Since the beginning of humankind unpredictable forces of nature have been among our most dangerous threats: volcanic eruptions, earthquakes, tsunamis, floods, tornados, hurricanes, and other disasters that trigger our fight-or-flight survival instincts. Pollution invoked climate change is exacerbating natural disasters and spurring unprecedented human migration. So when so many people are clamoring for safety and running for the hills, what does that mean for those who are already atop them?

Author and geographer Barry Vann explains what awaits the future of our planet and its human populations in his new book Forces of Nature: Our Quest to Conquer the Planet. In this fascinating yet sobering conversation with Josh Zepps, Vann elaborates on both the causes of migration as well as the outcomes of the population shifts to come. They discuss both the impact humans have had on our planet, and how our planet affects us in turn. Vann is optimistic that while society is prone to taking the path of least resistance, the conditions brought about by climate change will soon become so unbearable it will force us to make tough decisions that will be crucial for our survival.