When something is global, it's happening all over the world. It's easy to spot the connection between global and globe.
When the volcano in Iceland erupted, it quickly became a global event. Sure, things were tough in Reykjavík, but the dust and ash caused airport shutdowns and schedule disruptions around the world. Michael Jackson was a star in the United States from the time he was a little boy, but after he broke up with his brothers and went solo in the 1980s, he became a global phenomenon. There was hardly a country on earth where Michael Jackson wasn't a star.