Many of the current coral bleaching articles on the Great Barrier Reef state a staggering 93% damage with full recovery not expected in our lifetime, if at all. This has been described as the worst natural disaster to have ever occurred in Australia. The fallout from what is happening now will continue as species continue to move and disappear. The effect on mankind will be equally catastrophic in areas where billions of people depend on the ocean for their food.

The Great Barrier Reef and other global coral reefs (Western Australia,  Florida, Hawaiian Islands and the Caribbean)  are under threat from climate change with warming waters and increasing acidity. Other factors include agricultural and other chemicals coming into the ocean from local rivers. The major difference to this coral bleaching from those in the past is that much of the cause of the bleaching is attributed to man. Water temperatures need to decrease for the coral reefs to begin to recover but the full extent of the damage is still being surveyed. Some corals are more hardy than others and corals in shallow waters and those further north are more at risk to bleaching.

Coral Bleaching

Updated: 22 April 2016

Due to its extent and severity, the current mass coral bleaching on the Great Barrier Reef is worse than the previous mass bleaching events of 1998 and 2002.

Reef-wide assessments and analyses of bleaching will take several weeks to complete, and as the event is still unfolding, it may be several months until the full impact is known.

Overall, 93 per cent of reefs surveyed have shown bleaching to some extent. In general, there is a gradient of decreasing severity from north to south along the Reef.

While low-level coral mortality has been detected as far south as offshore Townsville, observations of severe coral mortality have so far been restricted to the Marine Park's Far Northern Management Area, above Cooktown.

The area between Cooktown and Townsville is displaying patchy moderate to severe bleaching, with some coral mortality.

Levels of bleaching between Townsville and offshore Mackay continue to range from being mainly minor to moderate, with some severe bleaching. Minor amounts of coral die-off have also been detected in this area.There continues to be only minor bleaching south of Mackay.

A map is available summarising the observed bleaching. (Link no longer available: Liz)

The Bureau of Meteorology has advised that mean sea surface temperatures for February and March 2016 over the Great Barrier Reef were the highest on record (since 1900).

Bleaching occurs when live corals are stressed from overheating. If the waters cool down quickly enough, the corals can survive, but if the corals remain stressed for many weeks, they will die off.