Following the unanimous ratification of the 1987 Montreal Protocol—in response to concerns about the role of concentrations of chlorofluorocarbons (CFCs) in ozone layer-depletion in the stratosphere—a process was put into place to gradually phase out and replace CFC-13 and all the other CFCs.[8] Research in the 1980s said that these man-made CFC compound compounds had opened a hole in ozone layer in the upper atmosphere or stratosphere that protects life on earth from UV radiation.[5]
CFC-13's ozone depletion potential (ODP) is high— 1[9] (CCl3F = 1)—it is categorized as a Class I in the IPCC's list of ozone-depleting substances.[9] CFC-13's radiative efficiency is high which results in a high global warming potential (GWPs) of 13 900 GWP-100 yr that is "surpassed by very few other greenhouse gases."[3] It is categorized as a Class I in the list of ozone-depleting Substances.[9]: 2
Increase in atmospheric abundance of CFC-13 in 2010s
Starting in the 2010s, despite a global ban on the production of CFCs, five of these ozone-damaging emissions were on the rise.[5]
The atmospheric abundance of CFC-13 rose from 3.0 parts per trillion (ppt) in year 2010 to 3.3 ppt in year 2020 based on analysis of air samples gathered from sites around the world.[10]
Contrary to the Montreal Protocol, the atmospheric emissions of CFC-13 and four other chlorofluorocarbons (CFCs), increased between 2010 and 2020.[11]
As of 2023, the drivers behind the increase in CFC-13 and CFC-112a emissions were not certain.[11]
^Touloukian, Y.S., Liley, P.E., and Saxena, S.C. Thermophysical properties of matter - the TPRC data series. Volume 3. Thermal conductivity - nonmetallic liquids and gases. Data book. 1970.