Climate change a factor in Australia's warmest year on record

November 14, 2005

Climatologists believe artificially induced climate change is the reason Australia is destined for the warmest year on record. Temperatures so far this year have averaged one degree above the 30-year average, the Bureau of Meteorology (BOM) told the Greenhouse 2005 – Action in Climate Change Conference being held in Melbourne this week.

The head of the National Climate Centre, Michael Coughlan, says Australia has had the warmest ever first 10 months of 2005, and seems likely to be a record-breaking year. "It's typically been a degree or more above the average for most of the months," said Mr Coughlan. "When you think you're averaging over hundreds of stations across Australia, to get a one degree warming over such a large area is fairly significant."



According to BOM, Australia has experienced its warmest start to a year on record (since 1950), with the January to October temperature averaging 1.03 degrees Celsius above the 30 year average (1961-1990). Annual mean temperatures have increased throughout Australia since 1910, particularly since the 1950s.

"If one draws a trend line from the mid-50s or early 50s, through to the present, it's a fairly steady upward trend. And it's interesting that this is not true only of Australia, but it's fairly typical throughout most continents now, most parts of the world," said Mr Coughlan.

As the average temperature has risen, there has been an increase in the incidence of hot days and hot nights, and a reduction in the number of cold days and nights. This warming is mirrored in the oceans around Australia.

Michael Coughlan says warm sea surfaces are a significant factor in the creation of cyclones and hurricanes. "One might expect, with those sea temperatures being warmer than they have been in the last few years, that the odds would be tipped towards perhaps a greater number of the cyclones than we have seen in the last few years," he says.

Warming is not the only sign of change in Australia’s climate. Other changes include a marked decline in rainfall in southwest and parts of southeast Australia, and recent reduction in rainfall through the eastern states. At the same time, rainfall in the arid interior and northwest has increased dramatically, in some places nearly doubling during the last 50-years.

"Climate change affecting Australia is real," says CSIRO's Dr Bryson Bates. "In 2005 the questions we face are how best to respond and adapt – from projections in agriculture to changing ecosystems, reduced catchment flows and downward rainfall trends," Dr Bates says.

The GREENHOUSE 2005 Action on Climate Change Conference is expected to attract 400 Australian and international delegates.