Coal-exit alliance must confront freeriding sectors to propel Paris-aligned momentum

S.L. Bi, N. Bauer & J. Jewell. (2023). Coal-exit alliance must confront freeriding sectors to propel Paris-aligned momentum. Nature Climate Change 1-10. DOI: https://doi.org/10.1038/s41558-022-01570-8

The global phase-out of coal by mid-century is considered vital to the Paris Agreement to limit warming well-below 2 °C above pre-industrial levels. Since the inception of the Powering Past Coal Alliance (PPCA) at COP23, political ambitions to accelerate the decline of coal have mounted to become the foremost priority at COP26. However, mitigation research lacks the tools to assess whether this bottom-up momentum can self-propagate toward Paris alignment. Here, we introduce dynamic policy evaluation (DPE), an evidence-based approach for emulating real-world policy-making. Given empirical relationships established between energy-economic developments and policy adoption, we endogenize national political decision-making into the integrated assessment model REMIND via multistage feedback loops with a probabilistic coalition accession model. DPE finds global PPCA participation <5% likely against a current policies backdrop and, counterintuitively, foresees that intracoalition leakage risks may severely compromise sector-specific, demand-side action. DPE further enables policies to interact endogenously, demonstrated here by the PPCA’s path-dependence to COVID-19 recovery investments.

Reply to: Why fossil fuel producer subsidies matter

J. Jewell, J. Emmerling, V. Vinichenko, C. Bertram, L. Berger, H. E. Daly, I. Keppo, V. Krey, D. E. H. J. Gernaat, K. Fragkiadakis, D. McCollum, L. Paroussas, K. Riahi, M. Tavoni & D. van Vuuren. (2020). Reply to: Why fossil fuel producer subsidies matter. Nature, 578 (7793), E5–E7. Open Access. DOI: https://doi.org/10.1038/s41586-019-1921-9.

Societal transformations in models for energy and climate policy: the ambitious next step

E. Trutnevyte, L.F. Hirt, N. Bauer, A. Cherp, A. Hawkes, O.Y. Edelenbosch, S. Pedde, & D.P. van Vuuren. (2020). Societal transformations in models for energy and climate policy: The Ambitious Next Step. One Earth, 1 (4), 423-433. Open Access. DOI: https://doi.org/10.1016/j.oneear.2019.12.002.

Whether and how long-term energy and climate targets can be reached depend on a range of interlinked factors: technology, economy, environment, policy, and society at large. Integrated assessment models of climate change or energy-system models have limited representations of societal transformations, such as behavior of various actors, transformation dynamics in time, and heterogeneity across and within societies. After reviewing the state of the art, we propose a research agenda to guide experiments to integrate more insights from social sciences into models: (1) map and assess societal assumptions in existing models, (2) conduct empirical research on generalizable and quantifiable patterns to be integrated into models, and (3) build and extensively validate modified or new models. Our proposed agenda offers three benefits: interdisciplinary learning between modelers and social scientists, improved models with a more complete representation of multifaceted reality, and identification of new and more effective solutions to energy and climate challenges.

News and views climate-policy models debated: clarifying the role of IAMs

J. Jewell. (2019). News and views climate-policy models debated: clarifying the role of IAMs. Nature, 573, 349–349. Open Access. URL: https://media.nature.com/original/magazine-assets/d41586-019-02744-9/d41586-019-02744-9.pdf.

Researchers and policymakers rely on computer simulations called integrated assessment models to determine the best strategies for tackling climate change. Here, scientists present opposing views on the suitability of these simulations.

Quantifying uncertainties influencing the long-term impacts of oil prices on energy markets and carbon emissions

D.L. McCollum, J. Jewell, V. Krey, M. Bazilian, M. Fay & K. Riahi. (2016). Quantifying uncertainties influencing the long-term impacts of oil prices on energy markets and carbon emissions. Nature Energy, 1 (7), 16077. Gated. DOI: https://doi.org/10.1038/nenergy.2016.77. Preprint.

Oil prices have fluctuated remarkably in recent years. Previous studies have analysed the impacts of future oil prices on the energy system and greenhouse gas emissions, but none have quantitatively assessed how the broader, energy-systemwide impacts of diverging oil price futures depend on a suite of critical uncertainties. Here we use the MESSAGE integrated assessment model to study several factors potentially influencing this interaction, thereby shedding light on which future unknowns hold the most importance. We find that sustained low or high oil prices could have a major impact on the global energy system over the next several decades; and depending on how the fuel substitution dynamics play out, the carbon dioxide consequences could be significant (for example, between 5 and 20% of the budget for staying below the internationally agreed 2 C target). Whether or not oil and gas prices decouple going forward is found to be the biggest uncertainty.

Comparison and interactions between the long-term pursuit of energy independence and climate policies

J. Jewell, V. Vinichenko, D. McCollum, N. Bauer, K. Riahi, T. Aboumahboub, O. Fricko, M. Harmsen, T. Kober, V. Krey, G. Marangoni, M. Tavoni, D.P. Van Vuuren, B. Van Der Zwaan & A. Cherp. (2016). Comparison and interactions between the long-term pursuit of energy independence and climate policies. Nature Energy 1, 1-9. Gated. DOI: https://dx.doi.org/10.1038/nenergy.2016.73.

Ensuring energy security and mitigating climate change are key energy policy priorities. The recent Intergovernmental Panel on Climate Change Working Group III report emphasized that climate policies can deliver energy security as a co-benefit, in large part through reducing energy imports. Using five state-of-the-art global energy-economy models and eight long- term scenarios, we show that although deep cuts in greenhouse gas emissions would reduce energy imports, the reverse is not true: ambitious policies constraining energy imports would have an insignificant impact on climate change. Restricting imports of all fuels would lower twenty-first-century emissions by only 2–15% against the Baseline scenario as compared with a 70%reduction in a 450 stabilization scenario. Restricting only oil imports would have virtually no impact on emissions. The modelled energy independence targets could be achieved at policy costs comparable to those of existing climate pledges but a fraction of the cost of limiting global warming to 2 ◦ C.

Global energy security under different climate policies, GDP growth rates and fossil resource availabilities

A. Cherp, J. Jewell, V. Vinichenko, N. Bauer & E. D. Cian. (2016). Global energy security under different climate policies, GDP growth rates and fossil resource availabilities. Climatic Change, 136 (1), 83-94. Open Access. DOI: https://doi.org/10.1007/s10584-013-0950-x.

Energy security is one of the main drivers of energy policies. Understanding energy security implications of long-term scenarios is crucial for informed policy making, especially with respect to transformations of energy systems required to stabilize climate change. This paper evaluates energy security under several global energy scenarios, modeled in the REMIND and WITCH integrated assessment models. The paper examines the effects of long-term climate policies on energy security under different assumptions about GDP growth and fossil fuel availability. It uses a systematic energy security assessment framework and a set of global and regional indicators for risks associated with energy trade and resilience associated with diversity of energy options. The analysis shows that climate policies significantly reduce the risks and increase the resilience of energy systems in the first half of the century. Climate policies also make energy supply, energy mix, and energy trade less dependent upon assumptions of fossil resource availability and GDP growth, and thus more predictable than in the baseline scenarios.

Post-2020 climate agreements in the major economies assessed in the light of global models

M. Tavoni, E. Kriegler, K. Riahi, D. P. van Vuuren, T. Aboumahboub, A. Bowen, K. Calvin, E. Campiglio, T. Kober, J. Jewell, G. Luderer, G. Marangoni, D. McCollum, M. van Sluisveld, A. Zimmer & B. van der Zwaan. (2014). Post-2020 climate agreements in the major economies assessed in the light of global models. Nature Climate Change, 5 (2), 119-126. Open Access. DOI: https://doi.org/10.1038/nclimate2475.

Integrated assessment models can help in quantifying the implications of international climate agreements and regional climate action. This paper reviews scenario results from model intercomparison projects to explore different possible outcomes of post-2020 climate negotiations, recently announced pledges and their relation to the 2 °C target. We provide key information for all the major economies, such as the year of emission peaking, regional carbon budgets and emissions allowances. We highlight the distributional consequences of climate policies, and discuss the role of carbon markets for financing clean energy investments, and achieving efficiency and equity.