Montreal Protocol - Wikipedia
Montreal Protocol - Wikipedia
The Montreal Protocol on Substances That Deplete the Ozone Layer[2] is an international treaty
designed to protect the ozone layer by phasing out the production of numerous substances that are
responsible for ozone depletion. It was agreed on 16 September 1987, and entered into force on 1
January 1989. Since then, it has undergone several amendments and adjustments, with revisions
agreed to in 1990 (London), 1992 (Copenhagen), 1995 (Vienna), 1997 (Montreal), 1999 (Beijing),
2007 (Montreal), 2016 (Kigali) and 2018 (Quito).[3][4][5] As a result of the international agreement, the
ozone hole over Antarctica is slowly recovering.[6] Climate projections indicate that the ozone layer
will return to 1980 levels between 2040 (across much of the world) and 2066 (over
Antarctica).[7][8][9][10] Due to its widespread adoption and implementation, it has been hailed as an
example of successful international co-operation. Former United Nations (UN) Secretary-General
Kofi Annan stated that "perhaps the single most successful international agreement to date has
been the Montreal Protocol".[11][12] In comparison, effective burden-sharing and solution proposals
mitigating regional conflicts of interest have been among the success factors for the ozone
depletion challenge, where global regulation based on the Kyoto Protocol has failed to do so.[13] In
this case of the ozone depletion challenge, there was global regulation already being installed
before a scientific consensus was established. Also, overall public opinion was convinced of
possible imminent risks.[14][15]
Location Montreal
2012 retrospective video by NASA on the Montreal
Protocol Effective 1 January 1989 if 11
states have ratified
The ozone treaty has been ratified by 198 parties
by then.
[16]
(197 states and the European Union), making it
the first universally ratified treaty in United Condition Ratification by 20
states
Nations history.[17]
Signatories 46
This truly universal treaty has also been
remarkable in the expedience of the policy- Ratifiers 198 (all United
For each group of ODSs, the treaty provides a timetable on which the production of those
substances must be reduced and eventually eliminated. This includes a 10-year phase-out for
developing countries[19] identified in Article 5 of the treaty.
Chlorofluorocarbons (CFCs) Phase-out Management Plan
shall accept a series of stepped limits on CFC use and production, including:
There was a faster phase-out of halon-1211, -2402, -1301, There was a slower phase-out (to zero by
2010) of other substances (halon 1211, 1301, 2402; CFCs 13, 111, 112, etc.) and some chemicals
were given individual attention (Carbon tetrachloride; 1,1,1-trichloroethane). The phasing-out of the
less damaging HCFCs only began in 1996 and will go on until a complete phasing-out is achieved by
2030.
There were a few exceptions for "essential uses" where no acceptable substitutes were initially
found (for example, metered dose inhalers commonly used to treat asthma and chronic obstructive
pulmonary disease were previously exempt) or Halon fire suppression systems used in submarines
and aircraft (but not in general industry).
The substances in Group I of Annex A are:
CFCl3 (CFC-11)
CF2Cl2 (CFC-12)
C2F3Cl3 (CFC-113)
C2F4Cl2(CFC-114)
C2F5Cl (CFC-115)
The provisions of the Protocol include the requirement that the Parties to the Protocol base their
future decisions on the current scientific, environmental, technical, and economic information that is
assessed through panels drawn from the worldwide expert communities. To provide that input to
the decision-making process, advances in understanding on these topics were assessed in 1989,
1991, 1994, 1998 and 2002 in a series of reports entitled Scientific assessment of ozone depletion,
by the Scientific Assessment Panel (SAP).[20]
In 1990 a Technology and Economic Assessment Panel was also established as the technology and
economics advisory body to the Montreal Protocol Parties.[21] The Technology and Economic
Assessment Panel (TEAP) provides, at the request of Parties, technical information related to the
alternative technologies that have been investigated and employed to make it possible to virtually
eliminate use of Ozone Depleting Substances (such as CFCs and Halons), that harm the ozone
layer. The TEAP is also tasked by the Parties every year to assess and evaluate various technical
issues including evaluating nominations for essential use exemptions for CFCs and halons, and
nominations for critical use exemptions for methyl bromide. TEAP's annual reports are a basis for
the Parties' informed decision-making.
Numerous reports have been published by various inter-governmental, governmental and non-
governmental organizations to catalogue and assess alternatives to the ozone depleting
substances, since the substances have been used in various technical sectors, like in refrigeration,
air conditioning, flexible and rigid foam, fire protection, aerospace, electronics, agriculture, and
laboratory measurements.[22][23][24]
Under the Montreal Protocol on Substances that Deplete the Ozone Layer, especially Executive
Committee (ExCom) 53/37 and ExCom 54/39, Parties to this Protocol agreed to set year 2013 as
the time to freeze the consumption and production of HCFCs for developing countries. For
developed countries, reduction of HCFC consumption and production began in 2004 and 2010,
respectively, with 100% reduction set for 2020. Developing countries agreed to start reducing its
consumption and production of HCFCs by 2015, with 100% reduction set for 2030.[25]
The HCFCs are transitional CFCs replacements, used as refrigerants, solvents, blowing agents for
plastic foam manufacture, and fire extinguishers. In terms of ozone depletion potential (ODP), in
comparison to CFCs that have ODP 0.6–1.0, these HCFCs have lower ODPs (0.01–0.5). In terms of
global warming potential (GWP), in comparison to CFCs that have GWP 4,680–10,720, HCFCs have
lower GWPs (76–2,270).
Hydrofluorocarbons (HFCs)
On 1 January 2019, the Kigali Amendment to the Montreal Protocol came into force.[26] Under the
Kigali Amendment countries promised to reduce the use of hydrofluorocarbons (HFCs) by more
than 80% over the next 30 years.[27] By 27 December 2018, 65 countries had ratified the
Amendment.[28] As of 31 October 2024, 160 states[29] and the European Union[30] have ratified the
Amendment.
Produced mostly in developed countries, hydrofluorocarbons (HFCs) replaced CFCs and HCFCs.
HFCs pose no harm to the ozone layer because, unlike CFCs and HCFCs, they do not contain
chlorine. They are, however, greenhouse gases, with a high global warming potential (GWP),
comparable to that of CFCs and HCFCs.[31][32] In 2009, a study calculated that a fast phasedown of
high-GWP HFCs could potentially prevent the equivalent of up to 8.8 Gt CO2-eq per year in emissions
by 2050.[33] A proposed phasedown of HFCs was hence projected to avoid up to 0.5C of warming by
2100 under the high-HFC growth scenario, and up to 0.35C under the low-HFC growth scenario.[34]
Recognizing the opportunity presented for fast and effective phasing down of HFCs through the
Montreal Protocol, starting in 2009 the Federated States of Micronesia proposed an amendment to
phase down high-GWP HFCs,[35] with the U.S., Canada, and Mexico following with a similar proposal
in 2010.[36]
After seven years of negotiations, in October 2016 at the 28th Meeting of the Parties to the Montreal
Protocol in Kigali, the Parties to the Montreal Protocol adopted the Kigali Amendment whereby the
Parties agreed to phase down HFCs under the Montreal Protocol.[37] The amendment to the
Montreal Protocol commits the signatory parties to reduce their HFC production and consumption
by at least 85 per cent from the annual average value in the period from 2011 to 2013. A group of
developing countries including China, Brazil and South Africa are mandated to reduce their HFC use
by 85 per cent of their average value in 2020-22 by the year 2045. India and some other developing
countries – Iran, Iraq, Pakistan, and some oil economies like Saudi Arabia and Kuwait – will cut
down their HFCs by 85 per cent of their values in 2024-26 by the year 2047.
On 17 November 2017, ahead of the 29th Meeting of the Parties of the Montreal Protocol, Sweden
became the 20th Party to ratify the Kigali Amendment, pushing the Amendment over its ratification
threshold ensuring that the Amendment would enter into force 1 January 2019.[38]
History
In the 1970s, the chemists Frank Sherwood Rowland and Mario Molina, who were then at the
University of California, Irvine, began studying the impacts of CFCs in the Earth's atmosphere. They
discovered that CFC molecules were stable enough to remain in the atmosphere until they got up
into the middle of the stratosphere where they would finally (after an average of 50–100 years for
two common CFCs) be broken down by ultraviolet radiation releasing a chlorine atom. Rowland and
Molina then proposed that these chlorine atoms might be expected to cause the breakdown of large
amounts of ozone (O3) in the stratosphere. Their argument was based upon an analogy to
contemporary work by Paul J. Crutzen and Harold Johnston, which had shown that nitric oxide (NO)
could catalyze the destruction of ozone. (Several other scientists, including Ralph Cicerone, Richard
Stolarski, Michael McElroy, and Steven Wofsy had independently proposed that chlorine could
catalyze ozone loss, but none had realized that CFCs were a potentially large source of chlorine.)
Crutzen, Molina and Rowland were awarded the 1995 Nobel Prize for Chemistry for their work on
this problem.
The environmental consequence of this discovery was that, since stratospheric ozone absorbs
most of the ultraviolet-B (UV-B) radiation reaching the surface of the planet, depletion of the ozone
layer by CFCs would lead to an increase in UV-B radiation at the surface, resulting in an increase in
skin cancer and other impacts such as damage to crops and to marine phytoplankton.
The Rowland-Molina hypothesis was strongly disputed by representatives of the aerosol and
halocarbon industries. The chair of the board of DuPont was quoted as saying that ozone depletion
theory is "a science fiction tale...a load of rubbish...utter nonsense". Robert Abplanalp, the president
of Precision Valve Corporation (and inventor of the first practical aerosol spray can valve), wrote to
the Chancellor of UC Irvine to complain about Rowland's public statements (Roan, p. 56.)
After publishing their pivotal paper in June 1974, Rowland and Molina testified at a hearing before
the U.S. House of Representatives in December 1974. As a result, significant funding was made
available to study various aspects of the problem and to confirm the initial findings. In 1976, the U.S.
National Academy of Sciences (NAS) released a report that confirmed the scientific credibility of the
ozone depletion hypothesis.[39] NAS continued to publish assessments of related science for the
next decade.
Then, in 1985, British Antarctic Survey scientists Joe Farman, Brian Gardiner and Jon Shanklin
published results of abnormally low ozone concentrations above Halley Bay near the South Pole.
They speculated that this was connected to increased levels of CFCs in the atmosphere. It took
several other attempts to establish the Antarctic losses as real and significant, especially after
NASA had retrieved matching data from its satellite recordings. This unforeseen phenomenon in the
Antarctic, as well as NASA's scientific images of the ozone hole played an important role in the
Montreal Protocol negotiations.[41] The impact of these studies, the metaphor 'ozone hole', and the
colorful visual representation in a time lapse animation proved shocking enough for negotiators in
Montreal, Canada to take the issue seriously.[42]
Also in 1985, 20 nations, including most of the major CFC producers, signed the Vienna Convention,
which established a framework for negotiating international regulations on ozone-depleting
substances.[43] After the discovery of the ozone hole by SAGE 2 it only took 18 months to reach a
binding agreement in Montreal, Canada. Mostafa Kamal Tolba, the head of the UNEP at the time,
was considered the "father of the Montreal Protocol" for his role in bringing the nations together for
an agreement.[44]
In 1986, an assessment spearheaded by NASA and sponsored by the United Nationals Environment
Program, the World Meteorological Organization, and various other organizations concluded that
continued CFC emissions at the 1980 rate would "reduce global average ozone by about 9 percent
by the latter half of the century." Based on these figures, the U.S. Environmental Protection Agency
estimated that in the United States alone there could be "over 150 million new cases of skin cancer
among people currently alive and born by the year 2075, resulting in over 3 million deaths."[40]
The CFC industry continued pushing back against regulation as late as 1986, when the Alliance for
Responsible CFC Policy (an association representing the CFC industry founded by DuPont) was still
arguing that the science was too uncertain to justify any action. In 1987, DuPont testified before the
US Congress that "We believe there is no imminent crisis that demands unilateral regulation."[45] And
even in March 1988, Du Pont Chair Richard E. Heckert would write in a letter to the United States
Senate, "we will not produce a product unless it can be made, used, handled and disposed of safely
and consistent with appropriate safety, health and environmental quality criteria. At the moment,
scientific evidence does not point to the need for dramatic CFC emission reductions. There is no
available measure of the contribution of CFCs to any observed ozone change..."[46]
In an unexpected policy change, however, the Alliance for Responsible CFC Policy issued a
statement in 1986 declaring that "large future increases...in CFCs...would be unacceptable to future
generations," and that it would be "inconsistent with [industry] goals...to ignore the potential for risk
to future generations." Three months before the protocol negotiations began, U.S. industry
announced its support for new international controls on CFCs.[40]
Multilateral Fund
The main objective of the Multilateral Fund for the Implementation of the Montreal Protocol is to
assist developing country parties to the Montreal Protocol whose annual per capita consumption
and production of ozone depleting substances (ODS) is less than 0.3 kg to comply with the control
measures of the Protocol. Currently, 147 of the 196 Parties to the Montreal Protocol meet these
criteria (they are referred to as Article 5 countries).
It embodies the principle agreed at the United Nations Conference on Environment and
Development in 1992 that countries have a common but differentiated responsibility to protect and
manage the global commons.
World Bank.
Up to 20 percent of the contributions of contributing parties can also be delivered through their
bilateral agencies in the form of eligible projects and activities.
The fund is replenished on a three-year basis by the donors. Pledges amount to US$3.1 billion over
the period 1991 to 2005. Funds are used, for example, to finance the conversion of existing
manufacturing processes, train personnel, pay royalties and patent rights on new technologies, and
establish national ozone offices.
Parties
As of October 2022, all Member States of the United Nations, the Cook Islands, Niue, the Holy See,
the State of Palestine as well as the European Union have ratified the original Montreal Protocol
(see external link below),[48] with the State of Palestine being the last party to ratify the agreement,
bringing the total to 198. 197 of those parties (with the exception of the State of Palestine) have
also ratified the London, Copenhagen, Montreal, and Beijing amendments.[16]
Effect
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.[49] 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.[50] 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,[51] however in 2003 the ozone hole grew to its second largest size.[52] 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."[53] However, a
more recent study seems to point to a relative increase in CFCs due to an unknown source.[54]
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.[55]
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.[56]
Policy experts have advocated for increased efforts to link ozone protection efforts to climate
protection efforts.[59][60][61] Policy decisions in one arena affect the costs and effectiveness of
environmental improvements in the other.
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.[62][63] 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.[64]
The year 2012 marked the 25th anniversary of the signing of the Montreal Protocol. Accordingly, the
Montreal Protocol community organized a range of celebrations at the national, regional and
international levels to publicize its considerable success to date and to consider the work ahead for
the future.[65] Among its accomplishments are:
The Montreal Protocol was the first international treaty to address a global environmental
regulatory challenge;
the first to embrace the "precautionary principle" in its design for science-based policymaking;
the first treaty where independent experts on atmospheric science, environmental impacts,
chemical technology, and economics, reported directly to parties, without edit or censorship,
functioning under norms of professionalism, peer review, and respect;
the first to provide for national differences in responsibility and financial capacity to respond by
establishing a multilateral fund for technology transfer; the first MEA with stringent reporting,
trade, and binding chemical phase-out obligations for both developed and developing countries;
and,
the first treaty with a financial mechanism managed democratically by an executive board with
equal representation by developed and developing countries.[66]
Within 25 years of signing, parties to the MP celebrate significant milestones. Significantly, the
world has phased-out 98% of the Ozone-Depleting Substances (ODS) contained in nearly 100
hazardous chemicals worldwide; every country is in compliance with stringent obligations; and, the
MP has achieved the status of the first global regime with universal ratification; even the newest
member state, South Sudan, ratified in 2013. UNEP received accolades for achieving global
consensus that "demonstrates the world’s commitment to ozone protection, and more broadly, to
global environmental protection".[67]
See also
International Day for the Preservation of the Ozone Layer World portal
Paris Agreement
R-134a
Section 608
Plastic bans
Notes
1. The full terms of the Montreal Protocol are available from the United Nations Environment
Programme (UNEP) Ozone Secretariat (http://ozone.unep.org/Publications/MP_Handbook/Sec
tion_1.1_The_Montreal_Protocol/) Archived (https://web.archive.org/web/20080703062032/
http://ozone.unep.org/Publications/MP_Handbook/Section_1.1_The_Montreal_Protocol/) 3
July 2008 at the Wayback Machine
References
2. Staff writer (2024). "Montreal Protocol on Substances that Deplete the Ozone Layer" (https://ui
a.org/s/or/en/1100031640) . UIA Global Civil Society Database. uia.org. Brussels, Belgium:
Union of International Associations. Yearbook of International Organizations Online. Retrieved
17 January 2025.
3. Hub, IISD's SDG Knowledge. "Kigali Amendment Enters into Force, Bringing Promise of
Reduced Global Warming | News | SDG Knowledge Hub | IISD" (https://sdg.iisd.org:443/news/k
igali-amendment-enters-into-force-bringing-promise-of-reduced-global-warming/) . Retrieved
7 March 2019.
4. McGrath, Matt (15 October 2016). "Deal reached on HFC greenhouse gases" (https://www.bbc.
com/news/science-environment-37665529) . BBC.
8. Susan Solomon; Anne R. Douglass; Paul A. Newman (July 2014). "The Antarctic ozone hole: An
update" (https://doi.org/10.1063%2FPT.3.2449) . Physics Today. 67 (7): 42–48.
Bibcode:2014PhT....67g..42D (https://ui.adsabs.harvard.edu/abs/2014PhT....67g..42D) .
doi:10.1063/PT.3.2449 (https://doi.org/10.1063%2FPT.3.2449) . hdl:1721.1/99159 (https://hd
l.handle.net/1721.1%2F99159) .
9. Canada, Environment and Climate Change (20 February 2015). "Ozone layer depletion:
Montreal Protocol" (https://www.canada.ca/en/environment-climate-change/corporate/interna
tional-affairs/partnerships-organizations/ozone-layer-depletion-montreal-convention.html) .
aem. Retrieved 22 April 2020.
10. World Meteorological Organization (WMO) (2022). "Scientific Assessment of Ozone Depletion:
2022" (https://ozone.unep.org/system/files/documents/Scientific-Assessment-of-Ozone-Deple
tion-2022-Executive-Summary.pdf) (PDF). GAW Report (278). Geneva: WMO: i.
11. "The Ozone Hole – The Montreal Protocol on Substances that Deplete the Ozone Layer" (http
s://archive.today/20120912223944/http://www.theozonehole.com/montreal.htm) .
Theozonehole.com. 16 September 1987. Archived from the original (http://www.theozonehole.
com/montreal.htm) on 12 September 2012. Retrieved 17 August 2007.
12. "Background for International Day for the Preservation of the Ozone Layer – 16 September" (htt
ps://www.un.org/en/events/ozoneday/background.shtml) . un.org. Retrieved 28 May 2017.
17. "UNEP press release: 'South Sudan Joins Montreal Protocol and Commits to Phasing Out
Ozone-Damaging Substances' " (https://web.archive.org/web/20160304093536/http://www.un
ep.org/Documents.Multilingual/Default.asp?DocumentID=2666&ArticleID=9010&l=en) .
Unep.org. Archived from the original (http://www.unep.org/Documents.Multilingual/Default.as
p?DocumentID=2666&ArticleID=9010&l=en) on 4 March 2016. Retrieved 11 July 2012.
18. "Class I Ozone-depleting Substances | Science | Ozone Layer Protection | US EPA" (https://web.
archive.org/web/20080511181352/http://www.epa.gov/ozone/ods.html) . Epa.gov. 15
February 2013. Archived from the original (http://www.epa.gov/ozone/ods.html) on 11 May
2008. Retrieved 28 October 2006.
19. An Interview with Lee Thomas, EPA’s 6th Administrator. Video (http://www.epaalumni.org/histo
ry/video/interview.cfm?id=28) Archived (https://web.archive.org/web/20200922211841/http
s://www.epaalumni.org/history/video/interview.cfm?id=28) 22 September 2020 at the
Wayback Machine, Transcript (https://www.epaalumni.org/userdata/pdf/60740780F5ACB3D5.
pdf#page=1) Archived (https://web.archive.org/web/20190412070306/https://www.epaalum
ni.org/userdata/pdf/60740780F5ACB3D5.pdf#page=1) 12 April 2019 at the Wayback
Machine (see p15). 19 April 2012.
23. The Technical and Economic Feasibility of Replacing Methyl Bromide in Developing Countries.
Friends of the Earth, Washington, 173 pp, 1996
24. Guidance on the DOE Facility Phaseout of Ozone-Depleting Substances. 1995. "Guidance on
the DOE Facility Phaseout of Ozone-Depleting Substances" (https://web.archive.org/web/2008
0227052411/http://homer.ornl.gov/nuclearsafety/nsea/oepa/guidance/ozone/phaseout.pd
f) (PDF). Archived from the original (http://homer.ornl.gov/nuclearsafety/nsea/oepa/guidanc
e/ozone/phaseout.pdf) (PDF) on 27 February 2008. Retrieved 3 December 2007.
25. "The Montreal Protocol on Substances that Deplete the Ozone Layer" (https://web.archive.org/
web/20181014170949/http://ozone.unep.org/montreal-protocol-substances-deplete-ozone-lay
er/32506) . United Nations Environment Programme. Archived from the original (https://ozon
e.unep.org/montreal-protocol-substances-deplete-ozone-layer/32506) on 14 October 2018.
Retrieved 16 November 2018.
27. Msuya, Joyce. "Kigali Amendment heralds new dawn for climate change action" (https://www.s
tandardmedia.co.ke/article/2001308090/kigali-amendment-heralds-new-dawn-for-climate-cha
nge-action) . The Standard. Retrieved 22 April 2020.
28. Msuya, Joyce (2 January 2019). "Kigali Amendment heralds new dawn for climate change
action" (https://www.standardmedia.co.ke/article/2001308090/kigali-amendment-heralds-new
-dawn-for-climate-change-action) . The Standard. Retrieved 2 January 2019.
29. "Amendment to the Montreal Protocol on Substances that Deplete the Ozone Layer" (https://tre
aties.un.org/Pages/ViewDetails.aspx?src=IND&mtdsg_no=XXVII-2-f&chapter=27) . United
Nations Treaty Collective. Retrieved 31 October 2024.
30. "Kigali Amendment hits milestone 100th ratification, boosting climate action" (http://www.une
p.org/news-and-stories/press-release/kigali-amendment-hits-milestone-100th-ratification-boos
ting-climate) . United Nations Environment Programme. 14 July 2020. Archived (https://web.a
rchive.org/web/20221103062228/http://www.unep.org/news-and-stories/press-release/kigali-
amendment-hits-milestone-100th-ratification-boosting-climate) from the original on 3
November 2022. Retrieved 20 September 2022.
32. Canada, Environment and Climate Change (2 December 2008). "Ozone-depleting substances"
(https://www.canada.ca/en/environment-climate-change/services/air-pollution/issues/ozone-l
ayer/depletion-impacts/substances.html#fn2) . aem. Retrieved 22 April 2020.
33. Velders GJ, Fahey DW, Daniel JS, McFarland M, Andersen SO (July 2009). "The large
contribution of projected HFC emissions to future climate forcing" (https://www.ncbi.nlm.nih.g
ov/pmc/articles/PMC2700150) . Proceedings of the National Academy of Sciences of the
United States of America. 106 (27): 10949–54. Bibcode:2009PNAS..10610949V (https://ui.ads
abs.harvard.edu/abs/2009PNAS..10610949V) . doi:10.1073/pnas.0902817106 (https://doi.or
g/10.1073%2Fpnas.0902817106) . PMC 2700150 (https://www.ncbi.nlm.nih.gov/pmc/article
s/PMC2700150) . PMID 19549868 (https://pubmed.ncbi.nlm.nih.gov/19549868) .
34. Xu, Yangyang; Zaelke, Durwood; Velders, Guus J. M.; Ramanathan, V (1 June 2013). "The role of
HFCs in mitigating 21st century climate change" (https://www.researchgate.net/publication/26
0830030) . Atmospheric Chemistry & Physics. 13 (12): 6083. Bibcode:2013ACP....13.6083X (h
ttps://ui.adsabs.harvard.edu/abs/2013ACP....13.6083X) . doi:10.5194/acp-13-6083-2013 (htt
ps://doi.org/10.5194%2Facp-13-6083-2013) .
39. National Academy of Sciences (1976). Halocarbons, effects on stratospheric ozone (https://na
p.nationalacademies.org/read/19978) . Washington, DC. ISBN 0-309-02532-X.
41. Grevsmühl, Sebastian V.; Briday, Régis (2023). "Satellite images as tools of visual diplomacy:
NASA's ozone hole visualizations and the Montreal Protocol negotiations" (https://doi.org/10.1
017%2FS000708742300002X) . The British Journal for the History of Science. 56 (2): 247–
267. doi:10.1017/S000708742300002X (https://doi.org/10.1017%2FS000708742300002X) .
PMID 36776108 (https://pubmed.ncbi.nlm.nih.gov/36776108) . S2CID 256825183 (https://ap
i.semanticscholar.org/CorpusID:256825183) .
43. "The Vienna Convention for the Protection of the Ozone Layer | Ozone Secretariat" (https://ozo
ne.unep.org/treaties/vienna-convention) . ozone.unep.org. Retrieved 22 April 2020.
44. "Dr. Mostafa Tolba, Father of Montreal Protocol, Dies at 93 - IGSD" (https://www.igsd.org/dr-mo
stafa-tolba-father-of-montreal-protocol-dies-at-93/) . 29 March 2016. Retrieved 28 September
2023.
45. Doyle, Jack (October 1991). "DuPont's Disgraceful Deeds: The Environmental Record of E.I.
DuPont de Nemour" (http://www.multinationalmonitor.org/hyper/issues/1991/10/doyle.htm
l) . The Multinational Monitor. Vol. 12, no. 10. Retrieved 8 September 2014.
46. "Du Pont: A Case Study in the 3D Corporate Strategy" (https://web.archive.org/web/201204060
93303/http://archive.greenpeace.org/ozone/greenfreeze/moral97/6dupont.html) .
Greenpeace. 1997. Archived from the original (http://archive.greenpeace.org/ozone/greenfreez
e/moral97/6dupont.html) on 6 April 2012. Retrieved 8 September 2014.
48. "2. a Montreal Protocol on Substances that Deplete the Ozone Layer Montreal, 16 September
1987" (https://treaties.un.org/pages/ViewDetails.aspx?src=TREATY&mtdsg_no=XXVII-2-a&cha
pter=27&clang=_en) . United Nations. Retrieved 2 October 2022.
49. "Has the Montreal Protocol been successful in reducing ozone-depleting gases in the
atmosphere?" (https://web.archive.org/web/20060614130414/http://www.al.noaa.gov/assess
ments/2002/Q%26As16.pdf) (PDF). Archived from the original (http://www.al.noaa.gov/asse
ssments/2002/Q&As16.pdf) (PDF) on 14 June 2006.
50. Mäder, J. A.; Staehelin, J.; Peter, T.; Brunner, D.; Rieder, H. E.; Stahel, W. A. (22 December 2010).
"Evidence for the effectiveness of the Montreal Protocol to protect the ozone layer" (https://ww
w.atmos-chem-phys.net/10/12161/2010/acp-10-12161-2010.html) . Atmospheric Chemistry
and Physics. 10 (24): 12161–12171. Bibcode:2010ACP....1012161M (https://ui.adsabs.harvar
d.edu/abs/2010ACP....1012161M) . doi:10.5194/acp-10-12161-2010 (https://doi.org/10.519
4%2Facp-10-12161-2010) . hdl:20.500.11850/27649 (https://hdl.handle.net/20.500.11850%2
F27649) .
51. "Top Story – 2001 Antarctic Ozone Hole Similar in Size to Holes of Past Three Years, NOAA and
NASA Report – October 16, 2001" (https://web.archive.org/web/20091231121817/http://www.
gsfc.nasa.gov/topstory/20011016ozonelayer.html) . gsfc.nasa.gov. Archived from the original
(https://www.gsfc.nasa.gov/topstory/20011016ozonelayer.html) on 31 December 2009.
Retrieved 16 September 2010.
55. Landers, Fredrick Poole (1997). "The Black Market Trade in Chlorofluorocarbons: The Montreal
Protocol Makes Banned Refrigerants a Hot Commodity" (http://digitalcommons.law.uga.edu/c
gi/viewcontent.cgi?article=1486&context=gjicl) . Retrieved 4 September 2019.
56. 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
Archived (https://web.archive.org/web/20150417175954/http://www.epa.gov/ozone/science/
effects/AHEF_2015_Update_Report-FINAL_508.pdf) 17 April 2015 at the Wayback Machine
57. 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 (https://doi.org/10.1088%2F1748-9326%2Fab
4874)
58. "EIA – Emissions of the Greenhouse Gases in the United States 2005" (https://web.archive.org/
web/20110421074012/http://www.eia.doe.gov/oiaf/1605/ggrpt/other_gases.html) .
eia.doe.gov. Archived from the original (http://www.eia.doe.gov/oiaf/1605/ggrpt/other_gases.
html) on 21 April 2011. Retrieved 16 September 2010.
59. 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 (https://doi.org/10.1073%2Fpnas.09025681
06)
60. 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 (https://doi.org/10.1016%2Fj.gloe
nvcha.2008.03.003)
63. Stephen A. Montzka; et al. (17 May 2018). "An unexpected and persistent increase in global
emissions of ozone-depleting CFC-11" (https://research-information.bristol.ac.uk/files/155735
096/318003_2_merged_1521470846.pdf) (PDF). Nature. 557 (7705): 413–417.
Bibcode:2018Natur.557..413M (https://ui.adsabs.harvard.edu/abs/2018Natur.557..413M) .
doi:10.1038/s41586-018-0106-2 (https://doi.org/10.1038%2Fs41586-018-0106-2) .
hdl:1983/fd5eaf00-34b1-4689-9f23-410a54182b61 (https://hdl.handle.net/1983%2Ffd5eaf00-
34b1-4689-9f23-410a54182b61) . PMID 29769666 (https://pubmed.ncbi.nlm.nih.gov/297696
66) . S2CID 21705434 (https://api.semanticscholar.org/CorpusID:21705434) .
64. M. F. Lunt; et al. (28 September 2018). "Continued Emissions of the Ozone-Depleting
Substance Carbon Tetrachloride From Eastern Asia" (https://www.ncbi.nlm.nih.gov/pmc/article
s/PMC7526663) . Geophysical Research Letters. 45 (20): 11, 423–11, 430.
Bibcode:2018GeoRL..4511423L (https://ui.adsabs.harvard.edu/abs/2018GeoRL..4511423L) .
doi:10.1029/2018GL079500 (https://doi.org/10.1029%2F2018GL079500) . PMC 7526663 (htt
ps://www.ncbi.nlm.nih.gov/pmc/articles/PMC7526663) . PMID 33005064 (https://pubmed.nc
bi.nlm.nih.gov/33005064) .
66. Canan, Penelope and Nancy Reichman (2013), "The Montreal Protocol" in J. Britt Holbrook
(Chief Editor) Ethics, Science, Technology, and Engineering: An International Resource, 2nd
Edition, Thompson Learning.
67. ozone.unep.org
Andersen, S. O. and K. M. Sarma. (2002). Protecting the Ozone Layer: the United Nations History,
Earthscan Press. London.
Andersen, S. O., K. M. Sarma and K. N. Taddonio. (2007). Technology Transfer for the Ozone
Layer: Lessons for Climate Change. Earthscan Press, London.
Benedick, Richard E. (1991). Ozone Diplomacy. Harvard University Press. ISBN 0-674-65001-8
(Ambassador Benedick was the Chief U.S. Negotiator at the meetings that resulted in the
Protocol.)
Brodeur, Paul (1986). "Annals of Chemistry: In the Face of Doubt." The New Yorker, 9 June 1986,
pp. 70–87.
Chasek, Pam, David Downie, and J.W. Brown (2013). Global Environmental Politics, 6th ed.,
Boulder: Westview Press.
Dotto, Lydia and Harold Schiff (1978). The Ozone War. New York: Doubleday (publisher).
Downie, David (1993). "Comparative Public Policy of Ozone Layer Protection." Political Science
(NZ) 45(2): (December): 186–197.
Downie, David (1995). "Road Map or False Trail: Evaluating the Precedence of the Ozone Regime
as Model and Strategy for Global Climate Change," International Environmental Affairs, 7(4):321–
345 (Fall 1995).
Downie, David (1999). "The Power to Destroy: Understanding Stratospheric Ozone Politics as a
Common Pool Resource Problem", in J. Barkin and G. Shambaugh (eds.) Anarchy and the
Environment: The International Relations of Common Pool Resources. Albany: State University of
New York Press.
David L. Downie (2012). "The Vienna Convention, Montreal Protocol and Global Policy to Protect
Stratospheric Ozone", in P. Wexler et al. (eds.) Chemicals, Environment, Health: A Global
Management Perspective. Oxford: Taylor & Francis.
Downie, David (2013) "Stratospheric Ozone Depletion." The Routledge Handbook of Global
Environmental Politics. New York: Routledge.
Farman, J.C., B.G. Gardiner, and J.D. Shanklin (1985). "Large Losses of Total Ozone in Antarctica
Reveal Seasonal ClOx/NOx Interaction." Nature 315: 207–210, 16 May 1985.
Gareau, Brian J. (2013). From Precaution to Profit: Contemporary Challenges to Environmental
Protection in the Montreal Protocol. New Haven & London: Yale University Press. ISBN 978-
0300175264
Litfin, Karen T. (1994). Ozone Discourses. Columbia University Press. ISBN 0-231-08137-5
Molina, Mario and F. Sherwood Rowland (1974). "Stratospheric Sink for Chlorofluoromethanes:
Chlorine Atomic Catalyzed Destruction of Ozone." Nature 249: 810–812, 28 June 1974.
Morissette, P.M. (1989). "The evolution of policy responses to stratospheric ozone depletion."
Natural Resources Journal 29: 793–820.
Parson, Edward (2003). Protecting the Ozone Layer: Science and Strategy. Oxford: Oxford
University Press.
Roan, Sharon (1989). Ozone Crisis: The 15-Year Evolution of a Sudden Global Emergency. New
York, John Wiley and Sons
United Nations Environmental Programme. (2012). The Montreal Protocol and The Green
Economy (https://web.archive.org/web/20151121215638/http://new.unep.org/ozonaction/Portal
s/105/documents/publications/green-economy-report.pdf) .
Velders, G. J. M., D. W. Fahey, J. S Daniel, M. McFarland, and S. O. Andersen. (2009). The Large
Contribution of Projected HFC Emissions to Future Climate Forcing (http://www.pnas.org/conten
t/early/2009/06/19/0902817106.full.pdf+html?with-ds=yes) . Proc. of the Natl. Acad. Of Sci.,
106(27), doi:10.1073/pnas.0902817106 (https://doi.org/10.1073%2Fpnas.0902817106) .
[1] (https://web.archive.org/web/20150919203230/http://www.ncseonline.org/cfc-ozone-puzzle-
environmental-science-global-arena-2000-chafee-memorial-lecture) by F.Sherwood Rowland and
Mario J.Molina
Has the Montreal Protocol been successful in reducing ozone-depleting gases in the atmosphere?
(http://www.esrl.noaa.gov/csd/assessments/ozone/2002/qandas16.pdf) (NOAA Aeronomy
Lab)
Doomsday Déjà vu: Ozone Depletion's Lessons for Global Warming (http://www.cei.org/gencon/0
25,01184.cfm) Archived (https://web.archive.org/web/20090910000608/http://cei.org/gencon/
025,01184.cfm) 10 September 2009 at the Wayback Machine by Ben Lieberman (https://web.ar
chive.org/web/20051213041936/http://www.cei.org/dyn/view_Expert.cfm?Expert=6)
Introductory note by Edith Brown Weiss, procedural history note and audiovisual material (http://le
gal.un.org/avl/ha/vcpol/vcpol.html) on the Montreal Protocol on Substances that Deplete the
Ozone Layer in the Historic Archives of the United Nations Audiovisual Library of International
Law (http://legal.un.org/avl/historicarchives.html)
Green Cooling Initiative (http://www.green-cooling-initiative.org/)