“Alongside the ecology of nature there exists what can be called a “human” ecology, which in turn demands a “social” ecology. All this means that humanity, if it truly desires peace, must be increasingly conscious of the links between natural ecology, or respect for nature, and human ecology. Experience shows that disregard for the environment always harms human coexistence and vice versa.”
Pope Benedict XVI, Jan. 1, 2007, The Human Person, the Heart of Peace (para 8)
See also: the full text of Benedict's encyclical Caritas in Veritate (Oct 2009) , Oblate-Franciscan JPIC resource list for discussion groups, Canadian bishops' overview of JPIC, Catholic Encyclopedia. Catholics play a major role in World Council of Churches ecumenical work on JPIC: see its history and current international campaigns.