On the Precipice

Sometime in the near geological future, the landscape of life on earth as we know it will be transformed. It’s a mass extinction, and it’s only happened five times before in Earth’s history. There have been severe ice ages, perplexing loses of oxygen from our oceans, massive volcanic eruptions, meteor impacts. And now, we’re on the precipice of a sixth mass extinction… and it’s nothing like our planet has ever seen before. In Season 8’s final episode, producer Miles Traer dives into the sixth mass extinction: Are we in it? What can the previous mass extinctions teach us about what’s going on today? And how is it going to affect not just our lives, but the long term trajectory of human evolution? Paleobiologist Jonathan Payne takes us back into the geologic past and searches for biological patterns hidden in the rock record. In the previous moments of ecological chaos, Payne finds a surprising trend that no longer holds true today. Then, biologist Rodolfo Dirzo takes us into the heart of complex ecosystems to find out why large animals are so crucial for their health and survival. Based on experiments in the tropics and in East Africa, he shares what he’s seen when those large animals disappear.


Environmental Icon David Suzuki

This week we bring you an intergenerational conversation featuring David Suzuki, who is a Canadian scientist, activist, and media figure. Since the 1970s, Suzuki has hosted both radio and television shows about the natural world and environmental issues. A self-described “elder,” Suzuki shares his views and long-term perspective on environmentalism with our producer Mike Osborne. Their wide-ranging conversation spans climate change, energy, shortfalls of the environmental movement, and the evolving relationship between humans and Earth’s ecosystems.

The Dino Crater

One of the best tales of all time from geologic history is the story of the meteor impact that killed the dinosaurs. As it turns out, though, there are still many unanswered questions about what exactly happened the moment the meteor connected with our planet. In fact, until recently, scientists had yet to collect sediment cores from the center of the impact crater. On today’s show, producer Michael Osborne talks with Sean Gulick, co-chief scientist of an expedition that recently drilled the Chicxulub crater off the coast of Mexico. Sean revisits the moment when the asteroid hit, and he discusses what the scientists hope to find from their drilled samples. Also, we have a short segment featuring a conversation with Science Magazine reporter Paul Voosen about a news update from the Anthropocene Working Group.

Early Humans and Megafauna

The Anthropocene is characterized by exponential global change driven by human activity. But humans have been impacting the planet since the very earliest days when we first appeared on the evolutionary tree. In fact, one of the longest running debates in paleontology centers on homo sapiens’ role in wiping out North America’s enormous land animals, known as megafauna. In this interview with paleontologist Liz Hadly, we talk about what life looked like in the Pleistocene, the pattern of human dispersal around the globe, and new scientific techniques that allow us to understand how ecosystems respond to perturbations, like the arrival of early humans.