EXTREME weather events in 2009 and March this year provided the people of NSW with an indication of what the state is increasingly likely to face as the climate changes, a report by the federal government's Climate Commission says.
The year 2009 was the hottest year on record in NSW and a rise in the number of similar heatwave events is predicted. The number of days reaching more than 35 degrees in Sydney is expected to triple by 2070.
Climate change ''cannot be ruled out'' as a factor in recent heavy rainfalls, such as the flash flooding in Sydney on March 8, the wettest March day for more than 25 years, the report says.
The state, on average, is expected to become drier, increasing the risk of longer, harsher droughts and of bushfires, but the intensity of downpours could also increase in a hotter climate, due to warmer ocean temperatures.
The report, The Critical Decade, NSW Climate Impacts and Opportunities, is released today. At a public forum at Parramatta Town Hall tomorrow night the public can question members of the commission, which is an independent panel of climate scientists and policy and business leaders.
The chief commissioner, Tim Flannery, said NSW was highly vulnerable to climate change.
''Changes in Sydney's climate will have far-reaching implications for health, agriculture, tourism, water security and biodiversity,'' said Professor Flannery, who will attend the forum.
But the state also had the opportunity to benefit from a boom in clean energy, he said.
NSW is a world leader in research on solar photovoltaics and has produced the heads of four of the six top global manufacturers of this technology, including Shi Zhengrong, the chief executive of the world's largest solar company, Suntech.
The report says an estimated $20 billion would be invested in solar power in Australia by 2020 and NSW was ''well placed'' to capitalise on this.
''Even if solar panels are imported from overseas, around 30 to 40 per cent of panel installation costs will go to local installers,'' it says.
The climate commissioners Will Steffen and Lesley Hughes, who will also attend the forum, said a shift to cleaner energy sources was needed to help minimise climate change risks.
''This is the critical decade for action. The longer we wait, the more difficult and costly it will be,'' Professor Steffen, of the Australian National University, and Professor Hughes, of Macquarie University, conclude in their report summary.
They say the coastal areas of NSW face significant risks from sea level rises. ''A 1.1-metre rise by the end of the century could put between 40,000 to 60,000 houses, 1200 commercial buildings and 250 kilometres of highway in NSW at risk of inundation.''
With a sea level rise of 0.5 metres, storm surge flooding in Sydney that is now considered a one-in-100-year event could occur every few months.