THE world could be tracking towards irreversible climate change as warming takes place much quicker than previously thought, an Adelaide academic has warned.
Climate change expert Barry Brook, of Adelaide University, told a Canberra conference — Imagining the Real Life on a Greenhouse Earth — atmospheric carbon dioxide levels were headed towards 600 parts a million, and forecast global temperature increases of up to six degrees.
Professor Brook said a global temperature increase of three degrees might result in the collapse of the Amazon rainforest, a four-degree increase would lead to the displacement of hundreds of million of people and the extinction of up to half the world's species, and a five-degree increase would create an ice-free planet and sea-level increases of 80 metres.
"We're seeing events predicted for the end of the 21st century happening already," Professor Brook said.
He cautioned that even the most ambitious international greenhouse gas reduction targets might not prevent a catastrophic increase in temperatures.
"Two degrees has the potential to lead to three or four degrees because of carbon-cycle feedbacks," Professor Brook said.
The Australian National University's Janette Lindesay warned that the earth was moving towards "tipping points", where climate change would become irreversible.
Barrie Pittock, of the CSIRO, said the amount of carbon dioxide going into the atmosphere had overtaken even the worst-case scenario included in last year's bench-mark report by the Intergovernmental Panel on Climate Change.
"We are at or exceeding the fossil-fuel-intensive scenario, which the latest IPCC report didn't cover because they thought it was too much," Dr Pittock said.
He listed nine reasons for the faster-than-expected increase in greenhouse gas emissions, including the rapid growth of China and India.
He said global temperatures, rising sea levels, polar ice reduction and rainfall changes were all happening much faster than previously predicted.
With AAP
THE Hawke government knew about the risks of climate change 25 years ago but did little about them, Labor heavyweight Barry Jones says. Dr Jones cast himself as an Australian version of climate campaigner Al Gore in a speech to a Canberra conference yesterday. He said he was the first politician to sound the alarm on global warming, as science minister in 1984. "Of course I wish I'd been listened to," he said. "The response from my political colleagues in Canberra was distinctly underwhelming. I think some of them were persuaded by lobbyists to say sooner or later a technological fix will come up." AAP
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