Scientists in 1985 discovered something that threatened the world we live in: The ozone layer had a hole in it. A big one. And this hole was growing very quickly. If it continued to grow, the consequences would be dire. Presented with the science, world leaders came up with an international agreement. The Montreal Protocol, as the treaty was called, may elicit shrugs today. But it staved off disaster for Earth. It was a remarkable success story, and our planet today would be a very different place if not for the Montreal Protocol and the so-called “blue sky” scientific research — research for curiosity’s sake — that led to the discovery of the rapid deterioration of the ozone layer, and its causes In this episode, we return to a program originally broadcast in January 2017 — one that is perhaps even more relevant today. Orbital Path is from PRX and produced by David Schulman. Justin O’Neill produced this episode. Orbital Path is edited by Andrea Mustain, with production oversight by John Barth and Genevieve Sponsler. Hosted by Dr. Michelle Thaller. Support for Orbital Path is provided by the Alfred P. Sloan Foundation, enhancing public understanding of science, technology, and economic performance.