Former prime minister Tony Abbott has been lambasted after unleashing on the “climate cult”, and declaring man-made global warming is “ahistorical and utterly implausible”.

Abbott also declared the Albanese government’s goal to achieve 82 per cent renewables by 2030 was “irrational” and said cost-of-living issues should be prioritised over cutting carbon emissions, in a speech in London on Tuesday (AEDT).

“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,” Abbott said at the British launch of an Institute of Public Affairs report on energy on Tuesday.

“I think that needs to be repeated. Ladies and gentlemen, the climate cult will eventually be discredited.”

Abbott, who infamously described the “so-called settled science of climate change” as “absolute crap” in 2009, joined the board of British conservative think tank the Global Warming Policy Foundation in February. It group aims to challenge governments’ “extremely damaging and harmful policies“ around climate change.

On Tuesday, Abbott said he would point to the period of mediaeval warming and the Little Ice Age as examples that climate had “nothing to do with mankind’s emissions”.

In 2019, he lost his Sydney seat of Warringah to independent Zali Steggall, after she campaigned heavily on stronger climate action. Steggall took aim at Abbott on Thursday.

“So wilfully obtuse to evidence and science!” she wrote on X.

“His legacy is one of reckless negligence to future generations that will bear the consequences of years of denial and delay. So much time and opportunity wasted.”

Another Sydney teal MP, Allegra Spender, described Abbott’s views as “absolutely shameful”.

“Former PM Tony Abbott led the fight against climate action from 2009 to 2015. He knowingly misled Australians by hiding his true beliefs and undermining climate action,” she wrote.

“Now we’re paying for wasted years of climate denial.”

Abbott’s speech also came on the day the IMF issued several recommendations for Australia, urging it to do more to address climate change. The IMF said an economy-wide carbon price was the most effective way to hit net zero emissions.

When Abbott led the Coalition to victory in 2014, one of its first acts was to repeal the Gillard government’s carbon tax.

The comments by the former Liberal leader – who was last month nominated to join the board of Fox Corporation by Lachlan Murdoch – also came as scientists warned the carbon dioxide budget for stopping the Earth heating 1.5 degrees above pre-industrial levels could run out in the next six years.

A study published in Nature Climate Change on Tuesday said the window was “rapidly closing” and at the current rate of emissions it was now more likely than not the key target of the Paris Agreement would be breached.

Scientists estimated there were about 250 gigatonnes of carbon dioxide (GtCO2) left to emit before warming of at least 1.5 degrees is locked in, which would take about six years without any drastic reductions.

A 2018 estimate from the Intergovernmental Panel on Climate Change (IPCC) found there to be a 50 per cent chance of staying within 1.5 degrees if global emissions were halved by 2030 and reduced to net zero by 2050.

This week’s study updated this by accounting for greenhouse gas emissions in the past five years as well as recent measures to cut air pollution that have reduced the amount of aerosols in the atmosphere, which have a slight cooling effect on the planet’s average temperature.

No single country has policies in place that are compatible with the 1.5 degree target, according to Climate Action Tracker, although almost every jurisdiction agreed to this at the landmark United Nations climate conference in Paris in 2015.

-with AAP