Articles | Volume 33, issue 2
https://doi.org/10.5194/npg-33-313-2026
© Author(s) 2026. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/npg-33-313-2026
© Author(s) 2026. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
19 Jun 2026
Research article |
| 19 Jun 2026
| 19 Jun 2026
Quantitative comparison of causal inference methods for climate tipping points
Niki Lohmann
CORRESPONDING AUTHOR
Center for Critical Computational Studies (C3S), Goethe University Frankfurt, Frankfurt am Main, Germany
Potsdam Institute for Climate Impact Research (PIK), Member of the Leipniz Association, Potsdam, Germany
David Strahl
Institute of Environmental Science and Geography, University of Potsdam, Potsdam, Germany
Annika Högner
International Institute for Applied Systems Analysis (IIASA), Laxenburg, Austria
Geography Department, Humboldt-Universität zu Berlin, Berlin, Germany
Willem Huiskamp
Potsdam Institute for Climate Impact Research (PIK), Member of the Leipniz Association, Potsdam, Germany
Matthias Boehm
Technische Universität Berlin, Berlin, Germany
Berlin Institute for the Foundations of Learning and Data (BIFOLD), Berlin, Germany
Nico Wunderling
CORRESPONDING AUTHOR
Center for Critical Computational Studies (C3S), Goethe University Frankfurt, Frankfurt am Main, Germany
Potsdam Institute for Climate Impact Research (PIK), Member of the Leipniz Association, Potsdam, Germany
Senckenberg Research Institute and Natural History Museum, Frankfurt am Main, Germany
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Jakob Harteg, Nico Wunderling, and Jonathan F. Donges
Earth Syst. Dynam., 17, 673–686, https://doi.org/10.5194/esd-17-673-2026, https://doi.org/10.5194/esd-17-673-2026, 2026
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We investigate how resilient Earth’s climate system is to disturbances by analysing glacial-interglacial cycles using a simple climate model. By simulating small and large shocks to ice volume, we show that Earth’s climate more easily returns to its natural path during warm periods. These results improve our understanding of how Earth resilience varies over time in systems driven by external forces.
Sasha Roewer, Lukas Fiedler, Marius Årthun, Willem Huiskamp, and Stefan Rahmstorf
Ocean Sci., 22, 1195–1211, https://doi.org/10.5194/os-22-1195-2026, https://doi.org/10.5194/os-22-1195-2026, 2026
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The Atlantic Meridional Overturning Circulation (AMOC) is weakening in response to global warming, while the Nordic Seas Overturning Circulation (NOC) is projected to strengthen. We suggest a feedback mechanism in which a weakened AMOC leads to reduced salt transport into the North Atlantic, decreasing the density in that region and potentially strengthening the NOC.
Jacques Bara, Nico Wunderling, and Wolfram Barfuss
Earth Syst. Dynam., 17, 333–352, https://doi.org/10.5194/esd-17-333-2026, https://doi.org/10.5194/esd-17-333-2026, 2026
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When one tipping element collapses the likelihood of another collapsing may be significantly affected. Using our simplified network model, we find that on the whole these interactions destabilise the Earth system, both in the short term and at equilibrium, though the effects are most noticeable after the year 2100. We find that to minimise tipping risks, it is essential to keep temperatures as close as possible to 1.5 °C in the short term and below 1 °C in the longer run.
Detlef P. Van Vuuren, Brian C. O'Neill, Claudia Tebaldi, Benjamin M. Sanderson, Louise P. Chini, Pierre Friedlingstein, Tomoko Hasegawa, Keywan Riahi, Bala Govindasamy, Nico Bauer, Veronika Eyring, Cheikh M. N. Fall, Katja Frieler, Matthew J. Gidden, Laila K. Gohar, Annika Högner, Andrew D. Jones, Jarmo Kikstra, Andrew King, Reto Knutti, Elmar Kriegler, Peter Lawrence, Chris Lennard, Jason Lowe, Camilla Mathison, Shahbaz Mehmood, Zebedee Nicholls, Luciana F. Prado, Qiang Zhang, Steven K. Rose, Alex C. Ruane, Marit Sandstad, Carl-Friedrich Schleussner, Roland Seferian, Jana Sillmann, Chris Smith, Anna A. Sörensson, Swapna Panickal, Kaoru Tachiiri, Naomi Vaughan, Saritha S. Vishwanathan, Tokuta Yokohata, Marco Zecchetto, and Tilo Ziehn
Geosci. Model Dev., 19, 2627–2656, https://doi.org/10.5194/gmd-19-2627-2026, https://doi.org/10.5194/gmd-19-2627-2026, 2026
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We propose a set of seven plausible 21st century emission scenarios, and their multi-century extensions, that will be used by the international community of climate modeling centers to produce the next generation of climate projections. These projections will support climate, impact and mitigation researchers, provide information to practitioners to address future risks from climate change, and contribute to policymakers’ considerations of the trade-offs among various levels of mitigation.
Nils Bochow, Jonathan Krönke, Julius Garbe, and Nico Wunderling
EGUsphere, https://doi.org/10.5194/egusphere-2026-614, https://doi.org/10.5194/egusphere-2026-614, 2026
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We provide a simple, updateable tool that turns comprehensive simulations into fast dynamical models for the three major tipping elements; the Greenland Ice Sheet, the West Antarctic Ice Sheet, and the Atlantic Meridional Overturning circulation. By fitting our framework to existing comprehensive simulations, it matches both short-term change and long-term stable states. This helps produce more consistent, policy-ready risk estimates as new simulations arrive.
John M. Anderies, Max Bechthold, Jonathan F. Donges, Ingo Fetzer, Nico Wunderling, Wolfram Barfuss, and Johan Rockström
EGUsphere, https://doi.org/10.5194/egusphere-2025-6345, https://doi.org/10.5194/egusphere-2025-6345, 2026
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This paper explores a new approach to understanding human-Earth system resilience. It introduces a measure that estimates how likely a system is to reach a safe and just state. Available knowledge about how the system works, its boundaries, and potential disruptions centrally constrain the measure. It could help decision-makers strike a balance between gaining knowledge, building capacity to act, and taking practical measures to improve resilience in many different types of systems.
Niklas Schwind, Mahé Perrette, Edward Byers, Annika Högner, Quentin Lejeune, Tessa Möller, Zebedee Nicholls, Peter Pfleiderer, Sarah Schöngart, Michaela Werning, and Carl-Friedrich Schleussner
EGUsphere, https://doi.org/10.5194/egusphere-2025-5781, https://doi.org/10.5194/egusphere-2025-5781, 2026
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We study how regional climate and climate impact indicators may respond to different emissions scenarios. Their possible outcomes are shaped by uncertainties in future emissions, global warming, regional effects of global warming, and the chaotic climate system. We introduce RIME-X, an emulator that combines multiple tools and datasets to estimate probabilistically how any emissions path may influence regional outcomes.
Florian Ulrich Jehn, James Mulhall, Simon Blouin, Łukasz G. Gajewski, and Nico Wunderling
Earth Syst. Dynam., 17, 151–166, https://doi.org/10.5194/esd-17-151-2026, https://doi.org/10.5194/esd-17-151-2026, 2026
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Large crop failures happen regularly around the world, threatening food security. We analyzed sixty years of global crop production data and found that every country has experienced major crop losses. Climate events like droughts cause most severe disruptions, with some African nations losing up to eighty percent of production. While global crop shocks above five percent are rare, regional disruptions occur frequently. These findings show our food system faces regular large-scale threats.
E. Keith Smith, Carl Folke, Niklas Kitzmann, Manjana Milkoreit, Per Olsson, Ricarda Winkelmann, Anne-Sophie Crépin, Christina Eder, Niklas Harring, Jobst Heitzig, Alexia Katsanidou, Timothy M. Lenton, Franz Mauelshagen, Kelton Minor, Ilona M. Otto, Armon Rezai, Jürgen Scheffran, Isabelle Stadelmann-Steffen, Rick van der Ploeg, Nico Wunderling, and Jonathan F. Donges
EGUsphere, https://doi.org/10.5194/egusphere-2026-177, https://doi.org/10.5194/egusphere-2026-177, 2026
This preprint is open for discussion and under review for Geoscientific Model Development (GMD).
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Achieving climate and sustainability goals requires rapid, large-scale change. We introduce criticality – the likelihood a system is near a social tipping point – and critical agency – the capacity to shape those conditions. Our framework shows how coalitions and policies can trigger desired shifts and avoid harmful ones, linking complex systems theory with evidence to guide policymakers and practitioners.
Anna Höse, Moritz Kreuzer, Willem Huiskamp, Stefan Petri, and Georg Feulner
EGUsphere, https://doi.org/10.5194/egusphere-2025-5128, https://doi.org/10.5194/egusphere-2025-5128, 2025
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This research investigates the interactions between the Atlantic Meridional Overturning Circulation (AMOC) and the Antarctic Ice Sheet, which are both recognized as critical climate tipping elements in the Earth system. We conduct a computer simulation with artificial freshwater input in the North Atlantic to collapse the AMOC for 1500 years. Our findings show no destabilization of the Antarctic Ice Sheet induced by changes in the Southern Ocean during this period.
Florian Ulrich Jehn, Łukasz G. Gajewski, Johanna Hedlund, Constantin W. Arnscheidt, Lili Xia, Nico Wunderling, and David Denkenberger
Earth Syst. Dynam., 16, 1585–1603, https://doi.org/10.5194/esd-16-1585-2025, https://doi.org/10.5194/esd-16-1585-2025, 2025
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The global food trade system can handle small disturbances, but large disasters could cause major disruptions. We looked at how nuclear war or severe infrastructure loss would affect global trade in key crops. Both would be catastrophic, but a nuclear war would cause more severe disruptions, with many countries losing most of their food imports. Both scenarios highlight the need for better preparation to protect global food security.
Nico Wunderling, Anna S. von der Heydt, Yevgeny Aksenov, Stephen Barker, Robbin Bastiaansen, Victor Brovkin, Maura Brunetti, Victor Couplet, Thomas Kleinen, Caroline H. Lear, Johannes Lohmann, Rosa Maria Roman-Cuesta, Sacha Sinet, Didier Swingedouw, Ricarda Winkelmann, Pallavi Anand, Jonathan Barichivich, Sebastian Bathiany, Mara Baudena, John T. Bruun, Cristiano M. Chiessi, Helen K. Coxall, David Docquier, Jonathan F. Donges, Swinda K. J. Falkena, Ann Kristin Klose, David Obura, Juan Rocha, Stefanie Rynders, Norman Julius Steinert, and Matteo Willeit
Earth Syst. Dynam., 15, 41–74, https://doi.org/10.5194/esd-15-41-2024, https://doi.org/10.5194/esd-15-41-2024, 2024
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This paper maps out the state-of-the-art literature on interactions between tipping elements relevant for current global warming pathways. We find indications that many of the interactions between tipping elements are destabilizing. This means that tipping cascades cannot be ruled out on centennial to millennial timescales at global warming levels between 1.5 and 2.0 °C or on shorter timescales if global warming surpasses 2.0 °C.
Willem Huiskamp and Shayne McGregor
Clim. Past, 17, 1819–1839, https://doi.org/10.5194/cp-17-1819-2021, https://doi.org/10.5194/cp-17-1819-2021, 2021
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This study investigates the reliability of paleo-reconstructions of the Southern Annular Mode (SAM) using climate model data. We find that reconstructions are able to capture ~ 60 % of the SAM variability at best, with poorer reconstructions managing only 35 %. Reconstructions perform best when they use more proxies sourced from the entire Southern Hemisphere land mass. Future reconstructions should endeavour to address both sampling and proxy–SAM correlation stability uncertainties.
Markus Drüke, Werner von Bloh, Stefan Petri, Boris Sakschewski, Sibyll Schaphoff, Matthias Forkel, Willem Huiskamp, Georg Feulner, and Kirsten Thonicke
Geosci. Model Dev., 14, 4117–4141, https://doi.org/10.5194/gmd-14-4117-2021, https://doi.org/10.5194/gmd-14-4117-2021, 2021
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In this study, we couple the well-established and comprehensively validated state-of-the-art dynamic LPJmL5 global vegetation model to the CM2Mc coupled climate model (CM2Mc-LPJmL v.1.0). Several improvements to LPJmL5 were implemented to allow a fully functional biophysical coupling. The new climate model is able to capture important biospheric processes, including fire, mortality, permafrost, hydrological cycling and the the impacts of managed land (crop growth and irrigation).
Moritz Kreuzer, Ronja Reese, Willem Nicholas Huiskamp, Stefan Petri, Torsten Albrecht, Georg Feulner, and Ricarda Winkelmann
Geosci. Model Dev., 14, 3697–3714, https://doi.org/10.5194/gmd-14-3697-2021, https://doi.org/10.5194/gmd-14-3697-2021, 2021
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We present the technical implementation of a coarse-resolution coupling between an ice sheet model and an ocean model that allows one to simulate ice–ocean interactions at timescales from centuries to millennia. As ice shelf cavities cannot be resolved in the ocean model at coarse resolution, we bridge the gap using an sub-shelf cavity module. It is shown that the framework is computationally efficient, conserves mass and energy, and can produce a stable coupled state under present-day forcing.
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Short summary
Causal inference methods could be used to study the interaction of climate tipping elements, which may degrade abruptly due to climate change. We compare three of these methods to determine their reliability and apply two of them to the Arctic summer sea ice and the Atlantic Meridional Overturning Circulation (AMOC). Our results imply that a weaker AMOC would stabilize Arctic summer sea ice, and that a loss of Arctic summer sea ice would likely stabilize the AMOC in the short term.
Causal inference methods could be used to study the interaction of climate tipping elements,...
