Great Barrier Reef survival "requires 25 percent CO2 cut"

Amy Pyett, Reuters 16 Nov 09;

SYDNEY (Reuters) - Australia's Great Barrier Reef has only a 50 percent chance of survival if global CO2 emissions are not reduced at least 25 percent by 2020, a coalition of Australia's top reef and climate scientists said on Tuesday.

The 13 scientists said even deeper cuts of up to 90 percent by 2050 would necessary if the reef was to survive future coral bleaching and coral death caused by rising ocean temperatures.

"We've seen the evidence with our own eyes. Climate change is already impacting the Great Barrier Reef," Terry Hughes, director of the ARC Center of Excellence for Coral Reef Studies at James Cook University, said in a briefing to Australian MPs on Tuesday.

Australia, one of the world's biggest CO2 emitters per capita, has only pledged to cut its emissions by five percent from 2000 levels by 2020.

It has said it would go further, with a 25 percent cut, if a tough international climate agreement is reached at U.N. climate talks in Copenhagen in December, but this is looking increasingly unlikely with legally binding targets now off the agenda.

"This is our Great Barrier Reef. If Australia doesn't show leadership by reducing emissions to save the reef, who will?" asked scientist Ken Baldwin, in calling for Australia to lead the way in cutting emissions.

But the Australian government is struggling to have a hostile Senate pass its planned emission trading scheme. A final vote is expected next week.

The World Heritage-protected Great Barrier Reef sprawls for more than 345,000 square km (133,000 sq miles) off Australia's east coast and can be seen from space.

The Australian scientists said more than 100 nations had endorsed a goal of limiting average global warming to no more than two degrees Celsius above pre-industrial temperatures, but even that rise would endanger coral reefs.

The scientists said global warming was already threatening the economic value of the Great Barrier Reef which contributes A$5.4 billion to the Australian economy each year from fishing, recreational usage and tourism.

The U.N. Intergovernmental Panel on Climate Change has concluded that the Great Barrier Reef could be "functionally extinct" within decades, with deadly coral bleaching likely to be an annual occurrence by 2030.

Bleaching occurs when the tiny plant-like coral organisms die, often because of higher temperatures, and leave behind only a white limestone reef skeleton.

(Editing by Michael Perry)

'Cut emissions or lose reefs'
ARC Centre of Excellence for Coral Reef Studies
Science Alert 17 Nov 09;

To have even a chance of saving the world’s coral reefs from extensive damage caused by global warming, carbon emissions in industrialised countries need to be cut by 25 per cent below their year 2000 levels by 2020 – and by 80-90 per cent by 2050.

That is the uncompromising warning delivered today by some of Australia’s most eminent marine and environmental scientists in a briefing to Australian Members of Parliament and Senators, in Parliament House, Canberra.

“The Great Barrier Reef (GBR) contributes $5.4 billion annually to the Australian economy - $5.1 billion from the tourism industry; $153 million from recreational activity; and $139 million from commercial fishing.

“The ‘outstanding universal values’ of the GBR, recognised by its inclusion on the World Heritage List in 1981, are now threatened by rapid climate change,” Professor Terry Hughes, Director of the ARC Centre of Excellence for Coral Reef Studies at James Cook University told the briefing.

Professor Hughes emphasised the consensus among reef scientists in Australia about the impacts of climate change on valuable environmental assets such as the Great Barrier Reef. “We’ve seen the evidence with our own eyes. Climate change is already impacting the Great Barrier Reef and reefs in Western Australia.”

According to Western Australian Premier's Fellow, Professor Malcolm McCulloch “Coral reefs are in the front line of the effects of climate change because of their sensitivity to both relatively small temperature rises and to acidification of the oceans due to increased levels of dissolved CO2. To date, atmospheric CO2 has risen to 390 parts per million, resulting in an increase in temperature of 0.7oC and a rise in ocean acidity of 0.1 unit of pH.”

Other leading scientists are equally concerned. “Unprecedented coral bleaching and extensive mortality due to thermal stress affected over 50 per cent of the GBR in 1998 and 2002, when summer maximum water temperatures were elevated by only 1-2oC. Some parts of the GBR have still not fully recovered,” Professor Ove Hoegh-Guldberg of the ARC Centre and the University of Queensland adds.

“Ocean acidification is accelerating and, in combination with thermal stress, has already detrimentally affected the growth and skeletal strength of corals on the GBR,” he says. “Ocean acidification will impact all marine calcifying organisms, potentially disrupting the entire ecology of the world’s oceans, resulting in severe socio-economic impacts on fisheries and other marine industries.”

“Coral cover is already declining on the GBR and globally, even on the most remote and best-managed reefs. Loss of coral cover reduces biodiversity, ultimately affecting fishing, tourism, coastal protection and World Heritage values,” Professor Ove Hoegh-Guldberg says.

Professor Hughes and colleagues advised the parliamentarians that the effects of atmospheric concentrations above 450 parts per million CO2 equivalent (currently seen as the most likely target to emerge from Copenhagen) and the consequent likely temperature increase of more than 2oC on the GBR “will be devastating, particularly given the impacts observed so far with only one-third this amount of warming.”

“A stabilisation level of no more than 450 parts per million in the concentration of CO2-equivalent greenhouse gases in the atmosphere could achieve, at best, an even chance of constraining warming below the 2°C target. To achieve even this 50:50 chance of avoiding 2°C of warming would require global emissions to peak no later than 2020, and then decline to 80-90 per cent below 2000 emissions by 2050.”

“To have a realistic chance of achieving this target, emissions from industrialised countries in 2020 need to be reduced by at least 25 per cent relative to their 2000 levels.”

The briefing, organised by the Federation of Australian Scientific and Technological Societies (FASTS), was accompanied by a statement signed by thirteen leading Australian researchers. The statement is available at www.fasts.org.

Original news release.