This is an excerpt (par. 51) of His Holiness Benedict XVI's third and final encyclical, Caritas in Veritate, promulgated on June 29, 2009. The emphases are all found in the original.
The way humanity treats the environment influences the way it treats itself, and vice versa. This invites contemporary society to a serious review of its life-style, which, in many parts of the world, is prone to hedonism and consumerism, regardless of their harmful consequences. What is needed is an effective shift in mentality which can lead to the adoption of new life-styles “in which the quest for truth, beauty, goodness and communion with others for the sake of common growth are the factors which determine consumer choices, savings and investments.” Every violation of solidarity and civic friendship harms the environment, just as environmental deterioration in turn upsets relations in society. Nature, especially in our time, is so integrated into the dynamics of society and culture that by now it hardly constitutes an independent variable. Desertification and the decline in productivity in some agricultural areas are also the result of impoverishment and underdevelopment among their inhabitants. When incentives are offered for their economic and cultural development, nature itself is protected. Moreover, how many natural resources are squandered by wars! Peace in and among peoples would also provide greater protection for nature. The hoarding of resources, especially water, can generate serious conflicts among the peoples involved. Peaceful agreement about the use of resources can protect nature and, at the same time, the well-being of the societies concerned.
The Church has a responsibility towards creation and she must assert this responsibility in the public sphere. In so doing, she must defend not only earth, water and air as gifts of creation that belong to everyone. She must above all protect mankind from self-destruction. There is need for what might be called a human ecology, correctly understood. The deterioration of nature is in fact closely connected to the culture that shapes human coexistence: when “human ecology” is respected within society, environmental ecology also benefits. Just as human virtues are interrelated, such that the weakening of one places others at risk, so the ecological system is based on respect for a plan that affects both the health of society and its good relationship with nature.
In order to protect nature, it is not enough to intervene with economic incentives or deterrents; not even an apposite education is sufficient. These are important steps, but the decisive issue is the overall moral tenor of society. If there is a lack of respect for the right to life and to a natural death, if human conception, gestation and birth are made artificial, if human embryos are sacrificed to research, the conscience of society ends up losing the concept of human ecology and, along with it, that of environmental ecology. It is contradictory to insist that future generations respect the natural environment when our educational systems and laws do not help them to respect themselves. The book of nature is one and indivisible: it takes in not only the environment but also life, sexuality, marriage, the family, social relations: in a word, integral human development. Our duties towards the environment are linked to our duties towards the human person, considered in himself and in relation to others. It would be wrong to uphold one set of duties while trampling on the other. Herein lies a grave contradiction in our mentality and practice today: one which demeans the person, disrupts the environment and damages society.
 Cf. John Paul II, Message for the 1990 World Day of Peace, 13: loc. cit., 154-155.
 John Paul II, Encyclical Letter Centesimus Annus, 36: loc. cit., 838-840.
 Ibid., 38: loc. cit., 840-841; Benedict XVI, Message for the 2007 World Day of Peace, 8: loc. cit., 779.
Pope Emeritus Benedict XVI served as pope from 2005 to 2013.