What do environmentalists compare to a spaceship?

Environmentalists often compare Earth to a spaceship to emphasize the idea that it is a closed system with finite resources. Just like a spaceship must carefully manage its supplies of air, water, and food to sustain its crew, Earth relies on sustainable practices to maintain the delicate balance of ecosystems and support human life. This analogy highlights the importance of conservation and responsible stewardship of the planet’s resources to ensure survival for future generations.