'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: Drought may take toll on Congo rainforest, study finds

add to favorites email to friend print save as pdf

Related Stories

Ranchers benefit from long-term grazing data

Apr 16, 2014

Scientists studying changes in the Earth's surface rely on 40 years of Landsat satellite imaging, but South Dakota ranchers making decisions about grazing their livestock can benefit from 70 years of data ...

Agriculture's growing effects on rain

Apr 15, 2014

(Phys.org) —Increased agricultural activity is a rain taker, not a rain maker, according to researchers at Pacific Northwest National Laboratory and their collaborators at the University of California Los ...

UN weather agency warns of 'El Nino' this year

Apr 15, 2014

The UN weather agency Tuesday warned there was a good chance of an "El Nino" climate phenomenon in the Pacific Ocean this year, bringing droughts and heavy rainfall to the rest of the world.

Warm US West, cold East: A 4,000-year pattern

Apr 16, 2014

Last winter's curvy jet stream pattern brought mild temperatures to western North America and harsh cold to the East. A University of Utah-led study shows that pattern became more pronounced 4,000 years ago, ...

Climate change as a matter of public health

Apr 08, 2014

For a long time people perceived climate change as an environmental issue–the concern of environmentalists, the concern of a few. It was reframed as a justice issue at the turn of the 21st century, when ...

Recommended for you

Untangling Brazil's controversial new forest code

16 minutes ago

Approved in 2012, Brazil's new Forest Code has few admirers. Agricultural interests argue that it threatens the livelihoods of farmers. Environmentalists counter that it imperils millions of hectares of forest, ...

China toughens environment law to target polluters

16 minutes ago

China on Thursday passed the first amendment to its environment protection law in 25 years, imposing tougher penalties on polluters after the government called for a "war" on pollution.

Sea floor conditions mimicked for drilling platforms

4 hours ago

Mobile jack-up drilling platforms used in the oil and gas industry are at risk of rejection before installation due to their use in harsher environments and deeper waters—but University of WA scientists ...

User comments : 0

More news stories

Untangling Brazil's controversial new forest code

Approved in 2012, Brazil's new Forest Code has few admirers. Agricultural interests argue that it threatens the livelihoods of farmers. Environmentalists counter that it imperils millions of hectares of forest, ...

How productive are the ore factories in the deep sea?

About ten years after the first moon landing, scientists on earth made a discovery that proved that our home planet still holds a lot of surprises in store for us. Looking through the portholes of the submersible ...

Genetic code of the deadly tsetse fly unraveled

Mining the genome of the disease-transmitting tsetse fly, researchers have revealed the genetic adaptions that allow it to have such unique biology and transmit disease to both humans and animals.

Ocean microbes display remarkable genetic diversity

The smallest, most abundant marine microbe, Prochlorococcus, is a photosynthetic bacteria species essential to the marine ecosystem. An estimated billion billion billion of the single-cell creatures live i ...