Western Australia
February 21, 2013
Projections made 25 years ago of where Western Australia’s climate would now be have proved reliable based on the latest weather observations.
How the Western Australian climate unfolded in the years since that initial projection will be presented at this year’s Western Australian Agribusiness Crop Updates event held on 25 and 26 February at Crown Perth.
Department of Agriculture and Food research officer Ian Foster said he had assessed the accuracy of climate projections made by the Bureau of Meteorology at the Greenhouse 88 Conference and found them to be fairly much on track.
“Winter rainfall in the South West was projected to decrease at a rate between six and 13 mm per decade, where in reality there has been a decrease of 22 mm per decade, showing that the region has dried out faster than predicted,” Dr Foster said.
In regards to temperature there has been an increase but not as much as expected.
“The projections pointed to a rate of warming between 0.3 and 0.4 °C per decade for winter and 0.2 and 0.3 °C warming per decade in summer, where actual temperatures have increased 0.14 °C per decade in winter and 0.03 °C per decade in summer,” Dr Foster said.
“We have seen the atmosphere become more stable, with a weakening and southward shift of winter weather systems. For growers this means later starts to winter rainfall and generally drier seasons.”
Climate change projections issued in 1988 for the most likely climate scenario in 2040 included:
- • winter rainfall systems moving further south,
- • increased sea surface temperatures with tropical cyclones moving south,
- • decreased winter rain between 10 and 20 per cent and up to 40 per cent more summer rain in the Wheatbelt and Goldfields regions, and
- • winter temperatures increasing by 1.8 to 2.1 °C, with summer temperatures increasing by 1.2 to 1.5 °C.
“With the decrease in rainfall we are currently experiencing and considering future climate projections, it is necessary for many sectors including agriculture to adapt,” Dr Foster said.
“To assist, the department has developed an enhanced weather station network that will aid our understanding of future climate, seasonal variability and extreme weather events.
“For growers the network enables them to make informed decisions to manage their businesses such as selecting the right conditions for spraying. Additionally the weather data will link into tools such as the crop yield estimator Yield Prophet to provide a more robust risk management tool.”
The WA Agribusiness Crop Updates 2013 is supported by department and the Grains Research and Development Corporation. More information is available at grains.agric.wa.gov.au
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