President Joe Biden will announce Tuesday that he is putting the brakes on uranium mining in a vast area around the Grand Canyon, in the first salvo of a trip aimed at warming Americans up to his climate policy.

Biden will give the area of nearly one million acres "national monument" status, White House climate advisor Ali Zaidi told reporters on Air Force One as it flew the 80-year-old Democrat to Arizona late Monday for a tour through the southwestern United States.

Zaidi said the area's new status will prohibit new uranium mining projects on the site, without affecting existing mining rights.

Local Native American tribes had sought such a ban for decades, seeking to curb mining activity around the immense, spectacular river valley.

The creation of a new protected area is both a tribute to the "vibrant story" of the Indigenous people there, and safeguards the "incredibly important ecosystem" around the Colorado River, Zaidi said.

Biden's multi-state trip comes as the region still recovers from a brutal, record-setting heat wave.

The president, who is running for re-election, plans to use the visit to "highlight how his administration has made historic investments in climate, conservation, and clean energy," according to the White House.

He will spend Tuesday in Arizona, before traveling the next day to neighboring New Mexico.

Both states and the surrounding region have experienced severe heat waves this summer, with Arizona's capital Phoenix in July recording the hottest month ever for a US city.

Scientists warn that global warming is making heat waves hotter, longer and more frequent.

- 'Existential threat' -

The trip comes just ahead of the one-year anniversary of Biden's signing of the Inflation Reduction Act (IRA), a mammoth package of climate investments and other programs that has become the centerpiece of his first term in office.

"The president has translated the greatest risks we face into our greatest economic opportunity," Zaidi said.

Biden regularly describes climate change as an "existential threat," and criticizes his Republican opponents for failure to act on the issue.

The IRA funnels some $370 billion into subsidies for America's energy transition, including tax breaks for US-made electric vehicles and batteries.

Since the climate law was signed, some $75 billion in new manufacturing investments have been announced, according to policy analyst Jack Conness of think-tank Energy Innovation: Policy and Technology.

Beyond the IRA, the overall amount unveiled by private companies across critical areas ranging from semiconductors to EVs is even larger.

The White House touts some $503 billion in commitments to key industries under the Biden administration, which has also seen the passage of other legislation including the American Rescue Plan and the Chips and Science Act.

But it remains unclear if the investment gains are translating into clear optimism on the ground, with a Gallup poll in June finding that 66 percent of Americans say the economy is getting worse.

And nearly 60 percent of Americans disapprove of Biden's handling of climate change, according to a Washington Post-University of Maryland poll conducted last month. The survey also found that few adults said they knew a good amount or great deal about the IRA.

With Biden's re-election campaign underway, the Democrat is touting his "Bidenomics" economic agenda, which involves bringing manufacturing back to the United States after decades of offshoring.

"Polls don't tell the whole story," his spokeswoman Karine Jean-Pierre said aboard Air Force One Monday. "The hope is that we'll get our message out."

Besides addressing the summer heat crisis, Biden's visit to Arizona comes with electoral incentives.

The 80-year-old Democrat narrowly won Arizona in 2020, and it is among the handful of states expected to be decisive in determining next year's presidential election.

On Thursday, Biden is expected to travel to Utah where the focus will be on veterans' programs.