Long stretches of the famously colourful reef, which is world heritage-listed and one of the country?s top tourist destinations, have turned ?snow-white? following bleaching which began six months ago, according to the resarchers.

Aerial survey of 520 sites across the 1,500-mile stretch of delicate coral reefs in north-east Australia found that the most pristine sections had been facing some of the worst bleaching in recorded history. Scientist in Australia have warned for years that climate change has led to warmer waters which threaten the long-term future of the reef.

Scientists say an underwater heat wave in Reef has led to devastating coral bleaching – the worst in history - which has damaged or killed 95 per cent of the northern reefs.

Scientists believe the bleaching was triggered by a temperature spike due to the El Nino weather pattern, which added to already warmer waters caused by climate change. Warmer temperatures can kill the tiny marine algae which are required to maintain the health of coral and give it colour.

The bleaching has affected virtually all species of the reef?s coral.Cloudy weather is believed to have kept temperatures down and prevented heavy damage in the southern parts of the reef.

The damage has raised fresh questions about whether UNESCO may list the marine park as ?in danger?. The organisation last year decided not to downgrade the park?s listing but expressed concern about the damage caused by mining and coastal pollution.

 Source:telegraph.co.uk,abc.net,thetimes,khaleejtimes