A perspective on the next generation of Earth system model scenarios: towards representative emission pathways (REPs)
Malte Meinshausen
,
Carl-Friedrich Schleussner
,
Kathleen Beyer
,
Greg Bodeker
,
Olivier Boucher
,
Josep G Canadell
,
John S Daniel
,
Aïda Diongue-Niang
,
Fatima Driouech
,
Erich Fischer
,
Piers Forster
,
Michael Grose
,
Gerrit Hansen
,
Zeke Hausfather
,
Tatiana Ilyina
,
Jarmo S Kikstra
,
Joyce Kimutai
,
Andrew D King
,
June-Yi Lee
,
Chris Lennard
,
Tabea Lissner
,
Alexander Nauels
,
Glen P Peters
,
Anna Pirani
,
Gian-Kasper Plattner
,
Hans Pörtner
,
Joeri Rogelj
,
Maisa Rojas
,
Joyashree Roy
,
Bjørn H Samset
,
Benjamin M Sanderson
,
Roland Séférian
,
Sonia Seneviratne
,
Christopher J Smith
,
Sophie Szopa
(1, 2)
,
Adelle Thomas
,
Diana Urge-Vorsatz
,
Guus J M Velders
,
Tokuta Yokohata
,
Tilo Ziehn
,
Zebedee Nicholls
Malte Meinshausen
- Fonction : Auteur
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Carl-Friedrich Schleussner
- Fonction : Auteur
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Kathleen Beyer
- Fonction : Auteur
Greg Bodeker
- Fonction : Auteur
- PersonId : 1393067
- ORCID : 0000-0003-1094-5852
Olivier Boucher
- Fonction : Auteur
- PersonId : 756451
- ORCID : 0000-0003-2328-5769
- IdRef : 071071474
Josep G Canadell
- Fonction : Auteur
- PersonId : 791004
- ORCID : 0000-0002-8788-3218
John S Daniel
- Fonction : Auteur
Aïda Diongue-Niang
- Fonction : Auteur
Fatima Driouech
- Fonction : Auteur
Erich Fischer
- Fonction : Auteur
- PersonId : 792806
- ORCID : 0000-0003-1931-6737
Piers Forster
- Fonction : Auteur
- PersonId : 802026
- ORCID : 0000-0002-6078-0171
Michael Grose
- Fonction : Auteur
Gerrit Hansen
- Fonction : Auteur
- PersonId : 1393068
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Zeke Hausfather
- Fonction : Auteur
Tatiana Ilyina
- Fonction : Auteur
- PersonId : 768693
- ORCID : 0000-0002-3475-4842
Jarmo S Kikstra
- Fonction : Auteur
- PersonId : 1289440
- ORCID : 0000-0001-9405-1228
Joyce Kimutai
- Fonction : Auteur
Andrew D King
- Fonction : Auteur
June-Yi Lee
- Fonction : Auteur
- PersonId : 1281437
- ORCID : 0000-0002-3986-9753
Chris Lennard
- Fonction : Auteur
- PersonId : 1152599
- ORCID : 0000-0001-6085-0320
Tabea Lissner
- Fonction : Auteur
Alexander Nauels
- Fonction : Auteur
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- ORCID : 0000-0003-1378-3377
Glen P Peters
- Fonction : Auteur
- PersonId : 776412
- ORCID : 0000-0001-7889-8568
- IdRef : 138519307
Anna Pirani
- Fonction : Auteur
- PersonId : 1281441
- ORCID : 0000-0001-7287-8347
Gian-Kasper Plattner
- Fonction : Auteur
- PersonId : 1393069
- ORCID : 0000-0002-3765-0045
Hans Pörtner
- Fonction : Auteur
Joeri Rogelj
- Fonction : Auteur
- PersonId : 776411
- ORCID : 0000-0003-2056-9061
Maisa Rojas
- Fonction : Auteur
Joyashree Roy
- Fonction : Auteur
Bjørn H Samset
- Fonction : Auteur
- PersonId : 802212
- ORCID : 0000-0001-8013-1833
Benjamin M Sanderson
- Fonction : Auteur
Roland Séférian
- Fonction : Auteur
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Sonia Seneviratne
- Fonction : Auteur
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Christopher J Smith
- Fonction : Auteur
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Sophie Szopa
- Fonction : Auteur
- PersonId : 1337767
- IdHAL : sszopa
Adelle Thomas
- Fonction : Auteur
Diana Urge-Vorsatz
- Fonction : Auteur
Guus J M Velders
- Fonction : Auteur
- PersonId : 1357630
- ORCID : 0000-0002-6597-7088
Tokuta Yokohata
- Fonction : Auteur
Tilo Ziehn
- Fonction : Auteur
- PersonId : 801793
- ORCID : 0000-0001-9873-9775
Zebedee Nicholls
- Fonction : Auteur
- PersonId : 803677
- ORCID : 0000-0002-4767-2723
Résumé
Abstract. In every Intergovernmental Panel on Climate Change (IPCC) Assessment cycle, a multitude of scenarios are assessed, with different scope and emphasis throughout the various Working Group reports and special reports, as well as their respective chapters. Within the reports, the ambition is to integrate knowledge on possible climate futures across the Working Groups and scientific research domains based on a small set of “framing pathways” such as the so-called representative concentration pathways (RCPs) in the Fifth IPCC Assessment Report (AR5) and the shared socioeconomic pathway (SSP) scenarios in the Sixth Assessment Report (AR6). This perspective, initiated by discussions at the IPCC Bangkok workshop in April 2023 on the “Use of Scenarios in AR6 and Subsequent Assessments”, is intended to serve as one of the community contributions to highlight the needs for the next generation of framing pathways that is being advanced under the Coupled Model Intercomparison Project (CMIP) umbrella, which will influence or even predicate the IPCC AR7 consideration of framing pathways. Here we suggest several policy research objectives that such a set of framing pathways should ideally fulfil, including mitigation needs for meeting the Paris Agreement objectives, the risks associated with carbon removal strategies, the consequences of delay in enacting that mitigation, guidance for adaptation needs, loss and damage, and for achieving mitigation in the wider context of societal development goals. Based on this context, we suggest that the next generation of climate scenarios for Earth system models should evolve towards representative emission pathways (REPs) and suggest key categories for such pathways. These framing pathways should address the most critical mitigation policy and adaptation plans that need to be implemented over the next 10 years. In our view, the most important categories are those relevant in the context of the Paris Agreement long-term goal, specifically an immediate action (low overshoot) 1.5 °C pathway and a delayed action (high overshoot) 1.5 °C pathway. Two other key categories are a pathway category approximately in line with current (as expressed by 2023) near- and long-term policy objectives, as well as a higher-emission category that is approximately in line with “current policies” (as expressed by 2023). We also argue for the scientific and policy relevance in exploring two “worlds that could have been”. One of these categories has high-emission trajectories well above what is implied by current policies and the other has very-low-emission trajectories which assume that global mitigation action in line with limiting warming to 1.5 °C without overshoot had begun in 2015. Finally, we note that the timely provision of new scientific information on pathways is critical to inform the development and implementation of climate policy. Under the Paris Agreement, for the second global stocktake, which will occur in 2028, and to inform subsequent development of nationally determined contributions (NDCs) up to 2040, scientific inputs are required by 2027. These needs should be carefully considered in the development timeline of community modelling activities, including those under CMIP7.
Format du dépôt | Fichier |
---|---|
Type de dépôt | Article dans une revue |
Titre |
en
A perspective on the next generation of Earth system model scenarios: towards representative emission pathways (REPs)
|
Résumé |
en
Abstract. In every Intergovernmental Panel on Climate Change (IPCC) Assessment cycle, a multitude of scenarios are assessed, with different scope and emphasis throughout the various Working Group reports and special reports, as well as their respective chapters. Within the reports, the ambition is to integrate knowledge on possible climate futures across the Working Groups and scientific research domains based on a small set of “framing pathways” such as the so-called representative concentration pathways (RCPs) in the Fifth IPCC Assessment Report (AR5) and the shared socioeconomic pathway (SSP) scenarios in the Sixth Assessment Report (AR6). This perspective, initiated by discussions at the IPCC Bangkok workshop in April 2023 on the “Use of Scenarios in AR6 and Subsequent Assessments”, is intended to serve as one of the community contributions to highlight the needs for the next generation of framing pathways that is being advanced under the Coupled Model Intercomparison Project (CMIP) umbrella, which will influence or even predicate the IPCC AR7 consideration of framing pathways. Here we suggest several policy research objectives that such a set of framing pathways should ideally fulfil, including mitigation needs for meeting the Paris Agreement objectives, the risks associated with carbon removal strategies, the consequences of delay in enacting that mitigation, guidance for adaptation needs, loss and damage, and for achieving mitigation in the wider context of societal development goals. Based on this context, we suggest that the next generation of climate scenarios for Earth system models should evolve towards representative emission pathways (REPs) and suggest key categories for such pathways. These framing pathways should address the most critical mitigation policy and adaptation plans that need to be implemented over the next 10 years. In our view, the most important categories are those relevant in the context of the Paris Agreement long-term goal, specifically an immediate action (low overshoot) 1.5 °C pathway and a delayed action (high overshoot) 1.5 °C pathway. Two other key categories are a pathway category approximately in line with current (as expressed by 2023) near- and long-term policy objectives, as well as a higher-emission category that is approximately in line with “current policies” (as expressed by 2023). We also argue for the scientific and policy relevance in exploring two “worlds that could have been”. One of these categories has high-emission trajectories well above what is implied by current policies and the other has very-low-emission trajectories which assume that global mitigation action in line with limiting warming to 1.5 °C without overshoot had begun in 2015. Finally, we note that the timely provision of new scientific information on pathways is critical to inform the development and implementation of climate policy. Under the Paris Agreement, for the second global stocktake, which will occur in 2028, and to inform subsequent development of nationally determined contributions (NDCs) up to 2040, scientific inputs are required by 2027. These needs should be carefully considered in the development timeline of community modelling activities, including those under CMIP7.
|
Auteur(s) |
Malte Meinshausen
, Carl-Friedrich Schleussner
, Kathleen Beyer
, Greg Bodeker
, Olivier Boucher
, Josep G Canadell
, John S Daniel
, Aïda Diongue-Niang
, Fatima Driouech
, Erich Fischer
, Piers Forster
, Michael Grose
, Gerrit Hansen
, Zeke Hausfather
, Tatiana Ilyina
, Jarmo S Kikstra
, Joyce Kimutai
, Andrew D King
, June-Yi Lee
, Chris Lennard
, Tabea Lissner
, Alexander Nauels
, Glen P Peters
, Anna Pirani
, Gian-Kasper Plattner
, Hans Pörtner
, Joeri Rogelj
, Maisa Rojas
, Joyashree Roy
, Bjørn H Samset
, Benjamin M Sanderson
, Roland Séférian
, Sonia Seneviratne
, Christopher J Smith
, Sophie Szopa
1, 2
, Adelle Thomas
, Diana Urge-Vorsatz
, Guus J M Velders
, Tokuta Yokohata
, Tilo Ziehn
, Zebedee Nicholls
1
LSCE -
Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette]
( 518 )
- Bât. 12,
avenue de la Terrasse,
F-91198 GIF-SUR-YVETTE CEDEX
- France
2
CLIM -
Modélisation du climat
( 1007954 )
- LSCE. CEA Paris-Saclay. Orme des merisiers. 91190 Saint-Aubin.
- France
|
Langue du document |
Anglais
|
Vulgarisation |
Non
|
Comité de lecture |
Oui
|
Audience |
Internationale
|
Date de publication |
2024-06-05
|
Nom de la revue |
|
Volume |
17
|
Page/Identifiant |
4533 - 4559
|
Numéro |
11
|
Domaine(s) |
|
DOI | 10.5194/gmd-17-4533-2024 |
Origine :
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