In the early 2000s Al Gore emerged from a devastating presidential election defeat with a new quest: to warn the world about global warming. Although some may think his climate work peaked with his 2005 film, An Inconvenient Truth, he has taken his mission far beyond the silver screen. Over the past decade the former vice president has trained thousands of climate leaders who are now spreading awareness about global warming in communities around the planet. He has also worked with government leaders on switching energy economies from fossil fuels to renewables, and has traveled to places such as Greenland and India to witness firsthand the damaging effects of our carbon-addicted world. Now Gore is back in theaters on August 4 with An Inconvenient Sequel: Truth to Power to convince the public we desperately need to act on climate change—and fast.

Scientific American spoke with Gore about his ongoing inspiration to tackle climate change and what actions he sees as the biggest hope for our warming world.

[An edited transcript of the interview follows.]

Why did you feel the need for a sequel to An Inconvenient Truth?

The 10-year anniversary of the first movie seemed like a good time to come back and tell the audience what’s new. There have been two huge changes in the last decade. Number one: climate-related extreme weather events have become far more serious and frequent, validating the predictions of the scientific community. [We wanted to give] people a visceral understanding of how these changes are affecting people all over the world, including throughout the United States. The scientific community has tremendous credibility, but it turns out Mother Nature is more persuasive than any of us.

The second big change: the solutions are here now. A decade ago they were visible on the horizon, but we had to rely on technology experts to reassure us they were coming. Now the stunning cost reductions for solar electricity, wind electricity, batteries, electric vehicles and hundreds of impressive efficiency improvements are all dramatically improving our ability to reduce emissions and become far more efficient.

We are now in the early stages of a global sustainability revolution, which has the magnitude of the industrial revolution and the speed of the digital revolution. Global emissions have stabilized in the last three years, giving hope that emissions will start reducing significantly very soon, as they have already done in the U.S., Europe and China.

What message do you hope people will take away from the film?

The directors of the second film, Bonni Cohen and Jon Shenk, have a cinema verité style, which is a different style from Davis Guggenheim’s [who directed An Inconvenient Truth]. It gives people a chance to see the action firsthand. They followed me around for two years and left a thousand times as much film on the cutting room floor as what they selected for the final version of the movie. It does leave audiences extremely hopeful, but with an increased sense of urgency. I’m very happy they’ve succeeded in doing both of those things.

Given the Trump administration’s actions, do you see U.S. politics as an effective way to address climate change? If not, what is the more powerful force?

American democracy has been hacked by big money and lobbyists for polluters long before Putin hacked our democracy. But people are beginning to react to what Trump is doing, validating the law of physics, which says that for every action there is an equal and opposite reaction. That is a phenomenon that sometimes plays out in politics. We saw it when the entire world reacted to Trump’s decision to pull out of the Paris agreement by immediately doubling down on their commitments. India just announced two months ago that, in the wake of Trump’s decision, within 13 years 100 percent of its new cars and trucks will have to be electric vehicles. Both India and China are closing hundreds of coal-burning plants and rapidly expanding their solar and wind facilities. We’re seeing the beginnings of a radical transformation of the world’s energy system, particularly in developing countries.

The political system here in the U.S. is still slow to respond—but the reaction to Trump here in the U.S. is also impressive and encouraging. After Trump’s announcement on Paris, governors, mayors and business leaders stepped up to fill the gap. I have been encouraged at how many cities have announced the goal of 100 percent renewable energy. In the movie the mayor of a very conservative Republican city in Texas has already achieved that goal. Atlanta and Pittsburgh have just announced that they’re going 100 percent renewable. If Atlanta and Pittsburgh can do it, any city can do it.

It has to be noted that even with all of the commitments in Paris put together, it’s still not enough. It’s an impressive foundation upon which to build stronger efforts at emissions reductions, and we could move faster if the U.S. president would provide leadership. But since he is in the grips of carbon polluters, we have to rely on state and local governments and business leaders to step up their actions.

What is the greatest obstacle to making progress on climate change? And what can be done about it?

The large carbon polluters have taken the playbook written by the tobacco industry, which responded to the scientific consensus linking cigarettes and lung and heart diseases by hiring actors, dressing them up as doctors and putting them in front of cameras to falsely reassure people that there were no consequences to smoking cigarettes. In my home state of Tennessee there’s an old saying that if you see a turtle on a fence post, you can be pretty sure it didn’t get there by itself. When we see a persistent level of climate denial, we can be pretty sure it didn’t occur spontaneously. The large carbon polluters have spent between one [billion and] two billion dollars putting out pseudoscience and creating false doubts.

But people are seeing through this now, partly because of the extreme weather events connected to the climate crisis. Just yesterday, seven inches of rain fell in Miami in two hours. The once-in-a-thousand-year events are occurring [much more frequently] now. Even people who don’t want to use the phrase “global warming” or “climate crisis” are finding new ways to express what they feel with their own senses, and they’re responding to political leaders who are using facts as a basis for new policies. In the meantime many contracts are being signed for electricity from solar energy at less than half the price of electricity from fossil fuels, even on an unsubsidized basis.

So I’m encouraged—but it is a race against time.