The idea of intergenerational equity is as old as humankind. Intergenerational equity arises from the elderly wanting their offspring to prosper in at least as favorable conditions as experienced. The natural behavioral law of intergenerational equity was lived for centuries and transpired in the social compound as practiced in ancient, traditional customs ever since. Intergenerational equality is grounded on a human-imbued wish for fairness as there is an ethical preference for fair welfare distribution among different generations. Acknowledging intergenerational equity as a natural behavioral law may serve as a legal basis for the codification of human rights of intergenerational equity. A pro-active overcompliance with contemporary sustainability legislation may stem from a broader social contract within society to incorporate novel responsibilities and embrace discretionary activities that contribute to societal welfare and the well-being of future generations. Globalization increasing internationalization of public and private concerns creates a need for an international outlook of intergenerational equity in order to solve global common goods predicaments and draw inferences on the harmonization of intergenerational justice on a global scale in the age of climate change.