Thursday, November 18, 2004

CSIRO warns: Australia to get hotter, wetter, with more extreme weather


Recent research by CSIRO and Bureau of Meteorology scientists puts forward that climate change is a reality in Australia and is set to make the Australian climate much warmer, wetter, with more extreme weather events. While average rain across the continent has increased over the last 50 years, certain areas such as south west Australian and parts of Eastern Australia may actually be much drier.

Average temperatures are set to rise, with the possibility that some inland towns may become inhabitable. Bush fires, droughts, storms and flooding will have increasing impact on social and economic infrastructure. The overwhelming consensus amoung scientists is that such climate change has been brought about through global warming caused to a large extent by greenhouse gases such as carbon dioxide produced by humans.

* Predictions for Victoria
* Climate hots up in NSW for Premier Carr
* Increase in extreme rainfall
* Australia is getting wetter, while droughts continue


Predictions for Victoria

In July a new regional analysis of climate change in Victoria showed that climate is changing and will have wide-ranging effects across the State.

"Overall, Victoria has already warmed by about half a degree Celsius since 1950," said Dr Penny Whetton, Leader of the Climate Impacts Group at CSIRO Atmospheric Research in Melbourne.

"By 2070 Victoria is likely to be 0.7 to 5.0 degrees Celsius warmer, compared to 1990," she said. "Climate change in Victoria is likely to lead to more hot days, fewer frosts, more heavy rainfall and drier conditions leading to greater bushfire risk."

Dr Whetton said that although there is considerable uncertainty about climate change at the regional to local scale, the science does show up differences in projected temperature and rainfall change across Victoria.

Regional projections show average warming is stronger in the northern regions, and less in the coastal regions. For example, in Benalla the current frequency of 17 winter days below zero degrees Celsius is projected to decline by 2070 to between 11 days and no frost days at all. The number of hot days will increase, for example, in Echuca the current frequency of 16 summer days over 35 degrees Celsius is projected to increase to between 20 and 49 days by 2070.

The risk of increased drought is strongest in the west and north, and weakest in east Gippsland. Water resources are likely to decline everywhere but this is more marked in the northern regions.

Dr Whetton said that although the risk of warming at the high end of range can be lowered by global reductions in greenhouse gas emissions, some regional climate change cannot be avoided and adaptation will be required. "Risks and opportunities vary substantially from region to region and adaptive responses will need to be planned," she said.

"For example, in the Wimmera the need to adapt broad-acre cropping, particularly wheat production, to a changing climate is probably the greatest concern."

"Concern about reduced natural snow cover and the impact that this may have alpine tourism would be greatest for the Northeast region, while increases in the risk of flooding of infrastructure are more significant for the urbanised Port Phillip region," she said.

Climate hots up in NSW for Premier Carr

In Sydney in November politicians and scientists with the International Taskforce on Climate Change, hosted by NSW Premier Bob Carr, gathered to discuss how to improve global action, in particular finding a way to bring Australia and the US back into the fold. Australia and the United States are the two major industrialised countries refusing to ratify the Kyoto treaty.

CSIRO scientist Kevin Hennessy, speaking to Anne Barker of the ABC radio program The World Today, said "Over the last 50 years Australia has warmed by about 0.8 of a degree Celsius. Now, to most people that probably doesn't sound like much and in fact to cold places it probably sounds like very good news. But in fact a small change in average temperature is associated with quite large changes in extreme temperatures and we then in fact experience increases in the number of hot days and hot nights and decreases in the number of cold days and frosty nights."

The Sydney Morning Herald on Monday November 15, lead with an article: 'Living in an oven - dire alert for NSW.' A CSIRO and BOM report produced by Kevin Henessy and other scientists predicts many parts of NSW will experience many more days with temperatures over 35 degrees, increased bush fire risk, and increased extreme weather events. NSW can expect soaring temperatures and a 70 per cent increase in the number of droughts by 2030.

Average days above 35 degrees
Town Now 2030 2070
Wilcannia 59 83 136
Cobar 41 65 128
Walgett 56 87 153
Gunnedah 19 40 103
Yamba 1 2 7
Bathurst 4 11 43
Sydney 3 6 18
Moruya 2 3 6
Canberra 5 13 42
Wagga 20 34 78
West Wyalong 26 42 93
Deniliquin 24 37 75
*Max of range in worst scenario - Source CSIRO, BOM

The New South Wales Premier, Bob Carr, presented the CSIRO/BOM report to the International Taskforce on Climate Change meeting in Sydney. Bob Carr said "This is deadly serious and it's upon us. Global warming has got New South Wales in its grip as much as any other part of the world. We face these terrible increases in average climate. Parts of our State are already very hot, but if you look at where they're going to be by 2012 and then after 2030, is really going to be living in an oven."

The International Climate Change taskforce co-chairman, and former British minister, Stephen Byers said "Unless action is taken by governments across the whole of the globe, then we're going to face droughts, we're going to face really extreme weather conditions. We know in the UK we've had floods this year that we've never seen before. Last year in Europe we had a heatwave which led to the loss of tens of thousands of lives. In America we've seen hurricanes hitting the coast of Florida and Louisiana. Wherever you look in the world, we're seeing the consequences of global warming."

In response to a question on ABC radio program PM on the content of the CSIRO report, Byers said: "Well no change is not an option. You can see very clearly the damaging effects to Australia of climate change. And the challenge for the John Howard Government is, is he prepared to take on the political challenge of saying yes, I recognise that something needs to be done. I don't believe that Kyoto is in the interests of Australia, which is what John Howard has said, but I recognise there will be a different way forward for Australia, and that we in Australia will do our bit to tackle global warming."

Bob Carr defended the possible construction of a new coal-fired power station in NSW on ABC Television program Lateline. Greens MP Ian Cohen accused Bob Carr of being hypocritical: "The Premier is deceiving the people of NSW about his Government's green credentials .... He will only become part of the problem on climate change, not the cure, unless he takes action to reduce the state's dependence on coal mining and coal-fired power." said Ian Cohen.

Environment groups gathered outside NSW Government House where Bob Carr addressed the International Climate Change Taskforce. They protested against the state's reliance on coal as a power source and the expansion of the coal industry in NSW.

"Mr. Carr will lose credibility if this meeting is a mere talk-fest," said Greenpeace Campaigns Manager Danny Kennedy. "With the Kyoto Protocol coming into force and climate change impacts becoming more obvious, the only responsible policy for any government is to commit to moving away from dirty coal, and towards clean, renewable energy. The sad reality is that New South Wales is a major greenhouse polluter with no long-term policies in place to effectively wean the state from its addiction to coal. NSW gets almost 90% of its electricity from dirty, polluting coal and positive sources like solar and wind are tragically underdeveloped. The Carr Government is allowing construction of five new coal mines and expansion of eight existing mines, and eleven new mines and one new coal-fired power plant are being proposed."

Kennedy accused the Howard Government of the key climate crime of the rejection of the Kyoto Protocol, but was adamant that State Labor Governments could be more proactive with climate friendly policies “The key cliat the state level. "If Premier Bob Carr put forward policy to dramatically reduce the biggest state’s addiction to coal, it would make him a leader on environmental issues and put considerable political pressure on John Howard to follow suit and sign Kyoto", said Kennedy.

Environmentalists campaigning against more coal fired power stations were supported by Clive Hamilton, the executive director of the Australia Institute. "I think there's a tremendous scope in Australia for the growth of new renewable energy industries, which ought to obviate the need for construction of any new coal-fired power stations," he said.

Increase in extreme rainfall

"The most extreme rainfall events we currently experience become more frequent in 2040, with the 1-in-40 year event of today corresponding with a 1-in-15 year event in future," said Dr Debbie Abbs, a climate scientist at CSIRO Atmospheric Research in Melbourne.

"The areas of greatest increase in intensity occur over mountainous terrain, inland from Coffs Harbour, Coolangatta and north of Brisbane."

Each year extreme rainfall events cause significant damage, as a result of flooding, in the highly urbanised regions along Australia's eastern coastline where population is increasing. Dr Abbs says that a 26% increase in flooding leads to a 60% increase in damage costs. "With projected increases in the intensity and frequency of extreme precipitation events, the community's exposure to extreme rainfall events is growing rapidly," says Dr Abbs.

"Global climate models simulate rainfall over areas as wide as 200 kilometres. Extreme rainfall over small areas is much more than that found over large areas where results are averaged out," said Dr Debbie Abbs.

Dr Abbs was presenting her research at the Australia New Zealand Climate and Water Forum in Lorne, Victoria, in early November.

Australia is getting wetter, while droughts continue

Averaged over the entire Australian continent, rainfall has increased over the past 50 years, according to new research by Dr Ian Smith, a climate scientist at CSIRO Atmospheric Research. While many areas over Australia recently have experienced drought, the trend in other areas has been towards wetter conditions. "Unfortunately, the wetter conditions have occurred in the more sparsely populated regions," said Smith.

Rainfall data compiled by the Bureau of Meteorology analysed by Dr Smith shows that rainfall has increased over the summer half of the year in large parts of western, northern and central Australia over the period 1952 to 2002. The subsequent two summers since the analysis was completed have also been relatively wet in those parts of the continent.

"The trends are sufficiently large and widespread to be classified as unusual in a historical context," says Dr Smith. "Furthermore, the wetter conditions may be signs of a changing climate, as foreshadowed by climate experts almost 20 years ago."

The study will be published in the Australian Meteorological Magazine. The trends towards wetter conditions contrast with the long-recognised trend towards drier regional conditions - such as the sudden decrease in rainfall in south-west Western Australia in the mid-1970s, a drying trend over south-east Australia since 1996, and a longer-term drying trend over southern Australia since the 1970s.

In a related research published in Geophysical Research Letters, Dr Richard Wardle of the University of Melbourne and Dr Smith looked at the relationship between increasing summer rainfall and Australia's rising temperature. "Using a climate model we found that forcing the land to absorb more energy causes a complex response whereby the monsoon region becomes wetter and cooler in summer but in the drier regions it becomes wetter and warmer," he says.

"This result is important because it indicates that a regional response to climate change can be very different to the large-scale response. This may be important when interpreting paleoclimate records and is likely to be important when estimating the effects of future climate change," Dr Smith says.

Meanwhile, "Australia has one of the worst records in greenhouse policy in the developed world." according to Frank Muller, a Professor at University of NSW. "The way the science has been heading, we may in our own lifetimes be seeing changes that will make us regret failing to take action earlier." he said.

Sources:

* CSIRO: Increased risk of drought due to climate change is strongest in the west and north of Victoria
* CSIRO: Climate change to increase extreme rainfall
* CSIRO: You think it's drier but Australia is wetter
* ABC Lateline: CSIRO warns of climate change
* ABC Lateline: Carr discusses the heat on NSW
* Greenpeace: Climate taskforce:Carr must reject coal and push Howard to join Kyoto
* ABC Radio - The World Today: CSIRO warns Australia will get hotter unless we reduce greenhouse gases
* ABC Radio - PM: Climate change taskforce warns of dangerous warming
* SMH: Carr fired up over coal power critics
* The Age: Australia's heart getting wetter

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