Climate change and the risk to water supply

Reference: 06/191

Science can assist the community to avoid rather than simply understand the potential negative effects of climate change, according to CSIRO Research Fellow, Dr Barrie Pittock

4 October 2006

In an address today to the Engineers Australia Water Forum in Brisbane, Dr Pittock – who is the retired leader of the CSIRO Climate Impacts Group – will explore the role scientists play in informing debate over the extent and likely effects of climate change, particularly in regard to water supply.

“Risk management demands that scientists describe and warn about seemingly extreme or alarming possibilities for any given scenario of human behaviour, such as increasing greenhouse gas emissions,” Dr Pittock says.

“That should be the case if those scenarios have even a small probability of occurring.”

He says the principles of the risk-management approach are applied in engineering design (for instance for the safety of dams and bridges) and in military planning (where large resources are devoted to guarding against and deterring threats). They are equally commonplace in insurance.

“The present drying trends in southwestern Australia – and possibly those in southeastern and eastern Australia – are partly attributable to human-induced climate change. They result from warming which is increasing evaporation in catchments, and in some cases, leading to a decreasing trend in rainfall.”

He says measures designed to help communities to cope with reduced water supply, such as water conservation and recycling, are necessary and indeed urgent.

”However, unless the basic cause – globally increasing greenhouse gas emissions from the burning of fossil fuels – is dealt with, periods of water shortage will become more frequent and severe.

“The climate system will respond to the present increases in emissions over many decades to come. What we emit now will worsen the situation for decades into the future,” he says.

He says measures designed to help communities to cope with reduced water supply, such as water conservation and recycling, are necessary and indeed urgent.

”Increasing levels of greenhouse gas emissions will lead to large impacts on many climate-affected systems – including more frequent water shortages in southern and eastern Australia – that may be very difficult to adapt to in decades to come.”

Dr Pittock is a senior author of the chapter on ‘key vulnerabilities’ in the Fourth Assessment Report of the Intergovernmental Panel on Climate Change which is due to be released in mid-2007. His most recent publication, in the 22 August 2006 edition of EOS (Transactions of the American Geophysical Union), is entitled: “Are scientists underestimating climate change?”