Now that the world’s population is approaching 7 billion (although see my big caveat here), there’s been a lot of understandable concern over whether the Earth’s natural resources can sustain this sort of pressure. So it’s only fair to quote Toby Ord on the upsides of a bigger population:
These upsides may even outweigh the downsides, making a larger population a good thing overall. One example is the rapidly growing information economy. If someone makes a hammer, only a few people get the benefit, but if someone records a new song, writes a computer program, or invents a new technology, everyone can benefit. These activities thus produce more value the more people we have. With twice as many people doing jobs like these, we could all get roughly twice the benefits (more art, culture, science, technology), or they could work roughly half as many hours. A larger population thus has the potential to make life much better, so long as we can find the resources to support it.
Nowadays, as Julia Whitty has noted, environmentalists tend to shy away from most discussions about population. Partly that’s because the topic has long been associated with a number of horrific ideas — eugenics, forced sterilization, China’s one-child policy and so on. And partly it’s because many greens would agree with Fred Pearce and Joe Romm that unsustainable consumption rates are a far bigger threat to sustainability than extra people, per se.
Indeed, this focus on consumption doesn’t get nearly as much attention, but it’s quite consistent with Ord’s perspective above. Most environmentalists aren’t worried about climate change and resource depletion because they’re somehow bad for Mother Earth. The Earth is a big floating rock and it’ll be fine no matter what we do. Rather, many greens fret because those disasters could be devastating to millions of people and prevent the human population from thriving. As Ord notes, a lot of the recent discussion about overpopulation has tended to elide this distinction. That said, his bit above about “so long as we can find the resources to support it” is still a big “if.”