WP3. Scenario generation
Marotzke (2019) performed the first computation of the probability that emissions reductions cause changes in important climate trends during the fifteen years following the reductions with the first single-model initial-condition large ensemble run with a comprehensive set of future scenarios of MPI-GE (Maher et al., 2019). The probabilities of the policy shift causing the desired changes in climate trends in the near term (here, 15 years) are quite low. By quantifying causation probabilities and the inherent aleatoric uncertainty, this paper may aid both the science community and the public in preparing for a rational discourse about seemingly surprising futures.
Suarez-Gutierrez et al. (2020a,b) use the power of MPI-GE to study how extreme events change and to determine which extremes can be avoided by limiting global warming, versus which extremes are within the range of possibilities for each warming level. The study highlight a new type of neutral-atmosphere, drought-driven heat extremes, and confirm that the increase in European heat extremes and associated variability increase are dominated by the local thermodynamic effect of moisture limitation. The different heat-stress hotspots highlight the different potential risks and related adaptation measures that are vital to battle extreme heat over different regions.
We developed strategies to include social science and policy aspects already in the rather stylized coupled economy-energy-climate model MIND. First, sea level targets were analyzed as polices closer to coastal planning and related adaptation measures (Li et al., 2020). Global sea-level rise targets will provide a more sustainable and more cost-effective solution to limit both short-term and long-term climate change. This should appeal particularly to stakeholders for whom sea-level rise is most important among all global warming impact categories, compared to a temperature target with the same sea-level rise by 2200. Second, we coupled MIND and the Cambridge Evolutionary Economics Model FTT:Power. The latter crudely represents frictions in implementing an energy transition which are found to cause an additional 30 years delay in implementation of a 2°C policy (Odenweller, MSc Thesis, 2020; Odenweller, under revision for Technological Forecasting and Social Change). Third, we considered occupational health impacts of global warming and economic productivity impact of occupational healths within MIND. Preliminary results indicated 0.1% reduction in time-aggregate consumption (balanced growth equivalents) due to additional consideration of health impacts in the model when climate target restrictions were not considered (Bekchanov, 2021). Finally, an investigation on possibilities of integrating MIND and multi-regional, multi-sectoral general equilibrium model (GRACE) model has been initiated which would allow for multiple representations of social dynamics impacts of global warming.
Along another dimensions, more realistic modeling was pursued by providing better empirical foundations for the relevant parameters and functional assumptions. Hänsel et al. (2020) update the Dynamic Integrated Climate–Economy (DICE) integrated assessment model based on new insights from bothe climate science and economics. They examine economically ‘optimal’ climate policy paths based on a range of expert views on the ethics of intergenerational welfare from Drupp et al. (2018) to find that around three-quarters (or one-third) of expert views on intergenerational welfare translate into economically optimal climate policy paths that are consistent with the 2°C (or 1.5°C) target. The expert views on intergenerational welfare and their implications for the social cost of carbon have served as the basis for policy advice, e.g. to the US Environmental Protection Agency and the US Council of Economic Advisors, as well as the European Commission. Drupp and Hänsel (2021) study fundamental drivers of changing relative prices of non-market goods and their implications for climate policy in the DICE model. The central calibration reveals that neglecting relative price changes would lead to a stabilization of global temperature change that is 0.6°C higher. Relative price changes of non-market goods thus have a non-negligible effect on plausible climate futures and should be considered in economic appraisal and environmental-economic accounting. These results have served as the basis for policy advice, e.g. to Her Majesty’s Treasury in the UK.
References:
Bekchanov M., 2021. Climate-health-economics nexus analysis using global climate-energy-economics model. Presentation at AURÖ workshop, 14-15 October 2021, Oldenburg, Germany.
Bekchanov M., 2021. An integrated climate-energy-economic model for assessing climate-productivity (health) -growth nexus. Poster presentation at international autumn school “Climate Policy and Energy System Transformation: New Opportunities and Challenges of the Consideration of Co-Benefits”, 13-17 September 2021, Freiberg, Germany.
Drupp, M. A., Freeman, M. C., Groom, B., & Nesje, F. (2018). Discounting disentangled. American Economic Journal: Economic Policy, 10(4), 109-34.
Drupp, M. A., & Hänsel, M. C. (2021). Relative prices and climate policy: How the scarcity of nonmarket goods drives policy evaluation. American Economic Journal: Economic Policy, 13(1), 168-201.
Hänsel, M. C., M. A. Drupp, D. J. Johansson, F. Nesje, C. Azar, M. C. Freeman, and T. Sterner (2020). Climate economics support for the UN climate targets. Nature Climate Change, 10(8), 781-789.
Li, C., H. Held, S. Hokamp, and J. Marotzke, 2020: Optimal temperature overshoot profile found by limiting global sea level rise as a lower-cost climate target. Science Advances, 6, eaaw9490, 10.1126/sciadv.aaw9490
Maher, N., S. Milinski, L. Suarez-Gutierrez, M. Botzet, M. Dobrynin, L. Kornblueh, J. Kröger, Y. Takano, R. Ghosh, C. Hedemann, C. Li, H. Li, E. Manzini, D. Notz, D. Putrasahan, L. Boysen, M. Claussen, T. Ilyina, D. Olonscheck, T. Raddatz, B. Stevens, and J. Marotzke, 2019: The Max Planck Institute Grand Ensemble: Enabling the Exploration of Climate System Variability. Journal of Advances in Modeling Earth Systems, 11, 2050-2069.
Marotzke, J., 2019: Quantifying the irreducible uncertainty in near-term climate projections. Wiley Interdisciplinary Reviews: Climate Change, 10, e563.
Odenweller, A., 2020. Socio-technical inertia in integrated energy-economy models for climate change mitigation. MSc Thesis, School of Integrated Climate System Sciences, University of Hamburg.
Suarez-Gutierrez, L., W. A. Müller, C. Li, and J. Marotzke, 2020: Hotspots of extreme heat under global warming. Climate Dynamics, 55, 429-447, 10.1007/s00382-020-05263-w
Suarez-Gutierrez, L., W. A. Müller, C. Li, and J. Marotzke, 2020: Dynamical and thermodynamical drivers of variability in European summer heat extremes. Climate Dynamics, 54, 4351-4366, 10.1007/s00382-020-05233-2.