All roads lead to Riyadh: How Saudi Arabia impacts the region

So much hinges on Saudi Arabia: from the COP21 summit, to the fight against ISIS and the war in Yemen, the nation that sits on one-third of global oil reserves has to do some quick arithmetic. Can it brave pressure in Paris and agree on a plan for a fossil fuel-free world, contain the growing influence of Iran and attack the jihadists who have sworn to take down the Wahhabi Kingdom while still defending its own brand of rigorous Islam?