Greta Thunberg has been torn apart by Tony Abbott, who dismissed the climate campaigner as a "teenager who hasn't spent enough time at school".
He demanded the public "find a better guru than that", warning that "too many" young people have been "propagandized" by "climate scares".
The 20-year-old is one of the most prominent climate activists, known for challenging governments over their approach to tackling climate change.
Abbott made the comments in conversation with GB News at the Alliance for Responsible Citizenship (Arc) Conference in London, the day after he told media outlets that net zero targets are unaffordable.
Asked whether he'd need to get on board with net zero if he is to "bring on the Greta Thunberg generation", the former Australian prime minister said: "It's a pretty crazy world that follows a teenager who hasn't spent enough time at school.
"Frankly, I mean, really and truly, if we are going to follow a guru, let's find a better guru than that.
"Now one of our difficulties is that too many of our youngsters have had a propagandized education which has been heavy on climate scares and light on history, light on the great books, light on an appreciation of all the things that have made our societies strong."
He continued: "What I said last night was that we cannot achieve net zero without impoverishing our societies - for instance, there's recently been a very thorough study of achieving net zero in Australia by very credible people.
"A team led by our former Chief Scientist Robin Batterham, who's actually one of the participants at this conference.
"And the Batterham team has said that achieving net zero would cost us $1.5 trillion in Australia by 2030 and upwards of $9 trillion by 2050.
"Now, given that Australia's annual GDP is about $2 trillion, we are going to have to sacrifice one year of our total production over the next seven years just to make the limited progress towards net zero that the government is trying to make in that time.
"And we would sacrifice something like five years of our total production in order to get to net zero over the next 30 years."
Abbott added: "And given that climate is by no means the only peril we face, - it's not even the most serious peril we face - this frankly, is not a rational way forward for our society.
"You ask the people in Ukraine right now what is the greatest challenge they face? They won't say climate.
You ask the people in Israel or indeed in Gaza, what is the great challenge they face? They're not going to say climate.
"You asked Taiwan what is the biggest threat it faces? It's not going to say climate."
LATEST DEVELOPMENTS:
The former Australian prime minister said: "It's a pretty crazy world that follows a teenager who hasn't spent enough time at school."
GBN
Speaking at the launch of a report on energy from the Institute of Public Affairs on Tuesday, Abbot claimed: "I think it is worth stating that the anthropogenic global warming thesis, at least in its more extreme forms, is both ahistorical and utterly implausible.
"And I think that needs to be repeated. Ladies and gentlemen, the climate cult will eventually be discredited."
This came just one week after scientists warned that 20 of the Earth's 35 "vital signs" are at record extremes, noting that in July the planet was at the hottest it has ever been in 100,000 years.
