That depends on what we mean by "global". Whilst there were certainly areas of the world that the First World War's fighting did not (thankfully) ravage, it would not be too far-fetched to say that on every landmass there were some consequences (political, economic, or otherwise) generated by the war. This previous brief overview on an earlier writeup should be of some interest to you, though fellow AH travelers with more specific discussions on how global the war was exactly are more than welcome to pitch in!