—Don Vollmar, Oakdale, California It may seem so, given that it took 100,000 years for modern Homo sapiens to reach a population of about 2 billion in 1900, which exploded to nearly 8 billion in only 122 more years. And humans do release significant greenhouse gases. Yet it’s not just that we live, but how we live, that has caused whatever humans have contributed to climate change. If we led simple agrarian lives, the current population would not be a problem. But if we want the increased standard of living much of the world now enjoys, we cannot sustain continued population growth.