Scientific discoveries, national regulations, and international agreements impact our lives. If we bring all three together in a solid but flexible governance structure, then we are able to address those impacts and share more evenly their consequences across different nations. This is what the Montreal Protocol has done in its 30years of life and will continue to do thanks to the recent Kigali Amendment. There are many lessons for diplomacy to be drawn from the recent negotiations, including the critical role of science. The most important lesson in reaching consensus is the injection of optimism, pride, ownership of the process, and building trust among all nations. The solid yet flexible foundation of the Montreal Protocol provided a firm grounding for the Kigali negotiations to experiment with the different negotiating techniques in a forum where countries, industry, non-governmental organizations, and scientists are brought together by the United Nations.