[quote=Halo]
Then we will have to find an alternative to plastics. One day, we're gonna run out. It isn't produced nearly as fast as we use it, and simple mathematics tells us that means it is gonna run out someday, and we're gonna have to rely on something else someday. If anything, it tells us that our investment in alternative energy sources is even more important - we need to stop using our reserves of oil on energy, when other options exist, so that we have as much as possible to produce other things that we can get from oil.And I don't think it's pessimistic, it's realistic. Believing oil will last forever and never preparing a fallback plan for when it runs out and everything goes tits up would be ridiculously over-optimistic.
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The only thing that we're in the threat of running out of is the easily obtained liquid oil, which still has a considerable amount left. But when you look at oil sands and shale, you have exponentially more oil in those states that have barely been tapped into because up until recently, there wasn't a sure way to refine it. It's kind of like an iceberg, where the part you see above the water is all the liquid oil ever, and the 90% below the water is oil sands and shale. It's a bit of a cartoonish exaggeration, but it's not too far off for all intents and purposes. We'll have a renewable energy solution in place far before we run the risk of running out of oil, assuming people keep working at it. Given how environmentally cognizant people have become in recent years, the trend is encouraging, at least.