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I have worked at CICERO since 2002. I was initially hired to program our first computable general equilibrium model, and started a PhD on the effectiveness and acceptability of environmental taxes two years later. After completing my PhD in 2008 I have managed research projects on environmental taxes, transport policy, behavioural interventions ("nudges"), and energy efficiency. I was Research Director of the Climate Policy unit in 2012 and 2013, and the Climate Economics Unit from 2014 to 2017. From 2014 to 2019 I was Director of our FME-center CICEP Center for International Climate and Energy Policy, and much of my outreach and research focused on the Paris Agreement. Since 2019 I have led the climate economics group. My primary research interest is climate policy instruments. I lead two projects funded by the Research Council of Norway, "Aviate" on the role of aviation in a low-carbon society and "Enable" on enabling the green transition in Norway. Most of my research is based on use surveys, lab and field experiments.
A number of microeconomic choice models are currently applied to demonstrate systematic biases in energy consumer behavior. The models highlight the hidden potential of energy savings from policies that target the so-called behavioral anomalies. Nevertheless, whether these patterns are repeatable or not is not clear, because the efforts to determine the transferability or generalizability of these models are practically nonexistent. This paper uses a unique collection of empirical data from five EU countries collected within the CONSEED project to refine and develop further the standard consumer decision model, validate it for policy purposes, and elaborate on its transferability between countries. The pooled samples allow for a more reliable investigation of the relative importance of the factors influencing consumers’ attitudes and beliefs towards energy investment decisions. Based on the statistical tests conducted to evaluate the “transferability” of the pooled models (i.e., the possibility of creating a “universal” model of EE from the pooled model), it can be argued that the models are transferable in specific cases since attitudinal factors and demographic characteristics play a significant role. Although the pooled models are validated, any extrapolation of the above-mentioned findings to specific populations in terms of “space” (i.e., country) and “target” (e.g., sectors and technologies) should be approached with caution from a policy perspective.
Areti Kontogianni; Dimitris Damigos; Michail Skourtos; Christos Tourkolias; Eleanor Denny; Ibon Galarraga; Steffen Kallbekken; Edin Lakić. Model Validity and Transferability Informing Behavioral Energy Policies. Energies 2021, 14, 3122 .
AMA StyleAreti Kontogianni, Dimitris Damigos, Michail Skourtos, Christos Tourkolias, Eleanor Denny, Ibon Galarraga, Steffen Kallbekken, Edin Lakić. Model Validity and Transferability Informing Behavioral Energy Policies. Energies. 2021; 14 (11):3122.
Chicago/Turabian StyleAreti Kontogianni; Dimitris Damigos; Michail Skourtos; Christos Tourkolias; Eleanor Denny; Ibon Galarraga; Steffen Kallbekken; Edin Lakić. 2021. "Model Validity and Transferability Informing Behavioral Energy Policies." Energies 14, no. 11: 3122.
The ability of the Paris Agreement to achieve its ambitious long-term temperature goal depends on mechanisms that can promote a ramp-up of ambitions. Pledge-and-review may facilitate deeper cooperation over time by enhancing trust between parties. It has been proposed that starting out with easier cooperation that entails larger shares of domestic benefits, such as cooperation on short-lived climate pollutants, could also help promote the credibility and trust necessary for the ramping-up of contributions over time. Using a lab experiment we explore how these two mechanisms perform across two stages in a controlled and stylized setting where individual participants face incentives that mirror those of countries deciding on national contributions. We find that starting with easier cooperation does not produce higher levels of trust, and it leads to lower levels of cooperation when cooperation becomes more difficult in stage 2. The pledge-and-review approach does not, in itself, lead to significantly higher levels of cooperation, but it does offset the negative effect of starting with the easy cooperation. It can be seen as a safeguard against failed strategies.
Todd L. Cherry; Steffen Kallbekken; Håkon Sælen; Stine Aakre. Can the Paris Agreement deliver ambitious climate cooperation? An experimental investigation of the effectiveness of pledge-and-review and targeting short-lived climate pollutants. Environmental Science & Policy 2021, 123, 35 -43.
AMA StyleTodd L. Cherry, Steffen Kallbekken, Håkon Sælen, Stine Aakre. Can the Paris Agreement deliver ambitious climate cooperation? An experimental investigation of the effectiveness of pledge-and-review and targeting short-lived climate pollutants. Environmental Science & Policy. 2021; 123 ():35-43.
Chicago/Turabian StyleTodd L. Cherry; Steffen Kallbekken; Håkon Sælen; Stine Aakre. 2021. "Can the Paris Agreement deliver ambitious climate cooperation? An experimental investigation of the effectiveness of pledge-and-review and targeting short-lived climate pollutants." Environmental Science & Policy 123, no. : 35-43.
An improved understanding of public support is essential to design effective and feasible climate policies for aviation. Our motivation is the contrast between high support for air travel restrictions responding to the COVID-19 pandemic and low support for restrictions to combat climate change. Can the same factors explain individuals’ support for restrictive measures across two different problems? Using a survey, we find that largely the same factors explain support. Support increases with expected effectiveness, perceived threat and imminence of the problem, shorter expected duration of the measure, knowledge, and trust, while support decreases with expected negative consequences for self and the poor. When controlling for all perceptions, there is no significant residual difference in support depending on whether the measures address climate change or COVID-19. The level of support differs because COVID-19 is perceived as a more imminent threat, and because measures are expected to be shorter-lasting and more effective.
Steffen Kallbekken; Håkon Sælen. Public support for air travel restrictions to address COVID-19 or climate change. Transportation Research Part D: Transport and Environment 2021, 93, 102767 .
AMA StyleSteffen Kallbekken, Håkon Sælen. Public support for air travel restrictions to address COVID-19 or climate change. Transportation Research Part D: Transport and Environment. 2021; 93 ():102767.
Chicago/Turabian StyleSteffen Kallbekken; Håkon Sælen. 2021. "Public support for air travel restrictions to address COVID-19 or climate change." Transportation Research Part D: Transport and Environment 93, no. : 102767.
William Brazil; Steffen Kallbekken; Håkon Sælen; James Carroll. The role of fuel cost information in new car sales. Transportation Research Part D: Transport and Environment 2019, 74, 93 -103.
AMA StyleWilliam Brazil, Steffen Kallbekken, Håkon Sælen, James Carroll. The role of fuel cost information in new car sales. Transportation Research Part D: Transport and Environment. 2019; 74 ():93-103.
Chicago/Turabian StyleWilliam Brazil; Steffen Kallbekken; Håkon Sælen; James Carroll. 2019. "The role of fuel cost information in new car sales." Transportation Research Part D: Transport and Environment 74, no. : 93-103.
Climate policy has received considerable attention from environmental economists for more than two decades. Although the international climate regime covers all greenhouse gases not covered under the Montreal Protocol on Substances that Deplete the Ozone Layer, climate policy and most economics research have focused on carbon dioxide (CO2) emissions. With the lack of progress on establishing effective global cooperation regarding CO2 emissions, short-lived climate pollutants (SLCPs) such as black carbon, tropospheric ozone, methane, and hydrofluorocarbons have recently been placed higher on the climate policy agenda. Although economists have generally not actively participated in the current policy debate about SLCPs, there has been much economics research on SLCPs or closely related topics. Economists have conducted substantial research on the valuation of non-CO2 gases, the estimation of abatement costs, and policies for regulating multiple pollutants simultaneously. Additional issues that would benefit from economics research include the political economy of SLCP mitigation and the establishment of (separate) international agreements to mitigate SLCPs.
Steffen Kallbekken; Stine Aakre. The Potential for Mitigating Short-lived Climate Pollutants. Review of Environmental Economics and Policy 2018, 12, 264 -283.
AMA StyleSteffen Kallbekken, Stine Aakre. The Potential for Mitigating Short-lived Climate Pollutants. Review of Environmental Economics and Policy. 2018; 12 (2):264-283.
Chicago/Turabian StyleSteffen Kallbekken; Stine Aakre. 2018. "The Potential for Mitigating Short-lived Climate Pollutants." Review of Environmental Economics and Policy 12, no. 2: 264-283.
The politically contentious issue of calculating countries' contributions to climate change is strongly dependent on methodological choices. Different principles can be applied for distributing efforts for reducing human-induced global warming. According to the 'Brazilian Proposal', industrialized countries would reduce emissions proportional to their historical contributions to warming. This proposal was based on the assumption that the political process would lead to a global top-down agreement. The Paris Agreement changed the role of historical responsibilities. Whereas the agreement refers to equity principles, differentiation of mitigation efforts is delegated to each country, as countries will submit new national contributions every five years without any international negotiation. It is likely that considerations of historical contributions and distributive fairness will continue to play a key role, but increasingly so in a national setting. Contributions to warming can be used as a background for negotiations to inform and justify positions, and may also be useful for countries' own assessment of what constitutes reasonable and fair contributions to limiting warming. Despite the fact that the decision from COP21 explicitly rules out compensation in the context of loss and damage, it is likely that considerations of historical responsibility will also play a role in future discussions. However, methodological choices have substantial impacts on calculated contributions to warming, including rank-ordering of contributions, and thus support the view that there is no single correct answer to the question of how much each country has contributed. There are fundamental value-related and ethical questions that cannot be answered through a single set of calculated contributions. Thus, analyses of historical contributions should not present just one set of results, but rather present a spectrum of results showing how the calculated contributions vary with a broad set of choices. Our results clearly expose some of the core issues related to climate responsibility.
Ragnhild B Skeie; Jan Fuglestvedt; Terje Berntsen; Glen Peters; Robbie Andrew; Myles Allen; Steffen Kallbekken. Perspective has a strong effect on the calculation of historical contributions to global warming. Environmental Research Letters 2017, 12, 024022 .
AMA StyleRagnhild B Skeie, Jan Fuglestvedt, Terje Berntsen, Glen Peters, Robbie Andrew, Myles Allen, Steffen Kallbekken. Perspective has a strong effect on the calculation of historical contributions to global warming. Environmental Research Letters. 2017; 12 (2):024022.
Chicago/Turabian StyleRagnhild B Skeie; Jan Fuglestvedt; Terje Berntsen; Glen Peters; Robbie Andrew; Myles Allen; Steffen Kallbekken. 2017. "Perspective has a strong effect on the calculation of historical contributions to global warming." Environmental Research Letters 12, no. 2: 024022.
Ibon Galarraga; Luis M. Abadie; Steffen Kallbekken. Designing incentive schemes for promoting energy-efficient appliances: A new methodology and a case study for Spain. Energy Policy 2016, 90, 24 -36.
AMA StyleIbon Galarraga, Luis M. Abadie, Steffen Kallbekken. Designing incentive schemes for promoting energy-efficient appliances: A new methodology and a case study for Spain. Energy Policy. 2016; 90 ():24-36.
Chicago/Turabian StyleIbon Galarraga; Luis M. Abadie; Steffen Kallbekken. 2016. "Designing incentive schemes for promoting energy-efficient appliances: A new methodology and a case study for Spain." Energy Policy 90, no. : 24-36.
The potential of taxes to correct environmental externalities has long been recognized among economists. Yet, this welfare-enhancing policy commonly faces strong opposition by citizens. Conversely, externality-correcting subsidies frequently enjoy high public support. We conduct a lab experiment to explore public support for Pigouvian taxes and subsidies. In an experimental market with a negative externality, participants vote on the introduction of Pigouvian taxes and subsidies under full or reduced information concerning how the tax revenues will be spent and the subsidy paid for. Theoretically the two instruments should produce identical outcomes. However, we find substantially greater support for subsidies than for taxes. This can partially be explained by the participants’ expectation that the subsidy will increase their own payoffs more than a tax, but not because it is expected to be more effective in changing behavior. Furthermore, we find that with greater uncertainty, the preference for subsidies is even stronger, a result which is consistent with loss aversion.
David R. Heres; Steffen Kallbekken; Ibon Galarraga. The Role of Budgetary Information in the Preference for Externality-Correcting Subsidies over Taxes: A Lab Experiment on Public Support. Environmental and Resource Economics 2015, 66, 1 -15.
AMA StyleDavid R. Heres, Steffen Kallbekken, Ibon Galarraga. The Role of Budgetary Information in the Preference for Externality-Correcting Subsidies over Taxes: A Lab Experiment on Public Support. Environmental and Resource Economics. 2015; 66 (1):1-15.
Chicago/Turabian StyleDavid R. Heres; Steffen Kallbekken; Ibon Galarraga. 2015. "The Role of Budgetary Information in the Preference for Externality-Correcting Subsidies over Taxes: A Lab Experiment on Public Support." Environmental and Resource Economics 66, no. 1: 1-15.
This paper examines the political difficulty of enacting welfare-enhancing Pigouvian taxes. Using referenda in a market experiment with externalities, we investigate the effect of trial periods on the acceptability of two theoretically equivalent variants of Pigouvian taxes. While implementing either tax is in subjects’ material self-interest, we find significant levels of opposition to both tax schemes, though the level differs considerably. Results show that trial runs can overcome initial tax aversion, significantly increasing acceptability. The effect is robust across tax schemes, but a trial with one scheme does not affect the acceptability of the other. Trial periods also mitigate initial biases in preferences of alternative tax schemes
Todd L. Cherry; Steffen Kallbekken; Stephan Kroll. The impact of trial runs on the acceptability of environmental taxes: Experimental evidence. Resource and Energy Economics 2014, 38, 84 -95.
AMA StyleTodd L. Cherry, Steffen Kallbekken, Stephan Kroll. The impact of trial runs on the acceptability of environmental taxes: Experimental evidence. Resource and Energy Economics. 2014; 38 ():84-95.
Chicago/Turabian StyleTodd L. Cherry; Steffen Kallbekken; Stephan Kroll. 2014. "The impact of trial runs on the acceptability of environmental taxes: Experimental evidence." Resource and Energy Economics 38, no. : 84-95.
To what extent and how can equity be operationalized in a spectrum of mitigation commitments? We approach this question through academic literature review and analysis of Parties' submissions and statements. We argue that a potentially feasible and constructive way forward is a mutual recognition approach. This approach implies that parties should accept a set or norms, and a range of interpretations of these norms, as legitimate. Parties should also respect a principle of reciprocity, which means that any (interpretation of a) principle of fairness invoked by oneself can legitimately be invoked also by others. We apply this approach to the issue of equity indicators, and propose a non-coercive template of indicators approach, building on two critical components: transparency and open, critical review of Parties' pledges and justifications thereof
Steffen Kallbekken; Hakon Saelen; Arild Underdal. Equity and spectrum of mitigation commitments in the 2015 agreement. Equity and spectrum of mitigation commitments in the 2015 agreement 2014, 1 .
AMA StyleSteffen Kallbekken, Hakon Saelen, Arild Underdal. Equity and spectrum of mitigation commitments in the 2015 agreement. Equity and spectrum of mitigation commitments in the 2015 agreement. 2014; ():1.
Chicago/Turabian StyleSteffen Kallbekken; Hakon Saelen; Arild Underdal. 2014. "Equity and spectrum of mitigation commitments in the 2015 agreement." Equity and spectrum of mitigation commitments in the 2015 agreement , no. : 1.
Silje H. Tørnblad; Steffen Kallbekken; Kristine Korneliussen; Torben K. Mideksa. Using mobility management to reduce private car use: Results from a natural field experiment in Norway. Transport Policy 2014, 32, 9 -15.
AMA StyleSilje H. Tørnblad, Steffen Kallbekken, Kristine Korneliussen, Torben K. Mideksa. Using mobility management to reduce private car use: Results from a natural field experiment in Norway. Transport Policy. 2014; 32 ():9-15.
Chicago/Turabian StyleSilje H. Tørnblad; Steffen Kallbekken; Kristine Korneliussen; Torben K. Mideksa. 2014. "Using mobility management to reduce private car use: Results from a natural field experiment in Norway." Transport Policy 32, no. : 9-15.
Steffen Kallbekken; Jorge H. Garcia; Kristine Korneliussen. Determinants of public support for transport taxes. Transportation Research Part A: Policy and Practice 2013, 58, 67 -78.
AMA StyleSteffen Kallbekken, Jorge H. Garcia, Kristine Korneliussen. Determinants of public support for transport taxes. Transportation Research Part A: Policy and Practice. 2013; 58 ():67-78.
Chicago/Turabian StyleSteffen Kallbekken; Jorge H. Garcia; Kristine Korneliussen. 2013. "Determinants of public support for transport taxes." Transportation Research Part A: Policy and Practice 58, no. : 67-78.
Nmr Publicering; Steffen Kallbekken; Håkon Sælen. Operationalizing Equity in the 2015 Agreement. Operationalizing Equity in the 2015 Agreement 2013, 1 .
AMA StyleNmr Publicering, Steffen Kallbekken, Håkon Sælen. Operationalizing Equity in the 2015 Agreement. Operationalizing Equity in the 2015 Agreement. 2013; ():1.
Chicago/Turabian StyleNmr Publicering; Steffen Kallbekken; Håkon Sælen. 2013. "Operationalizing Equity in the 2015 Agreement." Operationalizing Equity in the 2015 Agreement , no. : 1.
Steffen Kallbekken; Håkon Sælen. ‘Nudging’ hotel guests to reduce food waste as a win–win environmental measure. Economics Letters 2013, 119, 325 -327.
AMA StyleSteffen Kallbekken, Håkon Sælen. ‘Nudging’ hotel guests to reduce food waste as a win–win environmental measure. Economics Letters. 2013; 119 (3):325-327.
Chicago/Turabian StyleSteffen Kallbekken; Håkon Sælen. 2013. "‘Nudging’ hotel guests to reduce food waste as a win–win environmental measure." Economics Letters 119, no. 3: 325-327.
Experimental studies have compared cooperation across different nonmarket social dilemma settings, but the experimental literature has largely overlooked comparing cooperation across market and nonmarket settings. This paper reports the results from an experiment that compares behavior in theoretically equivalent public good games and market games with externalities. Both positive and negative external effects are considered. Results indicate that people tend to be less cooperative in the marketplace relative to the nonmarket setting, whether the external effect is positive or negative. Most striking is the finding that the combination of a positive external effect in a nonmarket setting (i.e., the standard public good game) stands apart from the other market and nonmarket settings.
Todd L. Cherry; Steffen Kallbekken; Stephan Kroll; David M. McEvoy. Cooperation in and out of markets: An experimental comparison of public good games and markets with externalities. Economics Letters 2013, 120, 93 -96.
AMA StyleTodd L. Cherry, Steffen Kallbekken, Stephan Kroll, David M. McEvoy. Cooperation in and out of markets: An experimental comparison of public good games and markets with externalities. Economics Letters. 2013; 120 (1):93-96.
Chicago/Turabian StyleTodd L. Cherry; Steffen Kallbekken; Stephan Kroll; David M. McEvoy. 2013. "Cooperation in and out of markets: An experimental comparison of public good games and markets with externalities." Economics Letters 120, no. 1: 93-96.
The potential of taxation to correcting environmental externalities has been long recognized among economists. Yet, this welfare-enhancing policy commonly faces strong opposition by citizens. Conversely, externality-correcting subsidies frequently enjoy high levels of public acceptance. We conduct a lab experiment to explore public support for Pigouvian taxes and subsidies. In an experimental market with a negative externality, participants vote on the introduction of Pigouvian taxes and subsidies under full or partial information concerning how the tax revenues will be spent and the subsidy paid for. Theoretically the two instruments should produce identical outcomes. We find substantially greater support for subsidies than taxes. This can partially be explained by the expectation that the subsidy will increase payoffs more than a tax, but not because it could be more effective in changing behavior. Furthermore, we find that under partial information, the preference for subsidies is even stronger.
David Heres; Steffen Kallbekken; Ibon Galarraga. Understanding Public Support for Externality-Correcting Taxes and Subsidies: A Lab Experiment. 2013, 1 .
AMA StyleDavid Heres, Steffen Kallbekken, Ibon Galarraga. Understanding Public Support for Externality-Correcting Taxes and Subsidies: A Lab Experiment. . 2013; ():1.
Chicago/Turabian StyleDavid Heres; Steffen Kallbekken; Ibon Galarraga. 2013. "Understanding Public Support for Externality-Correcting Taxes and Subsidies: A Lab Experiment." , no. : 1.
Providing consumers with information that can lead to more energy-efficient choices can help reduce energy use and greenhouse gas emissions while reducing costs to consumers. A natural field experiment is conducted in collaboration with an electrical retailer to test strategies for influencing sales of household appliances. The experiment involves two product categories, fridge-freezers and tumble driers. Information on lifetime energy cost of appliances is provided through a label and training of sales staff. For fridge-freezers, the authors find no significant effects. For tumble driers, the combined treatment and training treatment reduce average energy use of tumble driers sold by 4.9% and 3.4%, respectively. The effect is strongest initially, over 12% on average for the first 3 months for the combined treatment but declines over time. The effect is significant at the 5% level for the combined treatment while not significant for sales staff training.
Steffen Kallbekken; Hakon Saelen; Erlend A. T. Hermansen. Bridging the Energy Efficiency Gap: A Field Experiment on Lifetime Energy Costs and Household Appliances. Journal of Consumer Policy 2012, 36, 1 -16.
AMA StyleSteffen Kallbekken, Hakon Saelen, Erlend A. T. Hermansen. Bridging the Energy Efficiency Gap: A Field Experiment on Lifetime Energy Costs and Household Appliances. Journal of Consumer Policy. 2012; 36 (1):1-16.
Chicago/Turabian StyleSteffen Kallbekken; Hakon Saelen; Erlend A. T. Hermansen. 2012. "Bridging the Energy Efficiency Gap: A Field Experiment on Lifetime Energy Costs and Household Appliances." Journal of Consumer Policy 36, no. 1: 1-16.
Can a conditional commitment by a major actor (for example, the European Union) induce other major actors (such as the USA, China, India, or Japan) to do more to mitigate global climate change? We analyse this question by first estimating the impact of emission reductions by one of these actors on the mitigation costs of the others and, second, by exploring how domestic politics influence the willingness of the European Union and the USA to contribute. We find that an emission cut by any actor will reduce mitigation costs for all the others and thereby expand the settlement range. These cost reductions seem, however, insufficient to induce significant unilateral policy change. Emissions trading can cut aggregate costs further, but also redistribute wealth. Domestic politics tend to add weight to the concerns of powerful actors that stand to lose from more ambitious mitigation policies.
Arild Underdal; Jon Hovi; Steffen Kallbekken; Tora Skodvin. Can conditional commitments break the climate change negotiations deadlock? International Political Science Review 2012, 33, 475 -493.
AMA StyleArild Underdal, Jon Hovi, Steffen Kallbekken, Tora Skodvin. Can conditional commitments break the climate change negotiations deadlock? International Political Science Review. 2012; 33 (4):475-493.
Chicago/Turabian StyleArild Underdal; Jon Hovi; Steffen Kallbekken; Tora Skodvin. 2012. "Can conditional commitments break the climate change negotiations deadlock?" International Political Science Review 33, no. 4: 475-493.
Todd L. Cherry; Steffen Kallbekken; Stephan Kroll. The acceptability of efficiency-enhancing environmental taxes, subsidies and regulation: An experimental investigation. Environmental Science & Policy 2012, 16, 90 -96.
AMA StyleTodd L. Cherry, Steffen Kallbekken, Stephan Kroll. The acceptability of efficiency-enhancing environmental taxes, subsidies and regulation: An experimental investigation. Environmental Science & Policy. 2012; 16 ():90-96.
Chicago/Turabian StyleTodd L. Cherry; Steffen Kallbekken; Stephan Kroll. 2012. "The acceptability of efficiency-enhancing environmental taxes, subsidies and regulation: An experimental investigation." Environmental Science & Policy 16, no. : 90-96.
The stringency of policies needed to meet a climate target is influenced by uncertain oil prices because price changes cause emission changes, making the robustness of climate policy instruments important. As a result of its dependence on oil, emissions from the transport sector are particularly sensitive to oil price changes. We use a computable general equilibrium model to study the effects of including the transport sector in the EU’s emissions trading scheme under three future oil price scenarios. Our results show that there are potentially significant welfare gains from including transportation in the emissions trading scheme because the system as a whole helps absorb required changes in climate policy to meet the overall EU cap on emissions. There is, however, a cost in terms of somewhat greater permit price uncertainty.
Asbjørn Torvanger; Steffen Kallbekken; Petter Tollefsen. Oil price scenarios and climate policy: welfare effects of including transportation in the EU emissions trading system. Mitigation and Adaptation Strategies for Global Change 2011, 17, 753 -768.
AMA StyleAsbjørn Torvanger, Steffen Kallbekken, Petter Tollefsen. Oil price scenarios and climate policy: welfare effects of including transportation in the EU emissions trading system. Mitigation and Adaptation Strategies for Global Change. 2011; 17 (7):753-768.
Chicago/Turabian StyleAsbjørn Torvanger; Steffen Kallbekken; Petter Tollefsen. 2011. "Oil price scenarios and climate policy: welfare effects of including transportation in the EU emissions trading system." Mitigation and Adaptation Strategies for Global Change 17, no. 7: 753-768.