Australian National University Climate Change Institute director Mark Howden told a Senate inquiry examining the 2019-20 bushfires on Wednesday at a time when Australia was experiencing increasing impacts of climate change, research on the topic had fallen.

"Research on climate change has plummeted over the last decade," Professor Howden said.

"This is not a minor reduction. This is a major reduction. And it's taken us in many ways from being a global leader in terms of the various dimensions of climate change work ... and put us way behind the the leaders of in that area."

While research in some areas was being done in a "patchy and rather uncoordinated way", Professor Howden said there were "zero levels of research activity" on climate change relating to water, agriculture and biodiversity.

He said a national climate research centre was required to coordinate research across the country.

In the past, we have had one of those working out of Griffith University and Brendan Mackey's keenly involved in that. But that that itself, the funding has run out, and it's effectively a base shadow of what it used to be.

"So broadly in Australia, at the time we're seeing very, very substantial changes in our climate, very substantial impacts of those climate changes, we're actually dis-investing in the R&D that allows us to take sensible decisions on that."

The inquiry also heard if emissions continued at current rates, half the state of Queensland would experience 60 days per year where the maximum temperatures were above 40 degrees.

"We're talking about a profoundly different climatic regime to what we currently experience," Griffith Climate Change Response Program director Professor Brendan Mackey said.

Dr Andrew Johnson from the Bureau of Meteorology said said the increasing temperatures was likely to raise the risk of more intense bushfires.

Australia's average national temperature had risen 1.4 degrees since the turn of the 20^th century, with a 10 to 12 per cent fall in rainfall in south-eastern Australia since the 1990s, Dr Johnson said..

And while there was natural variability in Australia's climate that influenced the severity of bushfires, Dr Johnson said climate change was also playing a role.

"What the science is still really working through is is is the relative contributions, I suppose, between natural variability and the climate signal," Dr Johnson said.

"Weather is only one part of the fire story, I mean clearly the location of physical infrastructure, 'land management practices, the sources of ignition, all these things have to come together in a particular way to lead to a bushfire and the weather is an important part of that absolutely, but it's by no means the only thing.

"But from a weather point of view, that warming and drying trend absolutely increases the bushfire risk."