It is impossible to know when man will be destroyed.
But if man starts a nuclear war, there is a good chance that man will be destroyed. There are so many nuclear weapons on the earth now that they could easily annihilate the entire human race. If these were used to start a war, human beings would probably be wiped out immediately.
Another possible reason for the destruction of the earth is the destruction of the earth's environment. If the earth's ozone layer were to be completely destroyed, or if all the trees on the earth were to be killed by acid rain, it would be impossible for humans to survive. Therefore, the question of how we can live without polluting the earth and destroying its environment is one that we must seriously consider in the future.