A decade after "An Inconvenient Truth" sent shockwaves around the world with its dire warnings of environmental catastrophe, Al Gore is sounding the alarm on climate change again.

This time, the stakes are arguably higher with the US inauguration of Donald Trump, who has dismissed global warming as a fraud invented by the Chinese and nominated climate change skeptic Scott Pruitt to head the Environmental Protection Agency.

Despite worries over the potential environmental damage of a Trump administration, "An Inconvenient Sequel: Truth to Power" has a more hopeful message than its predecessor.

"We are going to prevail. I won't give all the evidence of why I am so confident, but I am. Always remember that the will to act is a renewable resource," the 68-year-old former US vice president said Thursday at the world premiere.

"And for those who have any doubt, just remember there are so many others who are yearning to do the right thing and see the right outcome."

The documentary -- screened at the Sundance Film Festival in Utah -- comes 11 years after "An Inconvenient Truth" re-energized the international environmental movement on its way to winning two Oscars and taking $50 million at the box office.

Since then Gore has trained an army of some 10,000 organizers to spread his environmental gospel, with cameras for "An Inconvenient Sequel: Truth to Power" following his sessions.

- 'Number one threat' -

At each he delivers an updated version of "An Inconvenient Truth" using the latest news footage and startling videos to show how the fossil fuels that powered so much innovation are leading to the demise of society.

"I came here just a few hours ago -- I landed from Davos -- and the World Economic Forum has said for the second year in a row the climate crisis is the number one threat to the global economy," Gore told the Sundance audience.

Gore, who was awarded the Nobel Peace Prize in 2007 for his work on climate change, points to a string of extreme droughts, record-breaking downpours and high tides, along with melting Arctic ice as evidence of climate change.

The cameras follow him to Paris for last year's global climate conference, where 150 world leaders eked out an agreement on cutting emissions in order to curb global warming.

Intriguingly, he is seen towards the end of the 100-minute movie heading for a meeting with the president-elect in December at Trump Tower in New York, but reveals nothing on screen about their meeting.

"I found it an extremely interesting conversation and to be continued, and I'm just going to leave it at that," he told reporters at the time.

- Denial -

Born in Washington, Gore shuttled between his home in Tennessee and a hotel in the capital while his father served in the House and later in the Senate.

Gore himself would go on to serve in the House of Representatives for three terms and was a two-time senator from Tennessee 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.

Asked in "An Inconvenient Sequel" if he plans a political comeback, he jokes that he is a "recovering politician" whose chances of going back to the life diminish with every year out of power.

"From the very start of this movement, the reality has been that the maximum that is politically feasible has fallen short of the minimum the scientists tell us is necessary to save the planet," Gore told the Sundance crowd.

"What do you do when you're faced with a gap like that? One option is to feel despair but despair ultimately is just another form of denial. The other option is to expand the limits of what is politically possible."

Directed by husband-and-wife filmmakers Bonni Cohen and Jon Shenk, "An Inconvenient Sequel" is due for wide release in the United States by Paramount on July 28.