Coming to grips with climate change will have a major impact on production of Australian rural commodities, adding an “environmental squeeze” to the traditional “cost price squeeze”, a leading CSIRO scientist said today.

Dr Chris Mitchell, from CSIRO’s Marine and Atmospheric Research, said key drivers of climate change are rapid changes in greenhouse gases, aerosol pollution, and ozone depletion, which have triggered global warming and are causing sea levels to rise at an accelerating rate.

Dr Mitchell told the ACGRA Cotton Conference on the Gold Coast that mean temperatures in Australia rose in the 1910-2005 period.

There has also been a downward trend in annual rainfall, particularly in eastern Australia over the past 55 years. While the Tasman Sea and Indian Ocean have become warmer, the Southern Ocean has become cooler.

As a result of these trends, Dr Mitchell has foreshadowed significant changes in the Australian cotton industry, some positive, some negative.

He said evidence from climatic prediction models points to a beneficial decline in the number of cold shock days over the next 20-50 years in the Bourke, Gunnedah, Moree and St George regions.

“The best available science indicates that climatic change will continue, even with aggressive efforts to reduce greenhouse gas emissions, hence continuous adaptation will be required, particularly as a result of pressure on water resources through rainfall and evaporation changes.

“This will create the need to drive water efficiency faster than the rate at which water becomes scarcer, and could also add to production costs,” Dr Mitchell said, adding that across the whole of Australia, over 90 per cent of annual rainfall is returned to the atmosphere through evapotranspiration.

However, he also acknowledged that climate change is a variable process, and that climate prediction models are far from perfect, although those that exhibit consistence in performance are gaining in validity.