'This can be done': UN's message on net-zero deadlines

Secretary-General Antonio Guterres says "warp speed" action is needed to save humanity from the thin ice it's on, and what happens this decade will be key to limiting warming to 1.5C or overshooting it with catastrophic consequences.

His comments follow the release of the latest Intergovernmental Panel on Climate Change (IPCC) report - a comprehensive summary of everything scientists have presented in six reports released in the past couple of years.

It says there is still an outside chance of warding off the worst effects of climate change.

Emissions are continuing to rise, albeit at a slower pace, and fossil fuels are continuing to attract public and private investment that dwarfs what is spent to mitigate climate change.

Adaptation efforts are poorly funded and piecemeal but there is a technical opportunity to do what needs to be done.

"To borrow the words of a very senior colleague in the IPCC, we are up the proverbial creek but we do have a paddle," says Australian National University Professor Frank Jotzo, who was on the report's core writing team.

Mr Guterres has outlined an acceleration action plan that asks developed countries to commit to reaching net zero as close as possible to 2040.

That's a decade earlier than the Albanese government has enshrined in law, and a decade sooner than many other developed countries have pledged, including the US and the European Union.

"This can be done. Some have already set a target as early as 2035," the UN chief says.

He also wants OECD countries including Australia to commit to "no new coal and the phasing out of coal by 2030" and block the exploitation of new and existing oil and gas reserves.

Emerging economies should aim to get as close as possible to net zero by 2050, Mr Guterres says.

Another of the Australian authors, University of Melbourne Professor Malte Meinshausen, says the report makes it very clear that the earth's existing stock of fossil fuel infrastructure is enough to max out the carbon budget for 1.5C.

"We will end up with 1.5C of warming, without additional abatement," he said.

Report editor and Australian National University Professor Mark Howden says children being born today are the ones who will pay.

"A child born now is likely, on average, to experience three to four times as many extreme climate events in their lifetime as their grandparents did."

He says the world has already warmed by 1.1C and the consequences of that are being felt now in the form of more frequent and severe disasters including heatwaves, floods and drought.

Meanwhile, Australia has gone from leader to "laggard" on climate change research and development.

"Australia's spend is falling and it's well below that of our peers in terms of the OECD. If we look at the adaption domain, we are lagging significantly. If we go back a decade, we were world leaders," Prof Howden says.

Prof Jotzo says there are some glimmers of hope, and while emissions are still rising the pace has slowed.

"It's actually happening. The aggregate effect globally of emissions policies is a very significant one."

The challenge now is to seize the "technical opportunity" to halve global emissions on the back of falling costs for technologies including solar and wind power.

"We can halve emissions globally between now and 2030 at incremental costs of less than $US100 per tonne of CO2 ... about four times the magnitude of the current price in the Australian emissions offset market," Prof Jotzo says.

"And it's in the rough order of the EU emissions trading price right now. So it's not a prohibitively high price, and if policy effort was consistently applied right across the world ...we'd see a halving of global emissions.

"We are unlikely, of course, to see that with the way things are presently organised but that potentially is there."

Australian Associated Press