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A Thomistic Explanation of Environmental Ethics

John Paul II declared to the world that there’s an ecological crisis, which has caused many to wonder about their moral obligation to protect and preserve the environment. This call from the pope encouraged certain theologians to argue for a per se moral obligation. By per se, I mean that man has some responsibility to care for the Earth’s environment because it is good and man is morally obligated to preserve this goodness. However, all that exists is a per accidens obligation. By this I mean that man needs to worry about damaging the environment only so far as it can have a harmful effect on man. A clear resolution to this debate ought to be found in the writings of the last three popes, who have developed the Church’s doctrine on this issue. Since the popes have the responsibility and power to develop Catholic doctrine and to address this modern question, they ought to hold the key to any arguments that would reveal a per se moral obligation of man to protect the environment. Even though this moral obligation cannot be found explicitly in Scripture or Sacred Tradition, many have hope for a development in the encyclical Laudato Si’, an encyclical entirely dedicated to man’s relationship with the Earth. However, in spite of the many papal writings on the environment from Pope John Paul onward, the popes never supported a per se moral obligation regarding the environment. Even though Pope Francis may appear to support this opinion in Laudato Si’, the entirety of this document reveals this novel doctrine to be false.

As implied by the Catholic Encyclopedia, most theologians who attempt to claim that Scripture or Sacred Tradition implies a command to care for the environment refer to “The Apologetic Approach.” Almost all appeal to the passage to be stewards of the Earth.1 From this passage, it would appear that there is at least a potential for per se moral obligations to care for the environment. Relying on this as their connection with eco-theology and tradition, we must examine the decrees from the Magisterium and observe if their doctrines have relied upon per se reasons to care for the environment. This is essential, because the third pillar of truth, which is the Magisterium, is the last resort to discover a per se argument to care for the environment.

Since the great concern for environmental ethics has become mainstream only in recent years, similar to issues of cloning and in vitro fertilization, we will begin with the modern popes to see if they have developed Catholic doctrine to allow this new understanding of man’s responsibility to the environment. Using this as the source for a new understanding of morality would not be a heretical and innovative understanding. Rather, it would be an execution of the Magisterium’s power and responsibility to organically develop Catholic doctrine, which was always buried within the teachings of the early Church.

The first pope to appear to give credibility to this new eco-theology was Pope John Paul II. He makes a clear statement affirming that there is a crisis in ecology. “Equally worrying is the ecological question which accompanies the problem of consumerism which is closely connected to it. In his desire to have and to enjoy rather than to be and to grow, man consumes the resources of the Earth and his own life in an excessive and disordered way.”2 Clearly, the pope has established the existence of an ecological crisis. This is certainly a development in terms of the terminology, but is the content really development on the Church’s moral teaching?

As we dig a little deeper, we see the pope referring to the importance of preserving animal species, ultimately directing this toward a concern for man’s good. “In addition to the irrational destruction of the natural environment, we must also mention the more serious destruction of the human environment, something which is by no means receiving the attention it deserves. Although people are rightly worried — though much less than they should be — about preserving the natural habitats of the various animal species threatened with extinction because they realize that each of these species makes its particular contribution to the balance of nature in general, too little effort is made to safeguard the moral conditions for an authentic ‘human ecology.’”3 This passage of concern for the extinction of animal species is a concern for the balance of nature. Though this could be interpreted to say the concern for the balance of nature is a concern for nature in and of itself,  but it appears that the concern for the balance of nature is out of concern for the flourishing of men. Thus, the per se interpretation of the pope’s intention can be held. However, it is strongly implied that this balance of nature is a concern for man because the pope immediately diverts the conversation from discussing nature to what he calls “authentic human ecology.”4 This, he says, is first and foremost concerned with developing an environment where the family can thrive.5 Thus, he directs the needs and ends of ecology toward the good of man, and not the maintenance of the environment for its own sake.

John Paul affirms this understanding of environmental theology in his other writings. The Catechism he created to combat the problems concerning modern man states, “Man’s dominion over inanimate and other living beings granted by the Creator is not absolute; it is limited by concern for the quality of life of his neighbor, including generations to come.”6 Thus, the Catechism is directing its concerns about the environment toward the good of man, which would imply a per accidens view of environmental obligations. Later in the encyclical, he also affirms this position when saying the responsibility toward the environment in which man lives is ordered toward the services of man’s personal dignity, his life, and the life of future generations.7 From these teachings, it would appear that John Paul II understood moral environmental obligations only in a manner that is per accidens and not per se.

Though environmental concerns started to become popular news only under John Paul, the environment was a major concern among political leaders and heavily addressed by Pope Benedict XVI. The pope even celebrated Mass for the restoration of proper ecology and talked about his concern for the preservation of the environment and the need to combat climate change.8 In a general audience, the pope talked about the Earth as a gift that was given to man by God and that must be preserved.9 He also stated, “We are all responsible for the protection and care of the environment.”10 Certainly, Pope Benedict XVI developed the doctrine of our obligations to the environment; however, there is nothing in his messages to indicate that our obligations to the environment are anything other than a per accidens obligation. This is affirmed by the fact that often the Holy Father finishes his statements on ecology by linking his concerns back to men. In the encyclical Caritas in Veritate, the pope stated, “Our duties towards the environment are linked to our duties towards the human person, considered in himself and in relation to others.”11

Though Pope Benedict did focus a considerable amount of his papal writings on ecology, his volumes are insignificant in comparison to the contributions of Pope Francis. This modern concern has been viewed as a central problem, and he designated an entire encyclical to discuss this problem and the nuances of the relationship of the environment to man and theology. This is the last and greatest hope for a per se obligation to care for the environment.

As we look at the reasons Pope Francis advocates for the care of the environment, we see him elaborate on the teaching of John Paul and Benedict. The pope talks about how failure to care for the environment has a drastic effect on poverty, which appeals to the decree of Sacred Scripture to feed the hungry.12 The Holy Father reveals how many nations rely on farming and agriculture to feed their families.13 So if our use of chemicals, etc. hurts the agriculture of our fellow men, especially those in third-world countries, we are contributing to poverty. Thus, the effects of hurting the environment are bad, not because the environment is an intrinsic good, but because hurting the environment harms man. By failing to be cautious about these environmental effects of the way we live our lives, we violate the command to care for the poor. When we act responsibly and care for the environmental impact on farmers in poor nations, we are following the command to feed the hungry — not in a direct manner, but in an indirect manner, similar to when a man gives money so that a hungry man can eat. In some of these poor countries, a bad harvest can result in starvation. Thus, this need to care for the environment is a moral obligation only because of the effects it has on one’s neighbor.

The pope also talks about the quality of life in cities as a reason to care for the environment.14 There are many cities where pollution has caused health problems and an unstable place to live a healthy life. A prime example is China, where factories were shut down to cut pollution during the Olympics.15 This pollution can also cause problems with regard to access to clean water, an effect of the wealth that often ends up harming the poor, which coincides with the pope’s concern over wealth distribution. It would be wrong to accuse the pope of forced wealth distribution as we observe in socialist countries; rather, we must have a concern for others’ assets. A factory that produces income has a moral obligation to take precautions to prevent its procedures from damaging the environment and having an indirect effect on human persons.16 As we can see, the concern is ultimately over the good of the human person.

When speaking about the loss of biodiversity, Pope Francis speaks about the God-intended usefulness for man within the different animal species.18 The pope talks about how the loss of medicines found in certain living beings is one of the great concerns when species face extinction.19 This is clearly a per accidens concern for the preservation of various species. However, the Holy Father does appear to offer a per se argument for the preservation of species in line with Duns Scotus. “It is not enough, however, to think of different species merely as potential ‘resources’ to be exploited, while overlooking the fact that they have value in themselves. Each year sees the disappearance of thousands of plant and animal species which we will never know, which our children will never see because they have been lost forever. The great majority become extinct for reasons related to human activity. Because of us, thousands of species will no longer give glory to God by their very existence, nor convey their message to us, we have no such right.”20 Here it would appear that Pope Francis has taken the opinion of Daniel Horan, OFM — that animals as part of creation have intrinsic value.

Anatoly Aseneta, relying on Laudato Si’, forms a new theology of man’s obligation toward animals as creatures of God’s creation as a per se moral obligation. This is a strong deviation from the traditional teaching as expressed by St. Thomas, who clearly states “He that kills another’s ox, sins, not through killing the ox, but through injuring another man in his property. Wherefore this is not a species of the sin of murder but of the sin of theft or robbery.”21 Asneta’s argument is similar to Daniel Horan mentioning how animals are loved by God and thus should also be loved by us.22 Though we can see how this is implied in the text of Laudato Si’, is this per se moral obligation really what the pope is calling for?

The fact that each animal has intrinsic worth would appear to mean that man must care for the environment for the sake of lesser animals. Though this intrinsic worth is not denied, this does not mean that man cannot destroy this variation in species from existing. There are certain variations of life such as malaria that cause great illnesses and are a variation of species that ought to be not just contained, insofar as they are harmful, but eliminated, even though they still have an intrinsic worth and value insofar as they exist. Thus, the fact that a species has an intrinsic value does not mean we ought to preserve that species for its own sake.

Where the pope says “we have no such right,”23 it would appear that he is appealing to the argument of Daniel Horan, OFM. However, this may not be the case. The pope does talk about a negative effect of extinction being that these species cannot give glory to God through their existence, nor convey their message to us. Though he acknowledges this negative effect, he does not state that these negative effects are the principle reason we do not have the right to lead animals to extinction — though I will admit that it is certainly a possible interpretation of the passage. The following paragraph is where the pope explains that the extinction of single species can cause a drastic effect on the entire ecosystem and have drastic effects on man’s sustainability and welfare. I am proposing that this is the principle reason for man not to have a right to destroy species, not because each species needs to glorify God.

There are several arguments not favorable to the idea that man has a moral obligation to prevent species from going extinct for the sole reason that they can glorify God. One reason is that certain species are harmful to man. The eradication of this bacterium that causes malaria, for example, has been called for by the pope in spite of its contribution to biological diversity, thus it would appear that there is no intrinsic need to preserve the differing species.24 This call from the pope was made without the desire to keep the bacterium alive in a safe environment, where it would not harm man but could still be used as a means of glorifying God. Nor has such a case ever been made by the popes toward non-intelligent life, as the Church has made for the preservation of children who will likely become enemies of the Church. Though during the Crusades, Muslim children were a greater potential threat than malaria preserved in a safe location, malaria can be destroyed, but children cannot.

In his encyclical Laudato Si’, Pope Francis talks about the role of biological evolution. This is a process in which only the fittest of the different variations survives, and we have a record of many species going extinct over time. Though it would be good for these variations of species to exist and glorify God, to accept evolution as a natural process demands that one accept that part of God’s plan is that species that cannot adapt will go out of existence. Modern evolutionary biology suggests that God has shown us through nature that He desires certain species to expire. Thus, it would be a contradiction for Pope Francis to believe in a per se reason to care for the environment. According to the writings of our Holy Father Pope Francis, then, the only moral obligations to care for the environment are per accidens.

One comes to the same conclusion through a traditional understanding of creation and rejecting the theory of evolution. St. Thomas did not believe that creation came about through evolution, but that the various perfections of animals were created by God for the good of man and that man has dominion over animals for his own good. St. Thomas says, “Dumb animals and plants are devoid of the life of reason whereby to set themselves in motion; they are moved, as it were by another, by a kind of natural impulse, a sign of which is that they are naturally enslaved and accommodated to the uses of others.”25 Though animals do have an ultimate end of glorifying God, as do all creatures, they are still subjected to the good of man. This is why St. Thomas says, “According to the Divine ordinance the life of animals and plants is preserved not for themselves but for man. Hence, as Augustine says, ‘by a most just ordinance of the Creator, both their life and their death are subject to our use.’”26 We can conclude that the tradition states that if an animal is harmful to man, not only can it be destroyed, but it ought to be destroyed for the good of humanity.

As we can see, there is a serious ecological crisis, but this is ultimately about the welfare of man and not the Earth. As we look through the writings of the popes, we do not see a radical new approach in our moral obligations to the environment. Rather, we see a gradual development of doctrine, which uses traditional theology to address modern problems. Though Pope Francis may appear to alter our doctrinal understanding in his grand encyclical on the environment, a close examination reveals that he is merely applying the principles of morality to modern situations. Thus, we can see that the only moral obligation to the environment is when the environment affects man.


  1. J. C. Logan/J. F. Haught, “Ecology,” 54.
  2. John Paul II, Encyclical on The hundredth Anniversary of Rerum Novarum Centesimus Annus (29 June 2009), §37.
  3. Id., §38.
  4. Id., §39.
  5. Id., §39.
  6. Catechism of the Catholic Church, 2nd ed. (Washington, D.C.: United States Catholic Conference, 2000), 2415.
  7. Centesimus Annus, §42.
  8. Pope Benedict XVI, Letter to the Ecumenical Patriarch of Constantinople on the Occasion of the Seventh Symposium of the Religion, Science and the Environment Movement (1 September 2007)
  9. Pope Benedict XVI, General Audience (26 August 2009)
  10. Pope Benedict XVI, Message for the Celebration of the World Day of Peace (1 January 2010)
  11. Pope Benedict XVI, Encyclical on Truth Caritas in Veritate (29 June 2009), §51.
  12. Pope Francis, Encyclical on Care for the Common Good Laudato Si’, (24 March 2015), §25.
  13. Laudato Si’, §128.
  14. Laudato Si’, §153.
  15. Johnathan Watts, “Olympics environment: Beijing shuts all building sites and more factories to clear the smog,” at The Guardian (28 July 2008), at www.theguardian.com.
  16. Laudato Si’, §109.
  17. Id., §20.
  18. Id., §32.
  19. Ibid.
  20. Id., §3.
  21. ST, II-II, q. 64, a. 1.
  22. Anatoly Aseneta, “Laudato Si’ on Non-Human Animals,” Journal of Moral Theology, Vol 6, No. 2 (2017) at https://eds.b.ebscohost.com.
  23. Laudato Si’, §33.
  24. Pope Francis, Apostolic Journey of His Holiness Pope Francis to Kenya, Uganda and the Central African Republic (25-30 November 2015).
  25. ST, II-II, q. 64, a. 1.
  26. Ibid.

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