Short answers, pulled from the story.
The Kigali Amendment is a legally binding international agreement to gradually reduce the production and consumption of hydrofluorocarbons. It was ratified by 171 states and the European Union. Unlike voluntary climate pledges, it creates enforceable rights and obligations in international law.
Full compliance with the Kigali Amendment could prevent more than 80 billion metric tons of carbon dioxide equivalent emissions by 2050. A successful phase-down could also hold back 0.5 degrees Celsius of warming above preindustrial levels by the end of the century.
HFCs trap heat thousands of times more powerfully than carbon dioxide. Their 100-year global warming potential ranges from 12 to 14,800, compared to 1 for carbon dioxide. Although HFCs persist in the atmosphere for only ten to twenty years, their heat-trapping intensity within that window far exceeds that of CO2.
Paul J. Crutzen, Mario Molina, and F. Sherwood Rowland revealed the damaging effect of chlorofluorocarbons on the ozone layer in 1974. Their findings led to the Montreal Protocol, signed in 1987 by the twenty major CFC producers and entered into force in 1989.
The Kigali Amendment sets three schedules. Developed countries must reduce HFC consumption to 15% of their baseline by 2036. A second group, including China and Brazil, must reach 20% of their baseline by 2045. A third group, including India and Saudi Arabia, must meet the same 20% target by 2047.
Greenland is excluded from the Kigali Amendment, even though Denmark ratified the agreement. The amendment's scope can vary across the territories of ratifying nations.