He once gave Donald Trump the benefit of the doubt, but mention the US president to Al Gore these days and you'll get a withering frown.
"He's a catastrophe, of course, but he has effectively isolated himself," the former US vice president says, his nostrils dilating a few millimetres past scorn but stopping short of open contempt.
A decade after his documentary An Inconvenient Truth sent shockwaves around the world with its dire warnings of environmental disaster, Gore is sounding the alarm on climate change again.
An Inconvenient Sequel: Truth to Power, released by Paramount on Friday, had its world premiere at the Sundance Film Festival a day before the January 20 inauguration.
Since then, the new US president has sent out a former CEO of oil giant ExxonMobil to represent America on the world stage and appointed an anti-climate litigator to run the Environmental Protection Agency.
He has moved to loosen restrictions on coal-fired power plants and vehicle emissions, slashed EPA funding, and reversed his predecessor Barack Obama's Clean Power Plan.
And then of course there was that announcement of withdrawal from the 196-nation 2016 Paris agreement on climate change.
"We're going to meet the US commitments regardless of what Donald Trump says," 69-year-old Gore tells AFP during an interview in Beverly Hills to promote his film.
"There's a law of physics that sometimes works in politics: for every action there's an equal and opposite reaction.
"It's as if the rest of the world is saying, 'We'll show you, Donald Trump'. Now there is a progressive uprising to organise in ways I haven't seen since the Vietnam War."
In one of the most intriguing scenes towards the end of the 100-minute An Inconvenient Sequel Gore is seen heading for a meeting with the then president-elect at Trump Tower in New York.
He voiced cautious optimism at the time that the environmental movement might be able to do business with the incoming president, but Gore has since given up hope.
"Where he's concerned — absent some unforeseeable circumstances — I'm not going to waste any more time trying to convince him because he's surrounded himself with this rogue's gallery of climate deniers," Gore says.
"Even though I have protected the privacy of those conversations, I will tell you that I had reason to believe that there was a chance that he would come to his senses. But I was wrong."
An Inconvenient Truth (2006) re-energised the international environmental movement on its way to winning two Oscars and taking $50 million at the box office.
Despite worries over the potential environmental damage of a Trump administration, the follow-up actually has a more hopeful message than its predecessor.
It follows Gore, who has trained an army of some 10,000 organisers to spread his environmental gospel, as he delivers rousing workshops around the world.
"There have been two huge changes since the last movie. Number one, the climate-related extreme weather events have become far more numerous and more destructive. That's true all over the world," Gore tells AFP.
"Number two, we have the solutions now. That's a hopeful message people need to be more aware of. The fact that these renewable energy technologies, batteries in electric cars and so many others, have come down in cost with such dizzying speed, is truly miraculous."
Born in Washington, Gore shuttled between his home in Tennessee and a hotel in the capital while his father served in the House of Representatives and later in the Senate.
Gore would himself go on to serve as a Congressman for three terms and was a two-time senator before becoming vice president under Bill Clinton during one of the country's greatest economic booms.
Gore narrowly lost the presidential election to George W. Bush in 2000 and reinvented himself as a seer on climate change after his White House dreams were blown away, winning the Nobel Peace Prize in 2007.
His opponents over the years have accused him of being a fantasist and even a fraud, but he says his years in politics have given him a thick skin.
Gore describes himself as a "recovering politician," however, and is adamant that he has no plans for a comeback for the 2020 presidential election.
"The longer I go without a relapse, the less likely one becomes," he tells AFP.