Climate change is a growing threat to national security and a concern for the military. Defense Secretary Jim Mattis has said climate change is already impacting global stability. Retired Vice Admiral Lee Gunn agrees. Gunn served in the U.S. Navy for 35 years and is on the board of directors of the American Security Project , a non-partisan organization whose mission is to educate the public about the changing nature of national security in the 21st century. He was on Sundial as part of the