The first wave of environmentalism, the period of conservation (from the mid-1800s to the early 1960s), focused on the protection of natural resources, scenic pockets of nature, and isolated species from degradation and destruction by humans. The second wave of environmentalism, the period of containment (from the mid-1960s through the 1970s), introduced the need to protect humans from the effects of an industrially abused and overpopulated world. The third wave of environmentalism, the period of co-optation (the 1980s and early 1990s) popularized and mainstreamed these efforts, revealing in the process that certain demographic groups disproportionately suffered from the effects of a degraded environment.
The fourth wave of environmentalism first arose in the late 1980s. By the mid-1990s, it was cresting above the third wave. Like its immediate predecessor, which achieved its own breadth and height from the combined force of the first two waves, the fourth wave of environmentalism is a synthesis of earlier efforts. It represents not so much a new environmental movement as an expanding horizon of sensibilities and a rechanneling of efforts. Fourth-wave environmentalism amplifies certain features of earlier waves, mitigates some of their conflicts, and integrates many of their cross-currents. At the same time, fourth-wave environmentalism bears its own distinct features.
Environmentalism has been and for the forseeable future will continue to be defined by many different voices. Each cause has its own