Environmental degradation is a process through which the natural environment is compromised in some way, reducing biological diversity and the general health of the environment. This process can be entirely natural in origin, or it can be accelerated or caused by human activities. Many international organizations recognize environmental degradation as one of the major threats facing the planet, since humans have only been given one Earth to work with, and if the environment becomes irreparably compromised, it could mean the end of human existence.

There are a number of ways in which environmental degradation can work. In a classic case, resources simply become depleted. Air, water, and soil are all resources which are vulnerable to depletion through overuse, as are natural resources like minerals and oil deposits. Habitat pressures which force animals into a small area can also contribute to resource depletion, as the animals consume a high volume of material in a small area.

Pollution is another cause of environmental degradation. When the environment becomes polluted, it means that toxic substances have rendered it unhealthy. Pollution can come from a variety of sources, including vehicle emissions, agricultural runoff, accidental chemical release from factories, and poorly-managed harvesting of natural resources. In some cases, pollution may be reversible with costly environmental remediation measures, and in other instances, it may take decades or even centuries for the environment to cope with the pollution.

Simple damage is also a common issue. Clearcutting, unsustainable development, and erosion are all forms of environmental damage. If the damage is extensive, the environment may not be able to reach a state of balance on its own, and the problem could become compounded. Erosion as a result of bad agricultural practices, for example, can strip the earth of its valuable topsoil, leaving coarse, useless soils behind. This infamously occurred in North America during the Dust Bowl of the 1930s, in which drought, poor farming practices, and severe weather led to a widespread stripping of fertile topsoil from farmlands.

A number of social and legal issues are involved in environmental degradation, ranging from the need to provide living space for humans to questions about who is responsible for environmental cleanup. For example, if a company acquires a company which released toxic chemicals into the environment in an era when this practice was commonplace, it may argue that it has no legal obligation to clean up the chemicals, although it may be obliged to do so under ethical principles.