Paul Greenberg cast his first fishing line before he got to first grade. The author of Four Fish: The Future of the Last Wild Food grew up in Greenwich, Connecticut, moving from cottage to cottage on various estates in the wealthy town. “I grew up kind of poor, sort of a ‘Slums of Beverly Hills’ story,” he said. And though his mom encouraged him to share her interest in birding, Greenberg said, “What got me going, to her chagrin, was going out and catching and eating fish.” While writing Four Fish, fishing transformed from something Greenberg saw as a personal hobby to something bigger — “an issue of the survival of the wild ocean.” Below, Greenberg explains why we eat the fish we eat, how we catch or farm it, and whether it’s risking the oceans.

Nuclear weapons once preoccupied all Americans. During the Cold War, as the U.S. and the Soviet Union amassed arsenals, aimed them at each other, and held the world in a delicate balance appropriately abbreviated as MAD, world leaders realized the need to control nuclear weaponry even as they sought to attain or expand nuclear capability. Today, more countries are members of the nuclear club, and more non-state actors are trying to join, but awareness about the danger of nuclear weapons seems disproportionately low. Before Zócalo and KCRW present Countdown to Zero, a documentary pressing for global disarmament, we asked four academics, writers, and scientists to explain just how dangerous the world is today, and how we can reign in loose nukes.