A new report from the Federal Government's Climate Commission says the heatwave and bushfires that have affected Australia this week have been exacerbated by global warming.
The report - Off the Charts: Extreme Australian Summer Heat - warns of more extreme bushfires and hotter, longer, bigger and more frequent heatwaves, due to climate change.
It says the number of record heat days across Australia has doubled since 1960 and more temperature records are likely to be broken as hot conditions continue this summer.
When Prime Minister Julia Gillard linked the heatwave with climate change this week, the acting Opposition Leader Warren Truss said that was utterly simplistic.
But climate change experts have no doubt that climate change is a factor in the current conditions.
The scientific advisor to the Climate Commission, Professor David Karoly, has written the report for the Climate Commission to answer questions about the link between heatwaves and climate change.
Not every summer will be hotter than the one before. In fact this year is markedly hotter than the last couple of years when we had relatively milder and wetter conditions.
But what we are going to find on average is more of the hot extremes and faster increases in the future, over the next 10 and 30 years, that we have seen over the last 30 years - more hot extremes, more heatwaves and more extreme fire conditions.
Climate scientists have been talking about these increases for more than 20 years in Australia. We are now seeing exactly what was predicted more than 20 years ago.
Professor David Karoly
"What we have been able to see is clear evidence of an increasing trend in hot extremes, reductions in cold extremes and with the increases in hot extremes more frequent extreme fire danger day," he said.
"What it means for the Australian summer is an increased frequency of hot extremes, more hot days, more heatwaves and more extreme bushfire days and that's exactly what we've been seeing typically over the last decade and we will see even more frequently in the future."
'Increases in extremes'
Professor Karoly says climate change has worsened this heatwave by extending it and increasing its intensity.
"What climate change is doing is worsening the conditions associated with heat waves so it makes them longer, it makes the intensity of the heat wave worse and together they lead to more frequent extreme fire danger days," he said.
Australia's average temperature has increased by 0.9 of a degree since 1910, and the report says small changes in average temperature can have a significant impact on the frequency and nature of extreme weather events.
Professor Karoly says, based on current projections of greenhouse gas emissions and climate change, the long-term outlook is even more dire.
"We are expecting in the next 50 years for two to three degrees more warming," he said.
"In other words two or three times the warming we've seen already leading to much greater increases in heatwaves and extreme fire danger days.
"So we're expecting future climate change to lead to much greater increases in extremes in the next 30 to 50 years."