I am a fan of the movie Mad Max: Fury Road. In the beginning of the movie, people speak of "Oil Wars" and people "Killing for Guzzolene (Gasoline)". But what are the odds of that happening? And could it be on a global scale?
closed as primarily opinion-based by Starfish Prime, StephenG, 011358 smell, Trish, Nahshon paz Jun 30 at 11:53
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Slim to none.
Firstly, the notion of "Peak oil" is an extremely fuzzy one... there are a lot of marginal reserves, and various places where we could get oil but currently don't. Should oil availability decrease without a corresponding drop in demand, it will become economical to work more marginal oil reserves and in the limit start drilling in places which would cause environmental uproar because hey, we gotta keep our cars rolling and jets flying, right?
After that, there's coal liquifaction which lets you derive liquid hydrocarbons from more crunchy kinds. This technology has been around since the 20s, and the only people to serious exploit it were nazi-era Germany and apartheid-era South Africa because for various reasons that I'm sure you can think of, they found it difficult to get access to much crude oil. Obviously, if Peak Oil can be a thing, then Peak Coal clearly will be as well. There's a hell of a lot of low-grade coal in the world but it won't last forever and there aren't really any practical fallbacks (peat would require far too much processing to be useful, and reserves are limited).
After that there's plain old hydrocarbon synthesis. I don't think we're far from the day when it will be practical to use artificial photosynthesis on an industrial scale to make things like ammonia (which can be used in internal combustion engines, and also to make fertiliser) or methanol (which can be used in internal combustion engines, and also to make more complex hydrocarbons, including resins and plastics). You could run this using solar or nuclear power. This also has the handy knock-on benefit that it is carbon-neutral or activey carbon-sequestering.
Still, all you have to do is to posit the existence of a bunch of incompetent warmongering xenophobes in charge of nuclear-armed nations and they'll push the Big Red Button for the stupidest of pretexts; it might not need to be for something as practical as oil, so as the author you can please yourself.
If your story needs it, superpowers might well go to conventional war over oil reserves, and once that war is going it could easily escalate to a nuclear level.
Say the US, Russia and China all have their proxies and bases in the Middle East. One of them faces defeat, but hey, just nuke Djibouti or Diego Garcia or Latakia, and the fortunes will turn. It is not a nuclear attack on an enemy homeland, the hawks will say, so the enemy won't turn this into a wider nuclear war. Except they miscalculated and it goes larger. First carrier battle groups at sea, then air and naval bases at the enemy homeland, then strategic strikes.
There is a strong argument that we are already near (or have reached) what is known as 'peak oil', or the point at which we can no longer pull it out of the ground fast enough to meet the growing demand. The reality is though that we've had alternative solutions for oil for some time, in varying degrees of readiness past the developmental level.
The list goes on.
To be sure, most of these are based on electricity, but that makes sense to me. Electricity is a very versatile energy transmission system and it allows us to do almost anything with it once it reaches the devices we use it for.
For the last decade there has been a concerted push within R&D labs of energy companies to convert to some of these sources, and the push towards electric cars is one of the obvious manifestations of this. Europe is already pushing for over a third of all new cars sold in 2030 to be electric, and other jurisdictions will likely follow.
This kind of wholesale change has already happened before because of issues with the incumbent solution; the great horse manure crisis at the turn of the 20th century was a key driver for the development and adoption of cars in the first place. It only makes sense that we replace them with something better when they in turn become a problem, or their energy source comes under threat.
Put simply, it may not seem like it most of the time but humans are smarter than that. They know the cost of war, and they know that oil is a resource that must eventually wane. As such, they'll look to convert their infrastructure to something else, and are already doing it.
That said, the nuclear missiles are an element of the solution in an indirect way; converting to nuclear power generation would provide the change in baseload power capabilities that the world needs to power a globe full of electric cars, and, if supplemented with renewables, would be far better for the environment in the long term.
The safety of said reactors is a matter that is out of scope of this answer, but suffice it to say that if we ran out of oil and switched to nuclear energy instead, the safety of our power plants would get solved too. If not, we'd just switch to something else. We've been doing that for millennia.