“We lost 30 per cent of the corals in the nine-month period between March and November 2016,” study’s author said
According to a new study published in Nature, the Great Barrier Reef has been partially destroyed by increased coral bleaching caused by global warming.
In 2016 the world’s biggest coral system and Unesco World Heritage Site that stretches for 2,300 kilometres in the Pacific Ocean experienced the worst heat wave in its existence.
“We lost 30 per cent of the corals in the nine-month period between March and November 2016,” Terry Hughes, study author and director of the Australian Research Council Centre of Excellence for Coral Reef Studies at James Cook University in Queensland, said in a statement.
Another marine heatwave hit Australia’s iconic natural heritage site in 2017, with severe heat stress and bleaching striking the central region. The event destroyed half of the corals, which is comparable to losing half of the trees in the Rocky Mountains in just two years.
Mark Eakin, the study’s co-author and coordinator for the US National Oceanic and Atmospheric Administration’s Coral Reef Watch, said the increase in marine heat waves is clearly linked to the rising temperatures caused by increasing levels of carbon dioxide and other greenhouse gases in the atmosphere.
“We’ve seen half of the corals on the Great Barrier Reef killed by climate change in just two years,” Eakin told CNN.
“This study shows that the coral reefs that have been least affected by heat stress in the past are more sensitive to heat stress than we realised. It also shows climate change threatens the diversity that is the hallmark of coral reefs.”
The fastest growing corals can renew themselves in 10 to 15 years. But according to researchers, global warming causes heatwave bleaching every six years meaning the corals don’t have the chance to regrow.
“The coral die-off has caused radical changes in the mix of coral species on hundreds of individual reefs, where mature and diverse reef communities are being transformed into more degraded systems, with just a few tough species remaining,” Andrew Baird, the study’s co-author, said in a statement.
“Global warming is rapidly emerging as a universal threat to ecological integrity and function, highlighting the urgent need for a better understanding of the impact of heat exposure on the resilience of ecosystems and the people who depend on them,” the study says.