Dry forecast: A detailed new extrapolation of Australia's future climate predicts that droughts will occur with increasing frequency.
Credit: CSIRO
SYDNEY: The most detailed assessment yet of Australia's climate, pins the blame for the current drought on global warming. It warns that annual rainfall in some regions could drop by another 30 per cent by 2070 if we don't take drastic action to reduce greenhouse gas emissions.
"There have been some extraordinary events in Australian weather over the last decade… but they seem less extraordinary when you consider climate change," said Scott Power a principal research scientist at the Bureau of Meteorology (BOM) in Melbourne and co-author of the new report.
Not by chance
Speaking today at the Greenhouse 2007 conference in Sydney, he added that the 11 years of below average rainfall in Victoria since 1990 "could be by chance, but that's getting increasingly unlikely." He likened it to tossing a coin. There was a chance that each exceptional year was due to natural fluctuations, but the more that occurred, the more likely it was due to a long-term trend.
Climate Change in Australia, the new report detailing the findings, was authored by experts at the BOM and government research agency the CSIRO. They collated the most up-to-date data on Australian climate and improved predictions (compared to those made in the last report in 2001) about how climate change will affect annual temperatures, rainfall and sea levels.
The report confirms that Australian temperatures have already risen by 0.9oC since 1950, and will increase by a minimum of another 1oC by 2030. However it also warns that if global greenhouse gas emissions do not drop below current levels, temperatures could rise by as much another 5oC by 2070.
According to the report, such a rise in temperature would have a multitude of knock-on effects, such as fewer frosts, many days above 35oC, more powerful cyclones and significantly less rainfall. The authors also noted that snowfall and the length of the winter season would decrease in Australian alpine regions.
Power said the findings are the most unequivocal evidence to date that Australia's current severe drought is in part due to "human intervention" in the climate and that similar extreme weather events will be more likely in the future. Droughts will increase across the whole of Australia, but will be most severe in the southwest, he said.
Best predictions yet
"Under the low [greenhouse gas] emission scenario in 2070, annual rainfall decreases in southern Australian range up to 20 per cent, and up to 30 per cent under the high emission scenario," said CSIRO scientist and co-author Penny Whetton. "An increase in the number of dry days is expected across the country. However, when it does rain, it is likely to be more intense."
The International Panel on Climate Change's (IPCC) fourth assessment report on climate change (see Global warming is our fault, Cosmos Online) had already predicted global sea levels will likely rise by another 18 to 59 cm by 2070. However, the new report warns it's not sea level changes themselves that will have the greatest impact on Australian coastlines – particularly in Victoria and Queensland – but rather the size of storm surges. These are huge waves, created by the wind and low pressure accompanying severe storms, and can cause significant damage to coastal areas. Such a storm surge struck the U.S. city of New Orleans in 2005, causing an estimated US$81.2 billion in damage.
"Everything in life and in business is about assessing risks and managing them. These new climate projections provide a much improved basis... to assess the changes in weather, and climate risks due to climate change," said David Karoly of the University of Melbourne's School of Earth and a co-author of one of the IPCC reports. "For the first time, they provided detailed probability-based assessments of climate change in different regions of Australia."
The report used data from the IPCC fourth assessment report, observations of Australian climate gathered over the last five years and 23 new "state-of-the-art" models of future climate change, said Whetton, to give "the best look yet at Australian climate in the future."
Find CSIRO videos here showing how the temperature will increase while rainfall decreases with global warming, taking into account a mid-range scenario of greenhouse gas emissions.
Howard fiddles while Australia burns!
"We will do nothing about it that might affect the economy."
Action needed now to save our children's futures
It's all very well arguing that a strong economy is important for a good life, but a strong economy needs a strong environment behind it, for all our resources - that's what this government needs to understand. We are reliant on the environment for life and we forget that we are apart of it, just like all the other species on this Earth. Why are we better than them? What gives us the right to change this world’s climate, even though we know the horrors of what might happen?
We have become too greedy and have ignored the signs of a changing climate for too long, it's time to do something drastic, because what world will we leave behind for our children? What will become of their lives in the volatile years ahead?
This government thinks short term, but what about their kids?
I agree with Alice,
How can politicians sleep when the world they are leaving behind for their kids is so grim? We need a new way of thinking and power sources - SOLAR POWER for example, it's a growing industry, why is Australia so unwilling to accept it?? We need these technologies now. Oh, and a new government!