I'm of the opinion that most, although not all, of global violence and crime can be eliminated. The West, for instance, has seen declines upwards of 80%, across all categories, including murder, rape, assault, etc. I think that if we were able to export the conditions of the West elsewhere, crime and violence would face a similarly steep drop. Democracy, liberalism, education all have a role to play, but by far the biggest contributor to social ills is poverty.
Poverty is a relative term. It means different things in different places. Most of the world, for instance, will never be able to make even half the American poverty line. I also think that people tend to view poverty somewhat simplistically - they think of it as a "state," i.e. in order to be impoverished, you need to essentially be a starving African child. Everything else is just the whining of those with relative privilege. In my opinion, that isn't the right way to look at it. Poverty has three essential components, that can exist in all societies, and that result in many social ills.
These three components are, in my opinion, lack of social mobility, lack of social cohesion, and large wealth inequality.
The reason I point this out is because remembering that poverty is relative is a very important thing. We can't possibly understand why poverty is so strongly correlated with various social ills without first understanding that being "impoverished" necessarily requires a comparison with other people within that society. An American in poverty may be objectively better off than an African in poverty, but the effects of greater crime and violence are just as large. Take a look at this data...
Global Ethnic Diversity Map
Global Wealth Inequality Map
Social Mobility Graph
Global Homicide Map
I wasn't able to find global data on social mobility, but the overwhelming consensus of sociologists is that social mobility and income inequality are heavily correlated. In the same way, the three components of poverty mutually support one another. Income inequality makes social mobility worse, lack of social cohesion makes social mobility worse, lack of social mobility makes income inequality worse. They reinforce and magnify one another.
You'll notice that these statement are true regardless of different "generalized" global culture. They hold true both between Western and Eastern nations, or First and Third World nations, but also within those categories. For instance, the United States has some of the worst social mobility in the Western world. It also has the highest income inequality and highest level of ethnic and cultural diversity. Consequently, it has the highest murder rate in the Western world, and along with Canada and Britain, is one of the most generally violent in the Western world. Whereas countries with a high degree of ethnic/cultural cohesion, a high degree of social mobility and a high degree of wealth equality, such as Denmark or Finland or Sweden, all are drastically less violent. Now, to be clear, there are exceptions to this thesis, but as a general idea, it seems to hold quite nicely.
But what about military conflicts? Does this correlation between poverty and military conflicts hold?
Again, generally speaking, it appears that the correlation holds. The higher the income inequality, the higher the ethnic/cultural fragmentation and the less social mobility, the greater the chance of political and military conflict.
It seems to me that one of the best ways to address global violence would be to address these issues head on. The Middle East, for instance, could be made much more peaceful by establishing reasonable national borders, that accurately reflect the ethnic and cultural demographics of the population. Crime and violence in the US, Canada and Britain could be reigned in by addressing social mobility, which requires heavy investments in public education and infrastructure. Everyone could stand to benefit from addressing wealth inequality. If we could develop a platform to attack these problems directly, and stay focused and united by doing those things most people can agree on (for instance, improving roads and internet access is a near universally supported movement), there is a chance that we could not only solve many of the fundamental problems of our society, but also have a global impact.
Thoughts?