Editing Montreal Protocol (section)

== Effect ==
[[File:Ozone cfc trends.png|thumb|250px|Ozone-depleting gas trends]]
Since the Montreal Protocol came into effect, the atmospheric concentrations of the most important chlorofluorocarbons and related chlorinated hydrocarbons have either leveled off or decreased.<ref>{{cite web|url=http://www.al.noaa.gov/assessments/2002/Q&As16.pdf|title=Has the Montreal Protocol been successful in reducing ozone-depleting gases in the atmosphere?|archive-url=https://web.archive.org/web/20060614130414/http://www.al.noaa.gov/assessments/2002/Q%26As16.pdf|archive-date=14 June 2006}}</ref> Halon concentrations have continued to increase, as the halons presently stored in fire extinguishers are released, but their rate of increase has slowed and their abundances are expected to begin to decline by about 2020. Also, the concentration of the HCFCs increased drastically at least partly because of many uses (e.g. used as solvents or refrigerating agents) CFCs were substituted with HCFCs. While there have been reports of attempts by individuals to circumvent the ban, e.g. by smuggling CFCs from undeveloped to developed nations, the overall level of compliance has been high. Statistical analysis from 2010 show a clear positive signal from the Montreal Protocol to the stratospheric ozone.<ref>{{cite journal|title=Evidence for the effectiveness of the Montreal Protocol to protect the ozone layer|journal=Atmospheric Chemistry and Physics |volume=10|issue=24|pages=12161–12171| date=22 December 2010 |doi=10.5194/acp-10-12161-2010|last1=Mäder|first1=J. A.|last2=Staehelin|first2=J.|last3=Peter|first3=T.|last4=Brunner|first4=D.|last5=Rieder|first5=H. E.|last6=Stahel|first6=W. A.|bibcode=2010ACP....1012161M |url=http://www.atmos-chem-phys.net/10/12161/2010/acp-10-12161-2010.html|doi-access=free|hdl=20.500.11850/27649|hdl-access=free}}</ref> In consequence, the Montreal Protocol has often been called the most successful international environmental agreement to date. In a 2001 report, NASA found the ozone thinning over Antarctica had remained the same thickness for the previous three years,<ref>{{cite web |url=http://www.gsfc.nasa.gov/topstory/20011016ozonelayer.html |title=Top Story – 2001 Antarctic Ozone Hole Similar in Size to Holes of Past Three Years, NOAA and NASA Report – October 16, 2001 |publisher=gsfc.nasa.gov |access-date=2010-09-16 |url-status=dead |archive-url=https://web.archive.org/web/20091231121817/http://www.gsfc.nasa.gov/topstory/20011016ozonelayer.html |archive-date=31 December 2009 }}</ref> however in 2003 the ozone hole grew to its second largest size.<ref>{{cite web |url=http://www.noaanews.noaa.gov/stories/s2099.htm |title=NOAA News Online (Story 2099) |publisher=noaanews.noaa.gov |access-date=2010-09-16 }}</ref> The most recent (2006) scientific evaluation of the effects of the Montreal Protocol states, "The Montreal Protocol is working: There is clear evidence of a decrease in the atmospheric burden of ozone-depleting substances and some early signs of stratospheric ozone recovery."<ref>Scientific Assessment of Ozone Depletion: 2006, http://www.esrl.noaa.gov/csd/assessments/2006/report.html {{Webarchive|url=https://web.archive.org/web/20100329095225/http://www.esrl.noaa.gov/csd/assessments/2006/report.html |date=29 March 2010 }}</ref> However, a more recent study seems to point to a relative increase in CFCs due to an unknown source.<ref>{{Cite web | url=https://www.sciencealert.com/it-looks-like-someone-is-producing-an-internationally-banned-ozone-destroying-chemical-once-again | title=A Mystery Source is Producing Banned Ozone-Destroying Chemicals, Shocking Scientists| date=16 May 2018}}</ref>

Reported in 1997, significant production of CFCs occurred in Russia for sale on the black market to the EU throughout the 90s. Related US production and consumption was enabled by fraudulent reporting due to poor enforcement mechanisms. Similar illegal markets for CFCs were detected in Taiwan, Korea, and Hong Kong.<ref>{{cite web|url=http://digitalcommons.law.uga.edu/cgi/viewcontent.cgi?article=1486&context=gjicl|title=The Black Market Trade in Chlorofluorocarbons: The Montreal Protocol Makes Banned Refrigerants a Hot Commodity|last=Landers|first=Fredrick Poole|access-date=4 September 2019|date=1997}}</ref>

The Montreal Protocol is also expected to have effects on human health. A 2015 report by the U.S. Environmental Protection Agency estimates that the protection of the ozone layer under the treaty will prevent over 280 million cases of skin cancer, 1.5 million skin cancer deaths, and 45 million cataracts in the United States.<ref>Updating Ozone Calculations and Emissions Profiles for Use in the Atmospheric and Health Effects Framework Model http://www.epa.gov/ozone/science/effects/AHEF_2015_Update_Report-FINAL_508.pdf {{Webarchive|url=https://web.archive.org/web/20150417175954/http://www.epa.gov/ozone/science/effects/AHEF_2015_Update_Report-FINAL_508.pdf |date=17 April 2015 }}</ref>

However, the hydrochlorofluorocarbons, or HCFCs, and hydrofluorocarbons, or HFCs, contribute to [[anthropogenic global warming]].<ref>Rishav Goyal, Matthew H England, Alex Sen Gupta, and Martin Jucker. "Reduction in surface climate change achieved by the 1987 Montreal Protocol" Environmental Research Letters 2019 14 (12) 124041; {{doi|10.1088/1748-9326/ab4874}}</ref> On a molecule-for-molecule basis, these compounds are up to 10,000 times more potent greenhouse gases than carbon dioxide. The Montreal Protocol currently calls for a complete phase-out of HCFCs by 2030, but does not place any restriction on HFCs. Since the CFCs themselves are equally powerful greenhouse gases, the mere substitution of HFCs for CFCs does not significantly increase the rate of anthropogenic climate change, but over time a steady increase in their use could increase the danger that human activity will change the climate.<ref>{{cite web |url=http://www.eia.doe.gov/oiaf/1605/ggrpt/other_gases.html |title=EIA – Emissions of the Greenhouse Gases in the United States 2005 |publisher=eia.doe.gov |access-date=2010-09-16 |url-status=dead |archive-url=https://web.archive.org/web/20110421074012/http://www.eia.doe.gov/oiaf/1605/ggrpt/other_gases.html |archive-date=21 April 2011 }}</ref>

Policy experts have advocated for increased efforts to link ozone protection efforts to climate protection efforts.<ref>Mario Molina, Durwood Zaelke, K. Madhava Sarma, Stephen O. Andersen, Veerabhadran Ramanathan, and Donald Kaniaru. "Reducing abrupt climate change risk using the Montreal Protocol and other regulatory actions to complement cuts in {{CO2}} emissions" PNAS 2009 106 (49) 20616-20621; {{doi|10.1073/pnas.0902568106}}</ref><ref>CS Norman, SJ DeCanio and L Fan. "The Montreal Protocol at 20: Ongoing opportunities for integration with climate protection." Global Environmental Change Volume 18, Issue 2, May 2008, Pages 330–340; {{doi|10.1016/j.gloenvcha.2008.03.003}}</ref><ref>UNEP press release, 2008 http://www.unep.org/Documents.Multilingual/Default.asp?DocumentID=593&ArticleID=6250&l=en&t=long {{Webarchive|url=https://web.archive.org/web/20101116011343/http://www.unep.org/Documents.Multilingual/Default.asp?DocumentID=593&ArticleID=6250&l=en&t=long |date=16 November 2010 }}</ref> Policy decisions in one arena affect the costs and effectiveness of environmental improvements in the other.

=== Regional detections of non-compliance ===

In 2018, scientists monitoring the atmosphere following the 2010 phaseout date reported evidence of continuing industrial production of CFC-11, likely in eastern Asia, with detrimental global effects on the ozone layer.<ref>{{cite web|url=https://www.npr.org/sections/thetwo-way/2018/05/17/611984631/banned-ozone-depleting-chemical-is-still-being-produced-somewhere-scientists-say|title=Banned Ozone-Depleting Chemical Is Still Being Produced Somewhere, Scientists Say|publisher=NPR|date=17 May 2018|access-date=17 May 2018}}</ref><ref>{{cite journal|title=An unexpected and persistent increase in global emissions of ozone-depleting CFC-11|author=Stephen A. Montzka |display-authors=etal |journal=Nature|volume=557|issue=7705|pages=413–417|date=17 May 2018|doi=10.1038/s41586-018-0106-2|pmid=29769666 |bibcode=2018Natur.557..413M |hdl=1983/fd5eaf00-34b1-4689-9f23-410a54182b61 |s2cid=21705434 |url=https://research-information.bristol.ac.uk/files/155735096/318003_2_merged_1521470846.pdf}}</ref> A monitoring study detected fresh atmospheric releases of carbon tetrachloride from China's [[Shandong]] province, beginning sometime after 2012, and accounting for a large part of emissions exceeding global estimates under the Montreal Protocol.<ref>{{cite journal|author=M. F. Lunt|display-authors=etal|title=Continued Emissions of the Ozone-Depleting Substance Carbon Tetrachloride From Eastern Asia|journal=Geophysical Research Letters|volume = 45|issue=20|pages=11,423–11,430|doi=10.1029/2018GL079500|date=28 September 2018|pmid=33005064|pmc=7526663|bibcode=2018GeoRL..4511423L |doi-access=free}}</ref>