September 10, 2008

Extreme Waves Threaten Australia’s Coastline

Scientists said on Wednesday that Australia's vast coastline is increasingly being battered by destructive "extreme waves" driven in part by climate change.

Government experts said research into wave size changes over the past 45 years showed waves of 3 meters (9.8 feet) in height or more were increasing, hitting Australia's southern coasts as severe storms become more frequent and intense.

"Extreme wave conditions are greatest south of the Australian continent, associated with the passage of extra-tropical storms along Australia's southern margin," they said in a report.

Climate scientists say Australia, the world's driest inhabited continent, is feeling an accelerated version of global warming, leading to extreme droughts and sudden severe storms.

The country was recently included by the United Nations in a list of vulnerable climate shift "hotspots" as it is vulnerable to shifts in temperature and rainfall because it already has many arid and semi-arid areas.

Average yearly temperatures are projected to increase by as much as 6 degrees Celsius by 2070.

Large coastal cities and towns in the continent's southeast make up the majority of Australia's habitable population, meaning storm surges and extreme waves will increasingly threaten communities with flooding and severe coastal erosion caused by pounding surf.

The report said ocean wave measuring buoys off the island state of Tasmania showed "increased wave heights and anticlockwise rotation of wave direction" in response to a shifting south of storms due to climate shift.

While more active surf could help Australia harness the power of waves to generate electricity and produce less pollution, it also posed risks, said Climate Change Minister Penny Wong.

"Large waves can also be destructive, leading to coastal inundation, erosion and the disturbance of marine habitats," Wong said.

Researchers noticed strong correlations between wave power and changes in climate drivers such as the length and strength of the northern tropical monsoon season.

They said the country must prepare a network of long-term coastal observation sites to improve large wave understanding.

The report was prepared by Australia's national science agency, the Commonwealth Scientific and Industrial Research Organization.


On the Net: