The report, released by the Global Coral Reef Monitoring Network, shows if current trends in carbon dioxide emissions continue, many of the remaining reefs may be lost over the next 20 to 40 years. This will have alarming consequences for some 500 million people who depend on coral reefs for their livelihoods.
Climate change is considered the biggest threat to coral reefs today. The main climate threats, such as increasing sea surface temperatures and seawater acidification, are being exacerbated by other threats including overfishing, pollution and invasive species.
“If nothing changes, we are looking at a doubling of atmospheric carbon dioxide in less than 50 years,” says Carl Gustaf Lundin, Head of the IUCN Global Marine Programme, one of the organizations behind the Global Coral Reef Monitoring Network. “As this carbon is absorbed, the oceans will become more acidic, which is seriously damaging a wide range of marine life from corals to plankton communities and from lobsters to seagrasses.”
Encouragingly, 45 percent of the world’s reefs are currently healthy. Another sign of hope is the ability of some corals to recover after major bleaching events, caused by warming waters, and to adapt to climate change threats.
However, the report shows that, globally, the downward trend of recent years has not been reversed. Major threats in the last four years, including the Indian Ocean tsunami, more occurrences of bleaching, outbreaks of coral diseases and ever-heavier human pressures, have slowed or reversed recovery of some coral reefs after the 1998 mass bleaching event.
“The report details the strong scientific consensus that climate change must be limited to the absolute minimum. If nothing is done to substantially cut emissions, we could effectively lose coral reefs as we know them, with major coral extinctions,” says Clive Wilkinson, Coordinator of the Global Coral Reef Monitoring Network.
Corals have a higher chance of survival in times of climate change if other stress factors related to human activity are minimized. Well-managed marine protected areas can also boost the health of coral reefs, but proper enforcement is difficult, especially in remote areas where the most pristine reefs are found.
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