Skyrocketing use by China, India and other industrializing countries ('the little tigers' of Asia, Brazil, etc.), is putting the pressure on supplies at this time, but yes, overpopulation exerts pressure on all resources and the planet which provides them. The need is for their petrochemical industries as well as for energy.

Oil reserves are actively being searched for, and will be exploited unless they are wholly beyond reason. Much of the 'half' remaining (that some people talk about), is difficult and expensive to produce, and may cause severe damage to environments if produced. In any case, its exploitation will not reduce the price paid per barrel.

Alternative sources are the best bet, and should be gradually implemented as petroleum diminishes.
Total, the French oil major, is calling for use of alternative sources of energy in their advs., in order to reserve as much petroleum as possible for petrochemicals and transportation needs.

Often ignored in the press is the need for petroleum input into petrochemicals. They contribute to nearly all the plastic-based substances we use. These usages are large and are constantly growing.

Much coal remains, but practical collectors and uses for greenhouse gases must be devised. It is the main fossil fuel used in the generation of electricity.