Calling this WW IV won't get far. Everyone knows the Cold War wasn't really WW III, and the present war hasn't yet evolved to WW III. It could be the early days of WW III, the run-up to war, but we're not there, yet. I think you're wrong. WW3, Hungary, Berlin, Korea, Vietnam, Cuba, Central America, Afghanistan. Plenty of dead.
Iran, Beirut, WTC 1, USS Cole, the African embassys, WW4 may have started before WTC2
When we think of World War, we associate millions of dead and maimed and mobilizations of several entire countries to the war effort. The relatively small actions since WW II lack that intensity. Wars they have been, but not World War. WW III, in that sense, has not begun. We instinctively know this, but it could be quantified in numbers of casualties per day or per hour. If there are 50 casualties a day, that is war. If there are 50 casualties per minute for 4 years, that is World War.