef growth over the next few decades if carbon dioxide emissions continue unchecked, according to new research on Australia’s Great Barrier Reef.
At more than 1,400 miles long, the reef is the world's largest coral reef and the planet's biggest structure made by living organisms.
The study was the first experiment in which seawater was made artificially acidic by the addition of carbon dioxide, and then allowed to flow across a natural coral reef community.
“Our findings provide strong evidence that ocean acidification will severely slow coral reef growth in the future unless we make steep and rapid reductions in greenhouse gas emissions,” said study lead author Rebecca Albright of the California Academy of Sciences.
The study said that "the persistence of coral reefs is at risk."
Ocean acidification, the shifting of the ocean's water toward the acidic side of its chemical balance, has been driven primarily by climate change.
This isn't the kind of acid that burns holes in chemist's shirt sleeves; ocean water is slightly alkaline. But since the start of the Industrial Revolution in the 1800s, the world's oceans have grown nearly 30% more acidic.
Why? Climate change, where heat-trapping carbon dioxide is emitted into the air by burning coal, oil and other fossil fuels, ends up as excess carbonic acid absorbed into the ocean.
Katharina Fabricius of the Australian Institute for Marine Science, who was not involved in the research, told the Atlantic that "we sort of knew that ocean acidification will affect reef growth. This experiment not only confirms that prediction, but informs us about the severity of the effect. It’s outstanding.”
Besides their beauty, reefs shelter land from storms, and are also a habitat for myriads of species.
"Coral reefs are therefore the most biologically diverse ecosystems of the planet, and provide a number of ecosystem services that hundreds of millions of people rely on," said Greg Torda of Australia's Centre of Excellence for Coral Reef Studies.
In addition to ocean acidification, coral reefs are also at risk of bleaching from increasingly warm seawater. Worldwide, the frequency of severe coral bleaching events has increased nearly fivefold in the past four decades, from once every 25 to 30 years in the early 1980s to once every six years in 2016, a January study said.
Ken Caldeira of the Carnegie Institution for Science, a co-author of the new study, said that "coral reefs offer economic opportunities to their surrounding communities from fishing and tourism. But for me, the reef is a beautiful and diverse outpouring of life that we are harming with our carbon dioxide emissions.
"For the denizens of the reef, there’s not a moment to lose in building an energy system that doesn’t dump its waste into the sky or sea," he added.
The study was published Wednesday in the peer-reviewed British journal Nature.
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