What a ridiculous idea! Seems pretty counterproductive. Maybe people are concerned that we are doing too much damage to the planet because we have too may people. Imagine how much damage a nuclear war would do to the planet! Once the war started, it would just escalate. This would lead to more destruction. War would probably distract people from any efforts that were being made before to take better care of the environment. During a war, some may take advantage of the turmoil and exploit even more resources while nobody is paying attention. Sure, you might have less people, but you'd have so many more problems.