Researchers urge reduction in CO2 emissions after study finds time running out to save coral reefs

A Kiwi researcher is calling for countries to reduce carbon dioxide emissions after a new study revealed there is only a short amount of time left to save coral reefs.

Victoria University marine biologist Dr Christopher Cornwall and French colleague Dr Steeve Comeau jointly led the international study which examined how coral reefs are likely to react to ocean acidification and warming.

The study, which was published in the journal PNAS on Tuesday, was based on data from 233 worldwide locations on 183 different reefs, with most in the Atlantic and Indian Oceans.

"We assessed how three different CO2 emission scenarios would impact coral reef growth in the future - the worst-case scenario and the best-case scenario," Dr Cornwall told Newshub. "What we found was that all three scenarios have large negative impacts on coral reefs."

The researchers found most coral reefs will be unable to maintain growth by the end of the century under the medium and high-impact scenarios.

"While 63 percent of reefs are projected to continue to accrete by 2100 under the low-impact pathway, 94 percent will be eroding by 2050 under the worst-case scenario, and no reefs will continue to accrete at rates matching projected sea-level rise under the medium- and high-impact scenarios by 2100."

Dr Cornwall said it could have devastating impacts for reefs and some islands.

"[It] has bad implications for things like low-lying Pacific island nations that rely on these coral reef ecosystems for shore line projection."

However, he said if the world can drastically reduce carbon dioxide emissions, many reefs will still be able to grow.

"Really what we need to do now is in the at least next 20 years, if not sooner, is turn our CO2 emissions down and if we can reverse our emissions and then potentially remove CO2 from the atmosphere, that's going to give the coral reefs the best hope for survival."