That being said, there’s a separate conversation over whether the Syrian conflict already is, in fact, a world war. Jordan’s King Abdullah has suggested as much recently, as has Pope Francis.* After all, the war in Syria has drawn in direct and proxy intervention from more than a dozen countries. It has spawned multiple fronts and overlapping alliances. It has spread into Iraq and challenged long-standing national borders. It has involved wanton brutality against civilians including genocide. It has sparked ancillary violence in neighboring countries and as far away as Paris. It has directly led to the worst refugee crisis the world has faced since World War II, not to mention the deaths of between 200,000 and 310,000 people, depending on the estimate.
Source : http://www.slate.com/blogs/the_slatest/2015/11/24/world_war_iii_we_re_not_seeing_the_beginning_of_a_world_war_in_syria_but.html