Ethical theories matter in the end because they guide what people and communities actually do. This final level looks at how environmental ethics meets practical choices.

Individual and systemic action

One debate concerns where to focus effort. Some stress individual choices: eating less meat, flying less, wasting less, buying secondhand. Defenders argue that personal choices express integrity, add up across millions of people and help shift social norms as others follow. Others stress systemic action: voting, advocacy, changing laws, building better infrastructure. They point out that one person's footprint is tiny and that many choices, such as whether a bus line exists, are made collectively, and they warn that a narrow focus on personal footprints can distract from changes only institutions can make. Many ethicists conclude that the two reinforce each other: people who change their own habits often become more engaged citizens, and good policies make sustainable choices easier for everyone.

Sustainability

Sustainability is often described with three pillars: environmental, social and economic. A deeper debate concerns weak versus strong sustainability. Weak sustainability holds that using up natural resources is acceptable as long as the total stock of capital, including machines, knowledge and infrastructure, is maintained, because human-made capital can substitute for nature. Strong sustainability holds that some natural capital, such as a stable climate or fertile soil, cannot be replaced and must be preserved in its own right.

Conservation and preservation

An early American debate still shapes environmental policy. Gifford Pinchot (1865 to 1946), the first chief of the U.S. Forest Service (1905), championed conservation: the wise, efficient use of natural resources for human benefit over the long term. He popularized the goal of “the greatest good of the greatest number for the longest time.”

John Muir (1838 to 1914), the Scottish-born naturalist who co-founded the Sierra Club in 1892, championed preservation: protecting wild places from development, for their own sake and for the spiritual renewal they offer people. The two clashed over Hetch Hetchy, a valley in Yosemite National Park that San Francisco wanted to dam for its water supply. Pinchot supported the dam; Muir wrote, “Dam Hetch Hetchy! As well dam for water-tanks the people's cathedrals and churches.” Congress approved the dam in 1913.

Technology and growth

A lively debate asks whether economic growth can continue without ruining the planet.

• Ecomodernists, in a 2015 manifesto and other writing, argue that technology can decouple human well-being from environmental damage. Denser cities, more productive farms, and nuclear and renewable energy could let humanity use less land and leave more room for wild nature. They note that some wealthy countries have cut emissions while their economies grew.
• Degrowth advocates, drawing on the 1972 report The Limits to Growth, argue that wealthy countries should deliberately reduce material and energy use while protecting well-being through shorter working hours, strong public services and fairer sharing. They argue that decoupling has been too slow, and that efficiency gains are often eaten up by more total consumption, an effect William Stanley Jevons described for coal in 1865 and now called the Jevons paradox.

Critics of ecomodernism warn of overconfidence in untested technology. Critics of degrowth warn that shrinking economies could hurt the poor, prove politically impossible and slow the innovation clean energy needs. Many positions lie between, often called green growth.

Bringing it together

Environmental ethics does not hand down a single answer. It offers a set of questions worth asking of any decision: who counts, what has value, what we owe the future and the vulnerable, and how we can act well together.

Worked example: one river, many views

Imagine a wild river running through a canyon near a growing region that needs clean electricity. A utility proposes a hydroelectric dam that would power 200,000 homes without burning fossil fuels, but would flood the canyon, block migrating fish and drown a site sacred to a local Indigenous nation.

• A Pinchot-style conservationist asks whether the dam is the wisest long-term use of the river. Clean power for many people is a large benefit, but so are fisheries and recreation. Careful accounting decides.
• A Muir-style preservationist holds that some places should not be traded at all. The canyon, like Hetch Hetchy, is worth more than any reservoir.
• An ecomodernist favors clean power, but may ask whether solar panels on already developed land, or a nuclear plant on a small footprint, could deliver the same energy while sparing the canyon.
• A degrowth advocate asks whether the region needs all that new power, or could cut demand through efficiency and different patterns of living.
• Environmental justice asks whether the Indigenous nation has a real voice, and whether its sacred site is being sacrificed for benefits that flow mostly to others.
• Future generations enter too: the dam would supply clean energy for decades but end the canyon for good.

What can an individual do? Learn the facts, attend the public hearings, support the option they find most just, and reduce their own electricity use. The individual and the systemic go together.

The case has no easy answer, and this course has not tried to give one. It has given you the questions that thoughtful people on every side should be asking.