Federal scientists said that greenhouse gas emissions and ozone depletion are behind the long-term decline in rainfall in southwestern Australia.

Scientists at the National Oceanic and Atmospheric Administration (NOAA) developed a high-resolution climate model to understand the pattern of rainfall across the world. The model forecasts a decline of 40 percent in average rainfall in southwestern Australia in the next few decades.

"This new high-resolution climate model is able to simulate regional-scale precipitation with considerably improved accuracy compared to previous generation models," said Tom Delworth, a research scientist at NOAA's Geophysical Fluid Dynamics Laboratory in Princeton, N.J. "This model is a major step forward in our effort to improve the prediction of regional climate change, particularly involving water resources."

According to researchers, global climate model was used to create several climate simulations to understand changes in rainfall in different parts of the planet. The most striking change, they found, was in southwestern Australia. This region has experienced substantial decline in rainfall in the past few decades.

The team found that only manmade greenhouse emissions plus ozone depletion can explain the decrease in rainfall in Australia. Researchers also accounted for other factors such as volcanic activity and sun's radiation, but found that none of them were related to the change in rainfall pattern in the region.

Southern Australia has witnessed a decline in rainfall since 1970. According to the scientists, the new model predicts that the region will continue to see a drop in rainfall levels throughout the 21st century.

"Predicting potential future changes in water resources including drought are an immense societal challenge," said Delworth in a news release. "This new climate model will help us more accurately and quickly provide resource planners with environmental intelligence at the regional level. The study of Australian drought helps to validate this new model, and thus builds confidence in this model for ongoing studies of North American drought."

The study published in the journal Nature Geoscience.

Related research has shown that South Asia is experiencing frequent bouts of extreme wet and dry spells, which could lead to drastic floods and even droughts in the future.