We send or carry living things to other continents constantly, on purpose or unknowingly. A world with fewer people would be a world with fewer living things moving around and ending up in the wrong places. The alteration of native habitats by unregulated development of housing areas and sprawl malls makes us wonder if some of our elected officials are in the real estate business. Adding people means finding places for them to live, more food to eat and water to drink, more fuel to keep warm. The means for acquiring these necessities have permanent impacts on the world's natural forests, rivers, and all other habitats not already being used by people.
Endless pollutants continue to be discovered that have serious environmental impacts.
Obviously, six billion people, especially the 250,000,000 in the United States, pollute on a grand scale. The environment suffers, and we suffer, in proportion to how many people are using the Earth's resources and then discarding them. Few weeks go by that a new organization is not formed to take up one side of an issue or the other. Special interest groups abound. But ironically, every environmental problem in the world today stems from human overpopulation, a point people in general and politicians and national news media in particular seldom mention.