Montreal Protocol

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Montreal Protocol on Substances that Deplete the Ozone Layer
Location Montreal
Effective 1 January 1989 if 11 states have ratified by then.
Condition ratification by 20 states
Signatories 46
Ratifiers 197 (all United Nations members, as well as Niue, the Cook Islands, the Holy See and the European Union)
Depositary Secretary-General of the United Nations
Languages Arabic, Chinese, English, French, Russian, and Spanish.
Retrospective video on the Montreal Protocol and the collaboration between policy-makers, scientists, and industry leaders to regulate CFCs.
The largest Antarctic ozone hole recorded as of September 2006

The Montreal Protocol on Substances that Deplete the Ozone Layer (a protocol to the Vienna Convention for the Protection of the Ozone Layer) 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 01 January 1989, followed by a first meeting in Helsinki, May 1989. Since then, it has undergone eight revisions, in 1990 (London), 1991 (Nairobi), 1992 (Copenhagen), 1993 (Bangkok), 1995 (Vienna), 1997 (Montreal), 1998 (Australia), 1999 (Beijing) and 2016 (Kigali, adopted, but not in force).[1][2] As a result of the international agreement, the ozone hole in Antarctica is slowly recovering.[3] Climate projections indicate that the ozone layer will return to 1980 levels between 2050 and 2070.[4][5] Due to its widespread adoption and implementation it has been hailed as an example of exceptional international co-operation, with Kofi Annan quoted as saying that "perhaps the single most successful international agreement to date has been the Montreal Protocol".[6][7] 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.[8] 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.[9][10]

The two ozone treaties have been ratified by 197 parties, which includes 196 states and the European Union,[11] making them the first universally ratified treaties in United Nations history.[12]

These truly universal treaties have also been remarkable in the expedience of the policy-making process at the global scale, where only 14 years lapsed between a basic scientific research discovery (1973) and the international agreement signed (1985 & 1987).

Terms and purposes[edit]

The treaty[13] is structured around several groups of halogenated hydrocarbons that deplete stratospheric ozone. All of the ozone depleting substances controlled by the Montreal Protocol contain either chlorine or bromine (substances containing only fluorine do not harm the ozone layer). Some ozone-depleting substances (ODSs) are not yet controlled by the Montreal Protocol, including nitrous oxide (N2O) For a table of ozone-depleting substances controlled by the Montreal Protocol see:[14]

For each group of ODSs, the treaty provides a timetable on which the production of those substances must be shot out and eventually eliminated.

Chlorofluorocarbons (CFCs) Phase-out Management Plan[edit]

The stated purpose of the treaty is that the signatory states

"Recognizing that worldwide emissions of certain substances can significantly deplete and otherwise modify the ozone layer in a manner that is likely to result in adverse effects on human health and the environment. Determined to protect the ozone layer by taking precautionary measures to control equitably total global emissions of substances that deplete it with the ultimate objective of their elimination on the basis of developments in scientific knowledge"

"Acknowledging that special provision is required to meet the needs of developing countries"

shall accept a series of stepped limits on CFC use and production, including:

from 1991 to 1992 its levels of consumption and production of the controlled substances in Group I of Annex A do not exceed 150 percent of its calculated levels of production and consumption of those substances in 1986;
from 1994 its calculated level of consumption and production of the controlled substances in Group I of Annex A does not exceed, annually, twenty-five percent of its calculated level of consumption and production in 1986.
from 1996 its calculated level of consumption and production of the controlled substances in Group I of Annex A does not exceed zero.

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.)[contradictory] 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, in the past metered dose inhalers commonly used to treat asthma and chronic obstructive pulmonary disease were 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:

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.

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[15][16][17]

Hydrochlorofluorocarbons (HCFCs) Phase-out Management Plan (HPMP)[edit]

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. They also agreed to start reducing its consumption and production in 2015. The time of freezing and reducing HCFCs is then known as 2013-2015.

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)[edit]

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.[18]

At 28th Meeting of the Parties to the Montreal Protocol in Kigali amendment was adopted to eliminate planet-warming HFC gases, They also figure in the basket of six greenhouse gases under the Kyoto Protocol. Developed countries following the Kyoto Protocol report their HFC emission data to the UNFCCC; .

The amendment to the legally-binding Montreal Protocol will ensure that the rich and industrialised countries bring down their HFC production and consumption by at least 85 per cent compared to their annual average values in the period 2011-2013. 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.


In 1973, 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.

But 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.[19] NAS continued to publish assessments of related science for the next decade.

Then, in 1985, British Antarctic Survey scientists Joe Farman, Brian Gardiner and Jonathan 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. The impact of these studies, the metaphor 'ozone hole', and the colourful visual representation in a time lapse animation proved shocking enough for negotiators in Montreal to take the issue seriously.[20]

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. After the discovery of the ozone hole it only took 18 months to reach a binding agreement in Montreal.

But the CFC industry did not give up that easily. As late as 1986, 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."[21] 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..."[22]

Multilateral Fund[edit]

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.

The Fund is managed by an Executive Committee with an equal representation of seven industrialized and seven Article 5 countries, which are elected annually by a Meeting of the Parties. The Committee reports annually to the Meeting of the Parties on its operations. The work of the Multilateral Fund on the ground in developing countries is carried out by four Implementing Agencies, which have contractual agreements with the Executive Committee:[23]

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.


As of 23 June 2015, all countries in the United Nations, the Cook Islands, Holy See, Niue and the supranational European Union have ratified the original Montreal Protocol[24] (see external link below), South Sudan being the last country to ratify the agreement, bringing the total to 197. These countries have also ratified the London, Copenhagen, Montreal, and Beijing amendments.[11]


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.[25] 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 for 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.[26] 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,[27] however in 2003 the ozone hole grew to its second largest size.[28] 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."[29]

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.[30]

However, the hydrochlorofluorocarbons, or HCFCs, and hydrofluorocarbons, or HFCs, are now thought to contribute to anthropogenic global warming. 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.[31]

Policy experts have advocated for increased efforts to link ozone protection efforts to climate protection efforts.[32][33][34] Policy decisions in one arena affect the costs and effectiveness of environmental improvements in the other.

25th anniversary celebrations[edit]

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.[35] 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.[36]

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".[37]

See also[edit]


 This article incorporates public domain material from the CIA World Factbook document "2003 edition".(referred to as Ozone Layer Protection)

  1. ^ Climate change: 'Monumental' deal to cut HFCs, fastest growing greenhouse gases
  2. ^ "Adjustments to the Montreal Protocol". United Nations Environment Programme Ozone Secretariat. 
  3. ^ Ewenfeldt B, "Ozonlagret mår bättre", Arbetarbladet 12-9-2014, p. 10.
  4. ^ "Ozone Layer on Track to Recovery: Success Story Should Encourage Action on Climate". UNEP. UNEP. 10 September 2014. Retrieved 18 September 2014. 
  5. ^ Susan Solomon; Anne R. Douglass; Paul A. Newman (July 2014). "The Antarctic ozone hole: An update". Physics today. Retrieved 18 September 2014. 
  6. ^ "The Ozone Hole-The Montreal Protocol on Substances that Deplete the Ozone Layer". 16 September 1987. 
  7. ^ "Background for International Day for the Preservation of the Ozone Layer - 16 September". Retrieved 2017-05-28. 
  8. ^ Of Montreal and Kyoto: A Tale of Two Protocols by Cass R. Sunstein 38 ELR 10566 8/2008
  9. ^ Environmental Politics Climate Change and Knowledge Politics Reiner Grundmann, Vol. 16, No. 3, 414–432, June 2007
  10. ^ Technische Problemlösung, Verhandeln und umfassende Problemlösung, (eng. technical trouble shooting, negotiating and generic problem solving capability) in Gesellschaftliche Komplexität und kollektive Handlungsfähigkeit (Societys complexity and collective ability to act), ed. Schimank, U. (2000). Frankfurt/Main: Campus, p.154-182 book summary at the Max Planck Gesellschaft
  11. ^ a b "Status of Ratification – The Ozone Secretariat". 
  12. ^ "UNEP press release: "South Sudan Joins Montreal Protocol and Commits to Phasing Out Ozone-Damaging Substances"". 
  13. ^ The full terms are available from
  14. ^ "Class I Ozone-depleting Substances | Science | Ozone Layer Protection | US EPA". 
  15. ^ Use of ozone depleting substances in laboratories. TemaNord 2003:516.
  16. ^ The Technical and Economic Feasibility of Replacing Methyl Bromide in Developing Countries. Friends of the Earth, Washington, 173 pp, 1996
  17. ^ Guidance on the DOE Facility Phaseout of Ozone-Depleting Substances. 1995.
  18. ^ "Climate of irrationality". Down To Earth. 18 September 2012. 
  19. ^ National Academy of Sciences (1976). Halocarbons, effects on stratospheric ozone. Washington, DC. 
  20. ^ Grundmann, Reiner, Transnational Environmental Policy: Reconstructing Ozone, London: Routledge, ISBN 0-415-22423-3
  21. ^ Doyle, Jack (October 1991). "DuPont's Disgraceful Deeds: The Environmental Record of E.I. DuPont de Nemour". The Multinational Monitor. 12 (10). The Multinational Monitor. Retrieved 8 September 2014. 
  22. ^ "Du Pont: A Case Study In the 3D Corporate Strategy". Greenpeace. 1997. Archived from the original on 2012-04-06. Retrieved 8 September 2014. 
  23. ^ Creating a real change for the environment. Secretariat of the Multilateral Fund for the Implementation of the Montreal Protocol. 2007. 
  24. ^ "EUROPA – PRESS RELEASES – Press Release – Environment: European Union hails universal ratification of the Montreal Protocol on protecting the ozone layer". 
  25. ^ [1] Archived 14 June 2006 at the Wayback Machine.
  26. ^ "Evidence for the effectiveness of the Montreal Protocol to protect the ozone layer". Atmospheric Chemistry and Physics. 22 December 2010. Retrieved 16 April 2017. 
  27. ^ "Top Story – 2001 Antarctic Ozone Hole Similar in Size to Holes of Past Three Years, NOAA and NASA Report – October 16, 2001". Retrieved 2010-09-16. 
  28. ^ "NOAA News Online (Story 2099)". Retrieved 2010-09-16. 
  29. ^ Scientific Assessment of Ozone Depletion: 2006,
  30. ^ Updating Ozone Calculations and Emissions Profiles for Use in the Atmospheric and Health Effects Framework Model
  31. ^ "EIA – Emissions of the Greenhouse Gases in the United States 2005". Retrieved 2010-09-16. 
  32. ^ 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
  33. ^ 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
  34. ^ UNEP press release, 2008
  35. ^ "Ozone Secretariat 25th Anniversary web page". 
  36. ^ Canan, Penelope and Nancy Reichman (2013, forthcoming), "The Montreal Protocol" in J. Britt Holbrook (Chief Editor) Ethics, Science, Technology, and Engineering: An International Resource, 2nd Edition, Thompson Learning.
  37. ^

Further reading[edit]

  • 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 – forthcoming). Global Environmental Politics, 6th Edition, Boulder: Westview Press.
  • Dotto, Lydia and Harold Schiff (1978). The Ozone War. New York: Double Day.
  • 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 9780300175264
  • Grundmann, Reiner. (2001). Transnational Environmental Policy: Reconstructing Ozone, London: Routledge. ISBN 0-415-22423-3
  • 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: 810–12, 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.
  • Velders, G. J. M., S. O. Andersen, J. S. Daniel, D. W. Fahey, and M. McFarland. (2007). The Importance of the Montreal Protocol in Protecting the Climate. Proc. of the Natl. Acad. Of Sci., 104(12), 4814–4819, doi:10.1073/pnas.0610328104.
  • 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. Proc. of the Natl. Acad. Of Sci., 106(27), doi:10.1073/pnas.090281716.
  • Velders, G. J. M., A. R. Ravishankara, M. K. Miller, M. J. Molina, J. Alcamo, J. S. Daniel, D. W. Fahey, S. A. Montzka, and S. Reimann. (2012). Preserving Montreal Protocol Climate Benefits by Limiting HFCs. Science, 335(6071), 922–923, doi:10.1126/science.1216414.

External links[edit]