Ten years after his Oscar-winning documentary An Inconvenient Truth made "climate change" a buzzword, Nobel Peace laureate Al Gore is back with a follow-up - An Inconvenient Sequel - which he hopes will galvanise action around clean energy and other environmental solutions.

Addressing the audience at a Beverly Hills screening of the film recently, the former vice-president of the United States says that unlike fossil fuels, "political will is a renewable resource - and this movie is designed to renew it".

Speaking in a gentle Southern drawl and with touches of folksy humour, the 69-year-old struck a note of cautious optimism about the possibility of averting an environmental disaster, even as he noted it was a "dangerous time" for the world given US President Donald Trump's withdrawal from the Paris climate agreement.

He says "there have been two huge developments - one bad and one good" - since the release of the first documentary in 2006.

That film, a box-office success and winner of the Best Documentary Feature and Best Original Song Oscars, was inspired by a slideshow presentation on climate change that Mr Gore has delivered more than 1,000 times as part of his environmental campaign, for which he eventually received the 2007 Nobel Peace Prize.

"The bad one is, obviously, the climate crisis is getting worse than the scientists predicted and it's getting worse even faster," he says, noting extreme weather events such as the devastating wildfires and hurricanes around the world.

"Every night on the news, it's like a nature hike through the (Bible's) book of Revelations and, all around the world, this is happening."

"But the second thing that's new, as the movie shows, is we have the solutions now and they continue to get cheaper week by week."

For instance, when the first film came out, solar and wind energy technology existed, but were too expensive to be viable alternatives. Now, in many parts of the world, they are more cost-effective than burning fossil fuels.

Asked about those who question the reality of climate change, Mr Gore observes that the US is "the only country in the world that has persistently high levels of climate denial".

In Tennessee, where he grew up, "they say if you see a turtle on top of a fence post, you can be pretty sure it didn't get there by itself".

"When you see these persistently high levels of climate denial, that didn't happen by itself.

"(Billionaire political donors) the Koch Brothers, Exxon Mobil (and others) took a page from the tobacco industry: When the scientists and doctors concluded that smoking cigarettes causes lung cancer and other diseases, the tobacco companies spent a huge amount of money trying to deny the truth. They hired actors and dressed them up as doctors and put them in television commercials falsely (saying that).

"The fossil-fuel polluters hired some of the same public relations firms and they have gone about this in a very determined way and they had ideological allies that wanted to, in the words of one of them, shrink the government to the point where it can be drowned in a bathtub. And they've been just running hog-wild.

However, he says "two-thirds of the American people know it's real and man-made and we have to stop it".

Mr Gore - who wrote and stars in An Inconvenient Sequel, which is directed by Bonni Cohen and Jon Shenk - also addresses President Trump's dismantling of environmental protections in the US, including his withdrawal from the 2016 Paris agreement on climate change.

He says: "A lot of people are not aware that under US and international law, the first day on which the US can actually legally withdraw from the Paris agreement is the first day after the next presidential election."

"If there is a new president," he continues as the audience whoops and cheers, "he or she can give 30 days' notice and we're back in."

Asked how he personally dealt with the news of Mr Trump's decision on the Paris accord, Mr Gore jokes about having had to deal with big disappointments before - a reference to his own ill-fated run for the White House in 2000.

But the former politician - who has four adult children with ex-wife Tipper Gore and is in a relationship with environmentalist Elizabeth Keadle - says "we really don't have time" to wallow in disappointments.

He observes that the effect of Mr Trump's move was not as bad as he had expected.

"Trump pulling out, I feared that it would do a lot of damage. I feared that other countries would follow his lead. But I was so happy the rest of the world stood up and said, 'We're still in.'

"There's a law of physics stating that for every action, there is an equal and opposite reaction. I think we're seeing a reaction to Trump on climate change, where countries that signed up to the Paris agreement because it seemed like everyone was doing it, but after Trump's announcement, they said, 'We can do better than that.'"

Mr Gore jokes that the Trump effect is not irreversible. The US is only "352 days into this experiment (of Trump's presidency) and in science and medicine, some experiments are terminated early for ethical reasons".

He declines to reveal what Mr Trump said to him in private discussions between the two after Mr Trump's election win, "but I don't think he's going to change his mind and I think the next several months are likely to be turbulent ones for our country".

But "we'll get through it," he says. "This is a challenging time for us. It's a dangerous time… but regardless of Trump, I am filled with hope that really and truly, we are going to solve the climate crisis."

"The remaining question is whether we will save it in time to avoid an unacceptable risk of passing some point of no return (environmentally). I'm optimistic on that too. We're going to win this. We can, we must, we will."