Huge International Agreement on Climate Change

You will likely have seen the news that there was an international agreement reached to limit the use of HFCs, the chemical used most commonly in refrigerators. 170 countries agreed to the deal negotiated in Kigali, and it is said that it will likely have a greater impact, and is certainly more enforceable, than the Paris Climate Change Accord. How did they manage to get the deal? How is it that the U.S. government is able to ratify it without obtaining the advice and consent of the Senate?

Meanwhile, here is some analysis on the entry into force of the Paris Climate Change Accord.