After 9/11, This Scientist Got to Study an Empty Sky

While the events of Sept. 11, 2001 were a tragedy, they also offered a rare opportunity to researchers - a chance to observe an empty sky. Because all flights were grounded for days after the attacks, former NASA atmospheric scientist Patrick Minnis documented how the sky changed without the presence of airplane vapor trails - one of the airline industry's main contributions to climate change. NBCLX Storyteller Chase Cain breaks down the science.