This consensus study assessed the national security implications of climate change for the U.S. Navy, Marine Corps, and Coast Guard. The study examined the potential impact climate change will have on future U.S. naval and allied force operations and capabilities and assessed the robustness of the Department of Defense’s infrastructure for supporting naval operations and capabilities in the context of potential climate change impacts. The study found, in part, that even the most moderate current trends in climate, if continued, will present new national security challenges for U.S. Naval Forces. The study provided targeted recommendations to address these challenges.