eldin raigmore wrote:
@Salmoneus, how right was I to think that "Hubbert curves" were not meant to apply to renewable resources?
Well, I'm no expert, so I'm guessing here. But I think it has to depend on how strictly you define a hubbert curve, and how strictly you define a renewable resource.
If you take a hubbert curve as one where production increases eventually reverse due to increasing extraction costs, and if you take a renewable resource to be one where extraction costs never increase, then clearly you can't have a hubbert curve for a renewable resource. But what if you take a hubbert curve more literally as just a (mostly) symmetrical logistic curve showing production increase and decline? Then of course it can be appropriate for a renewable resource, if that renewable resource stops being utilised for some reason.
Likewise, not all renewable resources are renewable in the perfect sense of the word - in fact, none of them are. The resource itself might be renewable in theory, but the resources necessary to extract and utilise that resource are finite, and may decline. I'll give two examples.
First, say that we discover nuclear fusion. We exploit it. Then nuclear plants start blowing up. Public opinion turns against fusion, and fewer plants are built. If you graphed the amount of energy produced from fusion over time, it would look like a hubbert curve - because although seawater is effectively renewable, public tolerance of safety concerns and the political capital necessary to induce that tolerance are finite resources.
Second, say that we develop a strange new form of energy that's renewable and perfectly clean, but expensive. We exploit it. But at the same time the earth experiences massive economic and environmental decline. We become poorer. We start no longer being willing to put up with more expensive energy in order to avoid a little polution. So we swtich back to coal or something. Again, the graph of energy from this source would look like a hubbert curve - because the finite resource here is the wealth of the society, or its willingness to sacrifice wealth for environmental improvements.
So it depends how you define things.