DEFORESTATION by European settlers may be to blame for making Australia鈥檚 drought longer, hotter and dryer than it would be otherwise.
The 鈥渂ig dry鈥�, Australia鈥檚 11-year drought, has been blamed on greenhouse gases and natural variability. To see if deforestation played a part, of the University of Queensland in Brisbane and colleagues used a climate model to simulate Australian conditions from the 1950s to 2003. They then compared the impact of today鈥檚 fragmented vegetation, obtained from satellite images, with that of 1788, prior to European settlement.
Over much of south-east Australia, where the drought has hit hardest, less that 10 per cent of the original vegetation remains. The team鈥檚 model showed that this land clearance has increased the length of droughts in the area by one to two weeks per year. In years of extreme drought, the loss of vegetation caused the number of days above 35 掳C to increase by six to 18 days, and the number of dry days to increase by five to 15 days (Geophysical Research Letters, in press).
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鈥淟and clearing may be having a similar impact on the drought as greenhouse gases,鈥� says McAlpine. Reforestation could minimise future droughts, he adds.
鈥淚t鈥檚 a nice piece of work,鈥� says of the University of New South Wales in Sydney, but he adds that the modelling needs to be confirmed.
