I meet former American Vice President Al Gore in a plush hotel room in Melbourne, on a wintery day.

“It’s nice to experience a mild winter,” he says to me in the smooth, measured voice he uses to tell crowds that they’re facing a possible mass extinction event. “It’s been so hot in the US.”

Gore was the 45th Vice President of the United States. After he lost his bid for the presidency in 2000, he became a campaigner for action on climate change, for which he was awarded the Nobel Peace Prize in 2007. A year earlier, he fronted the documentary An Inconvenient Truth, which became an unlikely global box office hit and a catalyst for changing minds and habits in relation to climate change.

It’s the aptly named An Inconvenient Sequel that brings Gore to our meeting in July. Eleven years on from the first film, many of Gore’s warnings have come true. An increase in biblical-style weather events including flood, drought and fire has been tied to climate change, and researchers fear the link between climate and terrorism. As perverse as it sounds, the sequel benefits from being able to show us the chaos, rather than just tell us.

“It’s important to be honest about the severity of the challenge we face,” Gore tells me. “This is the biggest crisis that’s ever confronted humanity. You can’t just take a Pollyann-ish view. You have to tell the story with integrity.”

But that also means telling the story of hope.

“There are two big differences between our situation now compared to a decade ago,” Gore says. “Firstly, climate-related extreme weather events are way more numerous, and way more destructive. Secondly, we now have solutions.”

The film sets up Gore as a charming, globetrotting problem-solver. "With the future of human civilisation in the balance,” he says in the film, “we should probably ratchet this up a bit." He hits the ground running like an activist Indiana Jones, roaming from Greenland to Florida to Beijing to Delhi, meeting local mayors and schmoozing with world leaders, shaking hands and taking names. Then he gives slideshow presentations, leaving in his wake a global army of climate advocates armed with powerful PowerPoint presentations of their own.

Gore cites huge leaps forward in renewable energy, electric vehicles, sustainable agriculture and forestry. “We’re in the early stages of a sustainability revolution,” he says. He lists ironic examples of changing times, noting that the Kentucky Coal Museum has switched to solar energy because it saves it money. “All over the world coal mines are being closed, and coal plants are being shuttered.”

We love coal in Australia, I tell him. We’re opening mines rather than closing them.

“We’ll see,” he says. “They don’t have the financing yet.”

People really do want progress, he says, but they’re being blocked by a handful of people with a lot of money and vested interests. It’s been established that climate denial is funded lavishly by carbon polluters. In the film, Gore points fingers at Exxon Mobil in particular.

“You know, in my home state of Tennessee, there’s an old saying,” says Gore. “If you see a turtle on top of a fencepost, you can be pretty sure it didn’t get there by itself. When you see these persistent voices of climate denial, you can be pretty sure they didn’t get there by themselves either.” (Case in point, Mark di Stefano’s story last year that linked fake anti-renewable energy Twitter accounts to the Australian mining lobby.)

It’s similar to the conversation steering that happened when scientists discovered the links between smoking and lung cancer. In fact, Gore points out, polluters are even using the same researchers as the tobacco companies did. It’s a propaganda war, and he believes he’s on the winning side.

“Those people are losing the conversation,” he says, “because reality is so completely different from what they’re trying to portray.

“They’re just trying to squeeze profits out of their business plan for a few more years before the public catches on that they’re having the wool pulled over their eyes. But people are seeing through it.”

An Inconvenient Sequel is in a way propaganda too, albeit with science – and morality – on its side. It’s filled with emotive imagery and even ends with a rousing anthem, Truth to Power, performed by OneRepublic. They’re all tactics deployed to sink the opposition.

Filmed in 2016, the spectre of an impending Donald Trump presidency looms heavily over every moment of optimism, and the film acknowledges the massive setback of Trump’s withdrawal of the USA from the groundbreaking Paris Agreement, a major greenhouse gas reduction framework spearheaded by President Obama.

“We always knew we’d have to wait to see the election outcome, and what that would lead to,” Gore says. In December, Gore sat down with Trump and left optimistic that the new President would continue the commitment to climate action espoused by the Obama White House. Did he really think Trump had changed his mind on something that he’s previously stated was a Chinese conspiracy?

“I did,” he says. “I didn’t think it made sense, even in his terms, to get out of the Paris Agreement. But I underestimated the ferocity of the polluters, and how much of a hold they have on Trump.”

He’s tight-lipped on exactly what happened in the meeting. Has he been in communication with Trump since?

“No,” he says. Gore has spent his entire adult life in front of journalists – it’ll take a better one than me to get him to open up about that one.

It’s well-documented that Gore was skeptical about making a movie about his work. “I was – about both the first movie and this one,” he says. “But wiser heads prevailed, and convinced me to go forward.

“The question is whether we’re winning fast enough to save the Great Barrier Reef, for instance,” he adds. “If we don’t act, the consequences are so catastrophic.”

An Inconvenient Sequel is on general release now. Intrepid Travel is offering a full refund via PayPal to anyone who has seen the film. Visit Intrepid Travel for details.