Approaching storm clouds near Griffith, NSW. (Gregory Heath)
Study indicates a changing climate in the south-east
Despite recent rainfall in parts of eastern Australia, a recently released scientific report indicates an increasing risk of below-average rainfall and runoff into streams, and drier conditions into the future in south-eastern Australia.
The South Eastern Australian Climate Initiative (SEACI) report: Climate variability and change in south-eastern Australia, highlights the effects of climate variability and change on the water resources of the south-east.
The SEACI report is a synthesis of findings resulting from the first phase of a collaborative research project between the Australian Department of Climate Change and Energy Efficiency, the Victorian Government Department of Sustainability and Environment, the Managing Climate Variability R&D Program, and the Murray-Darling Basin Authority. The research was undertaken by CSIRO and the Bureau of Meteorology.
A key finding of the report is that the recent 13-year drought was unprecedented in the historical record in terms of its extent, reduced year-to-year rainfall variability, and the seasonal pattern of the rainfall decline. As a result of the nature of the changes in rainfall, the reductions in runoff have been greater than expected.
"The research indicates that these changes can be linked to global warming, making it a likely contributor to the recent drought."
Dr David Post, SEACI Program Director
“While 2010 has brought welcome rains for much of south-eastern Australia, there is growing evidence from SEACI research that a long-term trend towards a drier climate is taking place,” said Program Director, CSIRO’s Dr David Post.
“Changes to large-scale atmospheric circulation patterns are impacting on rainfall and runoff in the south-east, particularly in the southern Murray–Darling Basin and Victoria.”
These observed changes indicate a shift in the overall climate of south-eastern Australia, similar to what has been experienced in rainfall and runoff in south-west Western Australia since the 1970s.
“The research indicates that these changes can be linked to global warming, making it a likely contributor to the recent drought.”
The report notes that natural climate variability is also likely to be a contributing factor to the rainfall and runoff decline.
“The next three years of research under Phase 2 of SEACI aim to improve our understanding of the extent to which these changes can be attributed to climate change; to improve projections of the impacts of climate change on water resources; and to advance seasonal forecasting of climate and streamflow,” Dr Post said.
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