Summation of world events:

As far as I can tell, Saudis are betting the farm on the following plan, and many world leaders are in on it.
The free world doesn't trust Putin. Putin gets away with tons of stuff because Russia supplies so much natural gas to Europe that no one can really object to much of anything Putin does.
The Saudis and other Arab countries have plenty of natural gas but nowhere to pipe it to. Syria and Iraq stand between Europe and the Arab world. No one was going to run a pipeline through those two countries with those crazy rulers -- they're worse than Putin. That would have given them too much power.
So Bush tries regime change in Iraq. Makes up weapons of mass destruction because he wants a pipeline. Fail.
So Obama tries to start something with Syria to push their government out. No one will support him, so he starts supporting the resistance. Then ISIS shows up and starts fighting Assad AND his resistance. Obama steps in and pretends to fight ISIS, but really only fights them if they fight the resistance. Assad is fair game. Obama wants the pipeline.
Putin sees Assad teetering and decides he has to annex Ukraine now. Once Assad falls, the Europeans might support fighting back. But as long as Assad is in power, Putin can grab what he thinks he needs. Europe will meekly go along because they need the natural gas only Putin can supply.
The Saudis, of course, REALLY want the pipeline. So they decide to support Obama by lowing the price of gas, essentially ensuring the US economy remains robust so that we continue to support regime change in Syria. Basically, it has turned the US into Saudi mercenaries, at least in part.
The refugees are the pawns in this game, meant to benefit the Saudis AND the Europeans. So Europe steps up and takes massive numbers of refugees. Why? Not because they are good guys, but if the war results in too big of a humanitarian crisis, the world populace, in the dark over all of this, will demand an end to the war and Assad will remain in power. So Germany, who will be the greatest beneficiary of stable supplies of gas, tells Greece, who owes Germany a lot of money, that they can get some serious financial concessions by accepting refugees. Greece complies.
Putin sees Assad teetering, and doesn't much care about him, but doesn't want the pipeline to be built. So Putin steps in to the war to defend Assad.
So all the world's major events come down to a pipeline vs no pipeline. They are all connected to it. The Saudis are "betting the farm" over it. The pipeline will represent untold billions of dollars for centuries.