The Kigali Amendment to the Montreal Protocol is an international agreement that helps countries slowly reduce the use and making of hydrofluorocarbons (HFCs). This agreement is legally binding, meaning countries must follow the rules set by international law.
The Montreal Protocol was first created to protect and repair the ozone layer. Countries that joined agreed to stop using chlorofluorocarbons (CFCs), which were harming the ozone layer. HFCs do not contain chlorine, so they do not harm the ozone layer. Because of this, HFCs have been used instead of CFCs under the Protocol. However, HFCs are strong greenhouse gases that help cause climate change. This amendment adds HFCs to the list of chemicals that countries agree to reduce over time.
As of March 27, 2025, 171 countries and the European Union have officially agreed to the Kigali Amendment.
Background
Many industrial products, such as refrigerants and cooling systems, use HFCs.
In the past, chlorofluorocarbons (CFCs) were used for these purposes. However, scientists Paul J. Crutzen, Mario Molina, and F. Sherwood Rowland discovered in 1974 that CFCs harm the ozone layer. To address this issue, the Montreal Protocol was signed in 1987 by 20 major CFC producers and became active in 1989. By 1987, all 197 member states of the United Nations and other countries had agreed to the Protocol. Since then, HFCs have mostly replaced CFCs in these applications.
Although HFCs do not harm the ozone layer, they are very strong greenhouse gases. Their time in the atmosphere is short (10 to 20 years) compared to carbon dioxide (CO₂), but they trap heat much more effectively. HFCs are thousands of times better at trapping heat than CO₂. Their global warming potential (GWP), which measures how much heat a gas traps compared to CO₂ over 100 years, ranges from 12 to 14,800. In contrast, CO₂ has a GWP of 1. Reducing HFC emissions could help lower global warming by preventing more than 80 billion metric tons of CO₂ equivalent emissions by 2050 and avoiding a total of 0.5 degrees Celsius of warming above preindustrial levels by the end of the century.
Details of the amendment
Article 5 of the Montreal Protocol set different rules for developing countries and developed countries. A country was classified as developing or developed based on its economic situation at the time of the agreement or if it asked for special consideration. Since the Protocol was created in the 1980s and many countries’ economies have changed, the Kigali Amendment created three new groups to meet updated requirements.
The first group, which includes older industrialized countries, must reduce the use of HFCs by 45% by 2024 and by 85% by 2036 compared to their use between 2011 and 2013. The second group, which includes China, India, and Brazil, must reduce HFC use by 80% by 2045. The third group, which includes India and several Middle Eastern countries that use a lot of air conditioning, has until 2047 to meet these targets.
Additionally, countries where the average monthly temperature is above 35°C (95°F) for at least two months each year for 10 years in a row may ask for an exception. Although Denmark approved the amendment, Greenland is not included.