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.2010, Review of Joachim Radkau, Nature and Power: A Global History of the Environment, , by David Christian, 2010 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.
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.Sebastian Oberthür, International Environmental Agreements July 2001, Volume 1, Issue 3, pp 357-377, Linkages between the Montreal and Kyoto Protocols – Enhancing Synergies between Protecting the Ozone Layer and the Global Climate
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 stratosphere has had a negative radiative forcing impact; however, anthropogenic increases in tropospheric abundance more than offset this.
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 anthropogenic changes in the amount of ozone. Projections show that CFCs and other halocarbons will have contributed to between 4-10% of total expected greenhouse warming by the year 2100.
Policy approach
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. 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 , 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. These countries have also ratified the London, Copenhagen, and Montreal amendments to the Protocol. , the Beijing amendments had not been ratified by two state parties.
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. The EU shifted its position as well after Germany, which has a substantial chemical industry, gave up its defence of the CFC industry 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.Reiner Grundmann, Transnational Environmental Policy, London: Routledge,
The Vienna Convention was installed before a scientific consensus on the ozone hole was established.Reiner Grundmann "Technische Problemlösung, Verhandeln und umfassende Problemlösung", (Technical trouble shooting, negotiating and generic problem solving capability) in Gesellschaftliche Komplexität und kollektive Handlungsfähigkeit (Complexity of society and collective ability to act), ed. Schimank, U. (2000). Frankfurt/Main: Campus, pp. 154–82 book summary at the Max Planck Gesellschaft On the contrary, until the 1980s the EU, NASA, NAS, UNEP, WMO and the British government had issued scientific reports with divergent conclusions. Sir Robert (Bob) Watson, Director of the Science Division at NASA, played a crucial role in the process of reaching a unified assessment.
Policy and consensus
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.Aant Elzinga, "Shaping Worldwide Consensus: the Orchestration of Global Change", in Elzinga & Landström eds. (1996) Internationalism and Science: 223-255. . 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.
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.
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. Current Sociology November 2010 vol. 58 no. 6 897-910, see Lever Tracy's paper in the same journal 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. 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.Michael Oppenheimer et al., "The limits of consensus", in Science Magazine's State of the Planet 2008-2009: with a Special Section on Energy and Sustainability, Donald Kennedy, Island Press, 01.12.2008, separate as It has become more important to provide a broader exploration of uncertainties. Others also see mixed blessings in the drive for consensus within the IPCC process and have asked for dissenting or minority positions to be includedMike Hulme, "Lessons from the IPCC: do scientific assessments need to be consensual to be authoritative?" in (eds.) Doubleday, R. and Willesden, J. March 2013, page 142 ff or for statements about uncertainties to be improved.Do scientific assessments need to be consensual to be authoritative? Curry, JA and PJ Webster, 2012: "Climate change: no consensus on consensus". CAB Reviews, in press, 2012
Public opinion
The two atmospheric problems have achieved significantly different levels of understanding by the public, including both the basic science and policy issues. People have limited scientific knowledge about global warming and tend to confuse it with or see it as a subset of the ozone hole.Compare Sheldon Ungar, 2000 and various web sites such as Gavin Schmidts realclimate complaint in depletion and global warming 2005 or the UCS FAQ on the topic 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.
The metaphors used in the CFC discussion (ozone shield, ozone hole) resonated better with non-scientists and their concerns. 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. The ozone hole was much more seen as a "hot issue" and imminent risk compared to global climate change, as lay people feared a depletion of the ozone layer (ozone shield) risked increasing severe consequences such as skin cancer, cataracts, damage to plants, and reduction of plankton populations in the ocean's photic zone. This was not the case with global warming.
Personal risk assessment and knowledge