Parts of Australia could be 5 degrees Celsius (9 degrees Fahrenheit) hotter and 80 percent drier by 2070 if global greenhouse gas emissions are not radically reduced, government data said Tuesday.
The report by the Bureau of Meteorology and the government's main research body, the Commonwealth Scientific and Industrial Research Organization, predicts lower rainfall, longer droughts and more searing hot days for Australia, known by locals as "the sunburned country."
Penny Whetton, a climate scientist with the CSIRO, said Australia is already locked in to a 1 C (1.8 F) increase in average temperatures by 2030 due to past carbon dioxide emissions, and that the figure could rise as high as 5 C (9 F) by 2070 if global emissions are not dramatically reduced.
Rainfall across Australia, already the world's driest inhabited continent, could fall by up to 30 percent by 2070, with longer periods of drought broken by short bursts of more intense downpours, Whetton said.
Under the most extreme scenario, Australia's northern city of Darwin could face as many as 230 days above 35 C (95 F) each year, compared with just 11 under present average temperatures.
Southwestern Australia, one of the country's premier wine-growing regions and an agricultural breadbasket, will be hotter and drier in coming decades, with periods of drought increasing by up to 80 percent by 2070.
Meanwhile, rainfall is forecast to increase in the country's tropical north, home to the World Heritage-listed Kakadu National Park, with more severe cyclones and coastal flooding also predicted.
"Some climate change for Australia is certainly inevitable, so we're going to need to adapt to its impact," Whetton told reporters at a climate change conference in Sydney. "However, for later on in the century, if we're able to reduce our global levels of greenhouse gas emissions we'll be able to reduce the risks of some of those higher rates of warming."
Report co-author Scott Power dismissed critics who claim such long-term variations in climate are part of the normal weather cycle, saying scientists were "more confident than ever" that human activity is largely responsible for global warming.
"Yes, you can still have a whole range of climatic variability from natural sources, but the changes we've seen over the past 50 years or so have been dominated by ... human increases in greenhouse gases," Powers told the Australian Broadcasting Corp. radio.