This essay focuses on how heat increases vulnerability of cultures, institutions, lifestyles, occupations, human rights, and community viability due to both rising global average temperatures and the resulting destabilizing societal consequences of inequity in a warmer world. It will illuminate the ways in which heat is the biggest climate-driven threat to global human security, particularly in non-island regions and states where social stability and improved development hold tremendous geopolitical importance. The essay will then discuss ways in which current legal and political responses are inadequately prepared to handle heat vulnerability.