Video (01:39) : Environmentally friendly leaders from around the world, including the New York City Mayor and California Governor, have gathered at the Vatican for a two-day conference rallying momentum ahead of Paris climate negotiations later this year.

After a day spent hearing Pope Francis and mayors from across the world speak at the Vatican on climate change and human trafficking, Minneapolis Mayor Betsy Hodges said she's been inspired to focus more on the links between sustainability and poverty.

"I really, profoundly understand in a new way that environmental justice is not just a sidebar to climate change action," she said in a phone call from the Vatican on Tuesday. "And that it's not just a sidebar to social justice work."

Hodges was one of about 60 local leaders from around the world invited to see the pope and participate in a summit on climate change and human trafficking, which was scheduled to continue Wednesday. The pope spoke for about 15 minutes Tuesday to the group, telling them that humans are causing "destruction" by "not taking care of human ecology and not having an ecological conscience."

"Individual countries might be able to make nice speeches at the United Nations, but if the work doesn't come from the periphery, moving to the center, there is no effect," he said.

After he concluded his remarks, the pope signed a declaration that states that "human-induced climate change is a scientific reality and its effective control is a moral imperative for humanity." Hodges and the other mayors posed for a group photo with the pope before lining up to add their signatures to the letter.

Hodges said the meeting came with far less pomp and circumstance than she'd expected, but added that the pope was a powerful presence during his time with the mayors.

Rome Mayor Ignazio Marino, fourth from left, arrives with mayors from around the world to attend a performance in Rome's Foro di Augusto, Tuesday, July 21, 2015. Dozens of environmentally friendly mayors from around the world are meeting at the Vatican this week to bask in the star power of eco-Pope Francis and commit to reducing global warming and helping the urban poor deal with its effects.

"I can see why he inspires people, but it's in part because he's very human, he's very relatable and he also cares a great, great deal about human beings," she said.

Hodges, whose trip was paid for by conference organizers, documented the meeting on Twitter, posting selfies with the mayors of Portland, Ore., and Oslo, Norway, and snapping a photo of the pope's seating location: "That's the chair they just set out for @Pontifex #MayorsCare #surreal."

Earlier Tuesday, about 35 summit participants took turns making speeches on the issues the pope addressed in his recent encyclical to Catholic Church leaders. He has argued that a fossil-fuel-based world economy exploits the poor and destroys the Earth.

Hodges also tweeted the views of many mayors as they addressed the gathering, including New York City's Bill de Blasio, a founding member of an alliance of cities around the world that have committed to reducing their emissions by 80 percent by 2050 or sooner.

"How could any version of business as usual make sense at this moment in history?" Hodges quoted de Blasio as saying.

Hodges has made sustainability a central focus of her administration. The city has a long list of goals, including reducing citywide greenhouse gas emissions by 30 percent by 2025, and it recently entered into a Clean Energy Partnership with local utilities. Minneapolis kicks off a new curbside organics recycling program next month, and Hodges is leading a "Climate Champs Challenge," encouraging residents with energy saving tips and strategies each month.

The city's efforts on climate change were recognized last year by the White House, which named Minneapolis a "Climate Action Champion" community.

Karen Monahan, an organizer with the Sierra Club's Minnesota North Star Chapter, said the summit was a "historic" event that gave Pope Francis, Hodges and other leaders involved a chance to improve lives around the world.

Monahan said Hodges and other city leaders have made a point of looking at climate change as an issue that is directly related to gaps in health, education and quality of life. As an example, she said problems with pollution can lead to higher asthma rates, which can contribute to absences at school for children in poor neighborhoods.

Some mayors at Tuesday's summit also spoke up about their concerns over human sex trafficking.

"Eye opening how often international mayors talk abt forced marriage as part of modern slavery," Hodges tweeted.

Jason Adkins, executive director of the Minnesota Catholic Conference, said the pope is encouraging people of all religions to consider the similarities in how people treat the Earth and their fellow humans. He stressed that the pope's encyclical and the message delivered Tuesday were about more than just climate change.

"Really, what the pope is calling everyone to — Catholic and non-Catholic alike — is a profound ecological conversion, a transformation of our own personal habits, but also the way we live in society," he said, "and that includes public policies pertaining to things like renewable energy standards, carbon emissions, soil and water conservation as well."

Adkins said the church is getting the message out to Twin Cities-area Catholics, including in a panel discussion scheduled for Sept. 9 at the University of St. Thomas.

Hodges said Tuesday that she was looking forward to several presentations scheduled for Wednesday and that she expected to return home with plenty of new information. She'll also return with some lighthearted observations, like one she tweeted on Tuesday while at the Vatican, seat of a church led exclusively by men: "As often happens, more men's rooms here than women's; probably understandable at the Vatican."

The Associated Press contributed to this report.