Slow response by The American government causes the recessions to get worse. A deeper slump in consumer spending followed by an Asian market collapse forces China into its own recession...something that the government is unable to handle... A recession in the two largest economies destroys the world economic system as money is hoarded by large corporations and individuals alike.
Arab spring happens in 2010 except more violent than otl... A caliphate or series of Islamist organizations take control of vast swaths of territory in Saudi Arabia, Jordan, Syria, Egypt, lebanon, Yemen, Nigeria, Iraq... the American troops in Iraq become warlords as the Iraqi government collapses around them...they become defacto allies with Iranian forces in the region.
The oil crunch caused by the middle eastern wars eliminates the Japanese and Korean economies from the world stage... The Japanese government nationalizes Sony, Toyota, Honda to focus on the production of electric trucks.
Apple goes out of business...GM is nationalized...Silicon valley is practically bankrupt.
Pakistan, Burma, Sri Lanka, and Nepal collapse...loose nukes flood Asia.
Israelis, Palestinians, and Islamists fight a 3 sided war.
Mexico is squeezed by revolutionaries and drug cartels...American PMCs are hired by northern Mexican states to keep the peace...a move that worries Mexican Feds.
Africa devolves into complete shit...including South Africa and Nigeria.
Refugees from Africa and the Middle East pour into unwelcoming Europe where right wing extremists now control major government positions.
It probably takes 20-30 years to get back to normal. The only winner is probably Russia which is able to get rich off of oil exports to Europe.