TY - JOUR A1 - Ueckerdt, Falko A1 - Frieler, Katja A1 - Lange, Stefan A1 - Wenz, Leonie A1 - Luderer, Gunnar A1 - Levermann, Anders T1 - The economically optimal warming limit of the planet JF - Earth system dynamics N2 - Both climate-change damages and climate-change mitigation will incur economic costs. While the risk of severe damages increases with the level of global warming (Dell et al., 2014; IPCC, 2014b, 2018; Lenton et al., 2008), mitigating costs increase steeply with more stringent warming limits (IPCC, 2014a; Luderer et al., 2013; Rogelj et al., 2015). Here, we show that the global warming limit that minimizes this century's total economic costs of climate change lies between 1.9 and 2 ∘C, if temperature changes continue to impact national economic growth rates as observed in the past and if instantaneous growth effects are neither compensated nor amplified by additional growth effects in the following years. The result is robust across a wide range of normative assumptions on the valuation of future welfare and inequality aversion. We combine estimates of climate-change impacts on economic growth for 186 countries (applying an empirical damage function from Burke et al., 2015) with mitigation costs derived from a state-of-the-art energy–economy–climate model with a wide range of highly resolved mitigation options (Kriegler et al., 2017; Luderer et al., 2013, 2015). Our purely economic assessment, even though it omits non-market damages, provides support for the international Paris Agreement on climate change. The political goal of limiting global warming to “well below 2 degrees” is thus also an economically optimal goal given above assumptions on adaptation and damage persistence. Y1 - 2019 U6 - https://doi.org/10.5194/esd-10-741-2019 SN - 2190-4979 SN - 2190-4987 VL - 10 IS - 4 SP - 741 EP - 763 PB - Copernicus CY - Göttingen ER - TY - JOUR A1 - Merfort, Leon A1 - Bauer, Nico A1 - Humpenöder, Florian A1 - Klein, David A1 - Strefler, Jessica A1 - Popp, Alexander A1 - Luderer, Gunnar A1 - Kriegler, Elmar T1 - State of global land regulation inadequate to control biofuel land-use-change emissions JF - Nature climate change N2 - Under current land-use regulation, carbon dioxide emissions from biofuel production exceed those from fossil diesel combustion. Therefore, international agreements need to ensure the effective and globally comprehensive protection of natural land before modern bioenergy can effectively contribute to achieving carbon neutrality. KW - agriculture KW - climate-change mitigation KW - energy policy KW - energy supply and demand KW - environmental economics Y1 - 2023 U6 - https://doi.org/10.1038/s41558-023-01711-7 SN - 1758-678X SN - 1758-6798 VL - 13 IS - 7 SP - 610 EP - 612 PB - Nature Publ. Group CY - London ER - TY - JOUR A1 - Amberg, Maximilian A1 - aus dem Moore, Nils A1 - Bekk, Anke A1 - Bergmann, Tobias A1 - Edenhofer, Ottmar A1 - Flachsland, Christian A1 - George, Jan A1 - Haywood, Luke A1 - Heinemann, Maik A1 - Held, Anne A1 - Kalkuhl, Matthias A1 - Kellner, Maximilian A1 - Koch, Nicolas A1 - Luderer, Gunnar A1 - Meyer, Henrika A1 - Nikodinoska, Dragana A1 - Pahle, Michael A1 - Roolfs, Christina A1 - Schill, Wolf-Peter T1 - Reformoptionen für ein nachhaltiges Steuer- und Abgabensystem BT - wie Lenkungssteuern effektiv und gerecht für den Klima- und Umweltschutz ausgestaltet werden können JF - Perspektiven der Wirtschaftspolitik N2 - Steuern und Abgaben auf Produkte oder Verbrauch mit gesellschaftlichen Folgekosten (externe Kosten) – sogenannte Pigou- oder Lenkungssteuern – sind ein gesellschaftliches „Win-Win-Instrument“. Sie verbessern die Wohlfahrt und schützen gleichzeitig die Umwelt und das Klima. Dies wird erreicht, indem umweltschädigende Aktivitäten einen Preis bekommen, der möglichst exakt der Höhe des Schadens entspricht. Eine konsequente Bepreisung der externen Kosten nach diesem Prinzip könnte in Deutschland erhebliche zusätzliche Einnahmen erbringen: Basierend auf bisherigen Studien zu externen Kosten wären zusätzliche Einnahmen in der Größenordnung von 348 bis 564 Milliarden Euro pro Jahr (44 bis 71 Prozent der gesamten Steuereinnahmen) möglich. Die Autoren warnen allerdings, dass die Bezifferung der externen Kosten mit erheblichen Unsicherheiten verbunden ist. Damit Lenkungssteuern und -abgaben ihre positiven Lenkungs- und Wohlstandseffekte voll entfalten können, seien zudem institutionelle Reformen notwendig. KW - Externalitäten KW - Pigou-Steuern KW - Nachhaltige Steuerreform KW - Energiewende Y1 - 2022 U6 - https://doi.org/10.1515/pwp-2021-0051 SN - 1465-6493 SN - 1468-2516 VL - 23 IS - 3 SP - 165 EP - 199 PB - De Gruyter CY - Berlin ER - TY - JOUR A1 - Harmsen, Mathijs A1 - Kriegler, Elmar A1 - van Vuuren, Detlef P. A1 - van der Wijst, Kaj-Ivar A1 - Luderer, Gunnar A1 - Cui, Ryna A1 - Dessens, Olivier A1 - Drouet, Laurent A1 - Emmerling, Johannes A1 - Morris, Jennifer Faye A1 - Fosse, Florian A1 - Fragkiadakis, Dimitris A1 - Fragkiadakis, Kostas A1 - Fragkos, Panagiotis A1 - Fricko, Oliver A1 - Fujimori, Shinichiro A1 - Gernaat, David A1 - Guivarch, Céline A1 - Iyer, Gokul A1 - Karkatsoulis, Panagiotis A1 - Keppo, Ilkka A1 - Keramidas, Kimon A1 - Köberle, Alexandre A1 - Kolp, Peter A1 - Krey, Volker A1 - Krüger, Christoph A1 - Leblanc, Florian A1 - Mittal, Shivika A1 - Paltsev, Sergey A1 - Rochedo, Pedro A1 - van Ruijven, Bas J. A1 - Sands, Ronald D. A1 - Sano, Fuminori A1 - Strefler, Jessica A1 - Arroyo, Eveline Vasquez A1 - Wada, Kenichi A1 - Zakeri, Behnam T1 - Integrated assessment model diagnostics BT - key indicators and model evolution JF - Environmental research letters N2 - Integrated assessment models (IAMs) form a prime tool in informing about climate mitigation strategies. Diagnostic indicators that allow comparison across these models can help describe and explain differences in model projections. This increases transparency and comparability. Earlier, the IAM community has developed an approach to diagnose models (Kriegler (2015 Technol. Forecast. Soc. Change 90 45–61)). Here we build on this, by proposing a selected set of well-defined indicators as a community standard, to systematically and routinely assess IAM behaviour, similar to metrics used for other modeling communities such as climate models. These indicators are the relative abatement index, emission reduction type index, inertia timescale, fossil fuel reduction, transformation index and cost per abatement value. We apply the approach to 17 IAMs, assessing both older as well as their latest versions, as applied in the IPCC 6th Assessment Report. The study shows that the approach can be easily applied and used to indentify key differences between models and model versions. Moreover, we demonstrate that this comparison helps to link model behavior to model characteristics and assumptions. We show that together, the set of six indicators can provide useful indication of the main traits of the model and can roughly indicate the general model behavior. The results also show that there is often a considerable spread across the models. Interestingly, the diagnostic values often change for different model versions, but there does not seem to be a distinct trend. KW - diagnostics KW - integrated assessment models KW - climate policy KW - Assessment Report IPCC KW - renewable energy KW - migration KW - AR6 Y1 - 2021 U6 - https://doi.org/10.1088/1748-9326/abf964 SN - 1748-9326 VL - 16 IS - 5 PB - IOP Publishing CY - Bristol ER - TY - JOUR A1 - Luderer, Gunnar A1 - Madeddu, Silvia A1 - Merfort, Leon A1 - Ueckerdt, Falko A1 - Pehl, Michaja A1 - Pietzcker, Robert C. A1 - Rottoli, Marianna A1 - Schreyer, Felix A1 - Bauer, Nico A1 - Baumstark, Lavinia A1 - Bertram, Christoph A1 - Dirnaichner, Alois A1 - Humpenöder, Florian A1 - Levesque, Antoine A1 - Popp, Alexander A1 - Rodrigues, Renato A1 - Strefler, Jessica A1 - Kriegler, Elmar T1 - Impact of declining renewable energy costs on electrification in low-emission scenarios JF - Nature energy N2 - Cost degression in photovoltaics, wind-power and battery storage has been faster than previously anticipated. In the future, climate policy to limit global warming to 1.5–2 °C will make carbon-based fuels increasingly scarce and expensive. Here we show that further progress in solar- and wind-power technology along with carbon pricing to reach the Paris Climate targets could make electricity cheaper than carbon-based fuels. In combination with demand-side innovation, for instance in e-mobility and heat pumps, this is likely to induce a fundamental transformation of energy systems towards a dominance of electricity-based end uses. In a 1.5 °C scenario with limited availability of bioenergy and carbon dioxide removal, electricity could account for 66% of final energy by mid-century, three times the current levels and substantially higher than in previous climate policy scenarios assessed by the Intergovernmental Panel on Climate Change. The lower production of bioenergy in our high-electrification scenarios markedly reduces energy-related land and water requirements. KW - climate-change mitigation KW - energy modelling KW - renewable energy Y1 - 2021 U6 - https://doi.org/10.1038/s41560-021-00937-z SN - 2058-7546 N1 - Corrigendum: https://doi.org/10.1038/s41560-022-01000-1 VL - 7 IS - 1 SP - 32 EP - 42 PB - Nature Publishing Group CY - London ER - TY - JOUR A1 - Bertram, Christoph A1 - Riahi, Keywan A1 - Hilaire, Jérôme A1 - Bosetti, Valentina A1 - Drouet, Laurent A1 - Fricko, Oliver A1 - Malik, Aman A1 - Nogueira, Larissa Pupo A1 - van der Zwaan, Bob A1 - van Ruijven, Bas A1 - van Vuuren, Detlef P. A1 - Weitzel, Matthias A1 - Longa, Francesco Dalla A1 - de Boer, Harmen-Sytze A1 - Emmerling, Johannes A1 - Fosse, Florian A1 - Fragkiadakis, Kostas A1 - Harmsen, Mathijs A1 - Keramidas, Kimon A1 - Kishimoto, Paul Natsuo A1 - Kriegler, Elmar A1 - Krey, Volker A1 - Paroussos, Leonidas A1 - Saygin, Deger A1 - Vrontisi, Zoi A1 - Luderer, Gunnar T1 - Energy system developments and investments in the decisive decade for the Paris Agreement goals JF - Environmental research letters N2 - The Paris Agreement does not only stipulate to limit the global average temperature increase to well below 2 °C, it also calls for 'making finance flows consistent with a pathway towards low greenhouse gas emissions'. Consequently, there is an urgent need to understand the implications of climate targets for energy systems and quantify the associated investment requirements in the coming decade. A meaningful analysis must however consider the near-term mitigation requirements to avoid the overshoot of a temperature goal. It must also include the recently observed fast technological progress in key mitigation options. Here, we use a new and unique scenario ensemble that limit peak warming by construction and that stems from seven up-to-date integrated assessment models. This allows us to study the near-term implications of different limits to peak temperature increase under a consistent and up-to-date set of assumptions. We find that ambitious immediate action allows for limiting median warming outcomes to well below 2 °C in all models. By contrast, current nationally determined contributions for 2030 would add around 0.2 °C of peak warming, leading to an unavoidable transgression of 1.5 °C in all models, and 2 °C in some. In contrast to the incremental changes as foreseen by current plans, ambitious peak warming targets require decisive emission cuts until 2030, with the most substantial contribution to decarbonization coming from the power sector. Therefore, investments into low-carbon power generation need to increase beyond current levels to meet the Paris goals, especially for solar and wind technologies and related system enhancements for electricity transmission, distribution and storage. Estimates on absolute investment levels, up-scaling of other low-carbon power generation technologies and investment shares in less ambitious scenarios vary considerably across models. In scenarios limiting peak warming to below 2 °C, while coal is phased out quickly, oil and gas are still being used significantly until 2030, albeit at lower than current levels. This requires continued investments into existing oil and gas infrastructure, but investments into new fields in such scenarios might not be needed. The results show that credible and effective policy action is essential for ensuring efficient allocation of investments aligned with medium-term climate targets. KW - Paris Agreement KW - energy investments KW - mitigation policies KW - climate policy KW - integrated assessment modelling Y1 - 2021 U6 - https://doi.org/10.1088/1748-9326/ac09ae SN - 1748-9326 VL - 16 IS - 7 PB - IOP Publishing CY - Bristol ER - TY - JOUR A1 - Schultes, Anselm A1 - Piontek, Franziska A1 - Soergel, Bjoern A1 - Rogelj, Joeri A1 - Baumstark, Lavinia A1 - Kriegler, Elmar A1 - Edenhofer, Ottmar A1 - Luderer, Gunnar T1 - Economic damages from on-going climate change imply deeper near-term emission cuts JF - Environmental research letters N2 - Pathways toward limiting global warming to well below 2 ∘C, as used by the IPCC in the Fifth Assessment Report, do not consider the climate impacts already occurring below 2 ∘C. Here we show that accounting for such damages significantly increases the near-term ambition of transformation pathways. We use econometric estimates of climate damages on GDP growth and explicitly model the uncertainty in the persistence time of damages. The Integrated Assessment Model we use includes the climate system and mitigation technology detail required to derive near-term policies. We find an optimal carbon price of $115 per tonne of CO2 in 2030. The long-term persistence of damages, while highly uncertain, is a main driver of the near-term carbon price. Accounting for damages on economic growth increases the gap between the currently pledged nationally determined contributions and the welfare-optimal 2030 emissions by two thirds, compared to pathways considering the 2 ∘C limit only. KW - climate change KW - climate mitigation KW - climate impacts KW - integrated assessment Y1 - 2021 U6 - https://doi.org/10.1088/1748-9326/ac27ce SN - 1748-9326 VL - 16 IS - 10 PB - IOP Publishing CY - Bristol ER - TY - JOUR A1 - Riahi, Keywan A1 - Bertram, Christoph A1 - Huppmann, Daniel A1 - Rogelj, Joeri A1 - Bosetti, Valentina A1 - Cabardos, Anique-Marie A1 - Deppermann, Andre A1 - Drouet, Laurent A1 - Frank, Stefan A1 - Fricko, Oliver A1 - Fujimori, Shinichiro A1 - Harmsen, Mathijs A1 - Hasegawa, Tomoko A1 - Krey, Volker A1 - Luderer, Gunnar A1 - Paroussos, Leonidas A1 - Schaeffer, Roberto A1 - Weitzel, Matthias A1 - van der Zwaan, Bob A1 - Vrontisi, Zoi A1 - Longa, Francesco Dalla A1 - Després, Jacques A1 - Fosse, Florian A1 - Fragkiadakis, Kostas A1 - Gusti, Mykola A1 - Humpenöder, Florian A1 - Keramidas, Kimon A1 - Kishimoto, Paul A1 - Kriegler, Elmar A1 - Meinshausen, Malte A1 - Nogueira, Larissa Pupo A1 - Oshiro, Ken A1 - Popp, Alexander A1 - Rochedo, Pedro R. R. A1 - Ünlü, Gamze A1 - van Ruijven, Bas A1 - Takakura, Junya A1 - Tavoni, Massimo A1 - van Vuuren, Detlef P. A1 - Zakeri, Behnam T1 - Cost and attainability of meeting stringent climate targets without overshoot JF - Nature climate change N2 - Global emissions scenarios play a critical role in the assessment of strategies to mitigate climate change. The current scenarios, however, are criticized because they feature strategies with pronounced overshoot of the global temperature goal, requiring a long-term repair phase to draw temperatures down again through net-negative emissions. Some impacts might not be reversible. Hence, we explore a new set of net-zero CO2 emissions scenarios with limited overshoot. We show that upfront investments are needed in the near term for limiting temperature overshoot but that these would bring long-term economic gains. Our study further identifies alternative configurations of net-zero CO2 emissions systems and the roles of different sectors and regions for balancing sources and sinks. Even without net-negative emissions, CO2 removal is important for accelerating near-term reductions and for providing an anthropogenic sink that can offset the residual emissions in sectors that are hard to abate. Y1 - 2021 U6 - https://doi.org/10.1038/s41558-021-01215-2 SN - 1758-678X SN - 1758-6798 VL - 11 IS - 12 SP - 1063 EP - 1069 PB - Nature Publishing Group CY - London ER - TY - JOUR A1 - Malik, Aman A1 - Bertram, Christoph A1 - Kriegler, Elmar A1 - Luderer, Gunnar T1 - Climate policy accelerates structural changes in energy employment JF - Energy policy N2 - The employment implications of decarbonizing the energy sector have received far less attention than the technology dimension of the transition, although being of critical importance to policymakers. In this work, we adapt a methodology based on employment factors to project future changes in quantity and composition of direct energy supply jobs for two scenarios - (1) relatively weak emissions reductions as pledged in the nationally determined contributions (NDC) and (2) stringent reductions compatible with the 1.5 °C target. We find that in the near-term the 1.5°C-compatible scenario results in a net increase in jobs through gains in solar and wind jobs in construction, installation, and manufacturing, despite significant losses in coal fuel supply; eventually leading to a peak in total direct energy jobs in 2025. In the long run, improvements in labour productivity lead to a decrease of total direct energy employment compared to today, however, total jobs are still higher in a 1.5 °C than in an NDC scenario. Operation and maintenance jobs dominate future jobs, replacing fuel supply jobs. The results point to the need for active policies aimed at retraining, both inside and outside the renewable energy sector, to complement climate policies within the concept of a “just transition”. KW - energy supply KW - employment KW - just transition KW - political feasibility KW - mitigation pathways KW - integrated assessment models Y1 - 2021 U6 - https://doi.org/10.1016/j.enpol.2021.112642 SN - 0301-4215 VL - 159 PB - Elsevier Science CY - Amsterdam ER - TY - JOUR A1 - Merfort, Leon A1 - Bauer, Nico A1 - Humpenöder, Florian A1 - Klein, David A1 - Strefler, Jessica A1 - Popp, Alexander A1 - Luderer, Gunnar A1 - Kriegler, Elmar T1 - Bioenergy-induced land-use-change emissions with sectorally fragmented policies JF - Nature climate change N2 - Controlling bioenergy-induced land-use-change emissions is key to exploiting bioenergy for climate change mitigation. However, the effect of different land-use and energy sector policies on specific bioenergy emissions has not been studied so far. Using the global integrated assessment model REMIND-MAgPIE, we derive a biofuel emission factor (EF) for different policy frameworks. We find that a uniform price on emissions from both sectors keeps biofuel emissions at 12 kg CO2 GJ−1. However, without land-use regulation, the EF increases substantially (64 kg CO2 GJ−1 over 80 years, 92 kg CO2 GJ−1 over 30 years). We also find that comprehensive coverage (>90%) of carbon-rich land areas worldwide is key to containing land-use emissions. Pricing emissions indirectly on the level of bioenergy consumption reduces total emissions by cutting bioenergy demand but fails to reduce the average EF. In the absence of comprehensive and timely land-use regulation, bioenergy thus may contribute less to climate change mitigation than assumed previously. KW - agriculture KW - climate-change mitigation KW - energy policy KW - energy supply and demand KW - environmental economics Y1 - 2023 U6 - https://doi.org/10.1038/s41558-023-01697-2 SN - 1758-678X SN - 1758-6798 VL - 13 IS - 7 SP - 685 EP - 692 PB - Nature Publ. Group CY - London ER - TY - JOUR A1 - Strefler, Jessica A1 - Kriegler, Elmar A1 - Bauer, Nico A1 - Luderer, Gunnar A1 - Pietzcker, Robert C. A1 - Giannousakis, Anastasis A1 - Edenhofer, Ottmar T1 - Alternative carbon price trajectories can avoid excessive carbon removal JF - Nature communications N2 - The large majority of climate change mitigation scenarios that hold warming below 2 °C show high deployment of carbon dioxide removal (CDR), resulting in a peak-and-decline behavior in global temperature. This is driven by the assumption of an exponentially increasing carbon price trajectory which is perceived to be economically optimal for meeting a carbon budget. However, this optimality relies on the assumption that a finite carbon budget associated with a temperature target is filled up steadily over time. The availability of net carbon removals invalidates this assumption and therefore a different carbon price trajectory should be chosen. We show how the optimal carbon price path for remaining well below 2 °C limits CDR demand and analyze requirements for constructing alternatives, which may be easier to implement in reality. We show that warming can be held at well below 2 °C at much lower long-term economic effort and lower CDR deployment and therefore lower risks if carbon prices are high enough in the beginning to ensure target compliance, but increase at a lower rate after carbon neutrality has been reached. KW - climate-change mitigation KW - climate sciences KW - environmental sciences Y1 - 2021 U6 - https://doi.org/10.1038/s41467-021-22211-2 SN - 2041-1723 VL - 12 IS - 1 PB - Nature Publishing Group CY - London ER - TY - JOUR A1 - Soergel, Bjoern A1 - Kriegler, Elmar A1 - Weindl, Isabelle A1 - Rauner, Sebastian A1 - Dirnaichner, Alois A1 - Ruhe, Constantin A1 - Hofmann, Matthias A1 - Bauer, Nico A1 - Bertram, Christoph A1 - Bodirsky, Benjamin Leon A1 - Leimbach, Marian A1 - Leininger, Julia A1 - Levesque, Antoine A1 - Luderer, Gunnar A1 - Pehl, Michaja A1 - Wingens, Christopher A1 - Baumstark, Lavinia A1 - Beier, Felicitas A1 - Dietrich, Jan Philipp A1 - Humpenöder, Florian A1 - von Jeetze, Patrick A1 - Klein, David A1 - Koch, Johannes A1 - Pietzcker, Robert C. A1 - Strefler, Jessica A1 - Lotze-Campen, Hermann A1 - Popp, Alexander T1 - A sustainable development pathway for climate action within the UN 2030 Agenda JF - Nature climate change N2 - Ambitious climate policies, as well as economic development, education, technological progress and less resource-intensive lifestyles, are crucial elements for progress towards the UN Sustainable Development Goals (SDGs). However, using an integrated modelling framework covering 56 indicators or proxies across all 17 SDGs, we show that they are insufficient to reach the targets. An additional sustainable development package, including international climate finance, progressive redistribution of carbon pricing revenues, sufficient and healthy nutrition and improved access to modern energy, enables a more comprehensive sustainable development pathway. We quantify climate and SDG outcomes, showing that these interventions substantially boost progress towards many aspects of the UN Agenda 2030 and simultaneously facilitate reaching ambitious climate targets. Nonetheless, several important gaps remain; for example, with respect to the eradication of extreme poverty (180 million people remaining in 2030). These gaps can be closed by 2050 for many SDGs while also respecting the 1.5 °C target and several other planetary boundaries. KW - climate-change mitigation KW - climate-change policy KW - socioeconomic scenarios KW - sustainability Y1 - 2021 U6 - https://doi.org/10.1038/s41558-021-01098-3 SN - 1758-678X SN - 1758-6798 VL - 11 IS - 8 SP - 656 EP - 664 PB - Nature Publishing Group CY - London ER -