The Future Is Munchkins

Will Saletan floats a pipe dream:

If we're devouring our planet, and we can't find more resources, and we refuse to have fewer children, where does that leave us? Hence my proposal: Shrinking our numbers isn't the only way to reduce our environmental impact. Another way is to shrink our size. Don't tell me it's impossible. Look what we've done to dogs. If you come up with a less crazy solution, let me know.