Strengthening Ambition for Climate Mitigation: The Role of the Montreal Protocol in Reducing Short-lived Climate Pollutants


  • Durwood Zaelke,

  • Stephen O. Andersen,

  • Nathan Borgford-Parnell


The level of ambition of the public and policy makers to protect the climate is currently far too low to slow the accelerating pace of climate impacts. Ambition can be strengthened using strategies that disaggregate the overall climate problem into manageable pieces, borrow existing laws and institutions to take fast action following a ‘start and strengthen’ approach. This is illustrated by the strategy to phase down the production and consumption of high global warming potential hydrofluorocarbons under the Montreal Protocol. Such an approach could cut the rate of global warming in half for the next several decades, and even more in the Arctic and other climate vulnerable regions. This can provide fast success and build the sense of urgent optimism needed to raise ambition to do more to address carbon dioxide emissions – the single largest contributor to climate change.


The level of ambition of the public and policy makers to protect the climate is currently far too low to slow the accelerating pace of climate impacts, despite the strong scientific consensus that human activity is the key cause. This article argues that the level of ambition can be strengthened by using strategies that disaggregate the overall climate problem into manageable pieces, borrowing existing laws and institutions to take fast action on specific sources, sinks and sectors, learn-by-doing, and following a ‘start and strengthen’ approach. This is illustrated by the strategy to cut short-lived climate pollutants (SLCPs), using existing laws and institutions when possible, and strengthening them when necessary.

SLCPs include hydrofluorocarbons (HFCs) manufactured as substitutes for ozone-depleting substances (ODSs), which are primarily used as refrigerants and foam-blowing agents and are produced as an unwanted by-products of the manufacture of hydrochlorofluorocarbon-22 (HCFC-22). SLCPs also include black carbon (soot) and tropospheric ozone and its precursors, including primarily methane. SLCPs cause significant warming and climate change during their relatively short atmospheric lifetime (days to a decade-and-a-half) in contrast to long-lived climate pollutants such as carbon dioxide (CO2) that damage the climate over much longer time horizons (multiple decades to millennia). Control of SLCPs therefore has a more immediate benefit in slowing the rate of climate change and reducing impacts.

Combined SLCP strategies have the potential to cut the rate of global warming in half for the next several decades, cut the rate of warming over the elevated regions of the Himalayan-Tibetan Plateau by at least half, and cut the rate of warming in the Arctic by two-thirds over the next 30 years, while saving millions of lives per year and preventing billions of dollars in crop losses.1 Speed matters profoundly, both to slow the accelerating rate of global and regional warming and to build the confidence that comes with the success needed to continuously strengthen ambition. Fast success in cutting SLCPs and the speedy, visible mitigation this would produce will also help raise ambition to do more to address CO2 emissions. Success with both CO2 and SLCPs is necessary to have a reasonable probability of limiting global temperate rise to 2°C compared to pre-industrial levels through 2100.2

This article considers the approach of disaggregating the broader climate problem by phasing down production and consumption of high global warming potential (GWP) HFCs under the Montreal Protocol on Substances that Deplete the Ozone Layer.3 We present market data confirming high growth rates in HFC production and emissions, the latest estimates of the additional growth in HFCs as substitutes for HCFCs now being phased out under the Montreal Protocol on an accelerated basis, and alarming projections of the portion of greenhouse gases HFCs will become if uncontrolled. We then present the opportunity to avoid and phase down HFCs and to reduce the risk of passing climate tipping points and triggering dangerous feedback loops that accelerate warming. We assert that it is necessary to immediately deploy fast-action solutions to cut HFCs, as well as other non-CO2 SLCPs, and we describe the various reasons why the Montreal Protocol would be as successful in phasing down HFCs as it was in successfully phasing out nearly 100 similar ODSs.

Climate Tipping Points and Feedback Loops: A Problem of Timing

Climate impacts are increasing in frequency and magnitude with the possibility of soon reaching tipping points, causing catastrophic climate change. Impacts from ongoing climate change are appearing sooner and are often more damaging than the most extreme scenarios depicted in the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report from 2007.4 Current and anticipated near-term climate impacts include sea-level rise of more than 1.6 metres by 2100; the loss of coral reefs, forests and other valuable ecosystems; and an increasing rate of species extinction, 100 to 1,000 times above the historic average.5 Over the past 30 years, weather-related disasters linked to climatic changes have increased nearly threefold.6 These and other impacts are already taking a toll on human health, food security and prospects for sustainable development.

Still worse is the possibility of reaching, within our lifetime, climate tipping points capable of causing catastrophic changes at a rate too fast for both the environment and our governance systems to adapt.7 This is likely to happen first in the regions that are warming faster than the global average. Global warming is expressed as an average, but is experienced unevenly in different regions, with some of the world's most vulnerable regions warming faster.8 The average annual temperature over the Arctic has increased twice as fast as the rest of the world since 1980,9 and the Himalayan-Tibetan Plateau, the planet's largest store of ice after the Arctic and Antarctic, is warming about three times faster than the global average.10 Additionally, Africa is warming approximately 1.5 times faster than the global average.11

Perhaps the greatest threat of accelerated regional warming is the increased chance of setting off dangerous feedbacks, triggering even larger scale climate impacts.12 For example, melting of Arctic snow and sea ice, which reached a record low September 2012,13 is accelerating warming as darker sea water and ground uncovered by receding sea ice and snow absorb more heat than the reflective ice and snow that once covered them.14 This amplifies regional warming that in turn is further reducing ice and snow cover, creating a warming feedback loop.15 Another effect is the thawing of near-surface permafrost, which could release billions of tonnes of carbon.16 As the rate of climate change continues to accelerate, the tipping points for these large-scale system changes may be imminent – at least on a decadal timescale, although there is significant remaining uncertainty.17

In addition to growing emissions of climate pollutants, the rate of change also is accelerating because of ongoing efforts to reduce the emissions of air pollutants – primarily sulphates that are cooling the atmosphere. While the measured warming from climate pollutants is about 0.76°C above pre-industrial levels, the total warming that is committed but yet unrealized from historic emissions through 2005 is calculated to be 2.4–4.3°C by 2050.18 Up to 1.15°C of this committed warming is currently being ‘masked’ by emissions of the cooling aerosols from fossil fuel and biomass combustion19 – emissions that are now being rapidly reduced to protect human health and ecosystems, including through stricter air pollution laws, improved enforcement and compliance with such laws, and the shift to cleaner energy sources. Unless commensurate reductions are made in the non-CO2 SLCPs, unmasking the committed warming will help push temperatures past the 2°C guardrail for avoiding dangerous anthropogenic interference with the climate system20 agreed upon by parties to the United Nations Framework Convention on Climate Change (UNFCCC).21

The Inadequacy of Current Mitigation Ambition

Recognizing the risk of accelerating climate impacts, the Heads of State and Government met in Copenhagen in 2009, agreeing to take action to meet the objective of stabilizing global average temperature rise at or below 2°C compared to pre-industrial temperatures.22 This goal was reaffirmed one year later in Cancún.23 Climate models indicate that meeting this goal requires limiting the total concentration of CO2 in the atmosphere to no more than 450 parts per million (ppm) by 2100.24 The decisions taken in Copenhagen and Cancún also instructed parties to investigate limiting temperature rise to 1.5°C – a target an increasing number of scientists and diplomats from vulnerable countries argue is needed to avoid serious and irreversible climate impact.25 The 1.5°C guardrail is associated with returning CO2 concentrations to 350 ppm26 from its current 395.77 ppm as of June 2012.27

There is a growing risk that the current pace of international climate negotiations is unlikely to produce significant action to limit global greenhouse gas emissions before critical thresholds are surpassed. At the Durban climate negotiations in 2011, parties agreed to develop a new agreement that will come into effect by 2020, leaving the next eight years, at least, without enforceable international measures that apply to all developed country parties, let alone to the fast growing developing countries, which remain reluctant to agree to binding commitments until significant progress is demonstrated by the developed countries.28 According to the United Nations Environment Programme (UNEP) Emissions Gap Report, annual global carbon dioxide equivalent (CO2-eq.) emissions must remain at or below 44 billion tonnes by 2020 to have a ‘likely’ (i.e., greater than 66%) chance of limiting global warming to 2°C.29 Under a business-as-usual scenario, global emissions of Kyoto gases are expected to reach 56 gigatonnes (Gt) CO2-eq. per year by 2020.30 If countries implement the lowest ambition Copenhagen pledges, global annual emissions are predicted to reach 53 Gt CO2-eq. by 2020 (9 Gt CO2-eq. per year above the goal) and 49 Gt CO2-eq. if countries move to higher conditional pledges (5 Gt CO2-eq. per year above the goal).31 Without a significant increase in ambition in the next eight years, annual global CO2-eq. emissions will be higher than needed to have a ‘likely’ chance of avoiding 2°C global warming.32

While more mitigation from CO2 is needed to close the emission gap, the difficulty of closing the gap through CO2 mitigation alone was described by the International Energy Agency: if construction of energy infrastructure continues at its current pace without additional action to de-carbonize, by 2015 locked-in emissions of CO2 from the infrastructure will have committed 95% of allowable emissions under the 2°C guardrail.33 By 2017 all allowable emissions will be taken up by the existing energy infrastructure.34 In addition to further CO2 mitigation, it is therefore necessary to immediately deploy fast-action solutions to cut HFCs, as well as other non-CO2 SLCPs. Here we argue that the Montreal Protocol is the treaty with the ambition and institutions to reduce HFCs.

Disaggregating the Climate Problem to Craft Fast-Action Mitigation Strategies: The Example of the Montreal Protocol

While climate negotiations move slowly forward under the UNFCCC with a view to putting in place an agreement that takes effect in 2020, it is possible to design a parallel and complementary set of fast-action mitigation strategies to address non-CO2 SLCPs, starting immediately. By disaggregating the overall climate problem into smaller and more manageable pieces it is possible to tailor specific mitigation strategies and in many cases to borrow existing national, regional and international laws and institutions to implement SLCP mitigation measures.

The Montreal Protocol, along with earlier national measures to reduce the chemicals that destroy the stratospheric ozone layer, illustrates the benefits of a disaggregated, focused approach that benefited from taking early action. In effect, the Montreal Protocol focused on one important cause of climate change – the fluorinated, chlorinated and brominated gases, including chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), carbon tetra chloride (CTC) and halons – and designed a treaty regime tailored to these specific gases. Without efforts to phase out ODSs, both through the Montreal Protocol and earlier voluntary and national measures, annual CO2-eq. emissions of ODSs could have contributed warming in 2010 that equalled or surpassed the contribution of CO2.35 The warming from ODSs could have exceeded that of CO2 within this century.36

The Montreal Protocol was signed by 24 Parties in 1987 and had the modest ambition to merely freeze halon production and reduce CFC production by 50% gradually over 12 years.37 However, over time, the Parties increased ambition and controlled a dozen new ODSs through amendments to the treaty and agreed to accelerate the phase-outs of production and consumptions through adjustments to it. Developing countries agreed to binding controls in exchange for financing of the agreed incremental costs from the Multilateral Fund (MLF), which is governed by a balanced executive committee of seven developed and seven developing country parties with a history of operating by consensus. The Montreal Protocol is unique in that every UN member State is a party – making it the only environmental treaty with universal membership – and in that every Party is in full compliance (with temporary exceptions for developing countries, usually as a result of delay in project financing by the MLF).38

Another important feature of the Montreal Protocol's success is its commitment to the full implementation of the principle of ‘common but differentiated responsibilities’. This has been achieved by including a requirement for developed countries to undertake their control measures first, followed by a grace period, typically of ten years, before developing countries undertake their control measures.39 Furthermore, a dedicated funding mechanism (the MLF) has been set up to pay for the full, agreed incremental costs of technology necessary for compliance.40 Another important feature is the treaty's ‘start and strengthen’ philosophy. Throughout its 25-year history, the Montreal Protocol has started by addressing a problem, learned by doing, gained experience and confidence, and then done more.41 This philosophy has allowed the Protocol to build confidence in the parties and their industries that progress is possible, to facilitate the fast development and deployment of technologies that make action easier and cheaper, and to build the ambition, momentum and political courage to do more.

This focused ‘start and strengthen’ approach could also be applied to other SLCPs to provide fast-action mitigation using existing legal and institutional mechanisms, often with further strengthening, and through new mechanisms aimed at specific sources, sinks or sectors. This starts with a phase-down of production and use of HFCs under the Montreal Protocol and with other fast-action mitigation measures to cut black carbon and methane. All of these ‘start and strengthen’ actions are politically and economically possible and can be deployed quickly to slow the rate of warming before the climate impacts overwhelm our limited supply of governance and diverts our attention from measures to mitigate climate change to desperate efforts to cope with increasing climate damage.

Reducing the Rate of Warming With Fast Action on HFCs and other Short-Lived Climate Pollutants

Unlike CO2, which has a profoundly long lifetime,42 SLCPs remain in the atmosphere for a period of days up to a decade-and-a-half, and reducing their emissions can cut the rate of global warming by up to half, the rate of warming in the high elevation Himalaya-Tibetan Plateau by at least half, and the rate of Arctic warming by up to two-thirds over the next thirty years.43 According to a recent integrated assessment by the UNEP and the World Meteorological Organization (WMO) combined mitigation of black carbon and tropospheric ozone (through reduction of its primary precursor, methane) can mitigate 0.5 ± 0.05°C of additional warming by 2070.44 Under this analysis, combined mitigation of CO2, black carbon and tropospheric ozone/methane can constrain global temperature rise to less than 1.5°C until approximately 2040 and to less than 2°C through 2070.45 Phasing down high-GWP HFCs can reduce the rate of warming by an additional 20% in 2050 beyond the estimated 0.5°C reductions from cutting black carbon and tropospheric ozone/methane.46

Effective control measures for black carbon and tropospheric ozone/methane, based upon existing technologies and often on existing laws and institutions, have been explored at length in a number of recent publications.47 Reducing HFCs can be accomplished most effectively through the Montreal Protocol, as discussed below, in conjunction with early complementary actions by private companies and regulations by national and regional governments now underway or under active consideration.48

Like methane and black carbon, HFCs are considered SLCPs because the average lifetime of the mix of HFCs, weighted by usage, is just 15 years.49 However, unlike other SLCPs, HFCs are factory-produced gases with no natural sources.50 They are manufactured chemicals used in large quantities in refrigeration, air conditioning, insulating foams and in small quantities in medicine, fire protection, solvent cleaning and other specialty uses.51 Many HFCs are super greenhouse gases with GWPs hundreds to thousands of times greater than that of CO2.52 The current mix of HFCs in use today has a weighted average of 1600 GWP.53

The growth in HFCs is a result of the expanding population, rising income and previous phase-outs of nearly 100 other similar fluorinated gases under the Montreal Protocol.54 With the phase-out of CFCs completed in 2010 and the phase-out of most HCFCs to be completed by 2030, HFCs are being used increasingly in applications that traditionally used ODSs.55 The presence of HFCs in the atmosphere is almost completely from their use as substitutes for CFCs and HCFCs, with the exception of HFC-23,56 which, unlike other HFCs currently in use as ODS substitutes, is the unintentional and unwanted by-product of HCFC-22 production and is often intentionally vented into the atmosphere.57

The atmospheric abundance of major HFCs used as substitutes for CFCs and HCFCs has increased 10–15% per year in recent years.58 HFCs are the fastest growing greenhouse gas in the United States, where emissions grew nearly 9% between 2009 and 2010 compared to a 3.6% growth for CO2 in the same time period.59 In coming decades, as the remaining HCFCs are phased out globally, much of the market for refrigerants and thermal-insulating foam production will be met by HFCs unless fast action is taken to reduce them.60

HFC use is growing in both developed and developing countries driven in part by rising temperatures and the subsequent increased demand for air conditioning, as well as by rising global incomes to purchase them.61 For example, the use of air conditioners by urban residents of China increased to 70% in 2004 from 8% in 1995,62 and the potential demand for air conditioning in Mumbai is projected to be almost a quarter of the entire United States demand.63

In 2000 the production, emission and radiative forcing of HFCs was less than 1% of the total forcing from long-lived greenhouse gases.64 Without fast action to limit their growth, the climate forcing of HFCs could increase from 0.012 watts per square metre (W/m2) in 2010 to as much as 0.40 W/m2 in 2050.65 Assuming no action is taken to mitigate them, HFC forcing will equal approximately 20% of CO2 forcing by 2050 – about the same as current annual emissions from transport – or up to 40% of CO2 forcing under a scenario where CO2 concentrations are limited to 450 ppm (see Figure 1).66

Figure 1.

HFCs Projected to be 20–40% of Radiative Forcing of CO2 in 2050

Notes: The red line shows the growth in HFC climate forcing for the Velders (2009) upper range HFC scenario. This is compared to the predicted CO2 forcing for the range of scenarios from IPCC-SRES, shown as the grey area, and a 450 ppm CO2 stabilization scenario, shown as a dashed line. While the climate forcing of HFCs is extremely low, compared to CO2 in 2010, it is projected to grow rapidly, contributing as much as 40% of the forcing from CO2 in 2050, if CO2 is held to 450 ppm.

Source: United Nations Environment Program, HFCs: A Critical Link In Protecting Climate and the Ozone Layer (UNEP, 2011)

Current Control of HFCs Through the Kyoto Protocol

While HFCs are similar to the nearly 100 other fluorinated gases controlled by the Montreal Protocol, they do not deplete the stratospheric ozone and thus were left to the UNFCCC and the Kyoto Protocol to address.67 This placed HFCs in the basket of six greenhouse gases addressed by the Kyoto Protocol where reductions in HFC emissions can be traded on the carbon market for increased CO2 emissions. The utility of the carbon market has been undermined by the inclusion of HFCs. During the Kyoto Protocol's initial period from 2008 to 2012, cheap HFC-related certified emission reductions (CERs), particularly reductions of HFC-23, 68 flooded the carbon market and threatened the integrity of the Protocol's Clean Development Mechanism (CDM).69 This has been widely criticized and led to the UN considering changes to the CDM and a ban on purchasing of HFC-23 CERs in the EU starting in 2013, as well as bans in New Zealand and Australia.70

The largest increase in HFC emissions will occur in the developing world as demand for high-GWP HFC products will increase dramatically due to the phase-out of ODSs under the Montreal Protocol and the increase in disposable income.71 However, through the limited application of the principle of ‘common but differentiated responsibilities and respective capabilities’, only developed countries are required to adopt ‘legally binding mitigation commitments or actions’ under the Kyoto Protocol, and developing countries are unlikely to accept emissions limitations or reduction commitments, HFCs included, in the mid-term under the UNFCCC.72 This is in contrast to the robust application of ‘common but differentiated responsibilities’ under the Montreal Protocol where developing countries accept mandatory control measures in exchange for a grace period, incremental financing for technology transfer and other benefits under the treaty.

The Kyoto Protocol also focuses on regulating HFCs at the point of emission, and does not provide control measures for production and consumption – the points in the HFC life-cycle where it is most cost-effective and efficient to monitor and reduce emissions. Incentives to reduce emissions in developing countries under the Kyoto Protocol via the CDM are ad hoc and require significantly more funding than the actual costs of reducing HFC emissions.73 Moreover, waiting for the new climate regime to reduce HFCs will leave the world with at least eight more years without an international agreement to control the unmitigated growth of HFCs. If the global 10–15% growth rate of HFCs continues, as it is expected to, the atmospheric abundance of HFC will more than double before a new agreement with legal force comes into effect.74

The conclusion is that the market-based strategies of the Kyoto Protocol have thus far failed to provide a solution to the dramatically increasing emissions of HFCs. We argue here that the Montreal Protocol is the most appropriate mechanism for quickly and effectively reducing production and consumption of HFCs.

Controlling HFCs Under the Montreal Protocol

HFCs are factory-made substitutes for CFCs and HCFCs, and can be most effectively controlled through a phase-down of their production and consumption under the Montreal Protocol than through any other existing mechanism. HFCs are potent greenhouse gases but they do not destroy the ozone layer so they were initially considered acceptable substitutes for CFCs and HCFCs – chemicals that both warm the planet and damage the ozone layer.75 The Montreal Protocol is ideally equipped to ensure a cost-effective, efficient and orderly phase-down of HFCs because HFCs are in the same family of gases, have similar chemical properties and are used in the same sectors as CFCs and HCFCs.76

The Montreal Protocol is already responsible for the global phase-out of 97% of the consumption and production of nearly 100 ozone-depleting substances and has put the stratospheric ozone layer on a path to recovery by mid-century.77 The 1987 treaty was originally designed to primarily protect the ozone layer. However, as early as 1975 CFCs were identified as powerful climate pollutants,78 and the scientific presentations and discussion at the working groups and negotiating meetings frequently included detailed climate discussions and debate. The phase-out of ODSs has made the Montreal Protocol the most successful international climate treaty to date.79

Through the phase-out of CFCs and other ozone depleting substances that cause warming, the Montreal Protocol has reduced climate emissions by up to 222 Gt CO2-eq. between 1990 and 2010 (see Figure 2).80 This is as much as five to twenty times greater than the reductions targeted in the first commitment period for the Kyoto Protocol, depending on how the mitigation is calculated.81 Without the Montreal Protocol, the projected radiative forcing by ODSs would have been roughly 0.65 W/m2 in 2010.82 This would have been 35% of the climate forcing of CO2 today, and made the collective radiative forcing of ozone-depleting substances second only to CO2.83

Figure 2.

Trends In CO2-eq. Emissions of CFCs, HCFCs and HFCs Since 1950 and Projected to 2050

Notes: The low HFC line represents predicted CO2-eq. emissions if the current mix of HFCs is replaced by HFC substitutes with average lifetimes less than two months and/or GWPs less than 20.

Source: United Nations Environment Program, HFCs: A Critical Link In Protecting Climate and the Ozone Layer (UNEP, 2011). The red HFC lines represent various emissions scenarios from: G.J.M. Velders et al., ‘The Large Contribution of Projected HFC Emissions to Future Climate Forcing’, 106:26 Proceedings of the National Academy of Sciences (2009), 10949; and B. Gschrey et al., ‘High Increase of Global F-gas Emissions until 2050’, 1:2 Greenhouse Gas Measurement and Management (2011), 85.

The significant benefits of the Montreal Protocol for both ozone and climate protection are due in part to its early start. For two-and-a-half decades, the treaty has been phasing out the production and consumption of substances that destroy the ozone layer and warm the climate. Other key features that make the Montreal Protocol so successful are discussed later and include its focus on upstream production and consumption, its approach to technology development and transfer, its dedicated funding source, and its robust capacity building for all 147 developing country parties. The combination of these features has allowed all parties to fully comply with the control measures, thereby achieving unprecedented success in phasing out nearly 100 dangerous chemicals.

Advantages of Phasing Down HFC Production and Consumption Through the Montreal Protocol

The Montreal Protocol enjoys several advantages that will allow it to quickly implement effective controls for HFCs, including a well-established infrastructure, decades-long expertise with highly independent scientific, environmental effects and technology and economics assessment panels, a fully financed multilateral fund and other cost-effective implementation tools, as well as experience phasing out nearly 100 similar chemicals.84

Advantages of the Montreal Protocol include its universal membership and its robust implementation of the principle of ‘common but differentiated responsibility’, including its dedicated funding mechanism: the MLF. Funding has always been allocated using consensus, but in the absence of consensus the MLF terms of reference would use a ‘double majority’ voting system, which requires a majority of the seven members of the MLF Executive Committee from developing countries and a majority of the seven members from developed countries for approval.85 Since its establishment in 1991, the MLF has provided more than US$3 billion in funding,86 and its permanent professional staff and associated organizations have acquired an in-depth understanding of all the sectors it finances, including detailed knowledge of technical options.87

The orderly and transparent phase-out schedule for the chemicals the Montreal Protocol targets has allowed markets to innovate and adjust, often resulting in significant cost and technical efficiencies.88 Past transitions from CFCs to HCFCs have helped drive technological innovation to create substitutes, and improved manufacturing processes and equipment. In many cases this innovation has produced gains in energy efficiency, reduced leakage or other technological improvements. The phase-out of CFCs is estimated to have spurred up to 60% improvement in energy efficiency of domestic refrigerators, and technology transfer to developing countries as part of the HCFC phase-out is expect to reduce energy consumption of room air conditioning units by 10–40%.89 As a backstop, the Montreal Protocol's ‘essential use’ and ‘critical use’ exemptions allow for continued use when environmentally acceptable options are not yet available.90

The Montreal Protocol has also supported national ozone officers in every developing country, which are organized into regional networks.91 These experienced officers are well prepared to implement the HFC phase-down schedules and to efficiently and cost effectively utilize the funding made available through the MLF.92 Further, the Montreal Protocol has several successful scientific and technical bodies with decades of experience working closely with industry: the Scientific Assessment Panel, the Environmental Effects Assessment Panel, the Technology and Economic Assessment Panel (TEAP) and the Technical Options Committees. These bodies produce real-time, policy-relevant reports based on their familiarity with technology, both commercially available and in-development, in every relevant sector.93

In sum, the Montreal Protocol can provide the fastest, most cost-effective means of reducing HFC production and consumption, particularly compared to actions now delayed and deferred under the UNFCCC and its Kyoto Protocol.

Proposed HFC Amendments to the Montreal Protocol

Recognizing the fast and effective opportunity presented for phasing down HFCs though the Montreal Protocol, the Federated States of Micronesia proposed an amendment to phase down high-GWP HFCs, with the United States, Canada and Mexico offering a similar amendment.94 Both the North American proposal and the Micronesian proposal would reduce 85–90% of HFC production and consumption, providing climate mitigation of 87–146 Gt CO2-eq. by 2050 (Figure 3).95

Figure 3.

Projected HFC Emission Reductions from the Micronesian and North American Proposals

Notes: The North American proposal and the Micronesian proposal are similar; both decrease the cumulative (2013–2050) direct GWP-weighted emissions of HFCs to 22–24 Gt CO2-eq. from 110–170 Gt CO2-eq., for a total of ∼87 to 146 Gt CO2-eq. in mitigation. This is equivalent to a reduction from projected annual emissions of 5.5 to 8.8 Gt CO2-eq./yr in 2050 to less than ∼0.3 Gt CO2-eq./yr.

Sources: Prepared by Dr Guus Velders, based on G.J.M. Velders et al., ‘The Large Contribution of Projected HFC Emissions to Future Climate Forcing’, 106:26 Proceedings of the National Academy of Sciences (2009), 10949; United Nations Environment Program, Proposed Amendment to the Montreal Protocol, Submitted by the Federated States of Micronesia (UN Doc. UNEP/OzL.Pro.WG.1/32/5, 11 May 2012), at 3–4; and United Nations Environment Program, HFCs: A Critical Link In Protecting Climate and the Ozone Layer (UNEP, 2011), at 22.

The Montreal Protocol TEAP has identified technically and economically feasible options to achieve these first control steps. While substitutes in some sectors are still being developed, climate friendly substitutes for high-GWP HFCs are already in commercial use in many sectors, including domestic, commercial and industrial refrigeration and some types of air conditioning systems.96 Many of these systems offer the same or higher levels of energy efficiency as their HFC counterparts.97 Some of the currently available substitutes include hydrocarbons (GWP <4) and CO2 (GWP 1).98 There also are several types of HFCs that have very low GWPs such as HFC-1234ze (GWP 6) used in foams and aerosols, and HFO-1234yf (GWP 4) used in mobile air conditioners.99 Not-in-kind solutions are also available, such as architectural designs that avoid the need for air conditioning entirely.100 There are many other alternatives in the research and development pipeline waiting for the right market signals. A decision to phase-down HFCs under the Montreal Protocol will provide a definitive signal to industry to accelerate development and deployment of additional climate-friendly alternatives.

The controls proposed under the Amendments represent up to 7% of the total CO2-eq. mitigation needed to have a 75% chance of staying below the 2°C guardrail.101 Agreement on the HFC amendment would eliminate the climate warming of one of the six Kyoto Protocol greenhouse gases by phasing down to a de minimis level production and consumption of HFCs that replaced about 15% of ODSs.

To date, efforts to agree to an HFC amendment have been delayed by India, China and Brazil, which, along with their allies, ague that all action to address climate change should occur within the UNFCCC rather than in both the UNFCCC and the Montreal Protocol. This is despite the infirmities of dealing with HFCs through the existing Kyoto and UNFCCC structures, discussed above. However, political momentum for an HFC amendment has been steadily growing. At the Montreal Protocol Meeting of the Parties in Bali in 2011, of the nearly 130 Parties in attendance, 108 signed the Bangkok Declaration calling for low-GWP alternatives to CFCs and HCFCs.102 The Consumer Good Forum – a global network of over 650 retailers, manufactures, service providers and other stakeholders from over 70 countries – pledged to begin phasing out HFCs in new equipment beginning in 2015.103 The United Nations Conference on Sustainable Development in June 2012 (Rio+20), attended by more than 100 Heads of State and Government, also called for the gradual phase-down of HFC production and consumption in the conference declaration ‘The Future We Want’, which states that:

We recognize that the phase-out of ozone-depleting substances is resulting in a rapid increase in the use and release of high global-warming potential hydrofluorocarbons to the environment. We support a gradual phase-down in the consumption and production of hydrofluorocarbons.104

With the support of the world's leaders behind the HFC phase-down, and with the Montreal Protocol being the treaty that controls upstream production and consumption while the Kyoto Protocol controls downstream emissions, the question now appears to be how quickly this can be agreed under the Montreal Protocol.

Relationship With the Kyoto Protocol and a Future Climate Agreement

Phasing down the upstream production and consumption of HFCs under the Montreal Protocol would not need to interfere with the operation of the Kyoto Protocol, which currently covers the downstream emissions of HFCs. In addition, Kyoto only mandates reductions from developed countries, while all Montreal Protocol Parties agree to mandatory controls on different schedules and with financing for the agreed incremental costs of developing countries, in keeping with the principle of ‘common but differentiated responsibilities and respective capabilities’.105

Phasing down high-GWP HFCs under the Montreal Protocol is consistent with the principles set forth in Article 3 of the UNFCCC, and would help achieve the UNFCCC's ultimate objective of ensuring ‘stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system’.106 This is the type of cooperation envisioned in Article 7.2(l) of the UNFCCC,107 and has already led to delegation of responsibility for greenhouse gases from aviation and bunker fuels to the International Civil Aviation Organization and the International Maritime Organization, respectively.108 Using the Montreal Protocol will ensure that the world's most effective environmental treaty quickly and efficiently solves this significant piece of the climate problem.


Disaggregating the overall climate problem into more focused and manageable pieces, starting with the HFCs and other SLCPs, and borrowing existing legal and institutional mechanisms to address these pieces has the potential to cut the rate of global warming by half, the rate of warming over the elevated regions of the Himalayas and Tibet by at least half, and the rate of Arctic warming by two-thirds, while saving millions of lives a year and improving food security. If combined with significant cuts in CO2 emissions, the two strategies can significantly increase the likelihood of keeping the world from breaching the 1.5°C guardrail for the next 30 years and 2°C for 60 years or more. Quickly reducing the rate of warming will slow impacts including sea-level rise, melting glaciers, loss of Arctic ice and the melting of permafrost and other accelerating feedback mechanisms that can push the climate past tipping points.

  1. 1

    United Nations Environment Programme (UNEP) and World Meteorological Organization (WMO), Integrated Assessment of Black Carbon and Tropospheric Ozone: Summary for Decision Makers (UNEP, 2011), at 5, 15.

  2. 2

    V. Ramanathan and Y. Xu, ‘The Copenhagen Accord for Limiting Global Warming: Criteria, Constraints and Available Avenues’, 107:18 Proceedings of the National Academy of Sciences (2010), 8055 ; see also M. Molina et al., ‘Reducing Abrupt Climate Change Risk Using the Montreal Protocol and Other Regulatory Actions to Complement Cuts in CO2 Emissions’, 106:49 Proceedings of the National Academy of Sciences (2009), 20616.

  3. 3

    This article does not focus on other SLCPs. For a detailed discussion see, e.g., E. Rosenthal and R. Watson, ‘Multilateral Efforts to Reduce Black Carbon Emissions: A Lifeline for the Warming Arctic?’, 20:1 Review of European Community and International Environmental Law (2011), 3.

  4. 4

    See, e.g., I. Allison et al., The Copenhagen Diagnosis: Updating the World on the Latest Climate Science (University of New South Wales Climate Change Research Centre, 2011); J. Romm, Illustrated Guide to the Science of Global Warming Impacts (15 December 2011), found at: <>.

  5. 5

    See, e.g., I. Allison et al., 4 above, at 29, 40; J.E.N. Veron et al., ‘The Coral Reef Crisis: The Critical Importance of < 350 ppm CO2’, 58:10 Marine Pollution Bulletin (2009), 1428 ; J. Silverman et al., ‘Coral Reefs May Start Dissolving When Atmospheric CO2 Doubles’, 36 Geophysical Research Letters (2009), L05606 . See also S. Solomon et al., Climate Stabilization Targets: Emissions, Concentrations and Impacts over Decades to Millennia (National Academies Press, 2011).

  6. 6

    C. Field et al. (eds.), Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation: A Special Report of Working Groups I and II of the Intergovernmental Panel on Climate Change (Cambridge University Press, 2012), found at: <>.

  7. 7

    T.M. Lenton et al., ‘Tipping Elements in the Earth's Climate System’, 105:6 Proceedings of the National Academy of Sciences (2008), 1786.

  8. 8

    Ibid., at 1788. See also J. Qiu, ‘China: The Third Pole’, 454:24 Nature (2008), 393 ; Arctic Monitoring and Assessment Programme (AMAP), Snow, Water, Ice and Permafrost in the Arctic: Executive Summary (AMAP Secretariat, 2011), found at: <>.

  9. 9

    See AMAP, 8 above, at 4.

  10. 10

    See J. Qiu, 8 above, at 393. See also R.V. Cruz et al., ‘Asia’, in: M.L. Parry et al. (eds.), Climate Change 2007: Impacts, Adaptation and Vulnerability, Contribution of Working Group II to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (Cambridge University Press, 2007), 469.

  11. 11

    J.H. Christensen et al., ‘Regional Climate Projections’, in: S. Solomon et al. (eds.), Climate Change 2007: The Physical Science Basis, Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (2007), 847.

  12. 12

    H.-J. Schellnhuber, ‘Tragic Triumph’, 100:1 Climatic Change (2010), 229. See also I. Allison et al., 4 above, at 223.

  13. 13

    According to data analyzed by the National Snow and Ice Data Center and NASA, on 16 September 2012 the Arctic reached a new record minimum of 1.32 million square miles, 18% less than the previous record minimum set in 2007 and nearly 50% less than the 1979–2000 average. National Snow and Ice Data Center, ‘Arctic Sea Ice Extent Settles a Record Seasonal Minimum’ (16 September 2012), found at: <>. See also C. Derksen and R. Brown, ‘Spring Snow Cover Extent Reductions in the 2008–2012 Period Exceeding Climate Model Projections’, Geophysical Research Letters (2012, forthcoming).

  14. 14

    M.G. Flanner et al., ‘Radiative Forcing and Albedo Feedback from the Northern Hemisphere Cryosphere between 1979 and 2008’, 4:3 Nature Geoscience (2011), 151. See also AMAP, 8 above; J. Stroeve et al., ‘Arctic Sea Ice Decline: Faster than Forecast’, 34 Geophysical Research Letters (2007), L09501.

  15. 15

    T.M. Lenton, ‘2°C or not 2°C? That is the Climate Question’, 473:7345 Nature (2011), 7.

  16. 16

    C. Koven et al., ‘Permafrost Carbon-climate Feedbacks Accelerate Global Warming’, 108:36 Proceedings of the National Academy of Sciences (2011), 14769. See also K. Schaefer et al., ‘Amount and Timing of Permafrost Carbon Release in Response to Climate Warming’, 63:2 Tellus B (2011), 165 ; S. Solomon et al., 5 above, at 223.

  17. 17

    See T.M. Lenton et al., 7 above; R.A. Kerr, ‘Ice-free Arctic Sea May be Years, Not Decades, Away’, 337:6102 Science (2012), 1591.

  18. 18

    V. Ramanathan and Y. Feng, ‘On Avoiding Dangerous Anthropogenic Interference with the Climate System: Formidable Challenges Ahead’, 105:38 Proceedings of the National Academy of Sciences (2008), 14245 . See also S. Solomon et al., ‘Technical Summary’, in: S. Solomon et al., 11 above, 19; H.-J. Schellnhuber, ‘Global Warming: Stop Worrying, Start Panicking?’, 105:38 Proceedings of the National Academy of Sciences (2008), 14239 .

  19. 19

    See V. Ramanathan and Y. Xu, 2 above.

  20. 20

    Decision 1/CP.16, The Cancún Agreements: Outcome of the Work of the Ad Hoc Working Group on Long-term Cooperative Action under the Convention (UN Doc. FCCC/CP/2010/7/Add.1, 15 March 2011), at 3.

  21. 21

    United Nations Framework Convention on Climate Change (New York, 9 May 1992; in force 21 March 1994) (‘UNFCCC’), Article 2. See also UNEP, The Emissions Gap Report: Are the Copenhagen Accord Pledges Sufficient to Limit Global Warming to 2°C or 1.5°C? A Preliminary Assessment (UNEP, 2010).

  22. 22

    Decision 2/CP.15, Copenhagen Accord (UN Doc. FCCC/CP/2009/11/Add.1, 30 March 2010), at paragraph 2.

  23. 23

    Decision 1/CP.16, 20 above, at 3.

  24. 24

    M. Meinshausen et al., ‘Greenhouse-gas Emission Targets for Limiting Global Warming to 2°C’, 458:7242 Nature (2009), 1158 . See also G. Luderer et al., ‘The Economics of Decarbonizing the Energy System: Results and Insights from the RECIPE Model Intercomparison’, 114:1 Climatic Change (2011), 9.

  25. 25

    Decision 2/CP.15, 22 above, at paragraph 12; Decision 1/CP.16, 20 above, at 3. See also J. Hansen et al., ‘Target Atmospheric CO2: Where Should Humanity Aim?’, 2 Open Atmospheric Science Journal (2008), 217.

  26. 26

    See J. Hansen et al., 25 above.

  27. 27

    NOAA Earth System Research Laboratory Global Monitoring Division, Trends in Atmospheric Carbon Dioxide: Recent Mauna Loa CO2 (June 2012), found at: <>. Returning atmospheric CO2 concentrations back to 350 ppm or lower by 2100 can be achieved through fast mitigation of greenhouse gases combined with carbon removal strategies such as reforestation, biochar and bioenergy with carbon capture and storage/reutilization. See T.M. Lenton, ‘The Potential for Land-based Biological CO2 Removal to Lower Future Atmospheric CO2 Concentrations, 1:1 Carbon Management (2010), 145 ; V. Ramanathan and Y. Xu, 2 above.

  28. 28

    Decision 1/CP.17, Establishment of an Ad Hoc Working Group on the Durban Platform for Enhanced Action (UN Doc. FCCC/CP/2011/9/Add.1, 15 March 2012), at paragraph 4. It should be noted that the EU has agreed in principle to a second commitment period under the Kyoto Protocol. See C. Hedegaard, ‘Climate Change: Our Common Challenge, Our Common Opportunity’. Speech delivered at the AMCEN Ministerial meeting, Arusha (Tanzania)’ (17 September 2012), found at: <>.

  29. 29

    See UNEP, 21 above, at 10.

  30. 30

    Ibid., at 16.

  31. 31

    Ibid., at 14.

  32. 32

    Ibid., at 10.

  33. 33

    International Energy Agency (IEA), World Energy Outlook: Executive Summary (IEA, 2011), found at: <>, at 205.

  34. 34

    Ibid. See also N.P. Myhrvold and K. Caldeira, ‘Greenhouse Gases, Climate Change and the Transition from Coal to Low-carbon Electricity, 7:014019 Environmental Research Letters (2012, forthcoming).

  35. 35

    In 2010, CO2-eq. emissions from ODSs could have reached as high as 76 Gt, annually, compared to 35 Gt from CO2. See G.J.M. Velders et al., ‘The Importance of the Montreal Protocol in Protecting Climate’, 104:12 Proceedings of the National Academy of Sciences (2007), at Table 1.

  36. 36

    See V. Ramanathan and Y. Xu, 2 above, at 8061.

  37. 37

    S.O. Andersen and K.M. Sarma, Protecting the Ozone Layer: The United Nations History (Earthscan, 2002), at 59–60.

  38. 38

    UNEP Ozone Secretariat, Key Achievements of the Montreal Protocol to Date (UNEP, 2012), found at: <>; UNEP, Handbook for the Montreal Protocol on Substances that Deplete the Ozone Layer, 9th edn (UNEP, 2012), at 310–426.

  39. 39

    Protocol on Substances that Deplete the Ozone Layer (Montreal, 16 September 1987; in force 1 January 1989) (‘Montreal Protocol’), Article 5.

  40. 40

    Ibid., Article 10. See also S.O. Andersen, K.M. Sarma and K.N. Taddonio, Technology Transfer for the Ozone Layer: Lessons for Climate Change (Earthscan, 2007); K.M. Sarma, S.O. Andersen, D. Zaelke and K.N. Taddonio, ‘Ozone Layer, International Protection’ in: R. Wolfrum (ed.), Max Planck Encyclopedia of Public International Law (Oxford University Press, 2012), online edition, found at: <>; D. Hunter, J. Salzman and D. Zaelke, International Environmental Law and Policy, 4th edn (Foundation Press, 2011), at 544, 578.

  41. 41

    See, generally, R.E. Benedick, Ozone Diplomacy: New Directions in Safeguarding the Planet (Harvard University Press, 1991); S.O. Andersen and K.M. Sarma, 37 above; S.O. Andersen, K.M. Sarma and K.N. Taddonio, 40 above.

  42. 42

    See S. Solomon et al., 5 above, at 75 (noting that a significant portion of CO2 remains in the atmosphere for millennia).

  43. 43

    G.J.M. Velders et al., ‘The Large Contribution of Projected HFC Emissions to Future Climate Forcing’, 106:26 Proceedings of the National Academy of Sciences (2009) at 10949; UNEP, HFCs: A Critical Link in Protecting Climate and the Ozone Layer (UNEP, 2011), at 10; UNEP and WMO, 1 above, at 5, 15.

  44. 44

    Ozone is created by ozone precursors including methane, carbon monoxide and volatile organic compounds. Methane is responsible for approximately 50% of ozone production so controlling methane will have a significant effect on ozone concentrations. As reported by D. Shindell et al., ‘Simultaneously Mitigating Near-term Climate Change and Improving Human Health and Food Security’, 335:6065 Science (2012), 183 . See also V. Ramanathan and Y. Xu, 2 above.

  45. 45

    See D. Shindell et al., 44 above, at 184.

  46. 46

    Institute for Advanced Sustainability Studies, ‘Short Lived Climate Forcers: Pathways to Action – Summary’ (20 March 2012). Cf. V. Ramanathan and Y. Xu, 2 above; G.J.M. Velders et al., ‘The Large Contribution of Projected HFC Emissions to Future Climate Forcing’, 106:26 Proceedings of the National Academy of Sciences (2009), 10949.

  47. 47

    The UNEP/WMO integrated assessment calculates that a combination of 14 mitigation measures – seven targeting emissions of methane and seven targeting emissions of black carbon – are capable of reducing global methane emissions by approximately 38% and emissions of black carbon by approximately 77%. See UNEP, Near-term Climate Protection and Clean Air Benefits: Actions for Controlling Short-lived Climate Forcers (UNEP, 2011), at 9–10. In all, these measures could realize ‘nearly 90% of the maximum reduction in net GWP’ from these sources. See D. Shindell et al., 44 above, at 183.

  48. 48

    Action at national and regional levels can help reduce HFCs. For example, the EU's F-gas Regulation phases out motor vehicle air conditioning refrigerants with GWP greater than 150 by 2017. See Council Regulation 842/2006 of 17 May 2006 on Certain Fluorinated Greenhouse Gases, [2006] OJ L161/1. The United States allows manufacturers of cars and light-trucks to generate CO2-eq. credits towards their compliance with CO2 emission standards and fuel economy CAFE standards by employing HFC alternative refrigerants in mobile air conditioning systems for model year 2012–2016 vehicles. See United States Environmental Protection Agency (EPA), ‘Office of Transportation and Air Quality, EPA and NHTSA Finalize Historic National Program to Reduce Greenhouse Gases and Improve Fuel Economy for Cars and Trucks’ (April 2010), found at: <>. There are many other examples including: creating national databases of equipment containing HFCs in Hungary, Slovenia and Estonia; mandatory refrigerant leakage checks for mobile equipment in Germany, Sweden and the Netherlands; and producer responsibility schemes requiring producers and suppliers of HFCs to take back recovered bulk HFCs for further recycling, reclamation and destruction in Sweden and Germany. See W. Schwarz et al., Preparatory Study for a Review of Regulation (EC) No 842/2006 on Certain Fluorinated Greenhouse Gases: Final Report (European Commission, 2011), found at: <>.

  49. 49

    See UNEP, 43 above, at 10.

  50. 50

    See S.O. Andersen, K.M. Sarma and K.N. Taddonio, 40 above.

  51. 51


  52. 52

    See G.J.M. Velders et al., 46 above.

  53. 53

    G.J.M. Velders et al., ‘Preserving Montreal Protocol Climate Benefits by Limiting HFCs’, 335:6071 Science (2012), 922, at 923.

  54. 54

    Ibid.; G.J.M. Velders et al., 46 above.

  55. 55

    See G.J.M. Velders et al., 46 above; UNEP and WMO, 1 above.

  56. 56

    HFC-23 is an ODS refrigerant with several different applications. HFC-23 is formed at the reactor stage during the manufacturing of HCFC-22. While the Montreal Protocol will eventually phase out the direct use of HCFC-22, its use as a feedstock currently escapes regulation under the Protocol, potentially causing global emissions of HFC-23 to increase as well, though not as rapidly as other HFCs. Unlike other HFCs, HFC-23 has a longer atmospheric lifetime of 270 years and a high 100-year GWP of 14,800. See Technology and Economic Assessment Panel (TEAP), Task Force Decision XX/8 Report: Assessment of Alternatives to HCFCs and Update of the 2005 TEAP Supplemental Report Data (TEAP, 2009); G.J.M. Velders et al., 46 above, at 10949. Allowing credits from the destruction of HFC-23 has created a perverse incentive to continue to produce HCFC-22. For more information, see Environmental Investigation Agency (EIA), HFC-23 Offsets in the Context of the EU Emissions Trading Scheme (EIA, 2010), found at: <>.

  57. 57

    WMO, Scientific Assessment of Ozone Depletion: 2010, Global Ozone Research and Monitoring Project (WMO, 2011); and G.J.M. Velders et al., 46 above.

  58. 58

    See WMO, 57 above, at 2.

  59. 59

    US EPA, Inventory of US Greenhouse Gas Emissions and Sinks: 1990–2010 (EPA, 2012), at 4–70, ES-4.

  60. 60

    See G.J.M. Velders et al., 46 above; G.J.M. Velders et al., 53 above.

  61. 61

    Increases in greenhouse gas emissions in the United States between 2009 and 2010 are partly due to warming temperatures increasing demand for air conditioning. See US EPA, 59 above. World sales of air conditioning in 2011 were 13% higher than in 2010. See S. Cox, ‘Cooling a Warming Planet: A Global Air Conditioning Surge’, Yale Environment (10 July 2012), 360, found at: <>. See also G. DePaula and R.O. Mendelsohn, ‘Development and the Impact of Climate Change on Energy Demand: Evidence from Brazil’, 1:3 Climate Change Economics (2010), 187.

  62. 62

    See UNEP, OzonAction, HCFC Phase Out: Convenient Opportunity to Safeguard the Ozone Layer and Climate (UNEP, 2008), at 6.

  63. 63

    M. Sivak, ‘Potential Energy Demand for Cooling in the 50 Largest Metropolitan Areas of the World’, 37:4 Energy Policy (2009), 1382, at 1383.

  64. 64

    See G.J.M. Velders et al., 53 above, at 922.

  65. 65


  66. 66


  67. 67

    Kyoto Protocol to the United Nations Framework Convention on Climate Change (Kyoto, 11 December 1997; in force 16 February 2005) (‘Kyoto Protocol’), Annex A.

  68. 68

    See 56 above.

  69. 69

    CDM projects reducing HFC emissions accounted for 28% of all CERs in the 2008–2012 commitment period, although HFCs only account for 1% of the global radiative forcing of all well-mixed greenhouse gases. In 2006, HFC destruction projects amounted to the largest greenhouse gas emission reductions under CDM on a CO2-eq. basis. See Pew Center on Global Climate Change, Clean Development Mechanism Backgrounder: October 2008 Status Report (Pew Center, 2008), at 8.

  70. 70

    See UNFCCC CDM Methodologies Panel, Forty-ninth Meeting Report: Note on the Revision of AM001 (June 2011), found at: <>; European Commission Press Release, ‘Emissions Trading: Commission Welcomes Vote to Ban Certain Industrial Gas Credits’ (21 January 2011), found at: <>; Government of New Zealand Press Release, ‘Industrial Gas Units Banned from New Zealand's ETS’ (22 December 2011), found at: <>; Australian Government Clean Energy Regulator, Carbon Pricing Mechanism: Eligible Emissions Units, found at: <>.

  71. 71

    TEAP, The Implications of the Montreal Protocol of the Inclusion of HFCs and PFCs in the Kyoto Protocol (TEAP, 1999) at 11.

  72. 72

    See Ad Hoc Working Group on Long-term Cooperative Action under the Convention, Negotiation Text (UN Doc. FCCC/AWGLCA/2009/8, 19 May 2009), at paragraph 55 (discussing legally binding mitigation commitments for developed countries) and paragraphs 70–73 (discussing nationally appropriate mitigation actions for developing countries). See also Ad Hoc Working Group on Further Commitments for Annex I Parties under the Kyoto Protocol, A Text on Other Issues Outlined in Document FCCC/KP/AWG/2008/8 (UN Doc. FCCC/KP/AWG/2009/8, 14 May 2009).

  73. 73

    See Carbon Finance, Cost-effectiveness of CDM Projects (18 November 2008), found at: <>.

  74. 74

    At a 10% annual growth rate, atmospheric concentrations of HFCs can expect to double every 7.27 years, and 4.96 years if the growth rate is 15%.

  75. 75

    See S.O. Andersen, K.M. Sarma and K.N. Taddonio, 40 above; R. Picolotti, ‘Our Planet: An Equitable Arrangement’ (2011), found at: <>.

  76. 76

    See R. Picolotti, 75 above; Montreal Protocol, 39 above, Articles 2 (discussing control measures), 2A (discussing CFCs), 2F (discussing Hydrochlorofluorocarbons) and 5 (discussing the special situation of developing countries).

  77. 77

    See M. Molina et al., 2 above.

  78. 78

    V. Ramanathan, ‘Greenhouse Effect Due to Chlorofluorocarbons: Climatic Implications’, 190 Science (1975), 50.

  79. 79

    K.A. Annan, Report of the Secretary-General, We the Peoples: The Role of the United Nations in the 21st Century (United Nations, 2000), found at: <>, at 56. See also UNEP, Global Environment Outlook 5: Environment for the Future We Want (UNEP, 2012), at 464; G.J.M. Velders et al., 53 above.

  80. 80

    The direct climate benefit of the 222 Gt CO2-eq. reduction is offset by about 30% due to a several factors, including indirect radiative forcing from reductions in the stratospheric ozone and climate forcing from increased use of substitutes of ozone depleting substances. The delay expressed here is the number of years required for the radiative forcing of CO2 to increase by the same amount as the radiative forcing of ozone depleting substances would have been by 2010. See G.J.M. Velders et al., 35 above; G.J.M. Velders et al., 53 above.

  81. 81

    See G.J.M. Velders et al., 35 above; G.J.M. Velders et al., 4 above; UNEP, The Montreal Protocol and the Green Economy: Assessing the Contributions and Co-benefits of a Multilateral Environmental Agreement (UNEP, 2012), at 53.

  82. 82


  83. 83

    See UNEP, 43 above, at 18.

  84. 84

    See, generally, S.O. Andersen, K.M. Sarma and K.N. Taddonio, 40 above; S.O. Andersen and K.M. Sarma, 36 above. See also K.M. Sarma et al., 37 above; D. Hunter, J. Salzman and D. Zaelke, 40 above.

  85. 85

    See M. Molina et al., 2 above.

  86. 86

    Report of the Sixty-Fifth Meeting of the Executive Committee of the Multilateral Fund for the Implementation of the Montreal Protocol (UN Doc. UNEP/OzL.Pro/ExCom/65/60/Corr.1, 13 January 2012), Annex 1, at 1.

  87. 87

    See M. Molina et al., 2 above.

  88. 88


  89. 89

    R. Shende, Convenient Opportunity to Address an Inconvenient Truth (September 2008), found at: <>. See also Speech by Rajendra Shende Chief of Energy and OzonAction at UNEP Division of Technology, Industry and Economics (Washington, DC, 2009), found at: <>.

  90. 90

    Montreal Protocol, 39 above, Articles 2H and 5.

  91. 91

    UNEP, ‘Compliance Assistance Programme: Regional Networks of National Ozone Units’ (October 2011), found at: <>.

  92. 92

    See M. Molina et al., 2 above.

  93. 93

    See, generally, S.O. Andersen, K.M. Sarma and K.N. Taddonio, 40 above; Ozone Secretariat, ‘Assessment Panels’, found at: <>.

  94. 94

    UNEP, Proposed Amendment to the Montreal Protocol, Submitted by the Federated States of Micronesia (UN Doc. UNEP/OzL.Pro.WG.1/32/5, 11 May 2012) (‘Proposed Amendment by Micronesia’); UNEP, Proposed Amendment to the Montreal Protocol, Submitted by the United States, Canada and Mexico (UN Doc. UNEP/OzL.Pro.WG.1/32/6, 11 May 2012) (‘Proposed Amendment by the US, Canada and Mexico’).

  95. 95

    Proposed Amendment by Micronesia, 94 above, at 9; Proposed Amendment by the US, Canada and Mexico, 94 above, at 10.

  96. 96

    See, generally, UNEP, Task Force Decision XX/8 Report: Assessment of Alternatives to HCFCs and HFCs and Update of the TEAP 2005 Supplement Report Data (UNEP, 2009), found at: <>; G.J.M. Velders et al., 53 above; UNEP, TEAP 2010 Progress Report, Vol. 1 (UNEP, 2010) (‘TEAP 2010 Progress Report’), found at: <>; UNEP, 43 above, at 27–33.

  97. 97

    See UNEP, TEAP 2010 Progress Report, 96 above; UNEP, 43 above, at 12, 28, 30.

  98. 98

    UNEP, 43 above, at 28.

  99. 99

    Ibid., at 28; D.J. Luecken et al., ‘Ozone and TFA Impacts in North America from Degradation of 2,3,3,3-Tetrafluoropropene (HFO-1234yf): A Potential Greenhouse Gas Replacement’, 44:1 Environmental Science and Technology (2010), 343.

  100. 100

    See UNEP, 43 above, at 27.

  101. 101

    The cumulative business-as-usual emissions from the six Kyoto gases from 2000–2050 is about 975 Gt CO2-eq. (equal to 650 x 1.5, under Figure 1, Scenario 6, in M.H. England, A. Sen Gupta and A.J. Pitman, ‘Constraining Future Greenhouse Gas Emissions by a Cumulative Target’, 106:39 Proceedings of the National Academy of Sciences (2009), 16539 ), which is equivalent to approximately 3575 Gt CO2-eq. The cumulative Kyoto-gas emission budget for 2000–2050 is 1500 Gt CO2-eq. if the probability of exceeding 2°C is to be limited to approximately 25%. See M. Meinshausen et al., 24 above. Therefore, the total mitigation need by 2050 is approximately 2075 Gt CO2-eq. The 87–147 Gt CO2-eq. from the proposed HFC phase-down represents 4–7% of the total mitigation needed by 2050, up to 8% if all HFCs are replaced by low-GWP substitutes. See G.J.M. Velders et al., 46 above.

  102. 102

    Report of the Combined Ninth Meeting of the Conference of the Parties to the Vienna Convention on the Protection of the Ozone Layer and the Twenty-third Meeting of the Parties to the Montreal Protocol on Substances that Deplete the Ozone Layer (UN Doc. UNEP/OzL.Pro.23/11, 8 December 2011), at paragraph 156. The Bangkok Declaration can be found at UNEP, Twenty-second Meeting of the Parties, Annex III: Declaration on the Global Transition away from Hydrochlorofluorocarbons (HCFCs) and Chlorofluorocarbons (CFCs) (Bangkok, 8–12, November 2010), found at: <>.

  103. 103

    Consumer Goods Forum, Better Lives through Better Business (29 March 2012), found at: <>, at 7.

  104. 104

    UN Conference on Sustainable Development, Conference Declaration, The Future We Want (UN Doc. A/CONF.216/L.1, 22 June 2012), at paragraph 222.

  105. 105

    Montreal Protocol, 39 above, Articles 2A (covering the phase-out of CFCs), 2F (covering the phase-out of Hydrofluorocarbons) and 5 (describing the phase-out grace period for developing countries).

  106. 106

    UNFCCC, 21 above, Article 2.

  107. 107

    Ibid., Article 7.2(l).

  108. 108

    Kyoto Protocol, 67 above, Article 2.2.


  • Durwood Zaelke is President of the Institute for Governance and Sustainable Development (IGSD), Director of the Secretariat of the International Network for Environmental Compliance and Enforcement, and co-Director of the Program on Governance for Sustainable Development, University of California, Santa Barbara's Bren School of Environmental Science and Management.

  • Stephen O. Andersen is Director of Research for IGSD, Co-chair of the Montreal Protocol's Technology and Economic Assessment Panel, and member of its Scientific Assessment Panel. From 1986 to 2009 Dr Andersen worked for the United States Environmental Protection Agency on stratospheric ozone and climate protection. He is co-author of two United Nations books on the Montreal Protocol, and author of numerous scientific, technical and environmental policy studies.

  • Nathan Borgford-Parnell is a law fellow at IGSD focusing on near-term mitigation of short-lived climate pollutants and carbon negative mitigation, and founder of Valkyrie Energy – a renewable energy consulting firm – and former Peace Corps volunteer in Albania (2003–2005).