In the beginning of the essay "lifeboat ethics," what object do environmentalists use as a metaphor for the earth?

In the beginning of the essay "Lifeboat Ethics", environmentalists use a spaceship as a metaphor for the Earth.

Explanation:

"Lifeboat Ethics" is an essay by Garret Hardin, published in 1974. Hardin mentions right from the get-go how wrong he thinks environmentalists are when they compare our planet to a spaceship. Environmentalists, in a very idealistic manner, claim that no person or institution has the right to destroy, waste, or use more than a fair share of the "spaceship's" resources, since we all live in it.

Hardin, on the other hand, would rather compare our planet, that is, the countries to lifeboats. The rich countries would be the lifeboats full of rich people, while the poor countries would be the poor people swimming in the ocean - that comparison comes from the known fact that, when ships sank, rich people were prioritized to be saved. A poor person would want to climb into a lifeboat, but there is a lot to be taken into consideration before allowing them to do so, such as the lifeboat's capacity. In summary, Hardin does not believe equality in sharing the planet's resources could be easily achieved as the environmentalists do.