Ozone depletion and climate change are environmental challenges whose connections have been explored and which have been compared and contrasted, for example in terms of global regulation, in various studies and books.
There is widespread scientific interest in better regulation of climate change, ozone depletion and air pollution, as in general the human relationship with the biosphere is deemed of major historiographical and political significance. [1] Already by 1994 the legal debates about respective regulation regimes on climate change, ozone depletion and air pollution were being dubbed "monumental" and a combined synopsis provided. [2]
There are some parallels between atmospheric chemistry and anthropogenic emissions in the discussions which have taken place and the regulatory attempts which have been made. Most important is that the gases causing both problems have long lifetimes after emission to the atmosphere, thus causing problems that are difficult to reverse. However, the Vienna Convention for the Protection of the Ozone Layer and the Montreal Protocol that amended it are seen as success stories, while the Kyoto Protocol on anthropogenic climate change has largely failed. Currently, efforts are being undertaken to assess the reasons and to use synergies, for example with regard to data reporting and policy design and further exchanging of information. [3]
Ozone depletion is not a primary cause of climate change, however there exists a physical science connection between the two phenomena. The Earth's atmospheric ozone has two major effects on the Earth's temperature balance. Firstly, it absorbs solar ultraviolet radiation, leading to the heating of the stratosphere. Secondly, it also traps heat in the troposphere by absorbing infrared radiation emitted by the Earth's surface. Ozone depletion in the stratopshere has had a negative radiative forcing impact, however anthropogenic increases in the tropospheric abundance more than offsets this. [4] Additionally, chlorofluorocarbons (CFCs) and other halocarbons which have caused ozone depletion are strong greenhouse gases, and the warming influence of the addition of these to the atmosphere has been greater than the net effect of the antropogenic changes in the amount of ozone. [4]
There are both links and major differences between ozone depletion and global warming and the way the two challenges have been handled. While in the case of atmospheric ozone depletion, in a situation of high uncertainty and against strong resistance, climate change regulation attempts at the international level such as the Kyoto Protocol have failed to reduce global emissions. [5] [6] The Vienna Convention for the Protection of the Ozone Layer and the Montreal Protocol were both originally signed by only some member states of the United Nations (43 nations in the case of the Montreal Protocol in 1986) while Kyoto attempted to create a worldwide agreement from scratch. Expert consensus concerning CFCs in the form of the Scientific Assessment of Ozone Depletion was reached long after the first regulatory steps were taken, and as of 29 December 2012 [update] , all countries in the United Nations plus the Cook Islands, the Holy See, Niue and the supranational European Union had ratified the original Montreal Protocol. [7] These countries have also ratified the London, Copenhagen, and Montreal amendments to the Protocol. As of 15 April 2014 [update] , the Beijing amendments had not been ratified by two state parties. [8]
After the Vienna Convention, the halocarbon industry shifted its position and started supporting a protocol to limit CFC production. US manufacturer DuPont acted more quickly than their European counterparts. [9] The EU shifted its position as well after Germany, which has a substantial chemical industry, gave up its defence of the CFC industry [5] and started supporting more regulation. Government and industry in France and the UK had tried to defend their CFC-producing industries even after the Montreal Protocol had been signed. [10]
The Vienna Convention was installed before a scientific consensus on the ozone hole was established. [5] On the contrary, until the 1980s the EU, NASA, NAS, UNEP, WMO and the British government had issued scientific reports with divergent conclusions. [5] Sir Robert (Bob) Watson, Director of the Science Division at NASA, played a crucial role in the process of reaching a unified assessment. [5]
Aant Elzinga wrote in 1996 about the consensus, that the Intergovernmental Panel on Climate Change has tried in the prior two reports a global consensus approach to climate action. [11] Stephen Schneider and Paul N. Edwards, noted in 1997, that after the IPCC Second Assessment Report, the lobby group Global Climate Coalition and a few self-proclaimed “contrarian” scientists tried to discredit the conclusions of the report. They pointed out that the goal of the IPCC is to fairly represent the complete range of credible scientific opinion and if possible a consensus view. [12]
In 2007, Reiner Grundmann compared climate actions in Europe and the United States, he interpreted the inaction besides existing consensus, and noted, Political agenda that drove US climate change policy. The high visibility of skeptical scientists in the media resonates with this, and wrote that Germany started ambitious goals, reduced emissions, because ‘balanced reporting’ led to a bias in climate change coverage in advantage of skeptical arguments in the U.S., but not so much in Germany. Additionally, Grundmann pointed out that after warnings from scientists in 1986 the German Parliament commissioned the Enquetekommission ‘Vorsorge zum Schutz der Erdatmosphäre’ (Precaution for the Protection of the Earth's Atmosphere), to assess the situation, consisting of scientists, politicians and representatives of interest groups. Three years later the report made an impact with the assessment of the state of the art in climate research, an assessment of the threat of climate change itself as well as suggestions for clear emissions reduction targets, even though he argues there was no consensus, and attributed the success of the report to strong precautionary action, and that no scientific outsiders or climate change deniers were involved. [13] [14]
A linear model of policy-making, based on a position that "the more knowledge we have, the better the political response will be", was not applied in the ozone case. [15] On the contrary, the CFC regulation process focused more on managing ignorance and uncertainties as a basis of political decision making, as the relationships between science, public (lack of) understanding and policy were better taken into account. [6] [13] [16] In the meantime, such a player in the IPCC process as Michael Oppenheimer conceded some limitations of the IPCC consensus approach and asked for concurring, smaller assessments of special problems instead of repetitions of the large-scale approach every six years. [17] It has become more important to provide a broader exploration of uncertainties. [17] Others also see mixed blessings in the drive for consensus within the IPCC process and have asked for dissenting or minority positions to be included [18] or for statements about uncertainties to be improved. [19] [20]
The two atmospheric problems have achieved significantly different levels of understanding by the public, including both the basic science and policy issues. [16] People have limited scientific knowledge about global warming and tend to confuse it with [21] or see it as a subset of the ozone hole. [22] Not only on the policy level, ozone regulation fared much better than climate change in public opinion. Americans voluntarily switched away from aerosol sprays before the legislation was enforced, while climate change has failed in achieving a broader scientific comprehension and in raising comparable concern. [16]
The metaphors used in the CFC discussion (ozone shield, ozone hole) resonated better with non-scientists and their concerns. [16] The ozone case was communicated to lay persons "with easy-to-understand bridging metaphors derived from the popular culture" and related to "immediate risks with everyday relevance", while the public opinion on climate change sees no imminent danger. [16] The ozone hole was much more seen as a "hot issue" and imminent risk compared to global climate change, [13] as lay people feared a depletion of the ozone layer (ozone shield) risked increasing severe consequences such as skin cancer, cataracts, [23] damage to plants, and reduction of plankton populations in the ocean's photic zone. This was not the case with global warming. [5]
Sheldon Ungar Archived 2021-05-06 at the Wayback Machine , a Canadian sociologist, assumes that while the quantity of specialized knowledge is exploding, in contrast scientific ignorance among lay people is the norm and even increasing. Public opinion failed to tie climate change to concrete events which could be used as a threshold or beacon to signify immediate danger. [16] Scientific predictions of a temperature rise of 2 °C (4 °F) to 3 °C (5 °F) over several decades do not resonate with people, for example in North America, who experience similar swings during a single day. [16] As scientists define global warming as a problem of the future, a liability in the "attention economy", pessimistic outlooks in general and the attribution of extreme weather to climate change have often been discredited or ridiculed in the public arena (compare the Gore effect). [24] Even when James Hansen tried to use the 1988–89 North American drought as a call to action, scientists kept stating, in line with the IPCC findings, that even extreme weather is not climate. [16] While the greenhouse effect, per se, is essential for life on earth, the case was quite different with the ozone hole and other metaphors about ozone depletion. The scientific assessment of the ozone problem also had large uncertainties; both the ozone content of the upper atmosphere and its depletion are complicated to measure and the link between ozone depletion and rates of enhanced skin cancer is rather weak. But the metaphors used in the discussion (ozone shield, ozone hole) resonated better with lay people and their concerns.
The idea of rays penetrating a damaged “shield” meshes nicely with abiding and resonant cultural motifs, including “Hollywood affinities.” These range from the shields on the Starship Enterprise to Star Wars ... It is these pre-scientific bridging metaphors built around the penetration of a deteriorating shield that render the ozone problem relatively simple. That the ozone threat can be linked with Darth Vader means that it is encompassed in common sense understandings that are deeply ingrained and widely shared. [16]
— Sheldon Ungar
The CFC regulation attempts at the end of the 1980s profited from those easy to grasp metaphors and the personal risk assumptions taken from them. The fate of celebrities like President Ronald Reagan, who had skin cancer removal from his nose in 1985 and 1987, was also of high importance. [25] In case of the public opinion on climate change, no imminent danger is perceived. [16]
Cass Sunstein and others have compared the differing approach of the United States to the Montreal Protocol, which it accepted, and the Kyoto Protocol, which it rejected. Sunstein assumes that the cost-benefit assessments of climate change action for the US were instrumental in the US' withdrawal from participation in Kyoto. [6] Daniel Magraw, also a lawyer, considers governmental motivations besides relative costs and benefits as being of higher importance. [6] Peter Orszag and Terry Dinan took an insurance perspective and assume that an assessment which predicted dire consequences of climate change would be more of a motivation for the US to change its stance on global warming and adopting regulation measurements. [6]
The US chemical company DuPont had already lost some of their zeal in defending their products after a strategic manufacturing patent for Freon was set to expire in 1979. A citizen boycott of spray cans gained importance in parallel. Not by chance, the United States banned the use of CFCs in aerosol cans in 1978. [26]
Government and industry in France and the UK tried to defend their CFC-producing industries even after the Montreal Protocol had been signed. [10] The European Community rejected proposals to ban CFCs in aerosol sprays for a long time. The EU shifted its position after Germany, which also has a large chemical industry, gave up its defence of the CFC industry [5] and started supporting moves towards regulation. After regulation was more and more enforced, DuPont acted faster than their European counterparts as they may have feared court action related to increased skin cancer, especially as the EPA had published a study in 1986 claiming that an additional 40 million cases and 800,000 cancer deaths were to be expected in the US in the next 88 years. [9] The identification and marketing of a 100% ozone-safe hydrocarbon refrigerant called "Greenfreeze" by the NGO Greenpeace in the early 1990s had a rapid significant impact in major markets of Europe and Asia. [27] [28] The climate change protocols were less successful. In the case of Kyoto, then secretary of the environment Angela Merkel, prevented a possible failure by suggesting to use 1990 as starting date for emission reduction. In so far the demise of the Eastern European heavy industry allowed for a high commitment, but actual emissions kept on growing on a global scale. [29]
There are various links between the two fields of human-atmospheric interaction. Policy experts have advocated for a closer linking of ozone protection and climate protection efforts. [30] [31]
Ozone is a greenhouse gas, [32] and changes in its atmospheric abundance due to human activity have radiative forcing effects. Ozone absorbs both ultraviolet (UV) radiation from the sun and infrared radiation emitted from Earth's surface. [4] Human activity has depleted ozone in the stratopshere and increased its abundance in the troposphere, producing opposing radiative forcing effects. [4] Estimates of the magnitudes of these effects have considerable uncertainty. The majority of models evaluate the overal radiative forcing impact of anthropogenic changes in ozone to be a moderate warming effect. [33] Such estimation is difficult for multiple reasons, including that, unlike most other greenhouse gases, ozone is not a well-mixed gas in the atmopshere, so modelling must take into account its spatial distribution. [33] Additionally knowledge of the pre-industrial levels of ozone in the atmopshere is incomplete. [34]
Many ozone-depleting substances are also greenhouse gases, some are thousands of times more powerful than carbon dioxide on a per-molecule basis over the short and medium term. [35] The increases in concentrations of these chemicals have produced 0.34 ± 0.03 W/m2 of radiative forcing, corresponding to about 14% of the total radiative forcing from increases in the concentrations of well-mixed greenhouse gases. [36] Because of their ozone depleting effects, production of CFCs and many other related substances have been banned globally by the 1987 Montreal Protocol and its subsequent revisions. By one model-based estimate, had these continued to be produced unabated global temperatures in 2100 would be 2.5 °C greater than they would otherwise have been; 1.7 °C from the direct greenhouse effect of the additional CFCs, and 0.8 °C from increased CO2 due to UV vegetation damage. [37]
Drew Shindell has used climate models to assess both climate change and ozone depletion. In his view, while research up to now has been more about the impact of CFC emissions on stratospheric ozone, the future will be more about the interaction between climate change and ozone feedback. [38] Already the natural ozone variability in the stratosphere seems to be closely correlated with the 11-year solar cycle of irradiance changes and has, via a dynamic coupling between the stratosphere and troposphere, a significant impact on climate. [38] Ozone acts like a shield in the stratosphere, and protects life from extremely harmful ultraviolet radiation that comes from the sun. In the absence of stratospheric ozone, life forms would simply not exist. [39]
As with carbon dioxide and methane, there are some natural sources of tropospheric chlorine, such as sea spray. Chlorine from ocean spray is soluble and thus is washed by rainfall before it reaches the stratosphere. It is stratospheric chlorine that affects ozone depletion. Only methyl chloride, which is one of the halocarbons, has a mainly natural source, [40] and it is responsible for about 20% of the chlorine in the stratosphere; the remaining 80% comes from man-made sources. [41] Chlorofluorocarbons, in contrast, are insoluble and long-lived, allowing them to reach the stratosphere. In the lower atmosphere, there is much more chlorine from CFCs and related haloalkanes than there is in hydrogen chloride from salt spray, and in the stratosphere halocarbons are dominant. [42]
The same CO
2 radiative forcing that produces global warming is expected to cool the stratosphere. [43] This cooling, in turn, is expected to produce a relative increase in ozone (O
3) depletion in the polar area and in the frequency of ozone holes. [44] Conversely, ozone depletion represents a radiative forcing of the climate system [45] of about −0.15 ± 0.10 watts per square metre (W/m2). [36]
The scientific community has been investigating the causes of climate change for decades. After thousands of studies, it came to a consensus, where it is "unequivocal that human influence has warmed the atmosphere, ocean and land since pre-industrial times." This consensus is supported by around 200 scientific organizations worldwide, The dominant role in this climate change has been played by the direct emissions of carbon dioxide from the burning of fossil fuels. Indirect CO2 emissions from land use change, and the emissions of methane, nitrous oxide and other greenhouse gases play major supporting roles.
Global warming potential (GWP) is an index to measure how much infrared thermal radiation a greenhouse gas would absorb over a given time frame after it has been added to the atmosphere. The GWP makes different greenhouse gases comparable with regard to their "effectiveness in causing radiative forcing". It is expressed as a multiple of the radiation that would be absorbed by the same mass of added carbon dioxide, which is taken as a reference gas. Therefore, the GWP has a value of 1 for CO2. For other gases it depends on how strongly the gas absorbs infrared thermal radiation, how quickly the gas leaves the atmosphere, and the time frame being considered.
The Montreal Protocol on Substances That Deplete 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 1 January 1989. Since then, it has undergone several amendments and adjustments, with revisions agreed to in 1990 (London), 1992 (Copenhagen), 1995 (Vienna), 1997 (Montreal), 1999 (Beijing), 2007 (Montreal), 2016 (Kigali) and 2018 (Quito). As a result of the international agreement, the ozone hole in Antarctica is slowly recovering. Climate projections indicate that the ozone layer will return to 1980 levels between 2040 and 2066. Due to its widespread adoption and implementation, it has been hailed as an example of successful international co-operation. Former UN Secretary-General Kofi Annan stated that "perhaps the single most successful international agreement to date has been the Montreal Protocol". 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. 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.
The ozone layer or ozone shield is a region of Earth's stratosphere that absorbs most of the Sun's ultraviolet radiation. It contains a high concentration of ozone (O3) in relation to other parts of the atmosphere, although still small in relation to other gases in the stratosphere. The ozone layer contains less than 10 parts per million of ozone, while the average ozone concentration in Earth's atmosphere as a whole is about 0.3 parts per million. The ozone layer is mainly found in the lower portion of the stratosphere, from approximately 15 to 35 kilometers (9 to 22 mi) above Earth, although its thickness varies seasonally and geographically.
Ozone depletion consists of two related events observed since the late 1970s: a steady lowering of about four percent in the total amount of ozone in Earth's atmosphere, and a much larger springtime decrease in stratospheric ozone around Earth's polar regions. The latter phenomenon is referred to as the ozone hole. There are also springtime polar tropospheric ozone depletion events in addition to these stratospheric events.
Chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) are fully or partly halogenated hydrocarbons that contain carbon (C), hydrogen (H), chlorine (Cl), and fluorine (F), produced as volatile derivatives of methane, ethane, and propane.
Sir Robert Tony Watson CMG FRS is a British chemist who has worked on atmospheric science issues including ozone depletion, global warming and paleoclimatology since the 1980s. Most recently, he is lead author of the February 2021 U.N. report Making Peace with Nature.
Radiative forcing is a concept used to quantify a change to the balance of energy flowing through a planetary atmosphere. Various factors contribute to this change in energy balance, such as concentrations of greenhouse gases and aerosols, and changes in surface albedo and solar irradiance. In more technical terms, it is defined as "the change in the net, downward minus upward, radiative flux due to a change in an external driver of climate change." These external drivers are distinguished from feedbacks and variability that are internal to the climate system, and that further influence the direction and magnitude of imbalance. Radiative forcing on Earth is meaningfully evaluated at the tropopause and at the top of the stratosphere. It is quantified in units of watts per square meter, and often summarized as an average over the total surface area of the globe.
A refrigerant is a working fluid used in cooling, heating or reverse cooling and heating of air conditioning systems and heat pumps where they undergo a repeated phase transition from a liquid to a gas and back again. Refrigerants are heavily regulated because of their toxicity and flammability and the contribution of CFC and HCFC refrigerants to ozone depletion and that of HFC refrigerants to climate change.
This glossary of climate change is a list of definitions of terms and concepts relevant to climate change, global warming, and related topics.
The Scientific Assessment of Ozone Depletion is a sequence of reports sponsored by WMO/UNEP. The most recent report is from 2018. The reports were set up to inform the Montreal Protocol and amendments about ozone depletion.
Chlorotrifluoromethane, R-13, CFC-13, or Freon 13, is a non-flammable, non-corrosive, nontoxic chlorofluorocarbon (CFC) and also a mixed halomethane. It is a man-made substance used primarily as a refrigerant. When released into the environment, CFC-13 has a high ozone depletion potential, and long atmospheric lifetime. Only a few other greenhouse gases surpass CFC-13 in global warming potential (GWP). The IPCC AR5 reported that CFC-13's atmospheric lifetime was 640 years.
Chloropentafluoroethane is a chlorofluorocarbon (CFC) once used as a refrigerant and also known as R-115 and CFC-115. Its production and consumption has been banned since 1 January 1996 under the Montreal Protocol because of its high ozone depletion potential and very long lifetime when released into the environment. CFC-115 is also a potent greenhouse gas.
This is a list of climate change topics.
Greenhouse gases (GHGs) are the gases in the atmosphere that raise the surface temperature of planets such as the Earth. What distinguishes them from other gases is that they absorb the wavelengths of radiation that a planet emits, resulting in the greenhouse effect. The Earth is warmed by sunlight, causing its surface to radiate heat, which is then mostly absorbed by greenhouse gases. Without greenhouse gases in the atmosphere, the average temperature of Earth's surface would be about −18 °C (0 °F), rather than the present average of 15 °C (59 °F).
Atmospheric methane is the methane present in Earth's atmosphere. The concentration of atmospheric methane is increasing due to methane emissions, and is causing climate change. Methane is one of the most potent greenhouse gases. Methane's radiative forcing (RF) of climate is direct, and it is the second largest contributor to human-caused climate forcing in the historical period. Methane is a major source of water vapour in the stratosphere through oxidation; and water vapour adds about 15% to methane's radiative forcing effect. The global warming potential (GWP) for methane is about 84 in terms of its impact over a 20-year timeframe, and 28 in terms of its impact over a 100-year timeframe.
1-Chloro-1,1-difluoroethane (HCFC-142b) is a haloalkane with the chemical formula CH3CClF2. It belongs to the hydrochlorofluorocarbon (HCFC) family of man-made compounds that contribute significantly to both ozone depletion and global warming when released into the environment. It is primarily used as a refrigerant where it is also known as R-142b and by trade names including Freon-142b.
Stephen Oliver Andersen is the Director of Research at the Institute for Governance & Sustainable Development (IGSD) and former co-chair (1989–2012) of the Montreal Protocol Technology and Economic Assessment Panel (TEAP) where he also chaired and co-chaired Technical Options Committees, Task Forces and Special Reports. He is one of the founders and leading figures in the success of the Montreal Protocol on Substances that Deplete the Ozone Layer that has phased out the chemicals that deplete the stratospheric ozone that protects the Earth against the harmful effects of ultraviolet radiation that causes skin cancer, cataracts, and suppression of the human immune system, destroys agricultural crops and natural ecosystems and deteriorates the built environment. Because ozone-depleting chemicals are also powerful greenhouse gases the Montreal Protocol also protected climate. Dr. Andersen was instrumental in the 2016 Kigali Amendment that will phase down hydrofluorocarbons once necessary to phase out chlorofluorocarbons (CFCs) fast enough to avoid ozone tipping points, but no longer necessary now that environmentally superior replacements are available or soon to be available. For his ambitious campaign saving the ozone layer, Dr. Andersen earned the 2021 Future of Life Award along with Joe Farman and Susan Solomon.
Akkihebbal Ramaiah (Ravi) Ravishankara ForMemRS FAAAS FRSC is a scientist specializing in Chemistry and Atmospheric Sciences, and University Distinguished Professor in the Departments of Chemistry and Atmospheric Sciences at Colorado State University, Fort Collins.
The timeline of international climate politics is a list of events significant to the politics of climate change.
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