I've seen that theory, and it seems to be just that, rather than the consensus. Regardless environmental destruction and overpopulation are now global so eithe

I've seen that theory, and it seems to be just that, rather than the consensus. Regardless environmental destruction and overpopulation are now global so either analogy still applies. As for number of planets anything >1 is a problem, but it seems a reasonable means of helping the public visualise the issue, just as the media use busses or football fields for comparative measure.