Monday 20 February 2006

MEDIA RELEASE

Tropical cyclones and climate change

Leading scientists provide an expert view of the current state of knowledge. They note that there has been a high level of interest in the topic and that substantial debate is still occurring within the scientific community. With regard to the recent tropical cyclone seasons they conclude: "No single high impact tropical cyclone event of 2004 and 2005 can be directly attributed to global warming, though there may be an impact on the group as a whole."

Dr Geoff Love, the Australian Director of Meteorology, has submitted to the World Meteorological Organization's Commission for Atmospheric Sciences, meeting in Cape Town, South Africa, a "Statement on Tropical Cyclones and Climate Change". The Statement was prepared by an expert group of scientists comprising Dr John McBride and Dr Jeff Kepert of the Bureau of Meteorology in Australia, Professor Johnny Chan of China, Julian Heming of the UK, and Dr Greg Holland, Professor Kerry Emanuel, Thomas Knutson, Dr Hugh Willoughby and Dr Chris Landsea of the US.

The paper reaffirms the finding of a 1998 study saying that any change in the frequency of tropical cyclones (hurricanes/typhoons) due to climate change cannot be determined due to a lack of knowledge and limitations of the available observing technologies. The little evidence that does exist indicates little or no change in global frequency.

It also says that while some recent studies have suggested the intensity of tropical cyclones (hurricanes/typhoons) has increased substantially over the past 50 years due to climate change, the scientific community is "deeply divided". Some researchers believe the climate record is too inconsistent to draw such a conclusion due to changes in observations equipment and methods over time. The panel says it cannot come to a definitive conclusion in this "hotly debated area".

The report makes a number of observations including:
* The rising damage bill and disruption associated with tropical cyclones (hurricanes/typhoons) is due to a large extent to increasing coastal populations and rising insured values in coastal areas. Any significant increase in storm activity would compound these problems.
* The primary cause of death in major cyclones of the past has been sea-water flooding. Projected rises in sea level are a concern.
* No single disaster caused by a tropical cyclone (hurricane/typhoon) in 2004 or 2005 - including Hurricane Katrina in the US - can be directly attributed to global warming. Rather, climate change may have an impact on the group as a whole.
* Further research is needed.

The paper
"Statement on Tropical Cyclones and Climate Change": http://www.bom.gov.au/info/CAS-statement.pdf

Further information
Dr Geoff Love, Director of Meteorology, (03) 9669 4558
Dr John McBride, Principal Research Scientist, Bureau of Meteorology, (03) 9669 4421

Ends