The link between climate change and human slavery is the topic of an international conference to be hosted by the Vatican later this month, in which Pope Francis will take part along with the mayors of major cities from around the world.

"These issues are intertwined: The objectification of people, and the objectification of the planet," said Michael Shank, George Mason University fellow and media consultant for the conference, during a briefing Wednesday at the Holy See Press office.

"This meeting is unique to many global meetings in that it's very practical," Shank continued, in that it involves "actors who can move quickly on the ground with their constituencies and voters, actors who are dealing with crises already."

"Modern Slavery and Climate Change: the Commitment of the Cities" is the title of the workshop presented during the July 15 press briefing. The event is part of the larger symposium sponsored by the Pontifical Academy of Sciences (PAS) from July 21-22, with the title: "Prosperity, People and Planet: Achieving Sustainable Development in Our Cities."

The conference will bring together mayors and other leaders from cities around the world, many of which have a history of environmental awareness, including several from the United States.

The gathering also comes just one month after  the release of Pope Francis' long-awaited encyclical on the environment, Laudato Si, meaning "Praise be to You," was published on June 18.

While the 184-page encyclical wades into controversial topics such as climate change, the document also argues it is not possible to effectively care for the environment without first working to defend human life.

"There is a clear link between the two human-induced emergencies of the climate crisis and the social crisis," said Bishop Marcelo Sanchez Sorondo, PAS chancellor, citing Pope Francis's recent encyclical on the environment, Laudato, Si.

"Following the Encyclical, our commitment is to make the whole of society aware of these phenomena and of the human responsibilities of these crises and to react firmly, as a new moral imperative for all of humanity in favour of the common good."

Bishop Sanchez told journalists the decision to bring these mayors together stemmed from a previous conference between police chiefs and bishops. Presumably speaking about the 2014 conference on Human Trafficking hosted by the PAS, the bishop said that, during that gathering, police chiefs explained that, while committed in their work, they answered to mayors and governors – not bishops.

"Following their advice, we have thus tried to bring together the mayors to determine the best practices to mitigate climate change and eradicate modern slavery," he said.

Bishop Sanchez went on to call on these mayors to commit to "promoting the empowerment of the poor" and vulnerable living in cities and urban settings, to ending "all forms of modern slavery," and to "developing resettlement and social integration programs for the victims" of trafficking.

"In short, we would like our cities and urban settlements to become more socially inclusive, safe, resilient and ecologically integrated," he said.

The symposium comes ahead of several international events focused to environment. These include the United Nations General Assembly's upcoming adoption of sustainable laws on Sept. 25, followed by the climate summit in Paris in late November which will center on reducing the impact of climate change.