Biden reflects on American leadership, progress made at G-20 summit

President Joe Biden reflected on the progress he made with other world leaders at this weekend's G-20 summit, including ways to combat climate change, as the event wrapped up in Rome on Sunday.

Kicking off his first solo press conference in four months, Biden characterized his meetings over the last three days as "productive" and said America has reclaimed its role on the world stage working with its allies.

Biden touted goals that were accomplished during the summit, including leaders across the world endorsing a 15% global minimum tax, and international coordination to address the supply chain crunch across the globe.

During the summit, Biden highlighted American leadership on the world stage, a campaign pledge he was looking to deliver on.

"I'm looking forward to continuing to make progress on critical global issues as we head off to Glasgow because of what we've seen again here in Rome, what I think is the power of America showing up and working with our allies and partners to make progress on issues that matter to all of us," Biden said

The president in particular lauded his in-person meetings with the world leaders.

"There's really no substitute for face-to-face discussions and negotiations among the leaders when it comes to building understanding and cooperation," Biden said. "When you're looking at someone straight in the eye when you're trying to get done -- they know me, I know them, we can get things done together."

He also spoke about his meeting during the G20 with the E3 countries -- France, Germany and the U.K. -- on the state of the Iran nuclear program and returning to the table for negotiations.

"We came together to reiterate our shared belief that diplomacy is the best way to prevent Iran from gaining a nuclear weapon, and we discussed how best to encourage Iran to resume serious good faith negotiations," Biden said of the meeting.

Biden responded to questions from ABC's Cecilia Vega about his climate proposal that is part of his reconciliation plan that Democrats back in Washington are still working to pass and on to the president's desk.

The president said the U.S. would be able to meet his administration's goal of reducing emissions by 2030, by 50%. When asked if he would be able to combat climate change solely on incentives and not punitive measures, the president said didn't believe that people needed to be punished.

Biden cited the success of tax credits for green retrofits, such as solar panel installations, and commitments from automakers to boost their electric fleets as examples of industries already taking charge of fighting climate change.

"Everybody knows which direction it's going and there's no indication that there has to be a punitive effort to get people to react the way in which we have to do. At least I don't believe so," he said."

Biden got emotional when asked about his meeting with Pope Francis Friday. The visit came as American Catholic bishops are divided on offering Biden, the second Catholic president in U.S. history, communion over his support for abortion rights.

The president told reporters that the pope told him he was a good Catholic and he should keep receiving communion.

Biden wouldn't say whether his visit with Francis would end the debate among the conservative bishops, saying that "a lot of this is personal."

He did praise the pope, calling him a "truly genuine decent man," and that he was "everything I learned about Catholicism."

Biden recalled the time that Francis met with him and his family during the pope's 2015 visit to the United States. The 10-15 minute meeting happened just months after Beau Biden died of cancer, and the president said Francis's words brought great comfort to his family.

"He knew about him. He knew what he did. He knew who he was. He knew where he went to school. He knew what a man he was," Biden said. "It had such a cathartic impact on [Beau's] children and my wife and our family, that it meant a great deal,"

ABC News' Jordyn Phelps and Ivan Pereira contributed to this report.