In technology, particularly in information based systems, advances can occur almost overnight. This likely applies to warfare as it becomes more information-based. As in technology, patterns and methods of warfare tend to stay within bounded equilibria depending on the type of war being fought. When an improvement arrives, the equilibrium point changes and warfare undergoes a rapid shift.
One of the ways to measure a equilibrium point was first demonstrated by Lewis Richardson over 50 years ago. He calculated that the distribution of casualties in conventional wars follow a power law distribution. Updates to his work show that this pattern of distribution continues to hold.In a new paper by Johnson, Spagat, and others called "From Old Wars to New Wars and Global Terrorism," (PDF) the authors demonstrate that a new pattern of war is emerging. To do this, they analyzed the frequency-intensity distributions of wars (including terrorism) and examined their power law curves. They found that conventional wars had a power law exponent of 1.8. An analysis of terrorism since 1968 found that the exponents were 1.71 (for G7 countries) and 2.5 (for non-G7 countries). This makes sense, conventional wars and G7 terrorism are both characterized by periods of relative non-activity followed by high casualty events (highly orchestrated battles). Non-G7 terrorism is a more decentralized and ad hoc type of warfare characterized by numerous small engagements and fewer large casualty events.
Here's where the analysis gets interesting. When the author's examined the data from Colombia and Iraq, they found that both wars evolved towards the coefficient for non-G7 terrorism (although from different directions). This finding doesn't fit the prevailing theories of warfare. A conventional understanding of fourth generation warfare, such the one posited by Thomas Hammes in the Sling and the Stone posit that 4th generation warfare began in earnest with Mao. However, within Mao's formulation (and Ho Chi Minh's variant), guerrilla wars are but a prelude to conventional war to seize control of the state. The power law for these wars should, based on this theory, tend towards the coefficient we see for conventional wars. In fact, we see the opposite. Guerrilla wars in both Colombia and Iraq have stabilized at a coefficient far from conventional warfare.
This has broad implications for 4th generation warfare theory -- which clearly dominated the types of wars we saw in the latter half of the twentieth century. The patterns of conflict we see today in Colombia and Iraq are a break from the previous framework (which may be an example of punctuated equilibrium). Unlike the previous models of guerrilla wars which sought to replace the state, these new wars have moved to a level of decentralization that makes them both unable to replace the state and extremely hard to eliminate. Is this new evolutionary equilibrium a fifth generation of warfare? It is extremely likely. This new form of warfare, or what I call open source warfare, is what this site (and my book) is dedicated to understanding.