Climate change fears worsen following University of Melbourne and CSIRO ­research

THE impact of climate change on the weather in Victoria could be twice as bad as previously thought.

THE impact of climate change on the weather in Victoria could be twice as bad as previously thought.

A team of University of Melbourne and CSIRO ­researchers believes popular computer predictions over-estimate the flow of rain run-off into rivers.

Victorian Government scientists believe the state faces a much warmer and drier ­future which could result in longer fire seasons, less rainfall in winter and spring south of the Great Dividing Range, and less rainfall in autumn, winter and spring in the north.

Scientists say climate change is already being felt across Victoria, with a rise in temperature and a drop in rainfall since 1950.

The university research found climate modelling failed­ to adequately cater for drought.

“Under prolonged dry conditions, modelling predicted twice as much run-off into rivers and catchments than was occurring,” Prof Andrew Western said.

Prof Western is a water­ ­resources expert and deputy head of the Department of ­Infrastructure Engineering at the University of Melbourne.

He said the findings are based on analysis of river flows during the devastating millennium drought, which ended in 2009.

He said an urgent review was needed of plans to manage water resources.

“It means we have to go back to the drawing board with our climate change risk assessment for our water ­resources,” he said.

University researchers and the CSIRO used government monitoring records of river flows and rainfall in about 120 catchments extending from South Australia, Victoria, NSW and Queensland.

River flows during the long drought were much less than the models predicted in about half of the catchments studied, they found.

The worst-hit areas where water flows were much less than the models predicted ­include western and central Victoria and parts of southern and northern NSW.

A spokeswoman for the Murray Darling Basin Authority said modelling for NSW and Victorian catchments was undertaken by state agencies.

“Any model is as good as data available and is also ­affected by context. Such global models may not suite local catchments, or may depend on seasonal variability,” the spokeswoman said.