Australia's Great Barrier Reef may be gone within decades, say eminent scientists, as rising carbon levels spell doom for the world's coral reefs.
In a paper published in the most recent edition of the prestigious Science magazine, scientists have outlined the most compelling case to date that coral reefs would disappear if carbon levels increased beyond present levels.
As a result, the lives of 100 million people and one million species could be devastated, the authors say.
Authors of the report are contributors to The Coral Reef Targeted Research and Capacity Building for Management (CRTR) Program, an international coral reef research initiative that is supported by the World Bank, the University of Queensland and over 40 research institutes and other third parties around the world.
Australian National University's Professor Roger Bradbury – chair of one of the CTRT working groups – said research had previously centred on the destructive impact of rising water temperatures on coral. The results of more recent research, however, had forced scientists to factor in the effects of increasing carbon emissions with shocking results.
"I was quite surprised by the magnitude of the change," Professor Bradbury told The Epoch Times. "We have been watching it for a few years and when you put all the numbers together, it is awesome."
The study, which included information collected over the last decade and computer simulations of ocean chemistry, identified present levels of carbon dioxide in the Earth's atmosphere at around 380ppm (parts per million).
"This is more than 80ppm above the maximum values of the past 740,000 years, if not [the past] 20 million years," the study said.
Temperature increases in tropical and subtropical waters over the last 50 years had already pushed "reef building corals to their thermal limits", the authors claim, but if carbon levels increase to over 450ppm, this will compound the devastation.
"Emission pathways that include higher CO2 [600 to 1000ppm] and global temperatures of 3°C to 6°C defy consideration as credible alternatives," the study said.
The ocean absorbs about one-third of carbon dioxide, or CO2, put into the atmosphere. While this can slow global warming, it also increases the acidity of sea water, said Professor Ove Hoegh-Guldberg, lead author of the study and marine science specialist from Australia's University of Queensland.
"This, in turn, decreases the ability of corals to produce calcium carbonate, which is what the all-important framework of coral reefs is made of," he said.
The Great Barrier Reef is the world's largest reef, stretching more than 2300km along the north-east coast of Australia. It is made up of around 3000 unconnected coral reefs and roughly 900 islands, and is home to over 1500 species of fish and 400 species of coral.
Considered to be one of the most pristine and important marine ecosystems on the planet, it is also the Earth's largest living structure visible from space.
Professor Bradbury said that for these reasons "the crash will be much more spectacular on the Barrier Reef" than any other coral areas.
Coral reefs, however, are not the only areas addressed in the report. Professor Bradbury said researchers were still discovering the extent of the impact of global warming, but it was evident that all ocean life would be affected by the combination of rising temperature and carbon levels.
"It is going to affect the productivity of the oceans in ways we don't understand," he said.
Marea Hatziolos, a coastal and marine specialist with the World Bank, said the demise of coral reef areas would be devastating to people around the world.
"Coral reefs contribute $US300 billion ($A350 billion) annually in goods and services to the global community," she said.
"Coral reefs are also important economic assets for almost 100 countries around the world," the CRTR website states. "However, nearly two-thirds of the world's reefs are under severe threat from impacts such as economic development and climate change."
"Reducing CO2 emissions must also be accompanied by reducing reef risks such as over-fishing, pollution and unsustainable coastal developments."
Professor Hoegh-Guldberg said the effects of coral reef destruction would be potentially devastating for developing countries that were in the process of establishing viable industries along their coastal regions.
"The warmer and more acidic oceans caused by the rise of CO2 from the burning of fossil fuels threaten to destroy coral-dominated reef ecosystems, exposing people to flooding, coastal erosion and the loss of food and income from reef-based fisheries and tourism," he said.
"This is happening just when many nations are hoping that growing industries like tourism and fisheries will allow them to develop beyond their often impoverished state."
The report's authors also warn of greater damage to coastal populations in developed countries, as a result of rising sea levels, destruction of mangroves and sea grass beds, and increased storm activity.
"It is a sobering thought that we have used the lower range of the United Nations' Intergovernmental Panel on Climate Change [IPCC] scenarios in our analysis yet still envisage serious if not devastating ramifications for coral-dominated reefs," Professor Hoegh-Guldberg said.
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