Early signs of a predicted mass coral bleaching on the Great Barrier Reef could be a prelude to future damage from climate change.
World leaders are meeting for the COP21 talks in Paris to negotiate limits to carbon emissions and global temperature rises above pre-industrial levels.
Climate change is recognised as one of the greatest threats to the future of the 2,000 kilometre-long, World Heritage-listed wonder off the Queensland coast, and to the billion-dollar industries, like tourism, it supports.
Stefan Armbruster reports.
A natural wonder of the world; the Great Barrier Reef is the only living organism that can be seen from outer space.
From around the world, tourists come to see the reef up close, like Luca and Kasis from Poland.
"It's endangered somehow, every year a little piece is gone, so we wanted to see this (before it's gone). The wildlife is really amazing, the fish are just in front of you, and there's nowhere in the world you can do this. So, that's why we wanted to see it."
Almost 20 million years old and World Heritage-listed, the reef is one Australia's greatest tourist attractions stretching more than 2,000 kilometres along the Queensland coast.
Tony Fontse migrated from California to Airlie Beach in central Queensland 30 years ago and works as a scuba dive operator.
"Well the tourism industry in the Whitsundays is booming. Last year we set a record regards to the number of people visiting the reef and this year we will smash that record."
A mass coral bleaching of the reef is predicted for early next year due to the El Nino weather pattern and higher water temperatures.
That's an ominous sign, says Professor Ove Hoegh-Guldberg, director of the Global Change Institute at the University of Queensland, who will be in Paris for the COP21 climate talks.
"The best outcome for the reef would be that we have a global agreement to limit global warming to below 2 degrees Celsius below the pre-industrial period. If we can do that then we have a good chance of having a Great Barrier Reef into the future."
Professor Hoegh-Guldberg was a contributor to the United Nations-sponsored Intergovernmental Panel on Climate Change working groups on oceans.
"But if we take the current commitments as our benchmark, which gets us to about 2.7 degrees above the pre-industrial period, we will lose places like the Great Barrier Reef, and if we don't do anything about the climate change issue we will see the Reef disappear in our lifetime. To stay below two degrees Celsius, below the pre-industrial levels and avoid unmanageable climate change, it's going to take leaving 80 per cent of fossil fuels in ground. That's challenging, one can jump up and down and object to it, but it is the science."
Prime Minister Malcolm Turnbull is to lead a delegation of Australian government ministers to the COP21 talks.
The Department of Foreign Affairs website states: "Australia wants the Paris Conference to deliver an ambitious and durable agreement that builds action by all countries towards the global goal to limit temperature rise to below 2 degrees Celsius above pre-industrial levels."
Reef industries are a vital part of the federal government's Northern Australia economic development White Paper released in September.
The reef is the only living organism that can be seen from outer space.
Almost 20 million years old, it's one Australia's greatest tourist attractions.
About two million people visit the reef every year, and overseas visitor numbers are growing fast thanks to the falling Australian dollar, says dive operator Tony Fontse.
"Without a Great Barrier Reef we won't have a tourism industry and right now we have an tourism industry that's worth $6b a year to Queensland and provides 69,000 jobs, and that's going to hurt."
The reef supports a tenth of the world's fish species, six of the seven turtles, endangered dugongs, whales and more than 600 types of coral.
The first mass coral bleaching was recorded in 1998 when water temperatures rose and broke the symbiotic relationship between coral and algae.
About 16 per cent of the world's reefs died.
Professor Hoegh-Guldberg fears there will be more bleaching in the future.
"Those reefs can develop into a slimy pile of rocks. So you go from having a beautiful coral garden to one that's dominated by organisms called cyanobacteria and the like. All the corals have died, all the habitat for the fish have disappeared, and you have an eco system that would be hard to say is a Great Barrier Reef... It might be the Great Slimy Reef that we're left with and that won't attract tourists and won't support fisheries - and this is why this issue is so important."
