At a 2021 climate conference, Defense Secretary Lloyd Austin said, "No nation can find lasting security without addressing the climate crisis." That sentiment reflects the Pentagon's three-decade evolution on climate change. Ali Rogin sat down with Sherri Goodman, a former Pentagon official who chronicles that transformation in her new book, "Threat Multiplier." PBS News is supported by - https://www.pbs.org/newshour/about/funders