- Bridie Smith
- The Age, February 5, 2009
THE cause of the record-breaking drought in south-eastern Australia has been discovered far off in the Indian Ocean, according to the surprise findings of a study that overturns decades of weather research.
While drought in Australia has traditionally been linked to El Nino events in the Pacific Ocean, researchers from the universities of NSW and Tasmania and the CSIRO have found that it is the Indian Ocean's cycle of warming and cooling that is to blame.
The water cycles of the Indian Ocean, which is experiencing unprecedented warming 2000 kilometres away, dictates the strength of the moisture-bearing winds that travel to Australia.
Caroline Ummenhofer from the University of NSW's Climate Change Research Centre said the winds from the Indian Ocean had been weak since 2006, which had reduced the volume of water they picked up and transported to Australia.
The research explains why a string of La Nina events in the Pacific Ocean, which usually bring rain, have failed to break the drought.
The findings are presented in a paper to be published in the US journal Geophysical Review Letters.