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Publications

Scientific publications

Peer-reviewed scientific publications of the consortium documenting and disseminating IAM COMPACT project outputs.
2024
Date
February 2024
Authors
Alaa Al Khourdajie
Jim Skea
Richard Green
Journal
Energy and Climate Change
Title
Climate ambition, background scenario or the model? Attribution of the variance of energy-related indicators in global scenarios
Short description

We attribute variations in key energy sector indicators across global climate mitigation scenarios to climate ambition, assumptions in background socioeconomic scenarios, differences between models and an unattributed portion that depends on the interaction between these. The scenarios assessed have been generated by Integrated Assessment Models (IAMs) as part of a model intercomparison project exploring the Shared Socio-economic Pathways (SSPs) used by the climate science community. Climate ambition plays the most significant role in explaining many energy-related indicators, particularly those relevant to overall energy supply, the use of fossil fuels, final energy carriers and emissions. The role of socioeconomic background scenarios is more prominent for indicators influenced by population and GDP growth, such as those relating to final energy demand and nuclear energy. Variations across some indicators, including hydro, solar and wind generation, are largely attributable to inter-model differences. Our Shapley–Owen decomposition gives an unexplained residual not due to the average effects of the other factors, highlighting some indicators (such as the use of carbon capture and storage (CCS) for fossil fuels, or adopting hydrogen as an energy carrier) with outlier results for particular ambition-scenario-model combinations. This suggests guidance to policymakers on these indicators is the least robust.




Date
February 2024
Authors
Connor McGookin
Diana Süsser
Georgios Xexakis
Evelina Trutnevyte
Will McDowall
Alexandros Nikas
Konstantinos Koasidis
Sheridan Few
Per Dannemand Andersen
Christina Demski
Patrícia Fortes
Sofia G. Simoes
Christopher Bishop
Fionn Rogan
Brian Ó Gallachóir
Journal
Energy Strategy Reviews
Title
Advancing participatory energy systems modelling
Short description

Energy system models are important tools to guide our understanding of current and future carbon dioxide emissions as well as to inform strategies for emissions reduction. These models offer a vital evidence base that increasingly underpins energy and climate policies in many countries. In light of this important role in policy formation, there is growing interest in, and demands for, energy modellers to integrate more diverse perspectives on possible and preferred futures into the modelling process. The main purpose of this is to ensure that the resultant policy decisions are both fairer and better reflect people's concerns and preferences. However, while there has been a focus in the literature on efforts to bring societal dimensions into modelling tools, there remains a limited number of examples of well-structured participatory energy systems modelling processes and no available how-to guidance. This paper addresses this gap by providing good practice guidance for integrating stakeholder and public involvement in energy systems modelling based on the reflections of a diverse range of experts from this emergent field. The framework outlined in this paper offers multiple entry points for modellers to incorporate participatory elements either throughout the process or in individual stages. Recognising the messiness of both fields (energy systems modelling and participatory research), the good practice principles are not comprehensive or set in stone, but rather pose important questions to steer this process. Finally, the reflections on key issues provide a summary of the crucial challenges and important areas for future research in this critical field.

Acknowledgements

Thanks to Andrzej Ceglarz and Amanda Schibline from the Renewables Grid Initiative for their valuable input in the workshops held. This research was funded by the Science Foundation Ireland MaREI Centre and ESB Networks under grant number 12/RC/2302/P2 and the US-Ireland R, D & D Partnership Programme funded by Science Foundation Ireland (SFI) together with the National Science Foundation under grant number 16/US-C2C/3290. It also involved researchers from H2020 ENCLUDE (GA: 101022791), EU LIFE programme JUSTEM (project ID 101076151), H2020 PARIS REINFORCE (GA: 820846), Horizon Europe IAM COMPACT (GA: 101056306), Horizon Europe DIAMOND (GA: 101081179), and the Portuguese Science Foundation FCT/MCTES (UID/04085/2020, 2020.00038. CEECIND).





Date
January 2024
Authors
Alexandros Nikas
Natasha Frilingou
Conall Heussaff
Panagiotis Fragkos
Shivika Mittal
Jon Sampedro
Sara Giarola
Jan-Philipp Sasse
Lorenzo Rinaldi
Haris Doukas
Ajay Gambhir
Anastasis Giannousakis
Nicolò Golinucci
Konstantinos Koasidis
Matteo Vincenzo Rocco
Evelina Trutnevyte
Georgios Xexakis
Georg Zachmann
Eleftheria Zisarou
Emanuela Colombo
Adam Hawkes
Brinda Yarlagadda
Matthew Binsted
Gokul Iyer
Rasmus Magni Johannsen
Jakob Zinck Thellufsen
Henrik Lund
Dirk-Jan Van de Ven
Journal
Energy
Title
Three different directions in which the European Union could replace Russian natural gas
Short description

Russia's invasion of Ukraine fuelled an energy crisis, which considerably impacted Europe given its heavy reliance on Russian natural gas imports. This study uses an ensemble of four global integrated assessment models, which are further soft-linked to two sectoral models, and explores the synergies and trade-offs among three approaches to living without Russian gas in Europe: (a) replacing with other gas imports, (b) boosting domestic energy production, and (c) reducing demand and accelerating energy efficiency. We find that substituting Russian gas from other trade partners would miss an opportunity to accelerate decarbonisation in end-use sectors while risking further fossil-fuel lock-ins, despite featuring the lowest gas price spikes and potentially reducing heating costs for end-users in the near term. Boosting domestic, primarily renewable, energy production on the other hand would instead require considerable investments, potentially burdening consumers. Energy demand reductions, however, could offer considerable space for further emissions cuts at the lowest power-sector investment costs; nonetheless, an energy efficiency-driven strategy would also risk relocation of energy-intensive industries, an aspect of increasing relevance to EU policymakers.




Tags
Regional modelling
Synergies
Mitigation
Interdisciplinary science

2023
Date
December 2023
Authors
Alexandros Nikas
Ajay Gambhir
Baptiste Boitier
Journal
Renewable and Sustainable Energy Transition
Title
Promoting sustainable transitions across the globe requires scenario co-creation with key stakeholders
Short description

The Paris Agreement rests on individual countries and regions identifying stretching but feasible mitigation pathways. These must be acceptable and achievable in the eyes of a range of stakeholders in those countries or regions, including those from civil society, governments, and businesses. This Special Issue explores a range of feasible yet ambitious greenhouse gas emissions reduction pathways in a diversity of regions/countries of the world, in principle compatible with the goals of the Paris Agreement on climate change. Each of these pathways have been developed using energy system models or whole-economy models, in most cases using mitigation scenarios co-created with a range of policy, civil society, academic, and business stakeholders.





Date
December 2023
Authors
Hanne Svarstad
Alfredo Jornet
Glen P. Peters
Tom G. Griffiths
Tor A. Benjaminsen
Journal
Nature Climate Change
Title
Critical climate education is crucial for fast and just transformations
Short description

If rapid and just transformations to low-carbon societies are to take place, citizens need to obtain the necessary knowledge and skills to critically examine and choose adequate climate policy options. An emphasis on critical climate education research and implementation is therefore required.




Date
November 2023
Authors
Baptiste Boitier
Alexandros Nikas
Ajay Gambhir
Konstantinos Koasidis
Alessia Elia
Khaled Al-Dabbas
Şirin Alibaş
Lorenza Campagnolo
Alessandro Chiodi
Elisa Delpiazzo
Haris Doukas
Arnaud Fougeyrollas
Maurizio Gargiulo
Pierre Le Mouël
Felix Neuner
Sigit Perdana
Dirk-Jan van de Ven
Marc Vielle
Paul Zagamé
Shivika Mittal
Journal
Joule
Title
A multi-model analysis of the EU’s path to net zero
Short description
The EU has committed to becoming a net-zero economy by 2050, with many member states having integrated this goal into national strategies. However, the bloc’s path toward achieving these targets remains unclear. We use five whole-system climate-economy models and two sectoral models to explore how the EU can keep net zero within reach by mid-century, offering insights into intermediate milestones and implications at sectoral and national levels. Our results indicate that a 62% emissions reduction in the Emissions Trading System and 40% in the Effort Sharing Regulation, compared with 2005 levels, are in line with cost-optimal paths toward the bloc’s 55% emissions cuts target by 2030. Bridging the gap with net zero in 2050 entails near-complete decarbonization of ETS, total decarbonization of electricity, and complete phaseout of unabated coal power by 2040, as well as rapid scale-up of negative emissions technologies and an 80% diffusion of renewables in the EU electricity mix by 2050.




Date
November 2023
Authors
Kevin Anderson
Holly Jean Buck
Lili Fuhr
Oliver Geden
Glen P. Peters
Eve Tamme
Journal
Nature Reviews Earth & Environment volume
Title
Controversies of carbon dioxide removal
Short description

Various methods of carbon dioxide removal (CDR) are being pursued in response to the climate crisis, but they are mostly not proven at scale. Climate experts are divided over whether CDR is a necessary requirement or a dangerous distraction from limiting emissions. In this Viewpoint, six experts offer their views on the CDR debate.




Date
October 2023
Authors
Diamantis Koutsandreas
Georgios P. Trachanas
Ioannis Pappis
Alexandros Nikas
Haris Doukas
John Psarras
Journal
Energy Strategy Reviews
Title
A multicriteria modeling approach for evaluating power generation scenarios under uncertainty: The case of green hydrogen in Greece
Short description

Clean energy technological innovations are widely acknowledged as a prerequisite to achieving ambitious long-term energy and climate targets. However, the optimal speed of their adoption has been parsimoniously studied in the literature. This study seeks to identify the optimal intensity of moving to a green hydrogen electricity sector in Greece, using the OSeMOSYS energy modeling framework. Green hydrogen policies are evaluated, first, on the basis of their robustness against uncertainty and, afterwards, against conflicting performance criteria and for different decision-making profiles towards risk, by applying the VIKOR and TOPSIS multi-criteria decision aid methods. Although our analysis focuses exclusively on the power sector and compares different rates of hydrogen penetration compared to a business-as-usual case without considering other game-changing innovations (such as other types of storage or carbon capture and storage), we find that a national transition to a green hydrogen economy can support Greece in potentially cutting at least 16 MtCO2 while stimulating investments of EUR 10–13 bn. over 2030–2050.





Date
September 2023
Authors
Jakob Wachsmuth
Philine Warnke
Ajay Gambhir
Sara Giarola
Konstantinos Koasidis
Shivika Mittal
Alexandros Nikas
Kathleen Vaillancourt
Haris Doukas
Journal
Renewable and Sustainable Energy Transition
Title
Co-creating socio-technical scenarios for net-zero emission pathways: comparison of five national case studies
Short description

The extent to which modelled future pathways support effective policymaking for sustainability transitions has been questioned for a long time, with one major issue being the insufficient integration with the perspectives of policymakers and other stakeholders. One proposal to address this issue has been to set up facilitative dialogues with stakeholders to extend model-based pathways to socio-technical scenarios. This paper presents the results of a first series of such co-creation workshops, where stakeholders discussed bottlenecks for model-based decarbonisation pathways and ways to overcome these bottlenecks through tailored policy mixes. The workshops took place in five countries: Brazil, Canada, Greece, Germany, and the UK, each with a specific sector focus. In all five workshops, it became clear that substantial tensions exist between the “ideal” modelled decarbonisation pathways and the real-world situation on the ground. Also, adverse political framework conditions, uncertainty of future policies and resistance of powerful actors were emphasised as overarching bottlenecks in most workshops. At the same time, in several instances stakeholders pointed out important aspects of transformative trajectories that are not covered by the models. Some challenges and solutions stand out in all countries in spite of the strong diversity of contexts: allocation of capital towards massive investments into low-carbon solutions; infrastructure development for generation and transport of hydrogen, capture and use of CO2 as well as electricity grid and storage adapted to renewable energy solutions; stakeholder and citizen dialogues, where agreement is reached on cornerstones of long-term decarbonisation trajectories; and demand-side measures complementing investments into low-carbon processes.





Date
September 2023
Authors
Glen P. Peters
Alaa Al Khourdajie
Ida Sognnaes
Benjamin M. Sanderson
Journal
npj Climate Action
Title
AR6 scenarios database: an assessment of current practices and future recommendations
Short description

Mitigation scenarios have become an important element of Intergovernmental Panel on Climate Change (IPCC) reports. We critically assess the curation of the IPCC mitigation scenarios database, with a focus on improving curation and utilisation. The existing method of curation favours particular models, and results may have limited statistical meaning. We draw lessons from experiences with the Coupled Model Intercomparison Project (CMIP) used by the IPCC Working Group I and II communities. We propose that the scientific community takes a more active role in curating the database around policy-relevant knowledge gaps, through an open and peer reviewed process of Model Intercomparison Projects (MIPs) supplemented with individual model studies. The database should be publicly accessible from the time of scenario submission, and actively involve a broad community in developing tools and analysing the database. These suggestions can broaden participation, increase transparency, and enhance the relevance of the database for users.




Date
August 2023
Authors
Ajay Gambhir
Shivika Mittal
Robin D. Lamboll
Neil Grant
Dan Bernie
Laila Gohar
Adam Hawkes
Alexandre Köberle
Joeri Rogelj
Jason A. Lowe
Journal
Nature Communications
Title
Adjusting 1.5 degree C climate change mitigation pathways in light of adverse new information
Short description

Understanding how 1.5 °C pathways could adjust in light of new adverse information, such as a reduced 1.5 °C carbon budget, or slower-than-expected low-carbon technology deployment, is critical for planning resilient pathways. We use an integrated assessment model to explore potential pathway adjustments starting in 2025 and 2030, following the arrival of new information. The 1.5 °C target remains achievable in the model, in light of some adverse information, provided a broad portfolio of technologies and measures is still available. If multiple pieces of adverse information arrive simultaneously, average annual emissions reductions near 3 GtCO2/yr for the first five years following the pathway adjustment, compared to 2 GtCO2/yr in 2020 when the Covid-19 pandemic began. Moreover, in these scenarios of multiple simultaneous adverse information, by 2050 mitigation costs are 4-5 times as high as a no adverse information scenario, highlighting the criticality of developing a wide range of mitigation options, including energy demand reduction options.




Tags
Global modelling

Date
August 2023
Authors
Panagiotis Fragkos
Eleni Kanellou
George Konstantopoulos
Alexandros Nikas
Kostas Fragkiadakis
Faidra Filipidou
Theofano Fotiou
Haris Doukas
Journal
Studies in Energy, Resource and Environmental Economics
Title
Energy Poverty and Just Transformation in Greece
Short description

Low-income population groups often face high energy poverty risks. This phenomenon can be exacerbated through the implementation of ambitious environmental policies to achieve the energy transition—said policies, such as the application of additional taxes on energy products, may lead to regressive social and distributional impacts on low-income households thus increasing the risk of energy poverty. This study focusses on Greece and combines a qualitative analysis of the EU and Greek policy context and strategic framework for energy poverty as well as related poverty alleviation measures with a state-of-the-art model-based assessment of the equity and distributional impacts of the net-zero transition in the country. We use the GEM-E3-FIT general equilibrium model, expanded to represent ten income classes differentiated by income sources, saving rates and consumption patterns. The new modelling capabilities of GEM-E3-FIT are applied to quantify the distributional impacts of ambitious emission reduction targets and at the same time explore their effects on energy-related expenditure and energy poverty by income class in Greece. The country’s transition to climate neutrality increases modestly the income inequality across income classes, with low-income households facing the most negative effects. However, using carbon tax revenues as lump-sum transfers to support household income and as reduced social security contributions have the potential to boost employment and scale down income inequality in Greece.




Tags
Regional modelling

Date
July 2023
Authors
Sara Giarola
Alexander Kell
Sonja Sechi
Mattia Carboni
Mattia Carboni
Pierluigi Leone
Adam Hawkes
Journal
Energies
Title
Sustainability Education: Capacity Building Using the MUSE Model
Short description
Education for sustainable development has among its pillars, capacity building, which equips future generations with the set of skills needed to face the challenge of the transformation of society for sustainable development. This paper presents a training course for a novel model of long-term energy planning (the ModUlar energy system Simulation Environment, MUSE), as an example of capacity building activities for sustainable development. The activities were part of the Joint Summer School on Modelling Tools for Sustainable development, held in Trieste (Italy) in 2022. This summer school was one of the first successful implementations of education and training courses in a super-hybrid mode in the post-COVID era. Describing the training activities for MUSE open-source, this paper addresses one of the challenges that education for sustainable development is expected to increasingly face in the future: the training of future professionals in the use of novel toolkits and the implementation of truly trans-disciplinary approaches.This paper discusses the pre-school online training course for MUSE, the summer school contents, and some student modeling outcomes. While doing so, it shows the importance of leveraging the abstract contents of a course with practical exercises when learning a new tool. Reflecting upon the students’ experience, this paper draws conclusions that can be used to improve future editions of the same course and be extended to the design of training courses for other tools.



Date
July 2023
Authors
Ajay Gambhir
Alexandros Nikas
Journal
PLOS Climate
Title
Seven key principles for assessing emerging low-carbon technological opportunities for climate change mitigation action
Short description

The proposed framework is an intuitively obvious one, yet still serves as a climate technology-specific “checklist” to ensure that any newly proposed technologies or products can succeed. There will be continuous changes to the regulations, infrastructures, and political contexts, in which new technologies will be developed, which is why each consideration is not intended as a one-shot “yes/no” process but must rather be continuously reviewed and reconsidered in light of potentially rapid developments.



Synergies


Date
July 2023
Authors
Jon Sampedro
Anil Markandya
Clàudia Rodés-Bachs
Dirk-Jan Van de Ven
Journal
The Lancet Planetary Health
Title
Short-term health co-benefits of existing climate policies: the need for more ambitious and integrated policy action
Short description

Climate change and air pollution are two interconnected major risks for human health. For calculations of the health co-benefits, we combine the Global Change Analysis Model (GCAM) with rfasst, a tool designed to calculate a range of adverse health and agricultural effects attributable to air pollution for alternative scenarios. In summary, health co-benefits associated with current policies and nationally determined contributions are relatively small. The results show that to reduce health impacts attributable to ambient air pollution rapidly, additional policy action that is explicitly designed for tackling air pollutant emissions will be needed.




Date
May 2023
Authors
Dirk-Jan van de Ven
Shivika Mittal
Ajay Gambhir
Robin Lamboll
Haris Doukas
Sara Giarola
Adam Hawkes
Konstantinos Koasidis
Alexandre C. Koberle
Haewon McJeon
Sigit Perdana
Glen P. Peters
Joeri Rogelj
Ida Sognnaes
Marc Vielle
Alexandros Nikas
Journal
Nature Climate Change
Title
A multi-model analysis of post-Glasgow climate targets and feasibility challenges
Short description

The COP26 Glasgow process resulted in many countries strengthening their 2030 emissions reduction targets and announcing net-zero pledges for 2050–2070 but it is not clear how this would impact future warming. Here, we use four diverse integrated assessment models (IAMs) to assess CO2 emission trajectories in the near- and long-term on the basis of national policies and pledges, combined with a non-CO2 infilling model and a simple climate model to assess the temperature implications. We also consider the feasibility of national long-term pledges towards net-zero. While near-term pledges alone lead to warming above 2 °C, the addition of long-term pledges leads to emissions trajectories compatible with a future well below 2 °C, across all four IAMs. However, while IAM heterogeneity translates to diverse decarbonization pathways towards long-term targets, all modelled pathways indicate several feasibility concerns, relating to the cost of mitigation and the rates and scales of deployed technologies and measures.




Tags
Global modelling
Regional modelling
Synergies

Date
April 2023
Authors
Ioannis Tsipouridis
Ngetich E. Kiprotich
Anita Jerotich Chebii
Nektarios Matsagkos
Georgios P. Trachanas
Journal
Technical Annals
Title
The Importance of “Loss and Damage” in Supporting Climate Policy Debate
Short description

Climate change is having profound impacts on human and natural systems. In recent years, there has been growing recognition of the need to address Loss and Damage (L&D) associated with the adverse effects of climate change, particularly in developing countries that are more vulnerable to its impacts. There is a range of studies, examining the concepts, resilience, adaptation and policy options for dealing with climate change losses and damages. This article discusses the actions, research and finance needs in Loss & Damage as well as the approaches to it on some topics such as adaptation, stakeholder engagement, governance and risk transfer.



Tags
Loss & Damage

Date
April 2023
Authors
Ajay Gambhir
Robert Lempert
Journal
Frontiers in Climate
Title
From least cost to least risk: Producing climate change mitigation plans that are resilient to multiple risks
Short description

Our plans to tackle climate change could be thrown off-track by shocks such as the coronavirus pandemic, the energy supply crisis driven by the Russian invasion of Ukraine, financial crises and other such disruptions. We should therefore identify plans which are as resilient as possible to future risks, by systematically understanding the range of risks to which mitigation plans are vulnerable and how best to reduce such vulnerabilities. Here, we use electricity system decarbonization as a focus area, to highlight the different types of technological solutions, the different risks that may be associated with them, and the approaches, situated in a decision-making under deep uncertainty (DMDU) paradigm, that would allow the identification and enhanced resilience of mitigation pathways.



Tags
Extremes

Date
February 2023
Authors
Anastasios Karamaneas
Konstantinos Koasidis
Natasha Frilingou
Georgios Xexakis
Alexandros Nikas
Haris Doukas
Journal
Renewable & Sustainable Energy Transition
Title
A stakeholder-informed modelling study of Greece's energy transition amidst an energy crisis: the role of natural gas and climate ambition
Short description

While fossil fuel prices soar during the 2022 global energy crisis, the European Union activates all available fossil-fuel levers and Greece still plans to use natural gas as a transition fuel for delignitisation, with strong concerns over potential exacerbation of energy poverty and hurdles to progress in climate action. This study assesses the trajectory of the Greek electricity mix and its reliance on natural gas under the current policy framework on the one hand, and an ambitious scenario aiming for complete decarbonisation by 2035 on the other. We model these scenarios using an energy system modelling framework, comprising LEAP and OSeMOSYS model implementations for Greece, and use a stakeholder-informed fuzzy cognitive mapping exercise to uncover transition uncertainties. While power generation from natural gas is projected to increase by almost 50% until 2030 under existing policies, the proposed decarbonisation scenario has the potential to achieve complete independence from Russian gas by 2026 while also leading to a cleaner and considerably cheaper power sector. This ‘higher climate ambition’ scenario is found feasible and more robust in case high fossil fuel prices persist post-2022, even if bottlenecks stressed by stakeholders such as community acceptance or technological constraints emerge and potentially constrain the expansion of certain renewable energy technologies. Apart from the added value of stakeholder input in modelling science, as reflected in the impact of barriers Greek stakeholders critically highlighted, our results emphasise that a diversified energy-supply mix alongside bold energy efficiency strategies are key to rapid and feasible decarbonisation in the country.




Tags
Regional modelling
Interdisciplinary science
Transdisciplinary science

Date
January 2023
Authors
Ajay Gambhir
Journal
Environmental Research Letters
Title
This really does change everything: attaining 1.5C needs all available mitigation levers
Short description

There are multiple ways in which society can theoretically transition from its current carbon-intensive state to a zero-carbon future, ideally fast enough to limit global warming to 1.5oC above pre-industrial levels. Although the carbon budget associated with this temperature is close to being consumed (IPCC 2021), it still remains achievable - just. Furthermore, we know what needs to be done to achieve it, because we know what contributes to CO2 emissions. We need energy sources, whose carbon content results in emissions. Reducing both our demand for energy and its carbon intensity (by increasing the share of zero-carbon fuels in our energy mix) is thus of paramount importance. Some industrial manufacturing processes, particularly in cement production, produce CO2 as a chemical by-product. Capturing that CO2, finding alternative ways to produce cement, or reducing cement demand, is therefore necessary. Our agriculture, forestry and other land use (AFOLU) can be a net source or sink of CO2, so making it a large net sink by enhancing carbon dioxide removals (CDR), for example through afforestation, would help. And we hope to have available a range of human-made CDR technologies and measures, such as bioenergy with carbon capture and storage (BECCS), Direct Air Capture (DAC) and enhanced weathering (EW). Scaling these in an
environmentally sustainable way would enhance our chances of keeping within the carbon budget. Finally, rapid progress in reducing short-lived greenhouse gases, particularly methane, would further help our chances of achieving 1.5oC.



Tags
Global modelling

2022
Date
December 2022
Authors
Jarmo S. Kikstra
Zebedee R. J. Nicholls
Christopher J. Smith
Jared Lewis
Robin D. Lamboll
Edward Byers
Marit Sandstad
Malte Meinshausen
Gidden
Joeri Rogelj
Elmar Kriegler
Glen P. Peters
Jan S. Fuglestvedt
Ragnhild B. Skeie
Bjørn H. Samset
Laura Wienpahl
Detlef P. van Vuuren
Kaj-Ivar van der Wijst
Alaa Al Khourdajie
Piers M. Forster
Andy Reisinger
Roberto Schaeffer
Keywan Riahi
Journal
Geoscientific Model Development
Title
The IPCC Sixth Assessment Report WGIII climate assessment of mitigation pathways: from emissions to global temperatures
Short description

While the Intergovernmental Panel on Climate Change (IPCC) physical science reports usually assess a handful of future scenarios, the Working Group III contribution on climate mitigation to the IPCC's Sixth Assessment Report (AR6 WGIII) assesses hundreds to thousands of future emissions scenarios. A key task in WGIII is to assess the global mean temperature outcomes of these scenarios in a consistent manner, given the challenge that the emissions scenarios from different integrated assessment models (IAMs) 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 1202 mitigation scenarios in AR6 WGIII. We evaluate the global mean temperature projections and effective radiative forcing (ERF) characteristics of climate emulators FaIRv1.6.2 and MAGICCv7.5.3 and use the CICERO simple climate model (CICERO-SCM) for sensitivity analysis. We discuss the implied overshoot severity of the mitigation pathways using overshoot degree years and look at emissions and temperature characteristics of scenarios compatible with one possible interpretation of the Paris Agreement. We find that the lowest class of emissions scenarios that limit global warming to “1.5 ∘C (with a probability of greater than 50 %) with no or limited overshoot” includes 97 scenarios for MAGICCv7.5.3 and 203 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 in this category that comply with three criteria for being “Paris-compatible”, including net-zero or net-negative greenhouse gas (GHG) emissions, 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 for SR1.5 and discuss their implications. This article also introduces a “climate-assessment” Python package which allows for fully reproducing the IPCC AR6 WGIII temperature assessment. This work provides a community tool for assessing the temperature outcomes of emissions pathways and provides a basis for further work such as extending the workflow to include downscaling of climate characteristics to a regional level and calculating impacts.




Tags
Global modelling

Date
December 2022
Authors
Sigit Perdana
Georgios Xexakis
Konstantinos Koasidis
Marc Vielle
Alexandros Nikas
Haris Doukas
Ajay Gambhir
Annela Anger-Kraavi
Elin May
Ben McWilliams
Baptiste Boitier
Title
Expert perceptions of game-changing innovations towards net zero
Short description

Current technological improvements are yet to put the world on track to net-zero, which will require the uptake of transformative low-carbon innovations to supplement mitigation efforts. However, the role of such innovations is not yet fully understood; some of these ‘miracles’ are considered indispensable to Paris Agreement-compliant mitigation, but their limitations, availability, and potential remain a source of debate. We evaluate such potentially game-changing innovations from the experts' perspective, aiming to support the design of realistic decarbonisation scenarios and better-informed net-zero policy strategies. In a worldwide survey, 260 climate and energy experts assessed transformative innovations against their mitigation potential, at-scale availability and/or widescale adoption, and risk of delayed diffusion. Hierarchical clustering and multi-criteria decision-making revealed differences in perceptions of core technological innovations, with next-generation energy storage, alternative building materials, iron-ore electrolysis, and hydrogen in steelmaking emerging as top priorities. Instead, technologies highly represented in well-below-2°C scenarios seemingly feature considerable and impactful delays, hinting at the need to re-evaluate their role in future pathways. Experts' assessments appear to converge more on the potential role of other disruptive innovations, including lifestyle shifts and alternative economic models, indicating the importance of scenarios including non-technological and demand-side innovations. To provide insights for expert elicitation processes, we finally note caveats related to the level of representativeness among the 260 engaged experts, the level of their expertise that may have varied across the examined innovations, and the potential for subjective interpretation to which the employed linguistic scales may be prone to.




Tags
Synergies

Date
December 2022
Authors
Ida Sognnaes
Title
What can we learn from probabilistic feasibility assessments?
Short description

In a new paper in Nature Energy, Odenweller et al. use uncertainty analysis to derive a probabilistic feasibility space for green hydrogen supply. Their analysis shows that even if electrolysis capacity grows as fast as wind and solar power have done, green hydrogen supply will remain scarce in the short term and uncertain in the long term.




Tags
Synergies