Helpful Texts

Link zum Mandala von Bruder Klaus
Ottmar Edenhofer Christian Flachsland Kai Lessmann

Who Owns the Atmosphere?

After the Climate Summit in Cancún


From: Stimmen der Zeit, 2/2011, P. 75-88


    Looking back at the Climate Conference in Cancún in 2010 and Copenhagen in 2009, OTTMAR EDENHOFER, professor of economics of climate change and deputy director of the Potsdam Institute for Climate Impact Research (PIK), CHRISTIAN FLACHSLAND, research associate at PIK, and KAI LESSMANN, head of the working group on "Policy Instruments Modeling" at PIK analyze the results of those conferences and refer to central desiderata of global cooperation.


After the sobering climate conference in Copenhagen in 2009, one could characterize the climate policy debate of 2010, "Much heat and little light." The conference in Cancún (Mexico) has at least got important institutional elements of a future climate regime under way. However, a binding agreement is still far away. Indeed, nobody does seriously any longer doubt that the rise in global average temperature is mainly caused by man and the burning of coal, oil and gas. Since the beginning of industrialization, the Earth has already warmed up by 0.7 ° C, and without climate policy measures further 4 ° C are not unlikely in the course of the 21th century. Due to the uncertainties about the behavior of the climate system, an even greater global warming cannot be excluded. In the climate debate, the skepticism as regards the reasons has been overruled by an overwhelming evidence. However, what is contested now is that the consequences of climate change are a cause for concern.

In public, this skepticism about the impact of climate change has gained increasingly approval {1}. Even the Intergovernmental Panel on Climate Change (IPCC) was precisely criticized for allegedly systematically exaggerating the consequences of climate change and preferentially describing the so-called "worst-case scenarios". That criticism was refuted by several expert panels {2}. But it is correct that the knowledge of the consequences of climate change is still very uncertain.


Climate Policy is an Insurance Policy against Catastrophic Climate Risks

One possible response to the uncertainty about the exact consequences of global warming is the plea to make no drastic reductions in emissions. One argues that climate protection is expensive, whereas people would be able to adapt themselves to climate change. Adaptation measures could be tackled at the local level and needn't be settled by intricate international agreements. Higher dikes, new irrigation systems, drought-resistant seed varieties that could be adapted to local conditions, and, the persons concerned had a personal interest in the implementation of such measures.



At first glance this argument sounds reasonable. However, this is only applicable if it is secured that the adaptation to climate change is possible, at morally still acceptable costs, also at a rise in global mean temperature of about 4 ° to 5 ° C or more. If this is not the case, then humankind would be exposed to an irreversible climate change, which could no longer be handled. It is scarcely disputed that this possibility would be equal to the destruction of the planet, and that it cannot be excluded. However, one can argue that the probability for this is very low.

This raises the question of how events with a low probability of occurrence but with a very great damage potential are to be handled. Martin Weitzman of Harvard University shows that the traditional methods of the risk and decision theory fail, if we have to reckon with climate impacts able to destroy the planet, and if this destruction must be avoided at all costs {3}. Under these conditions it is no longer possible to balance the additional damage of a tonne of CO2 against the additional cost of preventing one tonne of CO2. For this calculation does not guarantee that a "disaster" is avoided.

In fact, climate research has already identified such events, namely the partially irreversible so-called "tipping elements" in the Earth system. These can be activated above (uncertain) temperature threshold values. Tipping elements include the drying up of the Amazon Rain Forest and the melting of the Greenland ice sheet and of the West Antarctic ice sheet, which can led to the rise in global sea levels by several meters {4}. They could damage or even totally destroy the habitat in which mankind has been living since the Holocene. But the exact threshold at which they are is activated is unknown. As for the melting of the Greenland ice sheet, best estimates reckon with a rise in global mean temperature by 1 ° to 2 ° C above the current temperature level. Without climate policy, however, a global warming of up to 4 ° C or more is to be expected until 2100 {5}.

A different conclusion therefore results from the uncertainty about the consequences of climate change. Climate change should at least be limited to such an extent that irreversible and potentially infinite damages can be excluded. The costs of climate protection are then to be seen as insurance against a catastrophic climate change. Even if in the future it should turn out that dangerous climate change is less likely to happen than feared, and that the costs of climate protection are higher than expected - in view of today's best available knowledge, it is rational to protect oneself against mankind's catastrophe. The global 2° C target adopted in Cancún has exactly this function. It shall limit the risk of dangerous climate change. Only when catastrophic risks are excluded, it is reasonable to require that people adapt themselves to the inevitable residual climate change {6}.



Moreover, there will be in the next few years a heated debate about how much humankind is willing to pay in addition to such a "minimal insurance cover". The island states e.g. argue already that the 2 ° C target is insufficient, because the disappearance of smaller islands such as Tuvalu or the Maldives is thus virtually accepted. The industrialized and emerging countries, however, fear that even the adherence to the 2 ° C target will limit their economic development. It is expected that the Fifth Assessment Report (AR5) of the Intergovernmental Panel on Climate Change (IPCC), to be published in 2014, will provide the scientific basis for this discussion.


The Waste Disposal Space in the Atmosphere is Limited

The fixing of a climate target has serious economic consequences. The property rights for using the atmosphere will be redistributed. In a world without climate protection everybody could use the atmosphere for free. With the binding establishment of a global stabilization objective, the waste disposal space "atmosphere" is juridically declared as property of all humankind.

This limitation has an implication that is simply neglected by many experts. The tenures of the owners of coal, oil and gas are devalued, because there is globally a higher stock of fossil fuels in the ground than humankind is allowed to dump in the atmosphere under such agreement. About 12.000 gigatons of carbon as fossil fuels are still available underground. But to achieve the 2 ° C objective, only 230 gigatons may be deposited in the atmosphere. Even for the implementation of a 3° C target, only a few hundred gigatons may additionally be dumped in the atmosphere. The rest of the stocks of coal, oil and gas would remain unused in the ground and thus lose their value.

Since the atmospheric waste disposal space has become a scarce resource, its value will increase as long as fossil fuels are used. This leads to a redistribution of wealth and income from the owners of fossil resources to the owners of the atmosphere. This redistribution is a consequence of the fact that the atmosphere can no longer be used free of charge. It has nothing to do with the fact that climate policy as such is used for the purpose of redistribution of wealth. It also makes clear why there will be considerable resistance by the stakeholders concerned against every ambitious climate policy, and why it would be advantageous for the owners of these resources if there were no climate change and no climate policy. It is therefore understandable that the owners of coal, oil and gas try to show that climate change is not caused by man or that its consequences are not severe.



There are essentially two technical options to control the use of the waste disposal space. First, one could raise a CO2 tax and distribute the tax revenues. Alternatively, the carbon budget can be controlled directly by issuing emission allowances that are tradable among market participants. Everyone who wants to burn coal, oil or gas has then not only to pay the price of these fuels but also acquire the respective emission allowance. Since supply is fixed by the carbon budget, the price of emission allowances will rise on the market when demand is increasing. In this way procedures will be marketable which use no fossil fuels and are not dependent on the purchase of emission allowances. We consider here only the second option of an emissions trading scheme. First, because emissions trading has been laid down in the Kyoto Protocol and implemented in the EU, and secondly because we have shown elsewhere that emission trading has many advantages over the CO2 tax {7}.

However, the stipulation of a global carbon budget, i.e. the "size of the waste disposal site", is not enough. In addition it must also be defined how the usage rights of this disposal site are distributed.


The General Provision of Earthly Goods Calls for an Ambitious Climate Policy

It is certainly no exaggeration to state that climate policy implies a redistribution of wealth at a scale beyond historical comparison. Climate policy, so the allegation of some observers, is therefore a massive attack on the institution of private property, which can not be justified from an ethical perspective. It is therefore to be shown that it is ethically legitimate to stipulate usage rights to the atmosphere, even if as a result the property rights to coal, oil and gas resources are devalued. In addition, it has to be shown according to what standards these usage rights to the atmosphere should be distributed.

It is possible to substantiate an ambitious climate policy by resorting to a form of argumentation that can be regarded as classic, precisely in the justification of private property, and has been rethought by the Catholic social teaching in its confrontation with liberalism and Marxism. Already Thomas Aquinas has basically affirmed man's right of disposal of the goods of the earth - and thus also of man's domination over nature {8}. However, the use of the "created" natural ressources has to serve the common good of humankind.



According to him, the institution of private property as regards natural resources can only be justified if it is shown that it serves the common good more than public property rights. Private property is thus subject to social accountability. In fact, the definition of usage rights to the atmosphere serves the public welfare if it can be shown that a dangerous climate change can thus be prevented. If this devalues the title of ownership of coal, oil and gas, this can be justified by reference to the social obligation of private property.

With regard to fixing the allocation formula for the usage rights to the atmosphere, this conception of the universal destination of earthly goods admittedly does not allow direct conclusions. However, the recent social teachings by Pope John Paul II have defined the universal destination of earthly goods and thus the social accountability of private property more precisely, to the effect that they have to serve above all the poor {9}. This allows rejecting the claims of owners of coal, oil and gas. They expect a compensation for the fall in value which they suffer as result of the fixing of usage rights to the atmosphere. But this claim does not play a central role in the climate negotiations, although Saudi Arabia has repeatedly made this request.

In the climate negotiations the developing and emerging countries, especially China demand a distribution of emission allowances according to historical emissions {10}. The less emissions a country has caused in the past, the more emission allowances it has to have in the future. Two arguments are mainly presented for the principle of historical responsibility. First, with reference to the polluter pays principle, one demands from the states responsible for historic emissions a direct compensation for present and future damages caused by emissions. Second, it is argued that through the course of the human history all people - and thus all regions of the world - should have the same right to the use of the atmosphere. Due to the already spent high emissions of their ancestors, these emissions of the past shall be deducted from the budget of people in rich countries.

At first glance, the call for historical responsibility of developed countries is understandable. On closer inspection, however, this argument is hardly convincing, because persons living today can not be blamed directly for the actions (as e.g. emissions) of the deceased. In addition, one has to admit that previous generations knew little about the harmful effects of emissions. For this reason alone direct compensation claims for historical emissions, as e.g. before 1995, are problematic. What is more, it is generally difficult to ascertain clearly who was responsible for these historic emissions, the extent of responsibility, or the damages caused by those emissions. This applies equally to the call for balancing present-day advantages, due to historical emissions.



By contrast, developed countries repeatedly plead in favour of a distribution of the remaining waste disposal space in accordance with current emissions or the amount of the gross domestic product. They argue that they need a higher emission budget for the operation of their energy-intensive economies. This approach, however, would further consolidate the existing global inequalities of life chances, and this is not acceptable from the perspective of developing countries.

Regarding the question of the equitable distribution of emissions allowances, neither the principles of liability and compensation nor unilateral economic interests should therefore be decisive. By contrast, with regard to the future and the implementation of universal human rights the possibilities of extending the options for action of the poorest should be the major criterion. Moreover, when distributing emissions allowances, it seems fair to consider the regional differences in price for climate protection. Ultimately, a decision has to be permanently supported by all parties, and so the task is to find a politically acceptable compromise on the distribution of atmospheric property rights, a compromise that can convince also from an ethical perspective.

Against this background, the uniform distribution of emission allowances for every human being seems to be the comparatively simple and pragmatic solution. It can be shown that in a global emissions trading scheme this distribution key leads to a net allocation of the mitigation costs where the developing countries bear the least burden or even yield benefits. This is possible because developing countries can sell their unused emission allowances to industrial countries and receive goods and capital in return. In addition, compared to other allocation rules a uniform distribution of emission allowances leads to relatively small differences in regional mitigation costs {11}.

In principle, other distribution keys might be designed potentially coming closer to the demand for an extension of opportunities in particular for the poorest. One option e.g. is to increase the allocation of emission rights for poorer developing countries for a transitional period. An initially more generous equipment of the industrialized countries with emission allowances to satisfy their increased demand for them is discussed as well. On a medium to long-term basis, however, the equal treatment of all people in the distribution of the newly created wealth in "rights to the Earth's atmosphere" appears as a compelling option from the perspective of ethics and politics. Further consideration should nevertheless be given to the question of how to distribute the emission allowances in a way that above all the poor's capacity to act is increased. A global climate central bank or a network of regional climate central banks could be entrusted with the practical implementation of such a programme of limiting and distributing emission allowances.



Such a climate central bank would hold the remaining carbon budget as trustee for humankind.

What matters for countries as regards their future capacity to act is not only the distribution of emission allowances but above all the access to low-carbon technologies. The lower the costs of these technologies, the lower the costs of climate protection will be. The equal distribution of emission allowances should therefore be complemented by measures facilitating the access to low-carbon technologies especially for those who expect high mitigation costs.


Global Cooperation is a Challenge

The 'management' of the atmosphere as 'emission disposal site' has significant consequences for the distribution of wealth and income. But even if one considers the climate policy to be justifiablejustifiable from an ethical perspectice, one has to ask the question how an agreement on the limitation and allocation of property rights to the atmosphere can be reached in the political negotiations. It is helpful to assess the possibilities of an international climate agreement under the assumption that the states are primarily not oriented towards ethical considerations but towards their national interests {12}.

This is necessary because the monopoly of power and the sources of legitimacy for an obligatory formulation of policies rest with sovereign nation states today and will remain to do so. But experience teaches that nation states primarily act in their self-interest. This diagnosis has far-reaching consequences for the climate problem, because the stabilization of the global climate through emission reductions has the properties of a public good. The reduction accomplished by one country is beneficial for all countries, and no one can be excluded. The costs of provision remain with the country undertaking the climate policy effort. Thus, every rational agent serving his self-interest has an incentive to act as a free rider, and to wait for others to abate. In the end, no country will reduce its emissions, although this would be in the common interest of all. Humankind is in a classic prisoner's dilemma: The slyness of nation states leads to global stupidity.

States know of course that they are caught in a dilemma. Since there is no world government that is able to introduce and to enforce policies at the global level or at least to monitor and enforce the compliance with treaties, the signing of treaties is voluntary. That's why an international climate agreement must pay off for each of the nation states. Analyses of international environmental agreements show that in negotiations, conducted only by a few actors, solid treaties with a relatively high number of participants are possible - even between selfish states {13}.



Negotiations with many actors turn out to be more problematic. About 194 signatory states participate in the climate negotiations under the United Nations Framework Convention on Climate Change (UNFCCC). For a certain number of countries it is admittedly even then rational to form a coalition for climate protection. But for most of the other countries it is more advantageous to behave as free riders. As soon as some other countries pay for emission reduction, it is no longer worthwhile to bear the costs of emission reductions. The additional benefit of one's own efforts is too small, compared with the additional costs.

Regarding climate protection, this problem is even aggravated by the competitive disadvantages which a country suffers when it reduces emissions on a national level. If countries introduce a price on greenhouse gas emissions this raises the price of their products on world markets and demand for their emission-intensive goods will decrease. As far as internationally traded goods are concerned, this effect is balanced by an increase in production - and thus in emissions - in countries with less ambitious climate policy, thus the global emission reductions are lower than intended. In technical jargon this is referred to as 'carbon leakage'. Admittedly, only very few goods and sectors are affected, because labour costs e.g. are more important for competitiveness than the still relatively low price of emissions. In the political discussion, however, this effect plays an important role and intensifies the incentive to free-ride in the medium term.

Given this not very encouraging diagnosis, is there any reason to hope that the social dilemma of international climate protection can be overcome? Are international climate negotiations inevitably doomed to fail? The paradox of international environmental agreements is instructive in this context {14}. When participants would substantially benefit from an international environmental agreement, the incentive for free-riding is particularly high. In other words, the more necessary international environmental agreements are, the less likely it is that they come about. Conversely, the more dispensable they are, the more likely it is that they come about. Treaties to which many countries are affiliated will only be stable if no significant burden is imposed in addition to their national efforts. The additional benefit of such comprehensive agreements is therefore low. To ensure that an ambitious climate protection is reached, the states have either to assess the cost of emission reduction as very low or to regard the consequences of climate change as disastrous for their country. On each of those conditions they would drastically reduce their emissions even without international agreement. If the damage is in a comparable dimension to the costs of reduction, the paradox of international treaties will strike a blow.

A look at negotiations shows that these considerations are quite plausible. The Kyoto Protocol has not been signed by the U.S., for they would have had to bear the highest costs.



The Copenhagen agreement can hardly be regarded as a serious climate treaty, and at Cancún reduction targets were not even negotiated. The objectives agreed in Copenhagen can rather be seen as an expression of unilateral nation-state egoism. After all, the nation states have comitted themselves to a reduction in emissions which with 50 percent probability would limit the global warming to about 3 ° C, related to the pre-industrial level {15}. This result may be regarded a reason for hope, because here becomes apparent that a certain minimum level of climate protection is apparently in the self-interest of nation states, also without treaties. However, it remains unclear whether the announcements of the countries are credible if they will actually fulfil their pledges. For instance, the United States' promise to reduce their emissions until 2020 by 17 percent compared to the year 2005 in the Copenhagen Accord is linked with the condition that appropriate climate policy legislation will be adopted in the U.S.. After failure of domestic legislation for a U.S. emissions trading system in the summer of 2010, the chances for this are considered low for years to come. On the other hand, it is unclear to what extent the risk of a dangerous climate change is actually reduced by the Copenhagen agreements, because there remains a 20 percent probability that a global warming of 4° to 5° degrees come about.

Thus, while everybody would benefit from a global agreement, it seems unlikely that it will be achieved. It is therefore understandable that moral appeals are made to the main polluters to transcend their narrow national self-interest. But are there - beyond moral appeals - ideas on how global cooperation could be improved?


How can the Paradox of International Agreements be Overcome?

To date, no convincing proposals on how a successful international climate agreement may come about have been put forward. However, there are some promising approaches that suggest at least the direction in which solutions can be searched. What these approaches have in common is that they modify the ratio between costs and benefits of climate protection measures for each country in such a way that they are ready for more climate protection and greater cooperation.

First, the costs of climate protection can be reduced through efficient climate policies, technological innovation and positive additive effects of emission reductions. Second, for nation-states the benefits of climate policy agreements can be increased by linking climate agreements with other topics of international negotiations. These include such topics as technology agreements, transfer payments, and the threat of sanctions.



Third, also international reputation and ethical considerations could be important factors to influence the national interests of states in negotiations.


Reducing the Costs of Climate Protection

The paradox of international environmental agreements demonstrates that a reduction of abatement costs increases the willingness to cooperate and to invest in climate protection. It is therefore useful to consider measures that reduce the cost of emission reductions. The climate package of the European Union adopted until 2020 contains many useful elements of an effective climate policy: as e.g. an emissions trading system for companies, and technology policies as e.g. supporting pilot projects for carbon capture and storage, in order to investigate opportunities, costs and risks of this new option. At the same time, there is room for improvement: for example, all sectors, including transport and building sectors should be included in the EU emissions trading scheme. It is a good sign that now also China - in the light of its climate goals, for the first time published at the Copenhagen Conference - is examining the introduction of a domestic emissions trading system. Linking such regional systems is a promising option to reduce the costs of climate protection {16}.

An effective climate policy must also take into account all mitigation options, not only in the energy system but also in preventing deforestation and other greenhouse gases besides CO2, such as nitrous oxide and methane. In Cancún first steps for a forest protection agreement were made, because particularly cost-effective avoidance potentials are expected by the avoidance of deforestation. But here it has to be taken into consideration that by the growing demand for bio-energy (as e.g. in the transport sector) in the future the value of forest and agricultural land will rise, with the result that the costs of effective protection of rain forests may be higher than previously anticipated.

The development of climate-friendly technologies is essential for the cost-effective solution of the climate problem. The faster and cheaper alternatives to coal, oil, gas, deforestation and greenhouse gases are available, the lower the costs of mitigation. For this purpose, a carefully designed technology policy is necessary, which complements emissions trading {17}. By reducing the economic dependence on the scarce resource atmosphere, a good technology policy also reduces the value of the globally available emission allowances. As a result, less is at stake at the international negotiations on emission allowances. It is therefore likely that a good technology policy is an important contribution to a settlement of the above outlined conflicts over distribution.



For a world society solely dependent on the exploitation of fossil fuels, the climate negotiations would ultimately lead to a zero-sum game. The carbon budget allocated to one state is not available for another. However, the problem can be more easily solved if new technical possibilities are released, which are similarly inexpensive as fossil fuels.

Additional positive effects of climate protection, as e.g. clean air and reduced energy imports decrease the net costs of climate protection. Such positive additional effects have to be appropriately taken into account in case decisions are relevant to climate policy. Interestingly, such effects typically occur at sub-national level, and so also political units such as e.g. federal states or municipalities have an incentive to implement them. The Nobel Prize winner Elinor Ostrom has pointed out that a polycentric policy approach that coordinates and utilizes such potentials could lead to globally relevant emission reductions {18}. Beyond that, it could be argued that - from the perspective of national politicians - such regional efforts reduce the domestic costs of climate protection, and so they are able to agree to such ambitious international treaties.


Creating Additional Incentives and Threat of Sanctions

The theory of international environmental agreements shows that even between self-interested states the opportunities for cooperation can be improved by purposefully linking the negotiations on emission reduction with issues such as development- and research cooperation or financial compensation payments {19}. The accession of Russia to the Kyoto protocol for example was accelerated by the promise of the EU to support Russia in its efforts to join WTO in return. Possible future options include joint research agreements as well as direct transfers of money, technology or other goods. The perhaps most tangible result of Cancún is the promise of financial transfers from industrialized to developing countries amounting to 30 billion U.S. dollars between 2010 to 2012, and 100 billion dollars a year until 2020. A High-Level Advisory group announced by UN Secretary General Ban Ki-Moon and including e.g. climate economist Nicholas Stern and investment banker George Soros has worked out numerous proposals for mobilizing and implementing such transfers {20}. In Cancún it was decided on this basis to introduce a "Green Climate Fund" for the administration of these funds.

Sanction mechanisms as e.g. trade tariffs may also increase the opportunities for cooperation. However, these sanctions cause costs also in those States that threaten with these measures, and so the scope for credible sanctions is limited {21}. In addition, sanctions against other states are only enforceable if they are motivated by climate policy and do not - as protectionist measures - come into conflict with WTO regulations.



For example, in order to avoid competitive disadvantages due to reducing emissions, such customs duties could be liked with the CO2 content of traded goods from regions without CO2 pricing (provided that the practical challenges associated with it can be solved). The EU for example would thus ensure that the emission costs of all goods which are consumed here are included in the prices of end products, even if they are imported. In the light of the principle of equal treatment, this should be basically compatible also with WTO rules {22}.


The Role of Ethics and Reputation in International Relations

Even if in international relations other bases of legitimacy apply than in the relationship between constitutional states and their citizens, this does not at all mean that international relations are beyond the moral assessment. The bargaining power of states increasingly depends on their reputation in the world public. Thus in the theory of international relations a paradigm shift can be seen, as it analogously has been emerging for some time in modern economics. The restrictive behavior model of "rational egoist" is widened.

It is an almost trivial result of the theory of international environmental treaties: a certain degree of altruism leads to increased efforts to avoid emissions. In addition, states can in this way show that they are internationally credible negotiating partner, and this may pay off for them with regard to improved opportunities for cooperation in other policy areas. An important example for building reputation and trust in the context of international climate negotiations will be e.g. the adherence to the above-discussed financial transfers on the part of the industrialized countries. The empirical relevance of altruism and reputation in the field of climate protection may admittedly be assessed skeptically, given the limited willingness regarding transfer payments in development aid. But there is now an intensive discussion on the definition of national interests under the conditions of global risks beyond international climate policy.


Beyond Naive Hope and Unjustified Cynicism

Climate protection as an insurance against the possibility of catastrophic climate change will inevitably lead to a redistribution of the wealth of those who are the owners of coal, oil and gas to the owners of emission allowances. Given the problems of distribution and cooperation, political conflicts are inevitable.



That's why naive hopes for quick and easy solutions will probably be disappointed. However, there is also no reason for a cynicism grown out of frustration. Many world regions are quite willing to reduce their emissions even without an international climate protection treaty, and so the likelihood of catastrophic climate change is at least reduced. The European Union has adopted a climate protection programme that is valid until 2020 and points in the right direction. Even in the U.S., there are promising sub-national climate protection initiatives. China has, after all, for the first time committed itself to climate policy goals. Undoubtedly, the climate policy is an almost perfect example of Weber's dictum on the necessity of the "slow drilling of hard boards".

Similar challenges can be found in other areas of international politics, such as the coordination of monetary and trade policies. If globalization shall be designed and not only be suffered, then governments must find a new understanding of national interest and experiment with new forms of international cooperation beyond their narrow national self-interest.



{1} An example of this is the issue of the magazine "Focus" of November 29th 2010; there is titled "Prima Klima! Umdenken: Die globale Erwärmung ist gut für uns!" ["Fantastic Climate! Rethinking: Global Warming is Good for us!"]

{2} The most complete and most important opinion on management and procedures of the IPCC was presented on August 30th 2010 by the InterAcademy Council (IAC) - the international organization of national academies of the sciences. The IAC has qualified the IPCC as an important social innovation in the science system, and has classified the until now four progress reports as successful. However, it has made a number of proposals to improve management. These proposals were quite positively received, both by the leadership of the IPCC and by the plenary session of the IPCC, which took place in October in Busan (South Korea). On the whole, the IPCC has emerged stronger from this crisis. (InterAcademy Council: Climate change assessments. Review of the processes and procedures of the IPCC; see In addition, in 2010 several committees have evaluated the work of the IPCC. In its report published in July 2010, the Dutch environmental agency PBL Netherlands Environmental Assessment Agency reached the conclusion that, in spite of minor errors in individual questions, the basic messages of the Fourth Assessment Report about the impacts of climate change are all correct. The PBL report also points out that the summary (not the main text) of the Fourth Assessment Report - with the consent of the governments participating in IPCC - above all pays attention to the risks of climate change. The contentual robustness of the IPCC statements was confirmed by a comprehensive study of the U.S. Environmental Protection Agency (EPA), (see

{3} M. Weitzman, On Modelling and Interpreting the Economics of Catastrophic Climate Change, in: The Review of Economics and Statistics 91 (2009) 1-19.



{4} T. M. Lenton & al., Tipping elements in the Earth's climate system, in: Proceedings of the National Academy of Sciences of the United States of America 105 (2008) 1786-1793.

{5} Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, ed. by S. Solomon et al. (Cambridge 2007).

{6} See Global aber gerecht. Klimawandel bekämpfen, Entwicklung ermöglichen, edited by O. Edenhofer, H. Lotze-Campen, J. Wallacher and M. Reder (München 2010).

{7} O. Edenhofer and M. Kalkuhl, Das grüne Paradoxon - Menetekel oder Prognose, in: Jahrbuch Ökologische Ökonomik, volume 6: Diskurs Klimapolitik (Marburg 2009) 115-151.

{8} Thomas Aquinas, S. Th. II/II q. 66, a. 2.

{9} Päpstl. Rat für Frieden u. Gerechtigkeit, Kompendium der Soziallehre der Kirche (Freiburg 2004) 137-146.

{10} See about it Global aber gerecht (note 6).

{11} In the same place, chapter 6.

{12} A comprehensive introduction to the theory of international environmental agreements which here is resorted to gives S. Barrett, Environment and Statecraft. The Strategy of Environmental Treaty-Making (New York 2003).

{13} C. Carraro & D. Siniscalco, Strategies for the International Protection of the Environment, in: Journal of Public Economics 52 (1993) 309-328.

{14} S. Barrett, Self-Enforcing International Environmental Agreements, in: Oxford Economic Papers 46 (1993) 878-894.

{15} The source for these figures and those at the end of the paragraph is J. Rogelj et al., Copenhagen Accord pledges are paltry, in: Nature 464 (2010), 7292, 1126-1128.

{16} Ch. Flachsland, R. Marschinski & O. Edenhofer, Global Trading versus Linking. Architectures for international emissions trading, in: Energy Policy 37 (2009) 1637-1647.

{17} See Global aber gerecht (note 6).

{18} E. Ostrom, A Multi-Scale Approach to Coping with Climate Change and Other Collective Action Problems, in: Solutions (2010) 2/1.

{19} K. Lessmann and O. Edenhofer, Research Cooperation and International Standards in a Model of Coalition Stability, in: Resource and Energy Economics (in print).

{20} Report of the Secretary-General's Highlevel Advisory Group on Climate Change Financing, 5.11. 2010:

{21} K. Lessmann, R. Marschinski & O. Edenhofer, The effects of tariffs on coalition formation in a dynamic global warming game, in: Economic Modelling 26 (2009) 641-649.

{22} J. E. Stiglitz, Making Globalization Work. The Next Steps to Global Justice (London 2006).


Link to 'Public Con-Spiration for-with-of the Poor'