This chapter addresses the historical, international, and legal roots of environmental protection in the global shipping industry. The discussion begins with a review of the initial efforts among states to regulate the industry and the creation of the International Maritime Organization. The original maritime environmental treaties of the 1960s are considered and the early success of a 1970s era global treaty is then assessed. The particular challenge of regulating greenhouse gas emissions under the UNFCCC-Kyoto Protocol-Paris Agreement regime is reviewed. Concluding lessons about sustainability are offered.