All of life is dependent upon nature. When we harm nature, we harm all living beings and systems, including human beings. Humankind, despite whether or not one denies global warming, most certainly has destroyed many ecosystems which are the ultimate source of all drinkable water, forest products, grassland habitats, food sources, ocean and more.
Replacing all these systems with cities, factory farms, suburbs and industry, offers very little life giving land and waterways left unaffected. Pollution too, must be taken into account because air, water and soil quality do determine how healthy people (and others) can thrive. Trash and health issues are affected; because what we over-deplete is often wasted and disposed of in ways that harm living systems.
Let's also consider animals. A worrisome loss of bees and other pollinators occurs as nature is displaced. Without insects, pollinators, and seed depositors, there is no way to propagate or continue sustainable populations of plants and animals. For example, cattle when fed on grasslands do not rely upon the monoculture of artificially fertilized corn. Grazing cattle (or other livestock) do not add concentrated methane, or deteriorate landscapes, except when out of balance, invasive species. In their naturally evolved context, cattle replenish and support biodiversity. In the factory farm, they are yet another aberration that adds to the loss of biodiversity. When humans live in closer approximation with animals, they understand them more than they merely exploit them. It reduces human stress to have kindred feelings for plants, animals and landscapes.
Another simple way to look at it, is to realize that which evolved in nature arrived at the present system of life on earth. In “circle of life” fashion, such cycles continue to ensure life on earth. As humans developed agriculture, and later still, cities and factories, biodiversity began to decline. Most mega-fauna (large animals) are hunted to extinction where ever man shows up to compete for the resources, farm, mine, manufacture, develop and/or landfill.
But for many modern naturalists, biologists and ecopsychologists the greatest incompatibility is the attitude of human loss, modern stress, sense of despair, and often guilt, that accompany a once appreciative relationship with nature which sustains us. The spirit of competition is seen daily in nature, but far more often, moment to moment, that is, one sees cooperation. Each organism is supported by a network of food, water, soil, sky, weather, minerals and the building blocks of DNA. This is why it is called Mother Nature, but humanity now mocks the idea of the earth being a bountiful goddess. She is has been rendered finite by overuse. Consequences include shortages which lead to war, poverty, constant strife, epidemics and lost resources such as clean air, food, water, soil and medicine.
Disconnection and denial are extremely common for three specific reasons. Reason one is people moved indoors and no longer have access to healing beauty, generous bounty and freedom from noise, choking fumes and crowded rudeness. Reason two is that without this connection human beings without knowing it, further panic and look to products for "happiness." Reason three is that without our former appreciation of nature; people indoctrinate their children to think of the human species as somehow better, or superior, rather than wholly dependent and connected, by genetic family belonging to nature.
People are very often unconscious of their belonging to the healing and beauty of earth. They know there must be more to "Life", but they do not realize that they, and everything else, ARE "Life." That is what is missing! They know they feel better after a week on the beach or mountains, but they credit their hard work and corporate betters for giving them the time off, not the natural world which has been there all along.
It is much like the unconsciousness that continually kills marine life by plastic trash. Many people are wholly unaware of creating the great trash vortex. And, If they do learn of it, they feel helpless despair, not realizing that having the power to choose less plastic, can make a world of difference. Even their own empowerment, mental health and success in life are affected by feeling just slightly better about righteous choices. It would also help suffering turtles, seals, birds and fish. People are only happy when appreciated and appreciating. Respect for creation provides true satisfaction, that cannot be bought like an I pad, I phone, Tablet, video game or new car.
Living with present bad habits, human beings threaten biodiversity. This is easy illustrated by the idea of looking at waste. Nature cycles and recycles all elements after billions of years of evolution. But when people destroy a system or a species, much waste, squandering of resources and pollution can be cited. Annihilation of the American Bison for example, shows how eliminating one creature virtually extinguished native American ways of life. In nature, there is no waste. All debris and death provides the raw elements for more life and continuing living systems, such as hydrology system, food production system, oxygen production, and so on.
To summarize then, the worst and most serious consequence of being detached from nature is that we destroy the mother that gave birth to us and sustains us, physically, mentally, emotionally, -and very much even for atheists-spiritually. When people know this, as they learn best from severe and lethal consequences, earth as a healing nurturer can thrive once more.