FACTBOX-Forecast for Australia's climate: Even more extremes

Mon Feb 9, 2009 7:11am GMT

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Feb 9 (Reuters) - Australia has always been a land of weather extremes but scientists say the country will continue to get warmer over the coming decades, with more intense droughts and floods as well as longer fire seasons.

Following are some of the projections.

TEMPERATURES

Average temperatures in Australia have risen 0.9 degrees Celsius since 1950 and could rise sharply after the middle of this century.

Computer projections say best estimates of warming over the country by 2030 over 1990 levels is one degree Celsius. By 2050, the range is 1.2 degrees Celsius for low greenhouse gas emissions scenarios and 2.2 degrees Celsius if emissions continue to rise, with greater increases likely for inland areas.

By 2070, the models predict rises of 2.2 to 5 degrees Celsius in the high emissions scenario.

FIRE SEASON

Annual fire seasons are likely to be longer and with a greater number of days rated an extreme fire danger.

By 2020, there could be up to 65 percent more "extreme" fire danger days over 1990 levels. By 2050, under high temperature global warming computer scenarios, it could be a 300 percent increase.

RAINFALL

Less in the south and more in the far northwest.

Winter rainfall in south-west Western Australia has dropped sharply since the 1970s. The last decade has seen very low rainfall in southern and central Victoria, while north-west Australia has become substantially wetter since 1950.

Seasonal variations will become more extreme from 2050, depending on the amount of greenhouse gases pumped into the atmosphere by all nations.

For example, annual rainfall change is estimated at -30 percent to +20 percent in central, northern and eastern areas, while the range for southern areas is -30 percent to +5 percent.

DROUGHT

Longer and more extreme dry periods. South-west Western Australia, a major grains and wine-growing area, will be particularly hard hit and there will a drop in the number of rain-bearing low-pressure weather systems in the winter.

STORMS

A likely increase in the number of more intense cyclones in the tropical north, although the overall number of storms could decrease.

In the south, the risk of tornadoes during the cooler months of May to October is expected to decrease but there are signs of an increased risk of hail storms over the more densely populated south-east coast. (Sources: Climate Change in Australia - Technical report 2007 (here TR_Web_FrontmatterExecSumm.pdf); and "Bushfire Weather in Southe ast Australia: Recent Trends and Projected Climate Change Impacts", the Bushfire Cooperative Research Centre and Bureau of Meteorology) (Editing by Dean Yates)



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