PARIS -- More than 50 world leaders are joining bankers, energy magnates and others Tuesday in Paris for a summit that President Emmanuel Macron hopes will give new momentum to the fight against global warming -- despite U.S. President Donald Trump's rejection of the Paris climate accord.

Sean Penn, Arnold Schwarzenegger, Bill Gates, Michael Bloomberg and Elon Musk are among prominent figures joining the world leaders at the summit, where participants are expected to announce billions of dollars' worth of projects to help poor countries and industries reduce emissions.

French President Emmanuel Macron (L) greets US businesman and politician Michael Bloomberg upon his arrival at the Elysee palace on December 12, 2017 in Paris, for a lunch as part of the One Planet Summit. Getty

Speaking to CBS Evening News anchor Jeff Glor the day before the summit kicked off, Macron said he believed Mr. Trump's rejection of the Paris accord had conversely given his own movement "huge momentum."

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"Today we have a momentum, because I think we have two phenomenon; so withdraw of the U.S., which for me is a mistake, that equates an impulse for a lot of others to say, 'Okay, we have to react and do something,'" Macron told Glor in Paris. "If we decide not to move and not change our way to produce, to invest, to behave, we will be responsible for billions of victims. I don't want to be a leader in such a situation, so let's act right now."

Activists kept up the pressure with a protest in the shadow of the domed Pantheon monument on Tuesday, calling for an end to all investment in oil, gas and resource mining.

That wasn't far from the message from top officials opening the summit: They agreed that the global financial system isn't shifting fast enough away from carbon emissions and toward energy and business projects that don't aggravate climate change.

"Financial pledges need to flow faster through more streamlined system and make a difference on the ground," said Fiji's Prime Minister Frank Bainimarama, whose island nation is among those on the front lines of the rising sea levels and extreme storms worsened by human-made emissions.

"We are all in the same canoe," rich countries and poor, he said.

Japanese Foreign Minister Taro Kono described ways Japan is investing in climate monitoring technology and hydrogen energy, but said "we have to do more and better."

R20 founder and former California state governor Arnold Schwarzenegger rides the new Velib' Metropole self-service public bicycle by the Smovengo consortium as he arrives at a news conference ahead of the One Planet Summit in Paris, France, December 11, 2017. REUTERS

Some 3,100 security personnel are fanned out around Paris for Tuesday's event, including extra patrol boats along the Seine River. Macron will accompany the visiting leaders to the summit site on a river island by boat.

Macron, who's also using the event to raise his international profile, did not invite Mr. Trump.

The White House took issue on Tuesday with the description of that non-invite, however, with an administration official telling CBS News the French had asked the White House who to invite, and that it was decided an official from the U.S. Embassy in Paris would attend. The official stressed that the option for Mr. Trump to attend was there, but they decided to send someone else. CBS News has sought clarification from the French government on how any invites to U.S. officials were extended.

On Monday, Macron awarded 18 climate scientists -- most of them based in the U.S. -- multimillion-euro grants to relocate to France for the rest of Trump's term.

Mr. Trump has expressed skepticism about global warming and said the Paris accord would hurt U.S. business. He's said he wants the terms of the agreement renegotiated, a notion Macron firmly dismissed on Monday in his interview with CBS News.

"You have more than 190 countries as negotiators. I'm not ready to renegotiate with so many people, I'm sorry, around the table. The U.S. did sign the Paris Agreement. It's extremely aggressive to decide on its own just to leave, and no way to push the others to renegotiate because one decided to leave the floor," Macron said. "I'm sorry to say that. It doesn't fly." He said he would, however, happily welcome Mr. Trump back into the agreement should he reconsider his position.

The "Make Our Planet Great Again" grants -- a nod to Trump's "Make America Great Again" campaign slogan -- are part of Macron's efforts to counter Mr. Trump on the climate change front. Macron announced a contest for the projects in June, hours after Mr. Trump declared he would withdraw the U.S. from the Paris climate accord.

The summit, co-hosted by the U.N., World Bank and Macron, is being held on the second anniversary of the Paris climate accord, ratified by 170 countries.

Germany's Angela Merkel, who was once labeled the 'climate chancellor' for her efforts to curb global warming, has faced domestic criticism for failing to attend the summit.

Annalena Baerbock, a spokeswoman on climate issues for the opposition Green party, said Tuesday that Macron appeared to be overtaking Merkel as Europe's leading lobbyist on climate issues.

"I think that's not a good sign," Baerbock told public broadcaster Deutschlandfunk. She said Germany had lost international credibility on the issue by allowing its carbon emissions to stagnate over the past decade and refusing to join a recent international declaration on ending the use of coal, one of the most polluting fossil fuels.

Baerbock said Europe's biggest economy also could have sent a signal on climate financing - a major topic in Paris - by declaring that civil servants' pensions wouldn't be invested in fossil fuels companies anymore, as some countries have already done.

Macron hosted leading world philanthropists Tuesday morning to encourage more climate-related investment.