HFCs are the fastest growing greenhouse gases in much of the world. HFCs have caused only 1% of total global warming to date, but production, consumption, and emissions of these factory-made gases are growing at a rate of 10-15% per year, which will cause a doubling every five to seven years (Velders G. J. M, et al. 2012).
HFCs are factory-made gases primarily produced for use in refrigeration, air-conditioning, insulating foams, and aerosol propellants. Growth is accelerating as HFCs are used to replace chlorofluorocarbons (CFCs), which were previously phased out under the Montreal Protocol, and hydrochlorofluorocarbons (HCFCs), which are now being phased out (see Figure 1). HFCs were once thought necessary to replace ozone-depleting substances, but today are no longer needed in most sectors.
HFCs are considered short-lived climate pollutants, as they remain in the atmosphere for just days to a few decades, unlike long-lived CO2 emissions, which remain in the atmosphere for hundreds to thousands of years. The benefits of reducing short-lived climate pollutants, which contribute 40-45% to the current warming rate, can be felt within days to a decade of mitigation.
Fast action to reduce short-lived climate pollutants cut can the rate of warming in half by mid-century.
Using the Montreal Protocol Phase Down HFCs
Fast action under the Montreal Protocol can limit growth of HFCs, prevent 100 to 200 billion tonnes of CO2-eq emissions by 2050, and avoid up to 0.5°C of warming by 2100 (Xu et al. 2013), with additional climate benefits from parallel improvements in energy efficiency of air conditioners and other appliances.
At the international level, there is growing consensus that HFCs can be most effectively controlled through the phasedown of their production and consumption under the Montreal Protocol as a complement to controls of emissions under the Kyoto Protocol. The Montreal Protocol has the experience and expertise to ensure a fast, effective, and efficient phasedown of HFCs, which are in the same family of gases, have similar chemical properties, and are used in the same sectors as the CFCs already phased out and the HCFCs currently being phased out. (Zaelke et al. 2012).
World leaders recognized the threat posed by the growth of HFCs in the outcome document of the Rio +20 Summit in 2012 and called for the gradual phasedown of their production and consumption. As of July 2015 five proposals have been submitted by a total of 95 Parties to the Montreal Protocol to amend the treaty to phase down the upstream production and consumption of HFCs (leaving the accounting and reporting of the downstream emissions in the UN climate regime). The 95 Parties include a coalition of island States let by the Federated States of Micronesia and the Philippines, the Africa Group of 54 Parties, the U.S., Canada and Mexico, the EU-28, and India.
In November 2015, the Parties to the Montreal Protocol, recognizing the threat posed by the growth of HFCs agreed on the Dubai Pathway on Hydrofluorocarbons to “work within the Montreal Protocol to an HFC amendment in 2016.”
Past Success of the Montreal Protocol
The Montreal Protocol is widely considered one of the world’s most successful multilateral environmental agreements, having phased out 97% of almost 100 ozone-depleting substances (ODSs) – placing the ozone layer on the path to recovery.
Because many ODSs are also potent greenhouse gases, their phase-out under the Montreal Protocol has provided an often overlooked bonus for climate mitigation: Phasing out these 100 chemicals also has provided powerful climate protection, avoiding the equivalent of an estimated 9.5 billion tonnes of CO2 emissions per year – approximately five times more than the emissions reductions of the Kyoto Protocol’s first commitment period (2008-2012) (see Figure 2).
Fast Mitigation Can Prevent Warming and Reduce Climate Impacts
Fast mitigation of HFCs combined with mitigation of the other short-lived climate pollutants (SLCPs) — black carbon, methane, and tropospheric ozone — can avoid 0.6°C of future warming by 2050, and up to 1.5°C by end-of-century, with HFC mitigation contributing one-third of the avoided warming by end-of-century (Xu et al. 2013).
Reducing HFCs and the other SLCPs can significantly reduce future climate impacts, including slowing sea-level rise. Research led by Professor Veerabhadran Ramanathan at Scripps Institution of Oceanography, University of California, San Diego, calculates that cutting SLCPs can reduce the rate of sea-level rise by almost 20% by 2050 and nearly 25% by 2100; adding immediate and aggressive CO2 mitigation can double the end-of-century reductions (see Figure 4).
HFCs and Energy Efficiency
Improving energy efficiency of air conditioners in parallel with the HFC phase down could avoid up to 100 billion tonnes of CO2, at least doubling the mitigation benefits from a phasedown alone.
In addition to the direct climate benefits from HFC mitigation, a global HFC phasedown will catalyze additional climate benefits through improvements in the energy efficiency of refrigerators, air conditioners, and other products and equipment that use HFC refrigerants. (Complementary measures that encourage consumer choice of energy efficient appliances can speed the gains.) These efficiency gains will significantly reduce CO2 emissions.
The phaseout of CFCs under the Montreal Protocol, which began in the mid-1980s, catalyzed substantial improvements in air conditioning and refrigerant energy efficiency—up to 60% in some subsectors. These efficiency improvements were the result of replacing old products and equipment with a new generation of higher efficiency machines (US EPA, 2012).
Recent calculations by scientists at Lawrence Berkeley National Laboratory confirm that, in the room air conditioning sector, improving efficiency could avoid ~25 Gt of CO2 emissions in 2030, 33 Gt in 2040, and ~40 Gt in 2050, for cumulative mitigation up to 98 Gt. (Shah, et al. 2015).
Fast action under the Montreal Protocol can limit growth of hydrofluorocarbons (HFCs), prevent 100 to 200 billion tonnes of CO2-eq by 2050, and avoid up to 0.5°C of warming by 2100.
The Climate and Clean Air Coalition to Reduce Short-Lived Climate Pollutants (CCAC) is a voluntary partnership uniting governments, intergovernmental organisations, civil society and the private sector in the first global effort to address short-lived climate pollutants (SLCPs) as an urgent and collective challenge, in ways that protect the environment and public health, promote food and energy security, and address near term climate change. The Coalition’s work is complementary to the global action to reduce carbon dioxide, in particular efforts under the United Nations Framework Convention on Climate Change (UNFCCC).