India, Oct. 22 -- The world's coral reef ecosystems almost all face a high risk of collapse in the next 50 years, mostly due to warming oceans and heat waves, according to a global assessment released on Thursday.

The International Union for Conservation of Nature's assessment, announced on the sidelines of a UN biodiversity conference in Albania, found that 96 per cent of shallow-water reef systems are already critically endangered and could disappear by 2075.

Most of the world's famous reef systems -- including the Great Barrier Reef in Australia, the Coral Triangle in the Western Pacific Ocean and Southeast Asia, the Mesoamerican Barrier Reef System and the Red Sea coral reefs -- are all critically endangered, the highest level of th...