Pope Francis is proving to be the first “environmentalist pope.” It turns out he also may be the first urbanist pope–not counting the aptly named Pope Urban of the 3rd Century.

Today marks an important milestone in the global effort to combat climate change: the full support of the Pope, who today issued a wide-ranging Encyclical statement urging the world to pursue sustainable development, and clarifying the link between Catholic teaching and environmentalism. As part of this wide ranging document critiquing modern capitalism’s inability to create healthy and just environments, Pope Francis also specified his thinking on the importance of cities in the creation of a healthier and more equitable world.

He writes in Chapter 1 (What is Happening to Our Common Home) that “Nowadays, for example, we are conscious of the disproportionate and unruly growth of many cities, which have become unhealthy to live in, not only because of pollution caused by toxic emissions but also as a result of urban chaos, poor transportation, and visual pollution and noise. Many cities are huge, inefficient structures, excessively wasteful of energy and water. Neighbourhoods, even those recently built, are congested, chaotic and lacking in sufficient green space. We were not meant to be inundated by cement, asphalt, glass and metal, and deprived of physical contact with nature.”

For those already working on issues related to sustainable urbanism, none of this is particularly new. But for this thinking to come from the Catholic Church itself, an institution that commands the moral respect of millions of Catholics, is a momentous occasion.

As the first pope from the Global South, Francis’s background has no doubt exposed him to the problems of unsustainable development. Born as Jorge Mario Bergoglio in Argentina, Francis had exposure to urban poverty in Latin America throughout his career, often visiting residents of Buenos Aires’s shantytowns, or Villa miseria.

The encyclical, in addition to focusing on environmental degradation and poverty, also contains an even more subtle critique of the failure of modern urban environments to provide for people’s needs for community and cultural identity: “The extreme poverty experienced in areas lacking harmony, open spaces or potential for integration, can lead to incidents of brutality and to exploitation by criminal organizations. In the unstable neighbourhoods of mega-cities, the daily experience of overcrowding and social anonymity can create a sense of uprootedness which spawns antisocial behaviour and violence. Nonetheless, I wish to insist that love always proves more powerful.”

The Pope goes on to call for an investment in affordable public transportation, affordable housing, and re-investing in slum communities rather than demolishing them. Some in the U.S. might criticize the Pope as overstepping his theological bounds. But given the increasing number of Catholics in rapidly developing Asia and Africa, the Pope’s support for sustainable urban development might just have the biggest impact where such ideas are needed the most.