17 January 2004

Hotter summers, fewer frosts for Australia

Up to 15% less rainfall is expected in the south and east by 2030, especially in winter and spring. In the southwest, rainfall may decline by up to 20%. This is likely to be associated with more droughts.

'With likely increases in evaporation this means drier conditions in future, with reduced water supply and greater water demand. In the southwest, rainfall has already decreased by about 20% since the mid-1970s,' he says.

Australia has already warmed by about 0.8% since 1950. 'This doesn't sound like much but it has been associated with an increase in extremely hot days and hot nights, and a decrease in extremely cold days and cold nights,' says Mr Hennessy.

The Bureau of Meteorology recently announced that 2003 was Australia's 6th warmest year since 1910, with the global average temperature being the 3rd warmest since 1861. The hottest year, both globally and in Australia, was 1998.

The impacts of changes in climate are widespread, says Mr Hennessy. 'Hotter and drier conditions would lead to greater fire risk, more heat stress for humans, crops and livestock, greater energy demand for air conditioning. But there will also be less energy demand for winter heating and less frost damage, so there will be winners and losers.'

He says strategies to adapt to climate change include water demand management (for example, restrictions and recycling), breeding and selection of heat-tolerant and drought-tolerant crops, adjusting cropping calendars to take advantage of a longer frost-free period, more shade and water for livestock, and heat-smart buildings.

'However, some animals and plants may be highly vulnerable to climate change, with limited options for adaptation. For example, coral reefs are likely to experience more bleaching, and some Western Australian frogs and east Australian alpine mammals will find their habitats shrinking as the temperature rises.'

Gee, I'm glad the earth isn't warming.

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