PhD Comics Branches Out …
… into complete bullbleep. Yes, it's another instance of “Western civilization uses several Earths of resources” nonsense.
The interesting thing is that the resources used are almost never specified in this kind of nonsense, thereby leaving the disaster to be up to the imagination of the listener or reader. The apparent goal is to have the listener/reader think of so may different resources that we might be using up that he/she ends up believing the problem can only be solved by limiting population, redistributing global income, etc.. The question of how much of the Earth's resources are being used by Western civilization is sometimes combined, if not confused, with the question of how much of those resources that are being used by human beings are being used by Western civilization. This makes it possible to cite statistics that show that the United States is using 25% of the oil currently coming out of the ground and deriving the claim that we're using 25% of the Earth.
On those rare occasions when the resources in question are specified, it turns out that nearly all of it is based on the calculation that it will take the biospheres of several Earths to absorb the greenhouse gases currently being emitted.
The reason the self-congratulation-based community cannot specify that this is a disguised greenhouse-effect worry is they must bypass the occasionally-justified skepticism that greets greenhouse-effect worries. To make matters even worse from the point of view of a left-wing ideologue is that it invites queries about why nuclear energy is still considered unacceptable.