The encyclical letter Laudato Si is available here on the Vatican website.
LS 3 reminds us that the universal concerns of humankind are of great concern to Catholicism and to its pope. In this paragraph, we are reminded of Pope Paul’s concern for the environment:
4. In 1971, eight years after Pacem in Terris, Blessed Pope Paul VI referred to the ecological concern as “a tragic consequence” of unchecked human activity: “Due to an ill-considered exploitation of nature, humanity runs the risk of destroying it and becoming in turn a victim of this degradation”.[Octogesima Adveniens 21] He spoke in similar terms to the Food and Agriculture Organization of the United Nations about the potential for an “ecological catastrophe under the effective explosion of industrial civilization”, and stressed “the urgent need for a radical change in the conduct of humanity”, inasmuch as “the most extraordinary scientific advances, the most amazing technical abilities, the most astonishing economic growth, unless they are accompanied by authentic social and moral progress, will definitively turn against (humankind)”.[Address to FAO on the 25th Anniversary of its Institution (16 November 1970), 4: AAS 62 (1970), 833]
Paul VI cites concerns not only moral but social. Behaviors must change. Even behaviors that are not in themselves sinful.