In 1990, Pope John Paul II advocated "Peace With All Creation," saying,
“Today the ecological crisis has assumed such proportions as to be the responsibility of everyone…The…’greenhouse effect’ has now reached crisis proportions…”
Much earlier, in 1971, Pope Leo XIII declared in “Rerum Norvarum,”
By an ill-considered exploitation of nature (man) risks destroying it and becoming in his turn the victim of this degradation…the human framework is no longer under man’s control, thus creating an environment for tomorrow which may well be intolerable.
Clearly, for the Catholic Church, respect for all of God's creation is essential, and man must preserve the balance that God has ordained in nature. Simply put, to abuse anything created by God is wrong, and man must live in harmony with others and nature, as well.
To exploit nature and profit from this exploitation, as in, for instance, the production of natural gas, or oil, the dissemination of water, deforestation for profit, etc. is sinful because these activities are prompted by the one of the Cardinal Sins of the Church: Avarice. To commit such acts of exploitation that may perhaps threaten the lives of people, of course, is wrong as property owners risk committing murder. For instance, if a mine owner exploits people in order to obtain coal or other minerals and the mine collapses and kills miners, then the mine owner is guilty of murder.
The environment, then should be treated with regard and preserved as much as it can. The Catholic Church is against exploitation of any kind, whether of man or of nature.
Even though energy resources literally fuel our economy…we need to ask about ways we can conserve energy, prevent pollution, and live more simply.” –U.S. Bishops, “Global Climate Change.”