Every refrigerator and air conditioner contains chemical refrigerants that absorb and release heat to enable chilling. Refrigerants, specifically CFCs and HCFCs, were once culprits in depleting the ozone layer. Thanks to the 1987 Montreal Protocol, they have been phased out. HFCs, the primary replacement, spare the ozone layer, but have 1,000 to 9,000 times greater capacity to warm the atmosphere than carbon dioxide.
In October 2016, officials from more than 170 countries met in Kigali, Rwanda, to negotiate a deal to address this problem. Through an amendment to the Montreal Protocol, the world will phase out HFCs—starting with high-income countries in 2019, then some low-income countries in 2024 and others in 2028. Substitutes are already on the market, including natural refrigerants such as propane and ammonium.
Scientists estimate the Kigali accord will reduce global warming by nearly one degree Fahrenheit. Still, the bank of HFCs will grow substantially before all countries halt their use. Because 90 percent of refrigerant emissions happen at end of life, effective disposal of those currently in circulation is essential. After being carefully removed and stored, refrigerants can be purified for reuse or transformed into other chemicals that do not cause warming.
Montreal Protocol: UNEP. Montreal Protocol on Substances that Deplete the Ozone Layer: Final Act. United Nations Environment Programme, 1987.
ozone layer is beginning to heal: Solomon, Susan, et al. “Emergence of Healing in the Antarctic Ozone Layer.” Science 353, no. 6296 (2016): 269-274.
hydroflourocarbons [vs.] carbon dioxide: Myhre, Gunnar, Drew Shindell, François-Marie Bréon, William Collins, Jan Fuglestvedt, Jianping Huang, Dorothy Koch et al. “Anthropogenic and natural radiative forcing.” In Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge, UK, and New York: Cambridge University Press, 2013.
2016…amendment to the Montreal Protocol: Davenport, Coral. “Nations, Fighting Powerful Refrigerant That Warms Planet, Reach Landmark Deal.” New York Times. October 15, 2016; Johnston, Chris, et al. “Climate Change: Global Deal Reached to Limit Use of Hydrofluorocarbons.” The Guardian. October 15, 2016.
John Kerry…“biggest thing we can do”: Davenport, “Landmark Deal.”
reduce…warming…one degree Fahrenheit: Johnston et al, “Global Deal.”
[growth of] air-conditioning…by 2030: Shah, Nihar, Max Wei, Virginie Letschert, and Amol Phadke. Benefits of Leapfrogging to Superefficiency and Low Global Warming Potential Refrigerants in Room Air Conditioning. Lawrence Berkeley National Laboratory, 2015.
emissions…at end of life: Zhao, L., W. Zeng, and Z. Yuan. “Reduction of Potential Greenhouse Gas Emissions of Room Air-Conditioner Refrigerants: A Life Cycle Carbon Footprint Analysis.” Journal of Cleaner Production, 100 (2015): 262–268.
destruction…to reduce emissions: World Bank. Study on Financing the Destruction of Unwanted Ozone-Depleting Substances through the Voluntary Carbon Market. Washington, D.C.: The World Bank, 2010.
air-conditioning in…U.S. homes: HUD. American Housing Survey for the United States: 2009. Washington, D.C.: U.S. Department of Housing and Urban Development and U.S. Department of Commerce, 2011.
in urban Chinese households: Shah et al, Leapfrogging.
Correction: HFC substitutes are already on the market, including natural refrigerants such as propane and ammonia.
Correction: The Kigali accord ensures a step change is coming, and other practices focused on existing stocks could reduce emissions further.
Correction: HFCs are largely innocuous to the ozone layer, but they also are one of the most potent greenhouse gases known to humankind.
Revision: Our analysis includes emissions reductions that can be achieved through the management and destruction of refrigerants already in circulation. Over thirty years, containing 87 percent of refrigerants likely to be released could avoid emissions equivalent to 89.7 gigatons of carbon dioxide. Phasing out HFCs per the Kigali accord could avoid additional emissions equivalent to 25 to 78 gigatons of carbon dioxide (not included in the total shown here). The operational costs of refrigerant leak avoidance and destruction are high, resulting in a projected net cost of $903 billion by 2050.