26 June 2017

The costs of phasing down hydrofluorocarbons

The Kigali Amendment of the Montreal Protocol aims to phase down the consumption of hydrofluorocarbons (HFCs), chemicals that have strong global warming impacts. IIASA research provides the first analysis of costs and the importance of electricity savings and technological development for keeping implementation costs low.

© Volodymyr Tverdokhlib | Shutterstock

© Volodymyr Tverdokhlib | Shutterstock

HFCs are chemicals that have strong global warming properties without affecting the ozone layer and have therefore been used to replace ozone depleting substances chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs). 

A global phasing down of HFCs, as agreed in October 2016 under the Kigali Amendment to the Montreal Protocol could be implemented globally at a net profit if potential electricity savings are fully implemented across sectors and if regulations are implemented early enough to drive down compliance costs through technological development, according to a new study published in the journal Environmental Science and Policy. The study finds that the cost burden of compliance with the Kigali Amendment will be unevenly distributed across sectors and world regions, which justifies a redistribution of costs between regions.    

“Of particular importance for low costs is to transfer technology and knowledge to developing countries on how to reap opportunities for electricity-savings when switching away from HFCs,” says IIASA researcher Lena Höglund-Isaksson, who led the study. The study provides detailed cost estimates for world regions based on current emissions and the costs estimated, and shows that compliance with the Kigali Amendment could remove 61% of HFC emissions over the period 2018 to 2050 compared to expected emissions without the amendment. 

The study is based on a newly revised version of the IIASA GAINS model for fluorinated greenhouse gases (F-gases) including HFCs, perfluorocarbons (PFCs), and sulfur hexafluoride (SF6), which are strong contributors to  global warming, often with a few thousand times stronger global warming potentials per kilogram than CO2. The GAINS model is used to estimate the costs and benefits of reducing emissions of air pollutants and greenhouse gases, and has been used to support the design of air pollution and climate policies in Europe and Asia.  

Ozone and climate

Fluorinated gases or F-gases were invented in the 1920s to replace other chemicals that had been discovered to be toxic. These gases are very stable and non-reactive at ground-level, yet the very properties that made them safer for human exposure made them dangerous for the atmosphere. In the 1970s, scientists discovered that the chemicals became highly reactive when they reached the upper atmosphere, and were causing increasing depletion of the ozone layer. These gases are also powerful greenhouse gases, contributing to climate change.

The Montreal Protocol, agreed in 1987, was designed to reduce the amounts of ozone-destroying chemicals in the atmosphere, and is updated regularly in response to new scientific information. The purpose of the recent Kigali Amendment is to make sure the transformation away from ozone-depleting substances means choosing alternatives that are also climate change neutral.   

The study provides potentially important information for when Parties to the Montreal Protocol meet later this year to set up a Multilateral Fund to alleviate some of the cost burden on developing countries to comply with the Kigali Amendment.  

When accounting for existing regional and national F-gas regulations, another study by IIASA researchers recently published in Atmospheric Chemistry and Physics shows that without the Kigali Amendment, baseline F-gas emissions would be expected to increase from about 0.7 to 3.7 Pg CO2eq between 2005 and 2050, of which HFC emissions alone make up about 3 Pg CO2eq in 2050.  

The study projects that growth in emissions will be particularly pronounced in developing countries, owing to an expected strong increase in demand for air conditioning. Assuming all countries adhere to their commitments under the Kigali Amendment, the post-Kigali baseline emissions in 2050 are expected to remain globally at 0.2 Pg CO2eq HFC emissions and 0.9 Pg CO2eq total F-gas emissions.  

The researchers also found that the sector composition of future cooling demand differs considerably between developed and developing countries, which has implications for the abatement costs of adhering to the Kigali Amendment.  

“We found relatively more opportunities for low-cost or even profitable HFC abatement in industrial and commercial refrigeration, which are sectors expected to dominate cooling demand in developed countries, than in stationary and mobile air conditioning, which dominate future cooling demand in many developing countries,” says IIASA researcher Pallav Purohit, who also worked on the study.


Höglund-Isaksson, L. , Purohit, P. , Amann, M. , Bertok, I., Rafaj, P. , Schöpp, W. , & Borken-Kleefeld, J. (2017). Cost estimates of the Kigali Amendment to phase-down hydrofluorocarbons. Environmental Science & Policy 75, 138-147. 10.1016/j.envsci.2017.05.006.

Purohit, P. & Höglund-Isaksson, L. (2017). Global emissions of fluorinated greenhouse gases 2005-2050 with abatement potentials and costs. Atmospheric Chemistry and Physics 17, 2795-2816. 10.5194/acp-17-2795-2017.

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Last edited: 26 June 2017


Lena Höglund Isaksson

Senior Research Scholar

Pollution Management Research Group|Energy


and Environment Program

T +43(0) 2236 807 368

Pallav Purohit

Research Scholar

Pollution Management Research Group|Energy


and Environment Program

T +43(0) 2236 807 336

Science and policy impacts

Reducing air pollution worldwide

International Institute for Applied Systems Analysis (IIASA)
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