To investigate the rate of change, start climbing
Sydney Morning Herald
Tuesday June 16, 2009
SOARING way above the Bago Forest at Tumbarumba, a 70-metre tower covered in instruments is measuring the air, every hour, every day, to test whether the tall mountain ash trees in southern NSW are still helping to keep the planet cool.In a triumph for nature, this year the forest has been working overtime, absorbing more of our carbon dioxide than it has for some time, thanks to the return of good rainfall and the disappearance of a destructive sap-sucking insect, the psyllid.Five years ago, Helen Cleugh and colleagues from the CSIRO who were monitoring the Tumbarumba tower were disturbed to discover that the severe drought and an insect infestation had upset the natural order of this forest.Instead of helping absorb the carbon dioxide that humans were pushing into the atmosphere from burning fossil fuels, the forest was actually adding to the planet's problem. As leaves expired and the forest died, the natural cycle of carbon changed and the forest began producing more carbon than it absorbed."For a period the forest became a source of carbon dioxide," Dr Cleugh said. "That was a bit of a surprise to us."Dr Cleugh, along with about 100 of her colleagues from the CSIRO, the Bureau of Meteorology and some key academics, are the Australian Government's climate detectives. They help measure the world's greenhouse gas emissions. They observe climate change first hand. And, most importantly, they try to inform the politicians what will happen to Australia if greenhouse gas emissions are allowed to continue growing at the present rapid pace.Over the past two decades, these scientists from the Australian Climate Change Science Program have been at times ignored and criticised as well as encouraged. But this year, as they celebrate the 20th anniversary of their work, their role will move to centre stage, with climate science influencing the Federal Government's policies both at home and in the UN talks in Copenhagen in December.Yesterday, when Senator Steve Fielding met the Chief Scientist, Penny Sackett, she was armed with the advice of the climate scientists. Senator Fielding returned from Washington last week quoting climate change sceptics and told the Insiders program he had discovered information "that showed that over the past decade or so carbon emissions have been going up, but global temperature hasn't".If Senator Fielding had consulted the ACCSP before he left, he would have found this claim has been discredited. The ACCSP's 2007 report to the Australian Government states that Australian average temperatures have increased by 0.9 degrees since 1950.The findings correspond with climate change science advice from Britain's Hadley Centre, from NASA and from the US National Climate Data Centre showing seven of the hottest 10 years on record have been between 1999 and 2007.The manager of the ACCSP, Paul Holper, said the link between carbon emissions and temperatures underpins the advice of climate scientists around the world. That advice is to keep global greenhouse gas concentrations in the atmosphere below 450 parts per million to stop temperatures from rising above 2 degrees.When Mr Holper first began working for the CSIRO in 1989, concentrations of carbon dioxide were at 350 parts per million in the atmosphere. Today they are over 380 parts per million, a 10 per cent rise in two decades.Australia's scientists have played a critical role in accurately measuring this rise in carbon dioxide. Back in the mid-1970s, CSIRO scientists persuaded the government to fund an air-monitoring station at the aptly-named Cape Grim in Tasmania. It was the first greenhouse gas monitoring station in the southern hemisphere.Mr Holper says today the monitoring stations such as Tumbarumba and Cape Grim are vital. "They not only show us what is happening to greenhouse gas concentrations [but also] the rate of change. Otherwise we are stumbling around in the dark. It's those changes that dictate the ultimate level of global action that needs to be taken."
© 2009 Sydney Morning Herald