When I teach Pope Francis’s Laudato si’ to seminarians, I point out that he gives considerable attention to three crucial crises in his first chapter: climate change, fresh water, and the loss of biodiversity. Each of these crises are of a scope and scale that differs from the harm humans have done to portions of the earth throughout history; they involve real threats to “our common home” as a whole. I explain that these sorts of threats are a big reason why the pope decided to devote an entire encyclical to the environment, and not simply speak about it in the context of other social teachings, as previous popes had.

But I confess I am more animated by the first two crises. I get worked up cataloging the evidence of atmospheric catastrophe and acquainting my students with the decline in the Ogallala aquifer, on which the entire Plains agricultural system depends. It’s not hard to convince them that the spike in greenhouse gases and the dwindling supply of fresh water qualify as unprecedented crises. Then, nodding to the third crisis, I add, “Have you heard about the sixth great extinction? Tons of species are disappearing because of human activity.” And we move on.

The value of biodiversity—and the urgency of preserving it—can be hard to convey. Why? Too often we think of the environment only in terms of how it affects us, and the impact of habitat loss and species extinction on human beings simply isn’t as clear as the impact of climate change and desertification. I know I can get my students’ attention if I say, “We won’t be able to grow 25 percent of our crops,” or “coastal cities will be underwater.” By comparison, most talk of endangered species or extinction (except our own) can seem either sentimental or abstract.

But the recent UN report on the unprecedented scale of the threats to biodiversity should awaken us to the true gravity of the problem. It should also remind us that Catholic theological convictions about the environment extend beyond the question of what’s harmful to human beings to a deeper question: whether we truly believe what we say about God as the creator and destination of all things.

How does the report (whose release received less attention than the birth of a royal baby the same day) name the problem? The headline stat for the loss of biodiversity is frequently the danger of species extinctions: the report announces up to a million possible extinctions. Rapid declines in amphibians are particularly striking; in the span of just a few years, whole species have gone from thriving to disappearing. Thin skins make amphibians unusually sensitive to changes in environmental chemistry; their natural habitats of shallow streams, ponds, and wetlands are unusually threatened by human development; and they are now subject to a lethal skin bacteria, formerly confined to Africa, that has spread worldwide. On top of all that, they rely on fish-free waters to allow their eggs to survive, and that’s becoming harder for them to find as humans introduce fish species for aquaculture and sport. Estimates suggest about a third of known amphibian species are threatened.

Extinctions, however, are merely one symptom of a deeper problem: the shrinking and fraying of local ecosystems on which all life depends. As one UN panel member puts it, “The essential, interconnected web of life on Earth is getting smaller and increasingly frayed.” This is the key idea: loss of biodiversity is a matter of taking an intricate system and making it both less intricate and less tightly woven, and thus more subject to all sorts of disruptions. The ecosystems in today’s world are the product of remarkably complex patterns of coevolution, in which diverse life forms, from bacteria to large mammals, share symbiotic relationships that enable the continuation of life. When ecosystems are healthy, they are rich in genetic and species diversity, enabling what ecologists call resilience, an ability to absorb shocks, adapt, and maintain functional stability. Nature can and does adapt to changing conditions. But when ecosystems are frayed, and subjected to rapid change over decades and centuries rather than millennia, strikingly small disruptions can produce cascading effects with catastrophic consequences.

Yes, ecosystems have always changed and species have always gone extinct—but not at anything like the rate of current changes. It is this “rapidification” that Francis frequently criticizes as a key symptom of “tyrannic anthropocentrism.” Take the example of coral reefs, probably the most endangered ecosystem on the planet. These living wonders support up to 25 percent of all marine life. Submerged in saltwater and useless for human exploitation, they look safe from the threats faced by other, resource-yielding habitats like rainforests. Yet they are highly sensitive to water conditions, especially ocean acidification. (As oceans absorb more carbon dioxide from the atmosphere, they become more acidic.) Corals lack the mobility that even tree species have. They are profoundly affected by large-scale runoffs from poor land use. And worst of all, they are simply destroyed as byproducts of illegal but common practices like blast fishing and cyanide fishing—truly barbaric acts that feed a constant demand for live fish in restaurants and aquariums. The combination of indirect and direct threats to corals has led experts to predict their extinction by 2100, if not sooner.

For Catholics, the UN report makes clear the degree to which we are willing to disregard what Benedict XVI called “the grammar of creation,” which is “prior to us” and more comprehensive than our puny designs. A commitment to maintaining biodiversity rests on a bedrock conviction of the integrity of the grammar of the whole of creation, created by and destined for God. We simply can’t address this problem sufficiently if we remain anthropocentric in our environmentalism. True, the UN report works hard to suggest that biodiversity is “humankind’s most important, life-supporting safety net,” mentioning key “ecosystem services” like that provided by pollinators, whose extinction endangers our food supplies. But in fact, we just don’t know what will happen. What is already clear is that we are messing with a fragile system in ways that demonstrate that we do not know what we are doing. We can’t say what will happen to marine life if corals decline to almost nothing, or what will happen to Central American ecosystems if many amphibians disappear. But as Pope Francis reminds us, we already know that “thousands of species will no longer give glory to God by their very existence, nor convey their message to us.” To disrupt the natural world at this rate is simply not to “till and keep” it. Right now, we have way too much tilling and not enough keeping.

What to do? The UN report offers a ranking of the five biggest “direct drivers” of the loss of biodiversity, with “changes in land and sea use” topping the list. Such ranking is always risky—since everything is connected, causes like climate change and invasive species are also serious—but at least it helps us respond practically to what might otherwise be an overwhelming challenge. The destruction or significant fragmentation of habitats is a well-known problem but, again, we forget the scale and speed involved: for example, we’ve lost over 50 percent of tropical rainforests, the habitat richest in species. Some suggest that as many as four thousand species become extinct every year because of the loss of unique ecological niches in rainforests. Of course, rainforest destruction leads back to the enormous expansion of human consumption, and the UN report notes that urbanized areas have more than doubled since 1992, while the annual extraction of all natural resources has increased nearly 100 percent.

The voracious appetite for cheap commodities from afar is no longer limited to Americans and Europeans. Global patterns of resource use have changed a great deal in the past few decades, partly because of the large increase in global population, but also because more of the world has adopted Western measures of affluences and habits of consumption. To use a personal example: when I was two years old, my hometown of Chicago claimed the tallest building in the world. In 1990, when I graduated from high school, the world hadn’t changed much: our Sears Tower was still the tallest building in the world. Today? It’s currently ranked 21. And all the taller buildings except one are not in Europe or the United States. Of course, building skyscrapers is not the most resource-intensive of human endeavors, but it does indicate where there has been enormous growth in wealth. Certainly, American and European consumers should stop consuming so much, but we also need what both Benedict and Francis have recommended: some kind of enforceable international agreement that limits exploitation, particularly of the most sensitive habitats. Such an agreement will have to compensate (poor) countries for preserving their natural resources as much as they are now compensated for exploiting those resources. After all, the destruction of habitats frequently occurs because populations and nations are poor. If we want to save the rainforest or the coral reefs, we’ll have to pay to save them.

And we should. The next time I teach social ethics, biodiversity will get more attention. Like our disregard for the balance of the atmosphere and the character of water as the essential element of life, the disregard of biodiversity is a crucial mark of the gravity of our environmental sins—and a reminder that these sins are not reducible to the harm they do to human beings. It is likely that I will never see a rainforest or a coral reef in person. But I do believe that they are God’s wonders, made to give God praise. And their destruction proves that we are in the grip of what Francis calls a “practical relativism,” in which we reject God’s grammar, seeing it as “irrelevant unless it serves [our] own immediate interests.”