Much of the reduction might be for non-obvious reasons, like whatever happened around 1980.
Exactly. Much of the reduction is for the same reasons you no longer hear much about cults, or about hijacking planes to Cuba (or about anarchists car-bombing Wall Street or trying to shoot the Queen, for that matter), or about communism. There seems to be something about the shift from a traditional partially-industrialized society to a post-industrial one which triggers this sort of great social upheaval, which manifests in part as new religious movements (labeled cults) and violent action (terrorism or guerrilla), which eventually get discredited and cease to be alternatives. In Japan, you had the 'rush hour of the gods' with many syncretic Buddhist groups and the Red Army (to name the most infamous one) with a last gasp in Aum Shinrikyo; in America, you had those but also Weathermen etc; in South Korea with its later development the process is still ongoing, with the cults take on a Protestant Christian form - the recently deceased cult leader associated with the Sewol Ferry disaster an interesting example - and the violence tends to be associated with North Korea (various assassinations or attempts come to mind).
we should expect a reduction in Islamic terrorism
On some time-scale, yes. But saying when is a bit of a sucker's game. To use the American example: are we still in the '60s or have we passed into the '70s yet or maybe even '80s?
I'd be more confident in predicting that both cults and violence are on a long-term secular decline in South Korea, which seems to be over the hump.
but I'm not sure what the expected timeline for such a reduction would be.
That's a little difficult to say. I think you could probably use per capita GDP to try to pin down when one would expect 'the troubles' to begin, and extrapolate from there. (This would probably yield predictions like: East Asia to continue to quiet down; Middle East and nearby Islamic regions to remain stable in violence; Africa to increase in cults and movements like Boko Haram even as larger-scale violence and disorder decreases.)
I know you didn't make the graphs, but ...
I don't like line graphs. They're a kind of smoothing, but almost never the right choice. The first two graphs are smooth enough that it hardly matters what you do, but I redid the third as a scatterplot plus a loess curve.
Here's the loess superimposed on the line graph, if you want to compare them. I got the data here, linked from here
A find your hypothesis interesting but let's discuss a few different possible causal mechanisms than your primary suggestion (and it is possible that this drop is some combination of causes):
1) You bring up the possibility that the threat of Islamic terrorism has lead to a substantial increase in security levels, so more terrorist incidents are stopped or never get off the ground. If this is the primary cause then I'd expect most of the drop off to occur after the first bombing of the WTC in the 1990s, and a heavy post-9/11 drop-off but your graph shows a drop-off staring before then but then shows the most clear cut drop-off in the mid 1990s, so this may be part of the effect. The fact that the drop-off rate doesn't get massively faster after 9/11 possibly undermines this. I think your point is also a valid one which suggests this isn't what is happening or at least is only a small factor of what is going.
2) The American political scene may in some ways simply be more civilized than it was in the 1960s and 1970s. True in many ways things at the congressional level feel more partisan, but it may be that the groups which felt like they had no options other than violence don't fe...
We see a dramatic drop in terrorist acts in the US after 2000.
Do we? I see a sawtooth-decline starting in 1995/6, with 2000/1 not deviating from the trend.
Your analysis is surprisingly Americo-centric. The 1970s saw very serious terrorism (far worse than America) in the UK, Germany and Italy, all of which are now very peaceful countries. Did 9/11 also make terrorism un-Italian?
Secondly, your timing is all wrong. The fall in terrorism worldwide long predates the rise of specifically Islamic terrorism.
Thirdly, Islamic terrorism is the intellectual and organisational descendant of secular Arab terrorism and is received in much the same way. The only innovation is the suicide bomber. Yet in the period that you c...
half of all attributed [terrorist acts] in the US from 2000-2013 are tagged "Individual".
The NSA/FBI might be doing a great job of stopping coordinated terrorist attacks and infiltrating and deterring groups that might launch attacks on America. Plus, I get the sense that a significantly higher percentage of U.S. than European Muslims are willing to cooperate with the police to stop terrorism.
You're graphs are too low resolution to read.
As for individual actors in other nations, what about Anders Behring Breivik? You might find this list helpful:
I think you're behind some kind of image-fucking (i.e. recompressing) proxy server. Are you tethering on a cellphone network by any chance? (Or on an airplane?)
The lone gunman thing, where someone flips out and shoots up a Navy base, or bombs a government building because of a conspiracy theory, is distinctively American.
A conspiratorial explanation: perhaps the data has been manipulated to downplay terrorist coordination in America. There would be a couple reasons to do that, depending on the audience. For ordinary citizens, a collection of nutcases might be less scary than a dark underworld of coordinated cells. For terrorists and wannabe terrorists, a collection of uncool loners might less glamorous (as you...
If you stratified the data on terrorist ideology by sect, would Wahhabism by the underlying confounder, rather than Islam?
Islam explicitly advocates for violent Jihad. Countries like Australia should deal with terrorism as a policing and arts/culture issue, than a military problem. In fact, having no military might be in our best interest. There are a number of nations in the world with no militaries, some in particular unstable and criminal parts of the world, like Costa Rica, which don't have any military issues, as far as I know. In fact, it would seem ...
Yesterday I was using the Global Terrorism Database to check some suprisingly low figures on what percentage of terrorist acts are committed by Muslims. (Short answer: Worldwide since 2000, about 80%, rather than 0.4 - 6% as given in various sources.) But I found some odd patterns in the data for the United States. Look at this chart of terrorist acts in the US which meet GTD criteria I-III and are listed as "unambiguous":