Many people have suggested that the ongoing unrest in North African countries has been generated by high oil prices or problems with oil availability. It is always difficult to be certain about what drives events such as revolutions and civil wars. However, physical models of complex social systems can help us understand what are the driving forces of the events that we see. (Source)  One of the lectures of my class in materials science involves showing to the students an inflated balloon. I puncture it with an needle and it explodes. Then I ask to the students to explain to me exactly what has happened. Why did the balloon explode and not just deflate gradually?

It is not an easy question and, usually, my students cannot answer it. We learn as children that some objects break more easily than others. It is after a good number of failures that we learn how to handle glasses and china. And, yes, we do learn that puncturing an inflated balloon with a needle makes it explode. It looks normal to us because we have seen it happening many times. But it is difficult to explain exactly why.

Human societies, it seems, have some elements in common with inflated balloons. A society is not as simple as a balloon, of course, but it can easily explode in revolutions, collapse, breakdowns, civil wars and all sort of rapid and unpredictable changes. Societies, it seems, are fragile, at least in terms of the stability of their governments. This behavior looks normal to us because we have seen it happening many times. But, just as for balloons, it is difficult to explain exactly why societies "explode."

Of course, the difficulty of the problem has not prevented historians from proposing various causes for past collapses and revolutions in terms of economic, political, and social factors. Recently, crude oil has become popular as the cause of dramatic social changes. For instance, the collapse of the Soviet Union has been related to the local peaking of oil production (see this post of mine on The Oil Drum). Could crude oil be the "needle" that has been puncturing North African countries as well?

But how exactly is peak oil related to collapse? Why doesn't society simply adapt to the new conditions? I think we can gain some insight on these points if we consider human societies as complex systems which obey the laws of physics.

There are some common physical elements in the behavior of balloons, human societies and many other systems. One is that these systems accumulate energy. A balloon accumulates energy as pressurized gas, a society accumulates energy in forms that we tend to call "capital" (human capital, monetary capital, industrial capital, etc.). Both inflated balloons and societies are systems defined as "out of thermodynamic equilibrium" because of this accumulated energy.

The second principle of thermodynamics says that system will try to find the fastest possible way to reach equilibrium, that is the condition of maximum entropy. That means dispersing the accumulated energy to the largest possible number of states. The system will do that by following the available pathway that leads faster to that condition.

Thermodynamics doesn't say that a pathway (fast or slow) to equilibrium must necessarily exist. In the case of an inflated balloon, as long as the balloon walls are intact, there is no such pathway and the balloon stays inflated. But, if we puncture the balloon, we create a fast route to entropy increase. In the right conditions, that is, if the accumulated energy is sufficiently large, the crack created by the needle tip generates a rapidly expanding fracture. The balloon explodes.

Human societies are much more complicated than a balloon but, in the end they tend to reach equilibrium by dispersing the accumulated energy - that is, reaching a condition of maximum entropy. That means transforming the accumulated energy into what we call "waste" or "pollution". The dispersal process can take many different routes: a society is a tangle of feedbacks; with some stabilizing the system while others destabilizing it. Societies also grow new structures and new stocks of energy as they exploit natural resources. Then, when the stocks of non renewable energy are gradually exhausted, the rate of energy processing slows down - that's something we sometimes call "The Hubbert cycle." The fact that production shows a peak ("Hubbert's peak") is typical of crude oil, but it is a normal feature of dynamic systems of this kind. The cycle of a society often follows a "bell shaped" curve (e.g. for the Roman Empire)

Sometimes, the process of energy dispersal is smooth, but sometimes it is not smooth at all. Societies seem to be easily subjected to rapid and sudden changes as the system finds new pathways to disperse energy. In some cases, a growing society gets rid of a stumbling block to energy dispersal. This could be a good model for events such as the French Revolution that found such a stumbling block in the aristocrats of the time. In other cases, when a society is declining or reaching a peak, the problem may be that some structures built in order to manage large fluxes of energy become useless and must disappear. That may have been the case of the Red Army and of the Communist Party in the Soviet Union. In all cases, the social system is blocked in an out of equilibrium condition because of the lack of a path to release the stored energy. Such a path may be created, however, by positive feedbacks generated by apparently minor events, for instance an increase in oil prices. Then, when the pathway appears, the transition may be abrupt: it is what we call revolution or collapse.

How about Northern African countries? In this case, we don't have yet a clear picture yet of what is happening, especially for the case of Libya. But we know that the uprising in Egypt arrived shortly after that the curve of internal consumption crossing the one of national production. Egypt "exploded" when it became a net importer of crude oil (see e.g. this paper by Gail Tverberg). Tunisia went along the same path with consumption surpassing production around 2001. In the new condition of oil scarcity, these societies needed to get rid of energy expensive structures in the form of static governments that had been around for decades. That, of course, was not easy to do and it needed a trigger; something that released the accumulated pressure. Not unlike a punctured balloon.    

We should always be careful about simple explanations for complex events. More than all, we should be wary of falling in the trap of seeing a simple chain of cause and effects in complex systems. Oil prices are not a "cause" of the unrest - just a trigger for something that needed to happened for other reasons.

But, even with these caveats, we know that oil - as our main source of energy - plays a role in the recent unrest in North Africa and will continue to do so in the future -. and not just in North Africa.

To know more about energy dispersal and entropy in out of equilibrium systems, you may give a look the papers by Arto Annila and coworkers at the University of Helsinki. Not the kind of stuff you read to relax in the evening, but - if you can manage to digest it, at least in part - it can answer a lot of questions you have always been wondering about.