There is a news article on the recent excellent MacAlpine research group papers
McAlpine, C.A., J. Syktus, J.G. Ryan, R.C. Deo, G.M. McKeon, H.A. McGowan, and S.R. Phinn, 2009:A continent under stress: interactions, feedbacks and risks associated with impact of modified land cover on Australia’s Climate. Global Change Biology, in press. doi: 10.1111/j.1365-2486.2009.01939.x
Deo, R. C., J. I. Syktus, C. A. McAlpine, P. J. Lawrence, H. A. McGowan, and S. R. Phinn, 2009: Impact of historical land cover change on daily indices of climate extremes including droughts in eastern Australia, Geophys. Res. Lett., 36, L08705, doi:10.1029/2009GL037666.
The news article in New Scientist on May 16 2009 is titled Land clearances turned up the heat on Australian climate and reads
“DEFORESTATION by European settlers may be to blame for making Australia’s drought longer, hotter and dryer than it would be otherwise.
The “big dry”, Australia’s 11-year drought, has been blamed on greenhouse gases and natural variability. To see if deforestation played a part, Clive McAlpine 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’s 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’s 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 °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).
“Land clearing may be having a similar impact on the drought as greenhouse gases,” says McAlpine. Reforestation could minimise future droughts, he adds.
“It’s a nice piece of work,” says Andy Pitman of the University of New South Wales in Sydney, but he adds that the modelling needs to be confirmed.”
This excellent article highlights the role of land use change as a first order climate forcing. This climate forcing was inadequately reported on in the recent IPCC and CCSP climate assessments.