Issue #1434 4 November 2009
Confirmed – Australian coastline under climate change threat
The questions were bound to be asked at some stage. If climate change is causing polar ice caps to melt and low-lying island nations are already starting to disappear, how long can it be before coastal settlements in Australia come under threat from rising sea levels and extreme weather events? How ready is Australia to deal with this unfolding challenge? What about the planning and insurance issues?
Should affected property owners be compensated, relocated or barricaded against the swelling tides? Some deep official thinking has been going on but the results so far are not comforting for the 80 percent of Australians who live in our coastal zones.
A bi-partisan House of Representatives committee has spent the past 18 months looking at these and other climate change-related questions. Their report – Managing Our Coastal Zone in a Changing Climate – will end up on the desks of Climate Change Minister Penny Wong and Environment Minister Peter Garrett. Wong is due to deliver her first major assessment of the vulnerability of Australia’s coastline sometime this month. The task will not be a pleasant one.
The committee found that over 700,000 Australian addresses were within three kilometres of the current shoreline and less than six metres above sea level. The occupants face varying levels of risk. The committee worked on the conservative assumption from the UN Intergovernmental Panel on Climate Change (IPCC) that sea levels will swell by 80 centimetres by the year 2100. Senior CSIRO researcher John Church concedes “Even the IPCC recognise they did not represent the melting of ice sheets adequately and all the uncertainty is on the up side.” Recent estimates put the likely rise at between 1.4 and 2 metres.
A rise of 80 centimetres or even two metres may not sound like an extreme threat but other factors come into play to worsen the outlook. Ocean scientists apply what is called the Bruun rule which means that a one metre rise in sea level results in the shoreline being pushed back between 50 and 100 metres. John Hunter has been advising the government’s committee and notes that sea level rise will be accompanied by an increase in the frequency of extreme weather events. A 20 centimetre rise will increase the frequency of extreme events like storms and floods ten times.
A 50 centimetre rise would increase it by a factor of about 300. “If you have a flooding event which only happens every year at the moment, by the end of the century it will be happening every day,” Dr Hunt told The Sydney Morning Herald.
Councils have been pressed by real estate sharks to allow vulnerable seaside land to be developed for many years but an awareness of the climate change-related risk is starting to enter into the equation. NSW already spends around $200 million a year on coastal erosion and flooding. In Victoria, the Great Ocean Green resort development between Apollo Bay and Marengo has been canned because of the projected rise in sea levels. In 2008, the Victorian Civil and Administrative Tribunal blocked a proposal for six seaside homes for the same reason.
The properties set to be affected by climate change are valued at between $50 billion and $150 billion. Insurers are nervous and already exempt what are called “saltwater risks” like erosion from their coverage. Karl Sullivan – general manager of the Insurance Council of Australia – warned the House of Representative committee “Clearly where land is inundated or eroded by rising sea levels, coastal landowners and lenders in the banking and finance sector could face significant losses.”
Rising temperatures and sea levels threaten flora and fauna in freshwater wetlands. There will be an increase of mosquito-borne viruses like Ross River fever and dengue fever.
Next article – The UN Association of Australia presents case of Cuban Five
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