On October 15, 2016 in Kigali, Rwanda the majority of the world’s developed and developing countries executed a binding agreement to reduce emissions of hydrofluorocarbons (HFCs), a greenhouse gas that is emitted by air conditioners and refrigerators and is up to 1000 times more potent than carbon dioxide.

Developed nations, including the US, agreed to reduce HFCs use by 10% by 2019, and 85% by 2036 under the agreement. Developing nations are committed to freeze HFCs use levels by 2024-2028, and reduce those levels 80-85% by 2045-2047. The agreement is binding (in contrast to the voluntary commitments of the 2015 Paris climate agreement), so failure to meet these emission reduction timetables and targets may result in the imposition of trade sanctions. Developed nations have also agreed to help finance the cuts made by developing nations.

HFCs are a key chemical used in cooling systems worldwide, and represent a significant and growing portion of global greenhouse gas emissions. They were initially developed to replace chlorofluorocarbons, which were banned globally by the 1987 Montreal Protocol due to their harmful effects on the Earth’s ozone layer. The Kigali agreement was prepared as an amendment to the Montreal Protocol, and thus does not require US Senate ratification even though it has the legal force of a treaty.

Overall, the agreement is anticipated to reduce HFCs by the equivalent of 80 billion tons of carbon dioxide by 2047, or about 10 years’ worth of US total greenhouse gas emissions. With substantial participation from the chemical and air conditioning industries, the agreement is expected to facilitate the rapid development of alternatives to HFCs and more efficient cooling technologies.