Top 5 facts about AF energy conservation Published April 26, 2016 By Air Force Television Pentagon WASHINGTON (AFNS) -- Earth Day, which takes place annually on April 22, serves as a day to demonstrate support for environmental protection. The Air Force's overarching Earth Day theme continues to be "Conserve Today. Secure Tomorrow." For Earth Day 2016, the Air Force is highlighting its commitment to "cleaner, greener installations" with an emphasis on energy and water conservation.