GaNe [geɪn]

Mitigating climate change requires cooperation on an unprecedented scale, from local communities to the international sphere. Significant progress has been made in describing how individuals behave and interact: while game theory describes fundamental problems such as free-riding, networks can represent the complex structure of the global community, and behavioral economics and social psychology analyze how agents learn from experience and social interactions. Still, modeling decision making across different scales remains an interdisciplinary challenge. How cooperation may or may not emerge is an open question.

In this cross-institutional FutureLab between PIK and MCC, established in January 2019 and hosted by PIK's Research Department 4, a small team of interdisciplinary researchers explores and develops cutting-edge modeling and analysis methods for complex decision situations with several decision makers, and applies these to problems in national and international climate policy and sustainable management.

Our overarching question is: What are effective mechanisms and incentives for cooperative climate change mitigation by agents interacting on various levels?

Main Research Questions

• What are innovative theories and methods to study agents’ strategic interactions?
• What incentives and mechanisms result in reducing emissions?
• How should one design policy instruments and institutions to enhance cooperation on climate change mitigation?

Methods

In our work, we combine concepts and ideas from

• classical and evolutionary game theory
• behavioural economics and social psychology of decision making
• agent-based models of individual and social learning
• dynamical systems, complex networks, and statistical physics
• optimal control and viability theory
• welfare theory, social choice theory, and formal ethics
• political science of institutions
• mathematical logics and order theory

Topics

Our current research focusses on

• Mechanisms for cooperation: coalition formation, conditional commitments, group decision methods
• The social cost of carbon and welfare effects of climate policy (with Marc Fleurbaey, Princeton University)
• Game-theoretic analysis of resilience in sustainable management (with Simon Levin, Princeton University)
• Mathematical formalization and operationalization of concepts such as agency and responsibility (with Rupert Klein, FU Berlin, and Markus Brill, TU Berlin as part of the mathematics "Exzellenzcluster" MATH+)
• Agent-based modeling of social learning in key economic situations (with Yuki Asano and Doyne Farmer, Oxford University)
• Relationships between game-theoretical and physical equilibrium concepts and learning and other dynamical behaviours in games
• Models of opinion formation, social norms, group identities, and mobilisation (with Vitor Vasconcelos, Sara Constantino and Elke Weber, Princeton University, and Keith Smith, GESIS)

We participate in RD4's seminar series and in the MATH+ young researcher colloquium CHANGES+.

Work in progress

The following publications are currently under review, in revision, about to be submitted, or have been submitted:

• Heitzig J: Efficient Non-Cooperative Provision of Costly Positive Externalities via Conditional Commitments (submitted to Journal of Public Economics)
• Asano YM, Kolb JJ, Heitzig J, Farmer JD: Emergent inequality and endogenous dynamics in a simple behavioral macroeconomic model (under revision)
  
• Kornek U, Klenert D, Edenhofer O, Fleurbaey M: The social cost of carbon: How local redistribution shapes global carbon prices (submitted to JEEM)
• Heitzig J, Hiller S (2020) Degrees of individual and groupwise backward and forward responsibility in extensive-form games with ambiguity, and their application to social choice problems. In revision. arXiv:2007.07352 
• Heitzig J, Simmons FW (2020) Efficient democratic decisions via non-deterministic proportional consensus. Searching for a journal! arXiv:2006.06548

Publications

• Fleurbaey M, Kornek U (2021): When redistribution makes personalized pricing of externalities useless, accepted at Journal of Public Economic Theory
• Kolb JJ, Müller-Hansen F, Heitzig J, Kurths J (2020) Macroscopic approximation methods for the analysis of networked agent-based models: The example of a two-sector investment model. Accepted for Physical Review E
• Wiedermann M, Smith EK, Heitzig J, Donges JF (2020) A network-based microfoundation of Granovetter's threshold model for social tipping. Scientific Reports 10:11202
• Mathias JD, Debeljak M, Deffuant G, Diemer A, Donges JF, Gladkykh G, Heitzig J, Holtz G, Obergassel W, Pellaud F, Sánchez A, Trajanov A, Videira N (2020) Grounding social foundations for Integrated Assessment Models of climate change. Earth's Future 8:e2020EF001573.
• Raiser K, Kornek U, Flachsland C, Lamb W (2020): Is the Paris Agreement effective? A systematic map of the literature, https://doi.org/10.1088/1748-9326/ab865c Environmental Research Letters, online first
• Kornek U, Edenhofer O (2020) The strategic dimension of financing global public goods https://doi.org/10.1016/j.euroecorev.2020.103423 European Economic Review
• Emmerling J, Kornek U, Bosetti V, Lessmann K (2020) Climate thresholds and heterogeneous regions: implications for coalition formation, http://link.springer.com/article/10.1007/s11558-019-09370-0 Review of International Organizations
• Kornek U,  Flachsland C, Kardish C, Levi S, Edenhofer O (2020) What is important for achieving 2°C? UNFCCC and IPCC expert perceptions on obstacles and response options for climate change mitigation. Environmental Research Letters, online first
• Dorsch M, Flachsland C, Kornek U (2019) Building and enhancing climate policy ambition with transfers: allowance allocation and revenue spending in the EU ETS. Environmental Politics. doi:10.1080/09644016.2019.1659576
• Strnad FM, Barfuss W, Donges JF, Heitzig J (2019) Deep reinforcement learning in World-Earth system models to discover sustainable management strategies. Chaos 29:123122. doi:10.1063/1.5124673. arXiv:1908.05567

At the date of establishment of GaNe in January 2019, we built on the following works from our earlier work, many of which were carried out in the copan project:

• Kornek U, Marschinski R (2018) Prices vs quantities for international environmental agreements. Oxford Economic Papers, gpy016. doi:10.1093/oep/gpy016
• Heitzig J, Barfuss W, Donges JF (2018) A thought experiment on sustainable management of the Earth system. Sustainability 10(6):1947. doi:10.3390/su10061947
• Heitzig J, Kornek U (2018) Bottom-up linking of carbon markets under farsighted cap coordination and reversibility. Nature Climate Change 8:204–209. doi:10.1038/s41558-018-0079-z
• Kornek U, Steckel J, Lessmann K, Edenhofer O (2018) The Climate Rent Curse: New Challenges for Burden Sharing. International Environmental Agreements: Politics, Law and Economics, online first. doi:10.1007/s10784-017-9352-2
• G. Schwerhoff, U. Kornek, K. Lessmann, M. Pahle (2017) Leadership in Climate Change Mitigation: Consequences and Incentives. Journal of Economic Surveys, online first. doi:10.1111/joes.12203
• Meya J, Kornek U, Lessmann K (2017) How empirical uncertainties influence the stability of climate coalitions. International Environmental Agreements: Politics, Law and Economics. doi: 10.1007/s10784-017-9378-5
• Müller-Hansen F, Schlüter M, Mäs M, Donges JF, Kolb JJ, Thonicke K, Heitzig J (2017) Towards representing human behavior and decision making in Earth system models – an overview of techniques and approaches. Earth System Dynamics 8:977–1007. doi:10.5194/esd-8-977-2017
• Heitzig J, Kittel T, Donges J, Molkenthin N (2016) Topology of sustainable management of dynamical systems with desirable states: from defining planetary boundaries to safe operating spaces in the Earth System. Earth System Dynamics 7, 21-50. doi:10.5194/esd-7-21-2016
• Lessmann K, Kornek U, Bosetti V, Dellink R, Emmerling J, Eyckmans J, Nagashima M, Weikard HP, Yang Z (2015) The stability and effectiveness of climate coalitions: A comparative analysis of multiple integrated assessment models. Environmental and Resource Economics (online first)
• Auer S, Heitzig J, Kornek U, Schöll E, Kurths J (2015) The dynamics of coalition formation on complex networks. Scientific Reports 5:13386. doi:10.1038/srep13386
• Wiedermann M, Donges JF, Heitzig J, Lucht W, Kurths J (2015) Macroscopic description of complex adaptive networks co-evolving with dynamic node states. Physical Review E 91, 052801. doi:10.1103/PhysRevE.91.052801
• Kornek U, Lessmann K, Tulkens H (2014) Transferable- and Non-transferable Utility Implementations of Coalitional Stability in Integrated Assessment Models. CORE Discussion Paper 35
• Lessmann K, Marschinski R, Finus M, Kornek U, Edenhofer O (2013) Emissions trading with non-signatories in a climate agreement - An analysis of coalition stability. The Manchester School DOI: 10.1111/manc.12045
• Schmidt RC, Heitzig J (2013) Carbon leakage: grandfathering as an incentive device to avert relocation. Journal of Environmental Economics and Management (JEEM) 67(2):209–223. doi:10.1016/j.jeem.2013.12.004
• Heitzig J, Donges JF, Zou Y, Marwan N, Kurths J (2012) Node-weighted measures for complex networks with spatially embedded, sampled, or differently sized nodes. The European Physical Journal B 85(1):38. doi:10.1140/epjb/e2011-20678-7
• Heitzig J, Simmons FW (2012, online first 2010) Some chance for consensus: voting methods for which consensus is an equilibrium. Social Choice and Welfare 38(1):43–57. doi:10.1007/s00355-010-0517-y
• Heitzig J, Lessmann K, Zou Y (2011) Self-enforcing strategies to deter free-riding in the climate change mitigation game and other repeated public good games. Proceedings of the National Academy of Sciences of the United States of America (PNAS) 108:15739–15744. doi:10.1073/pnas.1106265108. Accompanying PNAS Commentary, Guardian article, Huffington Post article, Climatewire article.

Examples of possible thesis topics

• Numerical simulation of individual and social learning dynamics in simple games and assessment of their convergence towards strategic equilibria (physics)
• Solving a certain set of partial differential equations representing a model of farsighted strategy updating in simple games (mathematics)
• Design and implementation of a decentralized and confidential communication structure for a social app for consensus-finding (computer science)
• Analytical identification of equilibria in games in which agents have prospect theory preferences and can only adjust their behaviour smoothly, including existence proofs using fixed point theorems (mathematics)
• Identification of the topology of ties relevant for strategic decisions and cooperation: international diplomatic/trust/security/trade networks, public administration hierarchies, etc. (political science)
• Analyzing the role of heterogeneity of countries for the successful design of compensation funds for global public good provision; game-theoretic approach in an analytical model (economics)
• Modeling the impact of unilateral policy measures (taxes, permits, subsidies, targeted support etc) to induce multilateral cooperation in a multi-level public good game; reduced-form analytical modeling and/or numerical implementation with a network-approach (economics/physics)