What do World Wars do? They depopulate the planet

If you look at Ukraine, Boko Haram in Africa, ISIS now in Syria, Iraq, Libya (killing Egyptians) and the Houthis (paid for and armed by Iran) collapsing the Sunni Government in Yemen, we all see the seeds of the next World War that might be fought over oil because through Yemen and Saudi Arabia and Libya, the oil from Saudi Arabia and Libya might be cut off for years by what we are seeing happen slowly or not so slowly now.