Arrogance...We are fools to think we have that much influence on how this world works, one way or the other. At best, we only have a modest impact on our own existence.
We think far too highly of ourselves. Mother Nature hiccups, and we all buy the farm. Whether plastic bags take a year or a hundred or even a thousand to decompose, what difference will that make in the long run? If we ran out of oil tomorrow, how would that make any difference to how humanity will funtion 500 years from now? Any of these might be a temporary setback for us now, but the eventuality is that none of these things will make any difference over the long run, except maybe to force us to develop technologies a little bit faster to deal with the inconveniences.
Economics isn't really a natural science, any more than politics is.
I kind of agree. In the near term future, our lives specifically may be very much changed. If we suddenly had absolutley no petroleum products tomorrow, then our lives would change drastically. I'd be OK for a while. But many, including myself, would need to make some longterm changes to how I live, or I would not live. Many of us would not be able to make those changes, and because of that many would perish. But some would be able to make those changes. Some people would survive. There are areas in which most of the people still live a subsistence lifestyle, without a lot of dependence on petroleum. Provided enough can survive to maintain a population that can reproduce, the human race should still be here.