In a twist in the fight against climate change, a new study suggests a reduction in the atmospheric pollution over Asia may actually reduce the amount of tropical rainfall falling on Australia.
A team of international scientists, led by Dr Leon Rotstayn of the Australian Commonwealth Scientific and Research Organisation (CSIRO), used the latest computer climate simulation models to investigate the effect of Asian aerosol pollution on climate change in the Southern Hemisphere.
The research discovered that since the 1950 the "Asian haze" has increased the rainfall and cloudiness over north-west and central Australia by altering the delicate balance of temperature and winds between Asia and Australia.
"But it has nothing to do with Asian pollution being transported directly over Australia", said Dr Rotstayn in a statement.
Aerosols in the upper atmosphere cool the land and surrounding oceans by reflecting heat back into space – the opposite of carbon dioxide, a greenhouse gas which traps heat and is partly responsible for global warming. As economic activity in Asia has increased, so has the output of aerosols into the atmosphere.
The results, says Dr Rotstayn, imply that with the cleaning up of Asian emissions, tropical rainfall in Australia will decline, leading to an increase in the Australian climatic drying trend.
The research, to be published in the journal Geophysical Research , is important as it is the first study to show the effects of aerosol pollution on the climate of Australia.
Including aerosols in climate models and understanding their influence on cloud formation and rainfall is one of the biggest challenges facing climate scientists, says Dr Rotstayn.
"The message from this research is that aerosols are an essential inclusion if we are to accurately describe present and future Australian climate," he said.
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