The headline may represent the main fear being expressed by investors at the moment. Of course, I know that uncertainty about the future, as opposed to specific fears will always be a heavy weight on global stock markets.
It is obvious that as long as the war in Ukraine goes on getting worse and the risk of interaction between Russia and NATO forces is on the table, stock markets are going to keep trending down. I note with some nervousness that some Russian public figures (including incredibly the leader of the Russian Orthodox Church) are rabble rousing for an invasion of the Baltic states and basically anywhere that was once in the USSR. Serious commentators are going into print suggesting that nuclear war is really quite possible.