For the past decade he has been one of the most vocal opponents to climate change action - but now Barnaby Joyce has sealed a deal to end the 'climate wars'.
Under his leadership, the National Party has declared it will support a 2050 net zero carbon emissions target, a historic move that brings Australia into line with most of the developed world just a week before crunch climate talks in Glasgow.
After a week of internal meetings and debate, Mr Joyce revealed the junior Coalition party now backs the target and declared: 'I am 100 per cent on board with the goal of net zero by 2050.'
After a week of internal meetings and debate, Barnaby Joyce (centre with David Littleproud and Bridget McKenzie) revealed his party now backs a net zero target
The move harmonises Labor and Coalition climate change policy, ending a decade of the so-called 'climate wars' in politics.
It also marks a major shift for the Deputy Prime Minister who has until now opposed climate change action by either questioning the existence of global warming or insisting that Australia can make no difference.
As a Queensland senator in 2012, Mr Joyce called the issue 'an indulgent and irrelevant debate'.
'Even if climate change turns out to exist one day, we will have absolutely no impact on it whatsoever… we really should have bigger fish to fry than this one,' he said.
A year earlier he had slammed climate scientists for trying to 'scare' western societies.
'I don't feel the world is coming to a catastrophic end. I just feel that this is just another one of those pitches,' he said in a 2GB radio interview.
He said action was pointless, insisting 'there's definitely nothing you can do about it from Australia by yourself, except stuff up your economy'.
A turning point for Mr Joyce may have occurred in 2016 when, during a bad drought, he visited his parents' property near Tamworth with a reporter from the Sydney Morning Herald.
Staring at a creek that he used to play in as a child, he said: 'It's the driest I've ever seen it. When I look at this I start to wonder whether climate change might really be happening.'
In recent years the New England MP has not questioned the existence of climate change but argued that it's occurring naturally.
'I believe this is one of the greatest policy phantoms, the misguided and quite ludicrous proposition that Australia can have any effect on the climate,' he wrote on Facebook in 2019.
'If we could, we should be the first to make it rain and, more importantly, stop the recurrence of an ice age anytime in the coming millennium.'
He added: 'The very idea that we can stop climate change is barking mad. Climate change is inevitable, as geology has always shown.'
Mr Joyce went on to claim that temperatures would 'drop 10 degrees' when another ice age hits in about a thousand years.
'One may suggest that warmer weather is the better problem of the two,' he said.
This was despite the fact that 97 per cent of the world's climate scientists agree that humans are warming the globe with increasing greenhouse gas emissions.
Ex Opposition Leader Tony Abbott (centre) and then Senator Barnaby Joyce (left) visit Unique Meats butchery in 2011. Mr Joyce used to question the existence of climate change
And on Christmas Eve 2019, Mr Joyce posted a selfie video of him feeding his cattle on his farm where he acknowledged climate change was real but railed against action such as Labor's carbon price.
'You don't have to convince me the climate's not changing. It is changing. My problem has always been whether you believe a new tax is going to change it back,' he said.
Mr Joyce suggested only God could change the climate.
'And the other thing we've got to acknowledge is there's a higher authority that's beyond our comprehension - right up there in the sky - and unless we understand that it's got to be respected, then we're just fools, we're going to get nailed,' he said.
When Mr Joyce overthrew Nationals leader Michael McCormack in June, analysts said a major reason for the coup was to stop the party agreeing to a net zero target amid