Publications
186 results found
Zakeri B, Paulavets K, Barreto-Gomez L, et al., 2022, Pandemic, War, and Global Energy Transitions, ENERGIES, Vol: 15
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- Citations: 74
Kikstra JS, Nicholls ZRJ, Smith CJ, et al., 2022, The IPCC Sixth Assessment Report WGIII climate assessment of mitigation pathways: from emissions to global temperatures
<jats:p>Abstract. While the IPCC’s physical science report usually assesses a handful of future scenarios, the IPCC Sixth Assessment Working Group III report (AR6 WGIII) on climate mitigation assesses hundreds to thousands of future emissions scenarios. A key task is to assess the global-mean temperature outcomes of these scenarios in a consistent manner, given the challenge that the emission scenarios from different integrated assessment models come with different sectoral and gas-to-gas coverage and cannot all be assessed consistently by complex Earth System Models. In this work, we describe the “climate assessment” workflow and its methods, including infilling of missing emissions and emissions harmonisation as applied to 1,202 mitigation scenarios in AR6 WGIII. We evaluate the global-mean temperature projections and effective radiative forcing characteristics (ERF) of climate emulators FaIRv1.6.2, MAGICCv7.5.3, and CICERO-SCM, discuss overshoot severity of the mitigation pathways using overshoot degree years, and look at an interpretation of compatibility with the Paris Agreement. We find that the lowest class of emission scenarios that limit global warming to “1.5 °C (with a probability of greater than 50 %) with no or limited overshoot” includes 90 scenarios for MAGICCv7.5.3, and 196 for FaIRv1.6.2. For the MAGICCv7.5.3 results, “limited overshoot” typically implies exceedance of median temperature projections of up to about 0.1 °C for up to a few decades, before returning to below 1.5 °C by or before the year 2100. For more than half of the scenarios of this category that comply with three criteria for being “Paris-compatible”, including net-zero or net-negative greenhouse gas (GHG) emissions, are projected to see median temperatures decline by about 0.3–0.4 °C after peaking at 1.5–1.6 °C in 2035–2055. We compare the methods applied in AR6 with the methods used f
Kikstra JS, Nicholls ZRJ, Smith CJ, et al., 2022, Supplementary material to "The IPCC Sixth Assessment Report WGIII climate assessment of mitigation pathways: from emissions to global temperatures"
Schleussner C-F, Ganti G, Rogelj J, et al., 2022, An emission pathway classification reflecting the Paris Agreement climate objectives, COMMUNICATIONS EARTH & ENVIRONMENT, Vol: 3
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- Citations: 18
Gibson M, Pereira JP, Slade R, et al., 2022, Agent-based modelling of future dairy and plant-based milk consumption for UK climate targets, JASSS-THE JOURNAL OF ARTIFICIAL SOCIETIES AND SOCIAL SIMULATION, Vol: 25, ISSN: 1460-7425
A reduction in the production and consumption of meat and dairy across much of the world is critical for climate change mitigation, the alleviation of ecological stress, and improved health. We update an agent-based model (ABM) of historic UK milk consumption and apply it to scenarios of dairy reduction and adoption of plant-based milk (PBM) out to 2050. The updated model is comprised of a cognitive function, where agents perceive the physical, health and environmental characteristics of milk choice, which is modified by habit and social influence. We use European Social Survey 2018 and British Social Attitudes 2008 survey data to empirically inform the model. Taking a backcasting approach, we calibrate parameters against published UK dairy reduction targets (2030 and 2050), and test how different price relationships, and characterisations of environmental concern, may affect simulated milk consumption from 2020 to 2050. Scenarios for core targets (20% less dairy by 2030 and 35% by 2050) largely produced plausible consumption trajectories. However, at current pricing of dairy and PBM, simulated consumption was mostly unable to deliver on desired core targets, but this improved markedly with dairy prices set to organic levels. The influence of changing environmental concern on milk choice resulted in higher levels of dairy milk reduction. When modelled as transient, intense shocks to public concern, consumption patterns did not fundamentally change. However, small, incremental but permanent changes to concern did produce structural changes to consumption patterns, with dairy falling below plant-based alternatives at around 2030. This study is the first to apply an ABM in the context of scenarios for dairy reduction and PBM adoption in service to UK climate-related consumption targets. It can serve as valuable bottom-up, alternative, evidence on the feasibility of dietary shift targets, and poses policy implications for how to address impediments to behavioural change
Koberle AC, Vandyck T, Guivarch C, et al., 2022, The cost of mitigation revisited (Nov, 10.1038/s41558-021-01203-6, 2021), NATURE CLIMATE CHANGE, Vol: 12, Pages: 298-298, ISSN: 1758-678X
Allen MR, Peters GP, Shine KP, et al., 2022, Indicate separate contributions of long-lived and short-lived greenhouse gases in emission targets, NPJ CLIMATE AND ATMOSPHERIC SCIENCE, Vol: 5, ISSN: 2397-3722
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- Citations: 26
Gambhir A, George M, McJeon H, et al., 2022, Near-term transition and longer-term physical climate risks of greenhouse gas emissions pathways, NATURE CLIMATE CHANGE, Vol: 12, Pages: 88-+, ISSN: 1758-678X
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- Citations: 15
Fiedler S, Wyser K, Rogelj J, et al., 2021, Radiative effects of reduced aerosol emissions during the COVID-19 pandemic and the future recovery, Atmospheric Research, Vol: 264, Pages: 1-11, ISSN: 0169-8095
The pandemic in 2020 caused an abrupt change in the emission of anthropogenic aerosols and their precursors. We estimate the associated change in the aerosol radiative forcing at the top of the atmosphere and the surface. To that end, we perform new simulations with the CMIP6 global climate model EC-Earth3. The simulations use the here newly created data for the anthropogenic aerosol optical properties and an associated effect on clouds from the simple plumes parameterization (MACv2-SP), based on revised SO2 and NH3 emission scenarios. Our results highlight the small impact of the pandemic on the global aerosol radiative forcing in 2020 compared to the CMIP6 scenario SSP2-4.5 of the order of +0.04 Wm−2, which is small compared to the natural year-to-year variability in the radiation budget. Natural variability also limits the ability to detect a meaningful regional difference in the anthropogenic aerosol radiative effects. We identify the best chances to find a significant change in radiation at the surface during cloud-free conditions for regions that were strongly polluted in the past years. The post-pandemic recovery scenarios indicate a spread in the aerosol forcing of −0.68 to −0.38 Wm−2 for 2050 relative to the pre-industrial, which translates to a difference of +0.05 to −0.25 Wm−2 compared to the 2050 baseline from SSP2-4.5. This spread falls within the present-day uncertainty in aerosol radiative forcing and the CMIP6 spread in aerosol forcing at the end of the 21st century. We release the new MACv2-SP data for studies on the climate response to the pandemic and the recovery scenarios. Our 2050 forcing estimates suggest that sustained aerosol emission reductions during the post-pandemic recovery cause a stronger climate response than in 2020, i.e., there is a delayed influence of the pandemic on climate.
George M, Gambhir A, McJeon H, et al., 2021, Assessing multi-sector near-term transition and longer-term physical climate risks of greenhouse gas emissions pathways
George M, Gambhir A, McJeon H, et al., 2021, Assessing multi-sector near-term transition and longer-term physical climate risks of greenhouse gas emissions pathways
MacDougall AH, Rogelj J, Withey P, 2021, Estimated climate impact of replacing agriculture as the primary food production system, ENVIRONMENTAL RESEARCH LETTERS, Vol: 16, ISSN: 1748-9326
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- Citations: 1
Riahi K, Bertram C, Huppmann D, et al., 2021, Cost and attainability of meeting stringent climate targets without overshoot, NATURE CLIMATE CHANGE, Vol: 11, Pages: 1063-+, ISSN: 1758-678X
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- Citations: 64
Kikstra JS, Vinca A, Lovat F, et al., 2021, Climate mitigation scenarios with persistent COVID-19-related energy demand changes, NATURE ENERGY, Vol: 6, Pages: 1114-1123, ISSN: 2058-7546
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- Citations: 35
Sognnaes I, Gambhir A, van de Ven D-J, et al., 2021, A multi-model analysis of long-term emissions and warming implications of current mitigation efforts, Nature Climate Change, Vol: 11, Pages: 1055-1062, ISSN: 1758-678X
Most of the integrated assessment modelling literature focuses on cost-effective pathways towards given temperature goals. Conversely, using seven diverse integrated assessment models, we project global energy CO2 emissions trajectories on the basis of near-term mitigation efforts and two assumptions on how these efforts continue post-2030. Despite finding a wide range of emissions by 2050, nearly all the scenarios have median warming of less than 3 °C in 2100. However, the most optimistic scenario is still insufficient to limit global warming to 2 °C. We furthermore highlight key modelling choices inherent to projecting where emissions are headed. First, emissions are more sensitive to the choice of integrated assessment model than to the assumed mitigation effort, highlighting the importance of heterogeneous model intercomparisons. Differences across models reflect diversity in baseline assumptions and impacts of near-term mitigation efforts. Second, the common practice of using economy-wide carbon prices to represent policy exaggerates carbon capture and storage use compared with explicitly modelling policies.
Koberle AC, Vandyck T, Guivarch C, et al., 2021, The cost of mitigation revisited, Nature Climate Change, Vol: 11, Pages: 1035-1045, ISSN: 1758-678X
Estimates of economic implications of climate policy are important inputs into policy-making. Despite care to contextualize quantitative assessments of mitigation costs, one strong view outside academic climate economics is that achieving Paris Agreement goals implies sizable macroeconomic losses. Here, we argue that this notion results from unwarranted simplification or omission of the complexities of quantifying mitigation costs, which generates ambiguity in communication and interpretation. We synthesize key factors influencing mitigation cost estimates to guide interpretation of estimates, for example from the Intergovernmental Panel on Climate Change, and suggest ways to improve the underlying models. We propose alternatives for the scenario design framework, the framing of mitigation costs and the methods used to derive them, to better inform public debate and policy.
Ou Y, Iyer G, Clarke L, et al., 2021, Can updated climate pledges limit warming well below 2 degrees C? Increased ambition and implementation are essential, Science, Vol: 374, Pages: 693-695, ISSN: 0036-8075
Martin MA, Alcaraz Sendra O, Bastos A, et al., 2021, Ten new insights in climate science 2021: a horizon scan, Global Sustainability, Vol: 4, Pages: 1-20, ISSN: 2059-4798
A synthesis is made of 10 topics within climate research, where there have been significant advances since January 2020. The insights are based on input from an international open call with broad disciplinary scope. Findings include: (1) the options to still keep global warming below 1.5 °C; (2) the impact of non-CO2 factors in global warming; (3) a new dimension of fire extremes forced by climate change; (4) the increasing pressure on interconnected climate tipping elements; (5) the dimensions of climate justice; (6) political challenges impeding the effectiveness of carbon pricing; (7) demand-side solutions as vehicles of climate mitigation; (8) the potentials and caveats of nature-based solutions; (9) how building resilience of marine ecosystems is possible; and (10) that the costs of climate change mitigation policies can be more than justified by the benefits to the health of humans and nature.
Thiery W, Lange S, Rogelj J, et al., 2021, Intergenerational inequities in exposure to climate extremes Young generations are severely threatened by climate change, Science, Vol: 374, Pages: 158-160, ISSN: 0036-8075
Schultes A, Piontek F, Soergel B, et al., 2021, Economic damages from on-going climate change imply deeper near-term emission cuts, ENVIRONMENTAL RESEARCH LETTERS, Vol: 16, ISSN: 1748-9326
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- Citations: 10
Hoehne N, Gidden MJ, den Elzen M, et al., 2021, Wave of net zero emission targets opens window to meeting the Paris Agreement, NATURE CLIMATE CHANGE, Vol: 11, Pages: 820-+, ISSN: 1758-678X
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- Citations: 81
Hoepner AGF, Rogelj J, 2021, Emissions estimations should embed a precautionary principle, NATURE CLIMATE CHANGE, Vol: 11, Pages: 638-640, ISSN: 1758-678X
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- Citations: 6
Gibson M, Slade R, Pereira JP, et al., 2021, Comparing mechanisms of food choice in an agent-based model of milk consumption and substitution in the UK, JASSS-THE JOURNAL OF ARTIFICIAL SOCIETIES AND SOCIAL SIMULATION, Vol: 24, ISSN: 1460-7425
Substitution of food products will be key to realising widespread adoption of sustainable diets. We present an agent-based model of decision-making and influences on food choice, and apply it to historically observed trends of British whole and skimmed (including semi) milk consumption from 1974 to 2005. We aim to give a plausible representation of milk choice substitution, and test different mechanisms of choice consideration. Agents are consumers that perceive information regarding the two milk choices, and hold values that inform their position on the health and environmental impact of those choices. Habit, social influence and post-decision evaluation are modelled. Representative survey data on human values and long-running public concerns empirically inform the model. An experiment was run to compare two model variants by how they perform in reproducing these trends. This was measured by recording mean weekly milk consumption per person. The variants differed in how agents became disposed to consider alternative milk choices. One followed a threshold approach, the other was probability based. All other model aspects remained unchanged. An optimisation exercise via an evolutionary algorithm was used to calibrate the model variants independently to observed data. Following calibration, uncertainty and global variance-based temporal sensitivity analysis were conducted. Both model variants were able to reproduce the general pattern of historical milk consumption, however, the probability-based approach gave a closer fit to the observed data, but over a wider range of uncertainty. This responds to, and further highlights, the need for research that looks at, and compares, different models of human decision-making in agent-based and simulation models. This study is the first to present an agent-based modelling of food choice substitution in the context of British milk consumption. It can serve as a valuable pre-curser to the modelling of dietary shift and sustainable
Lamboll RD, Jones CD, Skeie RB, et al., 2021, Modifying emissions scenario projections to account for the effects of COVID-19: protocol for CovidMIP, GEOSCIENTIFIC MODEL DEVELOPMENT, Vol: 14, Pages: 3683-3695, ISSN: 1991-959X
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- Citations: 24
Nikas A, Elia A, Boitier B, et al., 2021, Where is the EU headed given its current climate policy? A stakeholder-driven model inter-comparison., Science of the Total Environment, Vol: 793, Pages: 148549-148549, ISSN: 0048-9697
Recent calls to do climate policy research with, rather than for, stakeholders have been answered in non-modelling science. Notwithstanding progress in modelling literature, however, very little of the scenario space traces back to what stakeholders are ultimately concerned about. With a suite of eleven integrated assessment, energy system and sectoral models, we carry out a model inter-comparison for the EU, the scenario logic and research questions of which have been formulated based on stakeholders' concerns. The output of this process is a scenario framework exploring where the region is headed rather than how to achieve its goals, extrapolating its current policy efforts into the future. We find that Europe is currently on track to overperforming its pre-2020 40% target yet far from its newest ambition of 55% emissions cuts by 2030, as well as looking at a 1.0-2.35 GtCO2 emissions range in 2050. Aside from the importance of transport electrification, deployment levels of carbon capture and storage are found intertwined with deeper emissions cuts and with hydrogen diffusion, with most hydrogen produced post-2040 being blue. Finally, the multi-model exercise has highlighted benefits from deeper decarbonisation in terms of energy security and jobs, and moderate to high renewables-dominated investment needs.
Rogelj J, Schleussner C-F, 2021, Reply to Comment on 'Unintentional unfairness when applying new greenhouse gas emissions metrics at country level', ENVIRONMENTAL RESEARCH LETTERS, Vol: 16, ISSN: 1748-9326
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- Citations: 2
Nicholls Z, Meinshausen M, Lewis J, et al., 2021, Reduced Complexity Model Intercomparison Project Phase 2: Synthesizing Earth System Knowledge for Probabilistic Climate Projections, EARTHS FUTURE, Vol: 9
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- Citations: 26
Grassi G, Stehfest E, Rogelj J, et al., 2021, Critical adjustment of land mitigation pathways for assessing countries’ climate progress, Nature Climate Change, Vol: 11, Pages: 425-434, ISSN: 1758-678X
Mitigation pathways by Integrated Assessment Models (IAMs) describe future emissions that keep global warming below specific temperature limits and are compared with countries’ collective greenhouse gas (GHG) emission reduction pledges. This is needed to assess mitigation progress and inform emission targets under the Paris Agreement. Currently, however, a mismatch of ~5.5 GtCO2 yr−1 exists between the global land-use fluxes estimated with IAMs and from countries’ GHG inventories. Here we present a ‘Rosetta stone’ adjustment to translate IAMs’ land-use mitigation pathways to estimates more comparable with GHG inventories. This does not change the original decarbonization pathways, but reallocates part of the land sink to be consistent with GHG inventories. Adjusted cumulative emissions over the period until net zero for 1.5 or 2 °C limits are reduced by 120–192 GtCO2 relative to the original IAM pathways. These differences should be taken into account to ensure an accurate assessment of progress towards the Paris Agreement.
Jones CD, Hickman JE, Rumbold ST, et al., 2021, The Climate Response to Emissions Reductions Due to COVID-19: Initial Results From CovidMIP, GEOPHYSICAL RESEARCH LETTERS, Vol: 48, ISSN: 0094-8276
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- Citations: 30
Rogelj J, Geden O, Cowie A, et al., 2021, Net-zero emissions targets are vague: three ways to fix, Nature, Vol: 591, Pages: 365-368, ISSN: 0028-0836
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