The number of coral reefs in the world is far less than what scientists had believed. They are also shrinking fast due to pollution, climate change and fishing. This was revealed during the most comprehensive mapping of the corals done by the United Nations Environment Programme (UNEP).

The mapping showed that coral reefs covered just 284,300 square km, or less than ten per cent of the world's seabed. Experts opine that this finding is significant, especially in the wake of large-scale destruction of the corals. "The mapping showed that the reefs are rapidly degrading due to human activities. They are overfished and poisoned,' said UNEP executive director Klaus Toepfer. He added that they are damaged by tourism and are being severely stressed by the warming of the world's oceans. Each of these pressures is bad enough in itself, but together, the cocktail is proving lethal, he added.