Letter: Overpopulation + overheated earth = mass migration

Even a casual glance at the headlines reveals a staggering number of places where humans and the Earth are being challenged by overpopulation and/or climate change. People, animals, insects and even plants are migrating because of a warming planet. Competition for limited land, food, water, energy and minerals is causing conflicts across the globe.We know that human population will be controlled at some point by a combination of war, famine, disease or the difficult political and individual choi