Ryan Avent imagines a wealthier world:
I don't think it's impossible to imagine a world in which four times as many people enjoy rich-world living standards as is currently the case. But for it to be possible, humanity must either start discovering and exploiting new earthlike planets, or come up with revolutionary new ways to increase terrestrial supplies of critical resources, or dramatically decrease the resource-intensity of wealth. The mechanism that will encourage one or some (or, I suppose, all) of these developments is high resource prices.
The Dish 