clipped from: www.abc.net.au   
Anna Mudeva

The world has lost almost a fifth of its corals and many of the remaining reefs could die in the next 20 to 40 years unless humans reduce greenhouse gas emissions, say the authors of a report.

dead coral

Further coral loss will have alarming consequences for some 500 million people who depend on reefs for their livelihood, according to a report by the Global Coral Reef Monitoring Network (GCRMN) presented at the UN conference on global warming in Poland.

"Climate change must be limited to the absolute minimum to save corals," says Julia Marton-Lefevre, head of the International Union for Conservation of Nature (IUCN), which is a member of the GCRMN.

"If nothing is done to substantially cut emissions, we could effectively lose coral reefs as we know them, with major coral extinction,"
The impact of the main climate threats, such as rising sea surface temperatures and seawater acidification, is being strengthened by other negative factors like overfishing, pollution and invasive species