At the office of the Pontifical Academy of Sciences, the staff is cleaning up, lingering mayors from overseas are packing up, and the organizer of the mayors conference targeting climate change, among other issues, was left to answer the question: now what?

Two months before Pope Francis visits New York for the United Nations meeting on climate change, the Vatican is assessing its just concluded conference of Mayors — and its relying on participants like Boston Mayor Marty Walsh to push the climate change agenda forward.

Bishop Marcelo Sánchez Sorondo, in halting English, says that the conference succeeded in part because mayors of what he called some of the world’s "most important cities," like Walsh, will be working with Pope Francis to raise awareness of climate change on a local level.

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"It's an issue that — scientists will back it up — saying that there is a major problem in the globe, with the environment," Walsh said. "I think that industrialized countries in particular need to start paying a lot more attention to this issue."

This has become a priority issue for Pope Francis and the Vatican Pontifical Academy of Sciences, Sorondo says.

"The crisis of climate, for the first time, the academy says that depends on human activity," he said.

This week the mayors of Boston and New York, as well as Paris, Rio de Janeiro, Mexico city and Johannesburg, among 60 others, shared models of best practices in tackling carbon emissions, reducing income inequalities and stamping out human trafficking. And they signed a declaration committing to forge an "Alliance for Sustainable Cities." The question now is: Will their words result in collective action moving forward or will they move policies no further than the papers that are being packed up here at the Pontifical Academy of Sciences at the end of an historic week?