Official Portrait image via Beto O'Rourke on Flickr.

(AP) — Democratic presidential candidate Beto O’Rourke has announced his first major policy initiative, a $5 trillion plan to combat climate change that he says will keep the Earth from sliding past the point of no return in less than a generation.

The former Texas congressman unveiled his proposal on Monday from California’s Yosemite National Park, a dramatic backdrop for a move he hopes can jumpstart a campaign that began to much national fanfare but has seen some of that luster fade in recent weeks.

The plan calls for increasing taxes on “corporations and the wealthiest among us” and “ending the tens of billions of dollars of tax breaks currently given to fossil fuel companies” while offering federal grants to encourage innovative housing and transportation improvements.

It includes $1.5 trillion in direct federal funding, while seeking to incentivize an additional $3.5 trillion from states, private capital and other sources over 10 years to improve aging infrastructure nationwide and to take “significant actions to defend communities” preparing for intensified floods, droughts, hurricanes, fires and other natural disasters fueled by a changing climate.

Like others in the packed field of Democrats seeking the White House, O’Rourke promised to sign climate change-fighting executive orders on the first day of his presidency — including rejoining the 2016 Paris Agreement, from which President Donald Trump withdrew the U.S.

O’Rourke had previously praised the Green New Deal , an ambitious but longshot initiative backed by some of the most liberal Democrats in Congress which calls for the U.S. to reach net-zero carbon emissions by 2030. But the plan announced Monday wants to achieve that goal by 2050, while promising to get halfway there in just the next 11 years.

“This country needs direction when it comes to meeting the single greatest threat that we’ve ever faced,” O’Rourke told reporters after a walking tour of Yosemite Valley, past pine trees and through the mist from a rushing waterfall.

The Sunrise Movement, the environmental group behind the Green New Deal, said in a statement that O’Rourke’s proposal “gets a lot right” but “gets the science wrong,” and expressed dismay that he was backing off previous support for net-zero emissions by 2030.

“Beto claims to support the Green New Deal, but his plan is out of line with the timeline it lays out and the scale of action that scientists say is necessary to take here in the United States to give our generation a livable future,” the group said in a statement.

California, meanwhile, already has set a goal of generating 100 percent of its electricity from noncarbon sources and achieving net-zero carbon emissions by 2045.

The announcement came during O’Rourke’s first visit as a presidential candidate to California, a state that’s experiencing more destructive and deadlier wildfires due in part to climate change. A blaze last summer caused a partial shutdown of Yosemite, and O’Rourke on Sunday met privately with firefighters in Mariposa County who battled it for weeks.

He toured the park, famous for its breathtaking vistas and giant sequoia trees, with Anne Kelly, director of the University of California-Merced’s Yosemite Field Station and Leslie Martinez, an environmental justice advocate from the state’s Central Valley, where O’Rourke planned to campaign later Monday. Kelly explained that the famously resilient sequoias are beginning to show signs of stress from a recent, multi-year drought.

O’Rourke called his first visit to Yosemite a “religious experience.”

“Driving in, there are no words that could express what I was seeing or the way that I was feeling,” he said. “And then to learn about some of the challenges that Yosemite faces … the composition of what we are seeing around us is changing literally before our eyes.”

O’Rourke stopped to talk to a few visitors as he concluded the walk, most of whom were not from California or even the United States.

The day before, he drove hours from San Francisco to Mariposa, home to fewer than 20,000 people and, in the 2016 presidential primary, only about 6,000 voters.

His California swing includes no fundraisers, which are typical for presidential hopefuls who are visiting the state that’s home to big donor bases such as Hollywood and Silicon Valley.

“It is unusual to come to California, where there are so many Democratic donors, and decide not to raise money,” said Rose Kapolczynski, who managed former U.S. Sen. Barbara Boxer’s campaigns. “Maybe he’s doing so well online that he thinks he cannot raise money on this trip and try to make a point of wanting to talk to people instead.”

O’Rourke opened his campaign last month to large crowds in key early states such as Iowa and New Hampshire but also in battleground areas that included Pennsylvania, Michigan and Ohio, as well as solid early fundraising . But he’s since seen some of the buzz around his upstart campaign die down.

He may be hoping his “I’ll-campaign-anywhere” style is novel enough to sprawling California to gain attention. The state moved its 2020 presidential primary to March with the goal of gaining more sway in the nominating contest. But with nearly 40 million people to reach in California alone, breaking through is tough for any candidate.

“We’re the black hole of politics,” said Bob Mulholland, a Democratic National Committee member from California who is supporting Harris. “Almost anything you do in this state, no one notices.”