Eleven years after “An Inconvenient Truth” rocked the Sundance Film Festival and went on to become an Oscar winner and box office success, Al Gore’s eco-warrior alter-ego is back on-screen at Sundance with a timely follow-up, “An Inconvenient Sequel: Truth to Power.”

Its release arrives on the heels of news that 2016 was, like the two years before it, the hottest on record. It also debuted the night before the inauguration of Donald Trump, a man who isn’t mentioned explicitly in the movie all that much — perhaps because his victory seemed so unlikely while the doc was being made — but certainly casts a shadow over the proceedings. At one point, we hear a sound bite of Trump’s saying he does not think the environment should be a priority for the country. After all, he once claimed climate change was a hoax perpetrated by the Chinese, even though an overwhelming majority of scientists say human-caused climate change is real. He also appointed Scott Pruitt to lead the Environmental Protection Agency, and although the Oklahoma attorney general said climate change is not a hoax, he has sued the agency more than once.

So should environmentalists despair? According to the documentary, directed by Bonni Cohen and Jon Shenk, not yet. The movie chronicles Gore’s many stumbling blocks, but it also reveals how he turned them into triumphs — eventually.

In one of the movie’s most memorable scenes, Gore travels to Georgetown, Tex., which is, per the city’s mayor, a red city in the reddest county in the red state of Texas. The reason for the visit is that Georgetown is heavily investing in renewable energy from the wind and sun, and once it goes 100 percent renewable, it will be the largest city in the country to do so.

It just made economic sense, the mayor tells Gore. Plus, don’t we have an obligation to leave the planet better than we found it?

Careful, Gore replies. With that kind of talk, someone might mistake the mayor for a liberal. The two laugh, then take a photo underneath a sign touting the Republican Party.

Not only is the scene an example of reaching across the aisle — something politicians have increasingly rejected — but it’s proof that concern for the environment, including climate change, is not necessarily a partisan issue. It’s a global one.

The truth still looks bleak: Greenland is melting, and Miami is flooding. Extreme weather events are happening more frequently. But Gore has seen setbacks before.

In its commentary on politics, “An Inconvenient Sequel” is about more than the environment, and it might be cathartic for those dreading the Trump years. The movie is really about bouncing back when you’re knocked down. Gore’s contentious loss to George W. Bush in 2000 comes up a lot in the movie — sometimes in funny ways. When a reporter from the Miami Herald is talking about Florida’s lackluster response to the environmental issues facing the state, she mentions that Florida can be a challenge. “I can confirm that,” Gore deadpans.

Time and again, we see that Gore has been thwarted. As vice president under Bill Clinton, he spearheaded the launch of a satellite into outer space to not just capture images of Earth but also to gather data and track weather events. Once Bush was elected, though, the program was shut down. And he pushed hard for the United States to sign the Kyoto Protocol to reduce greenhouse-gas emissions, but he couldn’t make it happen.

Then again, the DSCOVR satellite finally launched, in 2015. And we see in the movie that Gore helped broker another global climate deal, the Paris agreement.

In other words, he’s been riding a seesaw of setbacks and triumphs for a long time, showing that it’s not worth giving up over any single obstacle. Even though Trump says he may decide to simply pull out of the Paris agreement, Gore remains optimistic. In early December, the former vice president even met with the president-elect.

“He was receptive to some of what I had to say, and I appreciated that,” Gore told the Hollywood Reporter.

The message of the movie seems to be: If he’s not losing hope, no one else should be either.