CSIRO

In the future fewer tropical cyclones may form off Western Australia but they may become more intense, shows new research from a Western Australian climate research collaboration.

CSIRO climate scientist Deborah Abbs says there could be a 50 percent reduction in the number of storms in the second half of this century - from 2051-2090 - compared to the period from 1971-2000.

However, the climate model developed by Dr Abbs' team indicates a distinct shift towards more destructive storms.

"Despite a decrease in the number of tropical cyclones, there is a greater risk that a tropical cyclone that forms will be more severe in future," Dr Abbs said.

"Even a small increase in cyclone intensity is concerning because of the threat to life, property, industry and agriculture," Dr Abbs said.

"Despite a decrease in the number of tropical cyclones, there is a greater risk that a tropical cyclone that forms will be more severe in future."

Dr Deborah Abbs, CSIRO climate scientist

Dr Abbs is presenting her research at an annual meeting of scientists and policy makers of the Indian Ocean Climate Initiative (IOCI) which is a strategic research partnership between the WA government, CSIRO and the Bureau of Meteorology. IOCI's aim is to build the science-policy partnerships to examine the climate influences that are important for Western Australia.

Already a significant proportion of the Western Australian coastline, as well as offshore industry, is vulnerable to the threat of tropical cyclones, and this area is likely to change. Dr. Abbs' research shows 100-km southward movement in both the formation and decay regions of tropical cyclones in Western Australia by later this century: which means areas not currently affected may face the risk of tropical cyclones in the future.

The incidence and behaviour of tropical cyclones is complex. Wind speed alone does not fully explain a cyclone's potential to cause damage, particularly via wave or storm surge, so the researchers used an additional measure (called integrated kinetic energy) that accounts for both wind speed and the overall area covered by a cyclone's strong winds. Importantly, Dr Abbs' research shows this measure also indicates a distinct shift toward more destructive cyclones.

Western Australians have a long history of living with tropical cyclones. However, this research sends a clear message that we need to continue to plan towards and build upon our preparations and response to potentially more destructive storms in the future.

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