Since we are going down the rabbit hole. Peak Oil (proper noun) was most certainly all about imminent depletion of reserves and shortages. Back when it was a big deal I worked in oil and gas exploration geophysics services. I attended a conference (in Bahrain I think) where the head of exploration of Saudi Aramco gave a little talk about peak oil and how silly it was. He outlined just how much oil there is actually under the ground. The oil producing nations expect that demand will dwindle before supply runs out as world economies shift away from oil. (Maybe, given current global politics.)
The core problem with any resource estimates is that the idea of a reserve has at least three meanings. And this matters. You have proven reserves, probable reserves, and possible reserves. Moreover, this only covers stuff you have an enough data for to be counted as a reserve. You then get to resources, which are seperate again.
Proven reserves are reserves that you have a very high confidence the oil or gas that is there, and you can recover with current economic conditions. That is oil you can take to the bank. This is often the one referenced.
Probable reserves are a reserve you are pretty sure is recoverable. With a 50% probability. Reserves that you have good data for, at least some wells, understanding of the geology and recovery. You can’t necessarily take this to the bank, but you could certainly take it to the sharemarket.
Possible reserves are less certain again. You probably don’t know enough about the geology and recovery options to be sure of economic recovery, or whether there are hidden problems. But you know enough that there is almost certainly oil there.
Resources are where you still in the discovery phase. Contingent Resources are those where exploration has reached the point where there is a good understanding that there is a deposit there, but there isn’t enough knowledge or economic drivers to push operations further. Finally Prospective Resources are where you have good feeling about a province, and have probably done some initial exploration. These are resources you keep in your back pocket.
The problem with conversations about reserves is the structural mechanism that keeps resources and reserves in these bands. Oil companies almost never have open access to new regions. Countries open up areas in a controlled manner, and companies bid for exploration rights. If they find something they will need to negotiate production rights. If they have exploration rights they will be required to actually perform the exploration within a fixed time, or lose the rights. Once production commences they are on the hook for production rights payments. All this places a drag on taking resources to reserves to production. Companies only ever have enough proven (and producing) reserves as they need right now. It takes a long time to develop a field, so the pipeline is always progressing, but only as fast as projections for demand dictate. There are no upsides to bringing reserves up early.
The same effect applies to minerals and mining in general. Whenever there is handwringing about the world running out of X, be careful that X is not rate limited by these processes. Nothing is infinite out there, but there is usually more than we think. (The only one that really worries me is helium. Economic helium could be depleted within our lifetime in a very unfortunate manner. Our profligate use may come back to bite us.)
