Climate change scientist Tim Flannery says energy transition targets are critical for Hunter to avoid climate catastrophe

To avoid it, we need a whole-of-community transition, and targets are "critically important".

"The trouble is it is a time-limited problem ... we need fast action and that's why we need everyone empowered to change. We need the proper regulatory framework to drive that change quickly, sufficiently quickly, to get to where we need to go."

The alternative was to keep burning fossil fuels for a few more years, but it would cost us the planet, he said.

"Why should we forfeit our future just to burn fossil fuels for another few more years and deliver massive profits to some of the biggest polluting industries on the planet - there's no reason that has to happen."

Without change, we will trigger tipping points in the earth's climate system and produce some "very, very undesirable and unstoppable outcomes".

"Once the climate system is triggered into a new phase ... no matter what we do we'll be helpless, we won't be able to control that trajectory. So that's what we're trying to avoid. Action this decade is critically important.

"We really need to start taking this issue far more seriously, and politicians will be well-served to take a lead in this. There's something profoundly wrong with our political system at the moment that prevents that from happening."

As a trained palaeontologist who knows what past climates were like, picturing where the planet will end up was a tool that he uses to cope with 'climate grief,' Flannery recently told health professionals gathered in Sydney for the Royal Australian and New Zealand College of Psychiatrists annual Congress.

"If you do the sums about our current trajectory, a likely scenario is that we will create an atmosphere with a level of C02 (carbon dioxide) that was prevalent three to five million years ago," Flannery said.

"We are well on the way to doing that, incidentally. That means in some aspects we will create a climate such as that which existed three to five million years ago ... I studied that period, the pleistocene period, and I can tell you it wasn't all bad."

Biodiversity flourished, and it was a "pretty abundant and fertile period", Flannery said.

"What I am concerned about is the journey to get there because we will be making this journey far faster than any geological change that has ever occurred before and that implies climatic disruption, really profound climate disruption," he said. Australians didn't need to be told about it, because they'd lived it.

"You've lived through the fires, those megafires. Before those megafires the biggest area of forest we'd seen burnt was about 2 per cent of the broad leafed forests - those megafires of 2019-2020 burnt 21 per cent of our forest."

Since then there had been relentless floods, whole cities flooded and people misplaced, repeatedly.

Since he was named Australian of the Year in 2007, humanity has emitted between a quarter and a third of all of the green house gases the human species has ever emitted, he said. While those numbers were "very, very scary", there was now a a very solid base to shift from polluting forms of energy to clean energy, and the ground work for change was being laid.

"I am pretty confident that we will turn around emissions growth within the next three to five years ... and that will be a moment of great relief when at least we will be on course to start reducing emissions hard and fast," he said. "What we need to do is to reduce emissions by 8 per cent per year, year on year, between now and 2030.

"So while we are still growing emissions that is just a pipe dream but we can start ... and I think that reduction will gather pace as it goes along, like a stone running down hill, because everything will be in place to see that transition."

Aviation was a tough nut to crack, but it was only responsible for 2 to 4 per cent of emissions, and while the industrial sector was changing very slowly, people in cement and steel making, for example, were already looking for alternative pathways, some of which involved hydrogen or other new technologies which were progressing "very rapidly", he said.

Meanwhile, more and more electric vehicles were coming online, growing from the 50 Tesla vehicles produced in 2011 to 90 million vehicles now being added to the global fleet every year. We are also seeing a massive uptake of wind and solar which can be seen playing out at scale in China, he said.

"It looks now as if China will see its emissions peak around 2025 instead of 2030 and that's because of the roll out of wind and solar energy storage has been so rapid and such an efficient engine of change. So we can see that happening.

"So that should give us a sense of optimism and hope ... we are doing the right thing, we just need to do it faster. We need government policy and more than anything ... we need an aggressive target ... I am convinced that will leave us all more prosperous, with a more stable environment and in a better position overall."