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The Montreal Protocol on Substances that Deplete the Ozone Layer (Montreal Protocol) can be further strengthened to control ozone-depleting substances and hydrofluorocarbons used as feedstocks to provide additional protection of the stratospheric ozone layer and the climate system while also mitigating plastics pollution. The feedstock exemptions were premised on the assumption that feedstocks presented an insignificant threat to the environment; experience has shown that this is incorrect. Through its adjustment procedures, the Montreal Protocol can narrow the scope of feedstock exemptions to reduce inadvertent and unauthorized emissions while continuing to exempt production of feedstocks for time-limited, essential uses. This upstream approach can be an effective and efficient complement to other efforts to reduce plastic pollution. Existing mechanisms in the Montreal Protocol such as the Assessment Panels and national implementation strategies can guide the choice of environmentally superior substitutes for feedstock-derived plastics. This paper provides a framework for policy makers, industries, and civil society to consider how stronger actions under the Montreal Protocol can complement other chemical and environmental treaties. [ABSTRACT FROM AUTHOR]

Abstract The Montreal Protocol has halted 99% of global production of chemical substances that deplete stratospheric ozone, which protects life on earth from the harmful effects of ultraviolet (UVB) radiation. UVB causes skin cancer and cataracts, suppresses the human immune system, destroys plastics, and damages agricultural crops and natural ecosystems. Because ozone-depleting substances (ODSs) are powerful greenhouse gases, the Montreal Protocol also protects climate. From the authors' perspectives in multiple roles as environmental entrepreneurs, practitioners, and authorities, this paper explains how individuals, companies, and military organizations researched, developed, commercialized and implemented alternatives to ODSs that are also safer for climate. With the benefit of hindsight, the authors reflect on what was neglected or done badly under the Montreal Protocol and present lessons learned on how Montreal Protocol institutions can be renewed and revitalized to phase down hydrofluorocarbons (HFCs). [ABSTRACT FROM AUTHOR]

In 1974, Mario Molina and F. Sherwood Rowland warned that chlorofluorocarbons (CFCs) could destroy the stratospheric ozone layer that protects Earth from harmful ultraviolet radiation. In the decade after, scientists documented the buildup and long lifetime of CFCs in the atmosphere; found the proof that CFCs chemically decomposed in the stratosphere and catalyzed the depletion of ozone; quantified the adverse effects; and motivated the public and policymakers to take action. In 1987, 24 nations plus the European Community signed the Montreal Protocol. Today, 25 years after the Montreal Protocol was agreed, every United Nations state is a party (universal ratification of 196 governments); all parties are in compliance with the stringent controls; 98% of almost 100 ozone-depleting chemicals have been phased out worldwide; and the stratospheric ozone layer is on its way to recovery by 2065. A growing coalition of nations supports using the Montreal Protocol to phase down hydrofluorocarbons, which are ozone safe but potent greenhouse gases. Without rigorous science and international consensus, emissions of CFCs and related ozone-depleting substances (ODSs) could have destroyed up to two-thirds of the ozone layer by 2065, increasing the risk of causing millions of cancer cases and the potential loss of half of global agricultural production. Furthermore, because most ODSs are also greenhouse gases, CFCs and related ODSs could have had the effect of the equivalent of 24–76 gigatons per year of carbon dioxide. This critical review describes the history of the science of stratospheric ozone depletion, summarizes the evolution of control measures and compliance under the Montreal Protocol and national legislation, presents a review of six separate transformations over the last 100 years in refrigeration and air conditioning (A/C) technology, and illustrates government–industry cooperation in continually improving the environmental performance of motor vehicle A/C. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

The 1987 Montreal Protocol on Substances that Deplete the Ozone Layer is a landmark agreement that has successfully reduced the global production, consumption, and emissions of ozone-depleting substances (ODSs). ODSs are also greenhouse gases that contribute to the radiative forcing of climate change. Using historical ODSs emissions and scenarios of potential emissions, we show that the ODS contribution to radiative forcing most likely would have been much larger if the ODS link to stratospheric ozone depletion had not been recognized in 1974 and followed by a series of regulations. The climate protection already achieved by the Montreal Protocol alone is far larger than the reduction target of the first commitment period of the Kyoto Protocol. Additional climate benefits that are significant compared with the Kyoto Protocol reduction target could be achieved by actions under the Montreal Protocol, by managing the emissions of substitute fluorocarbon gases and/or implementing alternative gases with lower global warming potentials. [ABSTRACT FROM AUTHOR]

Discusses various aspects concerning the role of the military in protecting the ozone layer. Implementation of substitute materials and chemicals that eliminates the use of chlorofluorocarbons; Recommendations of North Atlantic Treaty Organization (NATO); Phaseout of halon products. INSETS: Recommendations of the Second International NATO/CCMS..;The strategy for managing halons..

The article presents an obituary for chemist and physicist Frank Sherwood Rowland.

In 2008, 95% of the vehicle fleet in the developed countries and 80% of fleet in the developing countries were equipped with mobile air conditioning systems (MACs). Greenhouse gases (GHGs) are emitted due to refrigerant leakage (direct emissions) and due to the energy consumed by MACs operation (indirect emissions). In response to reducing the global warming impact of MACs, policy makers and the industry are investigating alternative refrigerant systems that use low global warming potential (GWP) refrigerants. The GREEN-MAC-LCCP model assesses the direct and indirect CO2 equivalent emissions related to MACs usage, as well as those associated with the production, use and disposal of alternative refrigerants and MACs components. This model provides a platform for simple data input and provides an output summary as well as details that can be analyzed in a custom fashion by the user. It provides engineers and policy makers a state-of-the-art tool, based on sound engineering data and methods, in order to facilitate the process of evaluating alternate refrigerants with low lifecycle global warming impact as well as providing the total impact of any MACs on the environment It has been recognized as the standard of the MACs industry. [ABSTRACT FROM AUTHOR]

Hydrofluorocarbons (HFCs) are manufactured for use as substitutes for ozone-depleting substances that are being phased out globally under Montreal Protocol regulations. While HFCs do not deplete ozone, many are potent greenhouse gases that contribute to climate change. Here, new global scenarios show that baseline emissions of HFCs could reach 4.0–5.3 GtCO 2 -eq yr −1 in 2050. The new baseline (or business-as-usual) scenarios are formulated for 10 HFC compounds, 11 geographic regions, and 13 use categories. The scenarios rely on detailed data reported by countries to the United Nations; projections of gross domestic product and population; and recent observations of HFC atmospheric abundances. In the baseline scenarios, by 2050 China (31%), India and the rest of Asia (23%), the Middle East and northern Africa (11%), and the USA (10%) are the principal source regions for global HFC emissions; and refrigeration (40–58%) and stationary air conditioning (21–40%) are the major use sectors. The corresponding radiative forcing could reach 0.22–0.25 W m −2 in 2050, which would be 12–24% of the increase from business-as-usual CO 2 emissions from 2015 to 2050. National regulations to limit HFC use have already been adopted in the European Union, Japan and USA, and proposals have been submitted to amend the Montreal Protocol to substantially reduce growth in HFC use. Calculated baseline emissions are reduced by 90% in 2050 by implementing the North America Montreal Protocol amendment proposal. Global adoption of technologies required to meet national regulations would be sufficient to reduce 2050 baseline HFC consumption by more than 50% of that achieved with the North America proposal for most developed and developing countries. [ABSTRACT FROM AUTHOR]

Supplemental Materials:Supplemental materials are available for this paper. Go to the publisher's online edition of the Journal of the Air & Waste Management Association. [ABSTRACT FROM AUTHOR]

We use a regional-scale, three-dimensional atmospheric model to evaluate U.S. air quality effects that mould result from replacing HFC-134a in automobile air conditioners in the U.S. with HFO-1234yf. Although HFO-1234yf produces tropospheric ozone, the incremental amount is small, averaging less than 0.01% of total ozone formed during the simulation. We show that this production of ozone could be compensated for by a modest improvement in air conditioner efficiency. Atmospheric decomposition of HFO-1234yf produces trifluoroacetic acid (TFA), which is subject to wet and dry deposition. Deposition and concentrations of TFA are spatially variable due to HFO-1234yf's short atmospheric lifetime, with more localized peaks and less global transport when compared to HFC-134a. Over the 2.5 month simulation, deposition of TFA in the continental U.S. from mobile air conditioners averages 0.24 kg km-2, substantially higher than previous estimates from all sources of current hydrofluorocarbons. Automobile air conditioning HFO-1234yf emissions are predicted to produce concentrations of TFA in Eastern U.S. rainfall at least double the values currently observed from all sources, natural and man-made. Our model predicts peak concentrations in rainfall of 1264 ng L-1, a level that is 80× lower than the lowest level considered safe for the most sensitive aquatic organisms. [ABSTRACT FROM AUTHOR]

Current emissions of anthropogenic greenhouse gases (GHGs) have already committed the planet to an increase in average surface temperature by the end of the century that may be above the critical threshold for tipping elements of the climate system into abrupt change with potentially irreversible and unmanageable consequences. This would mean that the climate system is close to entering if not already within the zone of "dangerous anthropogenic interference" (DAI). Scientific and policy literature refers to the need for "early," "urgent," "rapid," and "fast-action" mitigation to help avoid DAI and abrupt climate changes. We define "fast-action" to include regulatory measures that can begin within 2-3 years, be substantially implemented in 5-10 years, and produce a climate response within decades. We discuss strategies for short-lived non-CO2 GHGs and particles, where existing agreements can be used to accomplish mitigation objectives. Policy makers can amend the Montreal Protocol to phase down the production and consumption of hydrofluorocarbons (HFCs) with high global warming potential. Other fast-action strategies can reduce emissions of black carbon particles and precursor gases that lead to ozone formation in the lower atmosphere, and increase biosequestration, including through biochar. These and other fast-action strategies may reduce the risk of abrupt climate change in the next few decades by complementing cuts in CO2 emissions. [ABSTRACT FROM AUTHOR]

The consumption and emissions of hydrofluorocarbons (HFCs) are projected to increase substantially in the coming decades in response to regulation of ozone depleting gases under the Montreal Protocol. The projected increases result primarily from sustained growth in demand for refrigeration, air-conditioning (AC) and insulating foam products in developing countries assuming no new regulation of HFC consumption or emissions. New HFC scenarios are presented based on current hydrochlorofluorocarbon (HCFC) consumption in leading applications, patterns of replacements of HCFCs by HFCs in developed countries, and gross domestic product (GDP) growth. Global HFC emissions significantly exceed previous estimates after 2025 with developing country emissions as much as 800% greater than in developed countries in 2050. Global HFC emissions in 2050 are equivalent to 9-19% (CO2-eq. basis) of projected global CO2 emissions in business-as-usual scenarios and contribute a radiative forcing equivalent to that from 6-13 years of CO2 emissions near 2050. This percentage increases to 28-45% compared with projected CO2 emissions in a 450-ppm CO2 stabilization scenario. In a hypothetical scenario based on a global cap followed by 4% annual reductions in consumption, HFC radiative forcing is shown to peak and begin to decline before 2050. [ABSTRACT FROM AUTHOR]