End Of Oil
This subject is about energy and in particular, fossil energy found in the earth in liquid "fields". These fields are discovered by geological "exploration" and then they are called "reserves". The existing reserves of oil are now less than the oil that has already been pumped out of the ground and consumed, thereby contributing to Global Warming due to increased atmospheric CO 2.
Now, there is no precise knowledge of when the proven reserves will be exhausted and how much more reserves may yet be found by exploration. however, the rate of consumption is now so very high and the rate at which new finds of oil fields has become so low that it is clear that if we continue on the same "road" that we have been traveling - that in a foreseeable time these geological reserves of oil will be gone. This is called End Of Oil.
Oil is so big in our energy sector and we are so dependent on this resource for both energy and for fertilizer - that there is no doubt that this depletion will be a crisis for humanity. With all the effort to date we still have not deployed alternative energy sources to equal even just 1% of our oil dependency. And as demand will soon far out pace supply (as we are on the decline side of the curve) there will be a price escalation causing great problems with all costs of all consumables - especially food.