Editing Chlorofluorocarbon (section)

==Impact as greenhouse gases==
[[Image:1979- Radiative forcing - climate change - global warming - EPA NOAA.svg |class=skin-invert-image|thumb|upright=1.5|The warming influence of greenhouse gases in the atmosphere has increased substantially in recent years. The rising presence of carbon dioxide from fossil fuel burning is the largest overall driver. The relatively smaller but significant warming impact from releases of the most abundantly produced CFCs (CFC11 and CFC12) will continue to persist for many further decades into the future.<ref name=NOAA_AGGI_2023>{{cite web |title=The NOAA Annual Greenhouse Gas Index (AGGI) |url=https://gml.noaa.gov/aggi/aggi.html |website=NOAA.gov |publisher=National Oceanic and Atmospheric Administration (NOAA) |archive-url=https://web.archive.org/web/20241005195609/https://gml.noaa.gov/aggi/aggi.html |archive-date=5 October 2024 |date=2024 |url-status=live }}</ref><ref>{{cite book |title=Intergovernmental Panel on Climate Change Fifth Assessment Report |chapter-url=http://www.ipcc.ch/pdf/assessment-report/ar5/wg1/WG1AR5_Chapter08_FINAL.pdf |chapter=Appendix 8.A |page=731 |access-date=2020-07-15 |archive-date=2017-10-13 |archive-url=https://web.archive.org/web/20171013100414/http://www.ipcc.ch/pdf/assessment-report/ar5/wg1/WG1AR5_Chapter08_FINAL.pdf |url-status=live }}</ref>]]
CFCs were phased out via the [[Montreal Protocol]] due to their part in [[ozone depletion]].

[[File:CFCs & Ozone.jpg|thumb|CFCs negatively affecting stratospheric ozone production]]

The atmospheric impacts of CFCs are not limited to their role as ozone-depleting chemicals. Infrared absorption bands prevent heat at that wavelength from escaping Earth's atmosphere. CFCs have their strongest absorption bands from C-F and C-Cl bonds in the spectral region of 7.8–15.3 [[μm]]<ref name="Rothman L.S. et 42 alia, 2009">{{cite journal |last1=Rothman |first1=L.S. |last2=Gordon |first2=I.E. |last3=Barbe |first3=A. |last4=Benner |first4=D.Chris |last5=Bernath |first5=P.F. |last6=Birk |first6=M. |last7=Boudon |first7=V. |last8=Brown |first8=L.R. |last9=Campargue |first9=A. |last10=Champion |first10=J.-P. |last11=Chance |first11=K. |last12=Coudert |first12=L.H. |last13=Dana |first13=V. |last14=Devi |first14=V.M. |last15=Fally |first15=S. |last16=Flaud |first16=J.-M. |last17=Gamache |first17=R.R. |last18=Goldman |first18=A. |last19=Jacquemart |first19=D. |last20=Kleiner |first20=I. |last21=Lacome |first21=N. |last22=Lafferty |first22=W.J. |last23=Mandin |first23=J.-Y. |last24=Massie |first24=S.T. |last25=Mikhailenko |first25=S.N. |last26=Miller |first26=C.E. |last27=Moazzen-Ahmadi |first27=N. |last28=Naumenko |first28=O.V. |last29=Nikitin |first29=A.V. |last30=Orphal |first30=J. |last31=Perevalov |first31=V.I. |last32=Perrin |first32=A. |last33=Predoi-Cross |first33=A. |last34=Rinsland |first34=C.P. |last35=Rotger |first35=M. |last36=Šimečková |first36=M. |last37=Smith |first37=M.A.H. |last38=Sung |first38=K. |last39=Tashkun |first39=S.A. |last40=Tennyson |first40=J. |last41=Toth |first41=R.A. |last42=Vandaele |first42=A.C. |last43=Vander Auwera |first43=J. |title=The HITRAN 2008 molecular spectroscopic database |journal=Journal of Quantitative Spectroscopy and Radiative Transfer |date=June 2009 |volume=110 |issue=9–10 |pages=533–572 |doi=10.1016/j.jqsrt.2009.02.013 |bibcode=2009JQSRT.110..533R |url=https://scholarworks.wm.edu/aspubs/1144 }}</ref>—referred to as the [[infrared window|"atmospheric window"]] due to the relative transparency of the atmosphere within this region.<ref>{{cite journal|last=Ramanathan|first=V|title=Greenhouse Effect Due to Chlorofluorocarbons: Climatic Implications|journal=Science |series=New Series|year=1975|volume=190|issue=4209|pages=50–52|jstor=1740877|doi=10.1126/science.190.4209.50 |bibcode=1975Sci...190...50R|s2cid=33736550}}</ref>

The strength of CFC absorption bands and the unique susceptibility of the atmosphere at wavelengths where CFCs (indeed all covalent fluorine compounds) absorb radiation<ref name="Identifying">{{cite journal |last1=Bera |first1=Partha P. |last2=Francisco |first2=Joseph S. |last3=Lee |first3=Timothy J. |title=Identifying the Molecular Origin of Global Warming |journal=The Journal of Physical Chemistry A |date=12 November 2009 |volume=113 |issue=45 |pages=12694–12699 |doi=10.1021/jp905097g |pmid=19694447 |bibcode=2009JPCA..11312694B |hdl=2060/20110023746 |hdl-access=free }}</ref> creates a "super" [[greenhouse effect]] from CFCs and other unreactive fluorine-containing gases such as [[perfluorocarbons]], [[hydrofluorocarbons|HFCs]], [[Hydrochlorofluorocarbon|HCFCs]], [[bromofluorocarbons]], {{chem2|SF6|link=Sulfur hexafluoride}}, and {{chem2|NF3|link=nitrogen trifluoride}}.<ref name="Ramanathan 2009 37–50">{{cite journal|last=Ramanathan|first=V|author2=Y. Feng|title=Air pollution, greenhouse gases and climate change: Global and regional perspectives|journal=Atmospheric Environment|year=2009|volume=43|issue=1|pages=37–50|doi=10.1016/j.atmosenv.2008.09.063|bibcode=2009AtmEn..43...37R}}</ref> This "atmospheric window" absorption is intensified by the low concentration of each individual CFC. Because {{CO2}} is close to saturation with high concentrations and few infrared absorption bands, the radiation budget and hence the greenhouse effect has low sensitivity to changes in {{CO2}} concentration;<ref>{{cite book |last1=Harnung |first1=Sven E. |last2=Johnson |first2=Matthew S. |title=Chemistry and the Environment |date=2012 |publisher=Cambridge University Press |isbn=978-1-107-02155-6 |page=365 }}</ref> the increase in temperature is roughly logarithmic.<ref>{{cite journal |last1=Roehl |first1=C. M. |last2=Boglu |first2=D. |last3=Brühl |first3=C. |last4=Moortgat |first4=G. K. |title=Infrared band intensities and global warming potentials of CF4, C2F6, C3F8, C4F10, C5F12, and C6F14 |journal=Geophysical Research Letters |date=April 1995 |volume=22 |issue=7 |pages=815–818 |doi=10.1029/95GL00488 }}</ref> Conversely, the low concentration of CFCs allow their effects to increase linearly with mass,<ref name="Ramanathan 2009 37–50"/> so that chlorofluorocarbons are [[greenhouse gas]]es with a much higher potential to enhance the greenhouse effect than {{CO2}}.

Groups are actively disposing of legacy CFCs to reduce their impact on the atmosphere.<ref>{{Cite web|url=https://www.nationalgeographic.com/environment/2019/04/disposing-old-cfcs-refrigerants-reduces-climate-change-greenhouse-gases-cheaply/|title=One overlooked way to fight climate change? Dispose of old CFCs.|date=2019-04-29|website=Environment|access-date=2019-04-30|archive-date=2019-04-29|archive-url=https://web.archive.org/web/20190429113314/https://www.nationalgeographic.com/environment/2019/04/disposing-old-cfcs-refrigerants-reduces-climate-change-greenhouse-gases-cheaply/|url-status=dead}}</ref>

According to [[NASA]] in 2018, the hole in the ozone layer has begun to recover as a result of CFC bans.<ref>{{cite web |url=https://www.nasa.gov/feature/goddard/2018/nasa-study-first-direct-proof-of-ozone-hole-recovery-due-to-chemicals-ban |author=Samson Reiny |title=NASA Study: First Direct Proof of Ozone Hole Recovery Due to Chemicals Ban |publisher=NASA |date=4 January 2018 |access-date=2 October 2019 |archive-date=24 September 2020 |archive-url=https://web.archive.org/web/20200924121730/https://www.nasa.gov/feature/goddard/2018/nasa-study-first-direct-proof-of-ozone-hole-recovery-due-to-chemicals-ban// |url-status=live }}</ref> However, research released in 2019 reported an alarming increase in CFCs, pointing to unregulated use in China.<ref>{{cite press release |title=Scientists discover the source of new CFC emissions |url=https://www.sciencedaily.com/releases/2019/05/190522141808.htm |work=ScienceDaily |publisher=University of Bristol |date=22 May 2019 }}</ref>