In a video for Reuters, Ian Bremmer discusses the biggest risks facing the markets in 2012 and says the next phase in the Middle East and the post-9/11 environment pose the greatest uncertainty:

Top Risks of 2012

As we begin 2012, political risks dominate global headlines in a way we’ve not experienced in decades. Everywhere you look in today’s global economy, concerns over insular, gridlocked, or fractured politics affecting markets stare back at you. Continuation of the politically driven crisis in the eurozone appears virtually guaranteed. There is profound instability across the Middle East. Grassroots opposition to entrenched governments is spreading to countries such as Russia and Kazakhstan that were thought more insulated. Nuclear powers North Korea and Pakistan (and soon Iran?) face unprecedented internal political pressure... Read the full top risks report here.