'Asian haze' impacts on Australian rainfall

Dec 12, 2006

Elevated particle emissions resulting from increased economic activity in Asia may have increased Australia’s tropical rainfall, according to new research on the way pollution influences our climate.

"Until now, there has been ample evidence that these particles have important effects on climate in the Northern Hemisphere but little such evidence in the Southern Hemisphere," says CSIRO Marine and Atmospheric Research scientist, Dr Leon Rotstayn.

"What we have seen in our latest climate simulations is that the ‘Asian haze’ is having an effect on the Australian hydrological cycle and generated increasing rainfall and cloudiness since 1950, especially over northwest and central Australia. The effect occurs because the haze cools the Asian continent and nearby oceans, and thereby alters the delicate balance of temperature and winds between Asia and Australia. It has nothing to do with Asian pollution being transported directly over Australia."

Dr Rotstayn says this implies that decreasing pollution in Asia later this century could reverse this effect and lead to an increase in Australian drying trends.

"We are really at the beginning of understanding the trends but sooner or later these emissions will be cleaned up and then a trend of increasing rainfall in the northwest and centre could be reversed. This is potentially serious, because the northwest and centre are the only parts of Australia where rainfall has been increasing in recent decades."

Dr Rotstayn stresses that climate modelling is a valuable tool for teasing out what is actually causing weather trends, rather than simply assuming that these trends are all related to greenhouse gases.

At a time when Australian science agencies are investing in new climate forecasting capabilities, the research – to be published early in 2007 in the Journal of Geophysical Research – increases confidence in the accuracy of future climate simulations for Australia.

An aerosol is a haze of particles in the atmosphere. Dr Rotstayn says representing aerosols in climate models and understanding their influence on cloud formation and rainfall is one of the biggest challenges facing climate scientists.

"Because the cooling effect of aerosol pollution is possibly comparable to the warming effect of increased levels of carbon dioxide, the message from this research is that aerosols are an essential inclusion if we are to accurately describe present and future Australian climate," he says.

The new research is based on simulations performed with a new low-resolution version of CSIRO’s global climate model – including a treatment of aerosols from both natural and human-induced sources.

Source: CSIRO Australia

Explore further: Mexico investigates mass fish death in lagoon

add to favorites email to friend print save as pdf

Related Stories

Changes in farming and climate hurting British moths

Aug 29, 2014

Britain's moths are feeling the pinch – threatened on one side by climate change and on the other by habitat loss and harmful farming methods. A new study gives the most comprehensive picture yet of trends ...

Is Hawaii prepared for the impacts of climate change?

Aug 21, 2014

The Hawaiian Islands represent a wide diversity of ecosystems and environments, including areas of breathtaking natural beauty as well as densely populated coastal cities. These unique environments are already ...

Recommended for you

Halliburton pays $1.1 bn for Gulf of Mexico BP spill

4 hours ago

Oil services company Halliburton said Tuesday it would pay a $1.1 billion settlement over its role in the 2010 Gulf of Mexico oil rig blowout that led to the United States' most disastrous oil spill.

Underwater grass comeback bodes well for Chesapeake Bay

4 hours ago

The Susquehanna Flats, a large bed of underwater grasses near the mouth of the Susquehanna River, virtually disappeared from the upper Chesapeake Bay after Tropical Storm Agnes more than 40 years ago. However, ...

Clean air halves health costs in Chinese city

7 hours ago

Air pollution regulations over the last decade in Taiyuan, China, have substantially improved the health of people living there, accounting for a greater than 50% reduction in costs associated with loss of life and disability ...

User comments : 0