TONY EASTLEY: The nation's top climate scientists and science bodies have for the first time endorsed a report that says the climate in Australia has already shifted.

The peer reviewed assessment says there is "strong consensus" around its central finding and it notes that in some cases the weather has "changed for good".

With the report warning of greater risks of more intense and severe weather, emergency services may have to rethink their strategies.

Here's environment reporter Sarah Clarke.

SARAH CLARKE: Last summer was by all means a record breaker. One-hundred and twenty-three were broken in 90 days. As well as heat waves and unprecedented temperatures there was heavy rainfall and major flooding.

But according to the Climate Commission this wasn't a one-off. In its most comprehensive assessment yet it says Australia has a future of records yet to be broken and "in some cases day-to-day weather has shifted for good".

Will Steffen is the report author.

WILL STEFFEN: Well what we see is a pattern emerging that the south-west of Western Australia and the south-east of Australia have become drier - the south-west since about the mid 1970s; the south-east since about the mid 1990s. And there's a similarity in pattern. They're both becoming drier in the cooler months of the year.

That tells us in the future we would expect to see dry conditions more often. And very importantly, we do not expect to see the previous pre-climate change weather conditions come back.

SARAH CLARKE: The planet's changing for good, to a certain extent.

WILL STEFFEN: Well for a long period of time. The best we can hope for I think - at least in the terms of our children and grandchildren - is to stabilise the climate.

But we will stabilise it at a temperature that probably is two degrees or more above the pre-industrial. That means some changes and patterns will lock in probably for centuries.

SARAH CLARKE: In this report the Climate Commission looks at droughts, tropical cyclones and sea level rise, as well as heatwaves, bushfires and heavy rainfall.

While it says the number of tropical cyclones won't increase, the influence of climate change means they will become more intense.

It also says one in 100 year flooding events are already becoming more common and sea level rise has already risen by 20 centimetres since 1880.

While there are still some questions raised about global warming and its influence, all the top climate scientists in Australia have backed this report - as well as the CSIRO, the Bureau of Meteorology and the UN's chief science body, the Intergovernmental Panel on Climate Change.

Professor Tim Flannery is a member of the Climate Commission.

TIM FLANNERY: I think it's really important that people understand where the debate is in climate science and where it isn't. And when you get a group like this that's endorsing or supporting this report in detail, I think that sends an important message that the scientific community is clear about these facts that we've laid out in the report.

SARAH CLARKE: With the report warning of greater risks of more intense and severe weather now, that has the emergency services bodies reassessing their plan of attack.

Paul Considine is from the Australasian Fire and Emergency Service Authorities Council.

PAUL CONSIDINE: We now need to sit down and have a think, not just in isolation but together with our governments and together with the communities that we serve, how we may need to react to these predicted future events.

TONY EASTLEY: Paul Considine from the Australasian Fire and Emergency Service Authorities Council; the report from Sarah Clarke.