Weighing up the costs of keeping cool

In October 2016, a global decrease in the use of certain greenhouse gases commonly used in a number of industries across the globe was agreed under the Kigali Amendment to the Montreal Protocol. A new study by the IIASA Air Quality and Greenhouse Gases program however, found that the cost burden of compliance with this amendment will be unevenly distributed across sectors and world regions, which justifies a redistribution of costs between now and the target date of 2050.

Room air conditioners near Kahn market, New Delhi. © Anders Isaakson

Hydrofluorocarbons (HFCs) are synthetically produced chemicals that are widely used as cooling agents in, for example, air conditioning and refrigeration systems, or as components in the production of, among other products, foams and aerosols. Although they have strong global warming properties, these gases do not affect the ozone layer. As a result, manufacturers have been using them to replace the ozone depleting chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) that are regulated under the Montreal Protocol. With increasing demand for the cooling and other services offered by HFCs and other fluorinated gases (F-gases) however, emissions of these powerful greenhouse gases are on the rise.

The GAINS model developed by IIASA researchers explores cost-effective emission control strategies that simultaneously tackle local air quality and greenhouse gases to maximize benefits at all scales. It assesses emissions on a medium-term time horizon, and specifies projections in five-year intervals until the year 2050. Researchers from the Air Quality and Greenhouse Gases program recently extended this model with a capacity to develop global emission scenarios for the F-gases, HFCs, perfluorocarbons (PFCs), and sulphur hexafluoride (SF6) [1].

Since its launch in 2006, GAINS has been implemented for the whole world, distinguishing 172 regions including 48 European countries and 46 provinces/states in China and India. The new resolution at the sector and technology level for each of the 172 regions is intended to provide sufficient detail to develop cost-effective emission reduction strategies for F-gases. When accounting for existing regional and national F-gas regulations, baseline F-gas emissions are expected to increase from about 0.7 to 3.3 Pg CO2eq between 2005 and 2050, of which HFC emissions alone make up about 2.9 Pg CO2eq in 2050. Growth in emissions is particularly pronounced in developing countries owing to an expected strong increase in demand for stationary and mobile air conditioning.

Baseline emissions of F-gases (HFCs, PFCs, and SF6) 2005 to 2050 by source sector. HCFC emissions are summed up at the top of the graph.

According to the researchers, the provisions of the Kigali Amendment could remove 61% of cumulative HFC emissions over the period 2018 to 2050 compared to expected emissions without implementation of the amendment [2]. It would be technically possible to remove as much as 84% if existing technology is employed to a maximum extent. Implementation costs are expected to remain very low in the coming two decades, but to rise sharply in the final decade leading up to 2050, unless future costs decline due to technological development and a full realization of expected energy-savings through careful implementation of alternatives to HFCs.

In a report prepared for the UN Environment Program on the impacts of the Kigali Amendment in Asia [3], the researchers also found that the expected CO2 reductions from electricity-savings linked to properly installed and maintained alternative technologies to HFCs, add about 10 to 12% of savings in greenhouse gas emissions to the total savings from a reduction in HFCs. Both estimates of costs and possible energy savings are potentially useful information for Parties to the Montreal Protocol when they next meet to set up the Multilateral Fund, which will alleviate some of the cost burden on developing countries to comply with the Kigali Amendment.


[1] Purohit P & Höglund-Isaksson L (2017). Global emissions of fluorinated greenhouse gases 2005–2050 with abatement potentials and costs. Atmospheric Chemistry and Physics, 17, pp. 2795-2816.

[2] Höglund-Isaksson L, Purohit P, Amann A, Bertok I, Rafaj P, Schöpp W, & Borken-Kleefeld J (2017). Cost estimates of the Kigali Amendment to phase-down hydrofluorocarbons. Environmental Science and Policy, 75, pp. 138-147.

[3] Purohit P, Höglund-Isaksson L, & Wagner F (2017). Impacts of the Kigali Amendment to phase-down hydrofluorocarbons (HFCs) in Asia. Report from IIASA on work completed for the United Nations Environment Programme (UNEP) under UNEP contract number: M1-32SLP-000009/32SLP/M99/11228/14AC0001/SB-000910.41.03. International Institute for Applied Systems Analysis, Laxenburg.

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