The global recession has encouraged a number of social uprisings, including the recent overthrow of Egypt's autocratic government and milder protests such as those across Europe and in Argentina. Right-wing extremism is predictably on the rise.
It's rather apocalyptic to argue that World War 3 is around the corner, given that I know little about history. Still, I'm placing my bet on increasing nationalism and economic warfare in the next 15 years.
What are people searching for? Right now in Google News, "world war 3" is ranked higher on autocomplete than "world war 2" (this is very possibly an artifact of their autocomplete algorithm). World War 3 picked up in news searches around mid-2009, although it's not clear what the units on these searches are; perhaps the phrase only became popular enough to appear at all at that time. It's also still less frequent than "world war 2".
At the same time, "world war 3" is almost as popular a query as "nationalism": the latter has become less prominent over time. Hedged bets such as "economic warfare" and "trade war" are much less frequent, until you look at concrete examples of these, such as "tariff". "tariff" really picked up in mid-2009 and is much more popular than any of the above queries. India, Norway, South Africa, and Hong Kong are by far the biggest country sources of these queries. Washington, D.C. ranks highest among American cities.
Link to this search