@article{MerfortBauerHumpenoederetal.2023, author = {Merfort, Leon and Bauer, Nico and Humpen{\"o}der, Florian and Klein, David and Strefler, Jessica and Popp, Alexander and Luderer, Gunnar and Kriegler, Elmar}, title = {State of global land regulation inadequate to control biofuel land-use-change emissions}, series = {Nature climate change}, volume = {13}, journal = {Nature climate change}, number = {7}, publisher = {Nature Publ. Group}, address = {London}, issn = {1758-678X}, doi = {10.1038/s41558-023-01711-7}, pages = {610 -- 612}, year = {2023}, abstract = {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.}, language = {en} } @article{LudererMadedduMerfortetal.2021, author = {Luderer, Gunnar and Madeddu, Silvia and Merfort, Leon and Ueckerdt, Falko and Pehl, Michaja and Pietzcker, Robert C. and Rottoli, Marianna and Schreyer, Felix and Bauer, Nico and Baumstark, Lavinia and Bertram, Christoph and Dirnaichner, Alois and Humpen{\"o}der, Florian and Levesque, Antoine and Popp, Alexander and Rodrigues, Renato and Strefler, Jessica and Kriegler, Elmar}, title = {Impact of declining renewable energy costs on electrification in low-emission scenarios}, series = {Nature energy}, volume = {7}, journal = {Nature energy}, number = {1}, publisher = {Nature Publishing Group}, address = {London}, issn = {2058-7546}, doi = {10.1038/s41560-021-00937-z}, pages = {32 -- 42}, year = {2021}, abstract = {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.}, language = {en} } @article{PiontekKalkuhlKriegleretal.2019, author = {Piontek, Franziska and Kalkuhl, Matthias and Kriegler, Elmar and Schultes, Anselm and Leimbach, Marian and Edenhofer, Ottmar and Bauer, Nico}, title = {Economic Growth Effects of Alternative Climate Change Impact Channels in Economic Modeling}, series = {Environmental \& resource economics : the official journal of the European Association of Environmental and Resource Economists}, volume = {73}, journal = {Environmental \& resource economics : the official journal of the European Association of Environmental and Resource Economists}, number = {4}, publisher = {Springer}, address = {Dordrecht}, issn = {0924-6460}, doi = {10.1007/s10640-018-00306-7}, pages = {1357 -- 1385}, year = {2019}, abstract = {Despite increasing empirical evidence of strong links between climate and economic growth, there is no established model to describe the dynamics of how different types of climate shocks affect growth patterns. Here we present the first comprehensive, comparative analysis of the long-term dynamics of one-time, temporary climate shocks on production factors, and factor productivity, respectively, in a Ramsey-type growth model. Damages acting directly on production factors allow us to study dynamic effects on factor allocation, savings and economic growth. We find that the persistence of impacts on economic activity is smallest for climate shocks directly impacting output, and successively increases for direct damages on capital, loss of labor and productivity shocks, related to different responses in savings rates and factor-specific growth. Recurring shocks lead to large welfare effects and long-term growth effects, directly linked to the persistence of individual shocks. Endogenous savings and shock anticipation both have adaptive effects but do not eliminate differences between impact channels or significantly lower the dissipation time. Accounting for endogenous growth mechanisms increases the effects. We also find strong effects on income shares, important for distributional implications. This work fosters conceptual understanding of impact dynamics in growth models, opening options for links to empirics.}, language = {en} } @article{SoergelKrieglerBodirskyetal.2021, author = {Soergel, Bjoern and Kriegler, Elmar and Bodirsky, Benjamin Leon and Bauer, Nico and Leimbach, Marian and Popp, Alexander}, title = {Combining ambitious climate policies with efforts to eradicate poverty}, series = {Nature Communications}, volume = {12}, journal = {Nature Communications}, publisher = {Nature Publishing Group}, address = {London}, issn = {2041-1723}, doi = {10.1038/s41467-021-22315-9}, pages = {12}, year = {2021}, abstract = {Climate change threatens to undermine efforts to eradicate extreme poverty. However, climate policies could impose a financial burden on the global poor through increased energy and food prices. Here, we project poverty rates until 2050 and assess how they are influenced by mitigation policies consistent with the 1.5 degrees C target. A continuation of historical trends will leave 350 million people globally in extreme poverty by 2030. Without progressive redistribution, climate policies would push an additional 50 million people into poverty. However, redistributing the national carbon pricing revenues domestically as an equal-per-capita climate dividend compensates this policy side effect, even leading to a small net reduction of the global poverty headcount (-6 million). An additional international climate finance scheme enables a substantial poverty reduction globally and also in Sub-Saharan Africa. Combining national redistribution with international climate finance thus provides an important entry point to climate policy in developing countries. Ambitious climate policies can negatively impact the global poor by affecting income, food and energy prices. Here, the authors quantify this effect, and show that it can be compensated by national redistribution of the carbon pricing revenues in combination with international climate finance.}, language = {en} } @article{MerfortBauerHumpenoederetal.2023, author = {Merfort, Leon and Bauer, Nico and Humpen{\"o}der, Florian and Klein, David and Strefler, Jessica and Popp, Alexander and Luderer, Gunnar and Kriegler, Elmar}, title = {Bioenergy-induced land-use-change emissions with sectorally fragmented policies}, series = {Nature climate change}, volume = {13}, journal = {Nature climate change}, number = {7}, publisher = {Nature Publ. Group}, address = {London}, issn = {1758-678X}, doi = {10.1038/s41558-023-01697-2}, pages = {685 -- 692}, year = {2023}, abstract = {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.}, language = {en} } @article{StreflerKrieglerBaueretal.2021, author = {Strefler, Jessica and Kriegler, Elmar and Bauer, Nico and Luderer, Gunnar and Pietzcker, Robert C. and Giannousakis, Anastasis and Edenhofer, Ottmar}, title = {Alternative carbon price trajectories can avoid excessive carbon removal}, series = {Nature communications}, volume = {12}, journal = {Nature communications}, number = {1}, publisher = {Nature Publishing Group}, address = {London}, issn = {2041-1723}, doi = {10.1038/s41467-021-22211-2}, pages = {8}, year = {2021}, abstract = {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.}, language = {en} } @article{SoergelKrieglerWeindletal.2021, author = {Soergel, Bjoern and Kriegler, Elmar and Weindl, Isabelle and Rauner, Sebastian and Dirnaichner, Alois and Ruhe, Constantin and Hofmann, Matthias and Bauer, Nico and Bertram, Christoph and Bodirsky, Benjamin Leon and Leimbach, Marian and Leininger, Julia and Levesque, Antoine and Luderer, Gunnar and Pehl, Michaja and Wingens, Christopher and Baumstark, Lavinia and Beier, Felicitas and Dietrich, Jan Philipp and Humpen{\"o}der, Florian and von Jeetze, Patrick and Klein, David and Koch, Johannes and Pietzcker, Robert C. and Strefler, Jessica and Lotze-Campen, Hermann and Popp, Alexander}, title = {A sustainable development pathway for climate action within the UN 2030 Agenda}, series = {Nature climate change}, volume = {11}, journal = {Nature climate change}, number = {8}, publisher = {Nature Publishing Group}, address = {London}, issn = {1758-678X}, doi = {10.1038/s41558-021-01098-3}, pages = {656 -- 664}, year = {2021}, abstract = {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.}, language = {en} }