The risks of other greenhouse gases

June 27, 2017

"As the stability of the world's climate is increasingly at risk and governments grapple with the monumental task of cutting emissions, there is a group of little known but powerful greenhouse gases that, left unchecked, could ultimately undermine the best efforts to tackle the climate crisis. Fluorocarbons, or F- gases that, left unchecked, could ultimately undermine the best efforts to tackle the climate crisis. Fluorocarbons, or F-gases, are the quintessential greenhouse gases, since chemical engineers designed them to trap heat and to be stable and durable.


The Intergovernmental Panel on Climate Change calculated that the cumulative build-up of these gases in the atmosphere was responsible for at least 17% of global warming due to human activities in 2005. And the use of these chemicals worldwide is on the rise, with increased consumption in developing countries like China and India.


Several chemical cousins make up the F-gas family: chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), and sulfur hexafluoride (SF6). The major applications of these chemicals today are in refrigeration and air-conditioning (including in cars), which account for 80% of F-gas use. The chemicals are also used as solvents, as blowing agents in foams, as aerosols or propellants, and in fire extinguishers. The most commonly used F-gases at the moment are the HFC's, a class of powerful greenhouse gases whose consumption is rising exponentially. HFCs were developed by the chemical industry in response to the discovery of damage to Earth's ozone layer due to CFC use. But this development ignored the known global warming effects of the newer chemicals.


F-gases have incredibly strong global warming potential (GWP) relative to carbon dioxide (CO2) pound per pound, or gram for gram, because they were built to trap heat very effectively. GWP is calculated relative to carbon dioxide, which is assigned a GWP of 1. Global warming potential depends on the ability of a molecule to trap heat and its "atmospheric lifetime" -- how long the chemical stays in the atmosphere before it is broken down or is absorbed or settles out into the ocean, soil, or biosphere, for instance.


GWPs are generally averaged over 100 years, as a baseline for comparison to carbon dioxide. The most popular HFC in use today has an atmospheric lifetime of about 14 years and a 100 year GWP of 1,400 but a 20 year GWP of 3,830. This means that one pound of this HFC is the same as 3,830 pounds of CO2 in terms of global warming impact for 20 years after it is released into the atmosphere. Of course, there is one benefit to this high short-term GWP: phasing out HFCs has an immediate global warming benefit. Cutting HFC use slows global warming right now, when it is most needed.


The chemical industry argues that HFCs can be safely contained and prevented from leaking into the atmosphere, but so far containment has been an unqualified failure -- more than 50% of all HFCs produced to date have already found their way into the atmosphere.


Greenpeace estimates that HFCs will become an ever-increasing portion of the global warming pollution load exactly when scientists say greenhouse gases need to be reduced rapidly. The popular HFC-134a alone, which currently accounts for about 1 percent of greenhouse gases, is expected to account for 10 percent of emissions by 2050 -- and releases will still be on the rise. Growing HFC emissions could significantly hamper efforts to keep global temperatures from exceeding crucial tipping points in climate change that have been identified by scientists.


Fortunately, there are environmentally safe, efficient, technologically proven, and commercially available alternative to F-gases in almost all domestic and commercial applications




The chemical industry does not profit from any of these alternatives."


Janos Mate, Kert Davies, and David Kanter. "The Risks of Other Greenhouse Gases," State of the World 2009. 2209, 52-53.

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