A small group of leaders can make a huge impact on the lives of millions of people. A single decision can cause ripples to expand and widen its effects, just like the wolves of Yellowstone.

When wolves were reintroduced to Yellowstone National Park after an absence of nearly 70 years, an incredible “trophic cascade” occurred. What is a trophic cascade and how exactly do wolves change rivers? George Monbiot explains in this riveting mashup.

For the Yellowstone environment, the wolves were the Key Leverage Point. Without them, the park declined, species died away, riverbanks eroded, the flora and fauna receded. By returning a small group of wolves, the entire park’s environment changed and lush, verdant new life returned.This is a very good example of how we can be optimistic about our own lives and planet earth as an ecosystem. It is easy to feel pessimistic, doubt what one person or a small group can do, stop trying, and give up.

This is a very good example of how we can be optimistic about our own lives and planet earth as an ecosystem. It is easy to feel pessimistic, doubt what one person or a small group can do, stop trying, and give up.