Heh, you know, before YouTube, people like that just used to stand around in shopping centres with sandwich boards... The Internet gives them a veneer of legitimacy, but you don't have to scratch far below the surface to see the sandwich board is still there.
They start off with the wrong concept, they think humanity designed a civilisation and then went and got the resources to build it, which is entirely the wrong way round, civilisation has constantly changed and shaped itself around resources, and, at the dwindllng of a resource, then some societies may suffer, but humanity as a whole will adapt to the new environment, and will maintain a civilisation, because that's our nature.
Too many of these prophets of doom confuse lifestyle with civilisation, our lifestyle may well change emphatically in the future, the whole 'throw-away' generation is going to have to unlearn the culture it was raised in, I think we are going to have to re-learn respect for longevity in our products, and how to maiontain them, I think we are going to have to discover new power sources, but then, it has been historically shown that mankind is only really at its most inventive when there is an overpowering requirement to be so, at this moment in time there isn't.
To put it bluntly, civilisation is what it is defined as by it's members, it cannot 'fall' as such, it sounds to me like this video is far more worried about the loss of luxuries in their own country than a global catastrophe.