170 countries have reached a historic deal to phase out Hydrofluorocarbons (HFCs) after years of protracted and at times seemingly intractable negotiations. Senior politicians meeting in Kigali, Rwanda accepted an amendment to the Montreal Protocol that will see developed countries reduce their use of HFCs from 2019.

HFCs are potent greenhouse gases with a significantly higher global warming potential than carbon dioxide and are widely used as refrigerants, aerosol sprays and in solvents. HFCs have been widely used as an alternative to Chlorofluorocarbons (CFCs) since the Montreal Protocol came into effect to prevent ozone depletion.

It is estimated that the current mix of HFCs being widely used have an impact 1,600 times stronger than CO2 per tonne emitted. The current atmospheric concentration of HFCs account for 1% of the total warming caused by all greenhouse gases, but consumption rates are increasing significantly as global temperatures rise and developing countries gain access to electricity and demand grows for refrigeration and air-conditioning. Under the current trajectory, with usage increasing at over 10% a year, HFCs could account for as much as 19% of global greenhouse gas emissions by 2050. The Paris Agreement has an aspirational goal of limiting global warming to 1.5C and phasing out HFCs could avoid an estimated 0.5C of global warming by the end of the century a not insignificant contribution.

Given that the adverse impact of HFC use was largely an unintended consequence of the Montreal Protocol, signatories agreed that securing an international amendment to the existing Protocol was the most effective course of action.

Countries agreed to an amendment that will see developed countries start to reduce their HFC use from 2019. The new agreement contains flexibility to cater for the differing capacities of the 170 nations, with three separate pathways.

Developed countries must reduce HFC use by 10% by 2019 from 2011-2013 levels, and 85% by 2036.

A second group of developing countries, including China and African nations, are committed to launching the transition in 2024. A reduction of 10% compared with 2020-2022 levels should be achieved by 2029, and 80% by 2045. A third group of developing countries, including India, Pakistan and Arab Gulf states, must begin the process in 2028 and reduce emissions by 10% by 2032 from 2024-2026 levels, and then by 85% by 2047.