Overshoot: Communicating the risks of exceeding and returning to a 1.5°C level of global warming

Hvordan kan vi etablere “Overshoot” som et begrep som skaper felles forståelse for nye målsetninger når 1,5?°C-målet overskrides? Effektiv kommunikasjon er avgjørende for kunnskapsgrunnlaget forskere og beslutningstakere benytter når de tar avgjørelser knyttet til nødvendige tiltak i møte med klimaendringene. Nå som det er klart at 1,5?°C-målet ikke vil nås, er det viktig at alle involverte aktører utvikler et felles språk for nye målsetninger, forstår konsekvensene og evner å handle raskt. Det skal utvikles en verktøykasse som forklarer konsekvensene av et Overshoot-scenario. Gjennom tett samarbeid mellom forskere og kommunikasjonsfaglige skal det utvikles fritt tilgjengelig materiale, tilpasset ulike kanaler, for å effektivt nå ut til forskjellige målgrupper. Visualiseringene vil fungere som byggesteiner for forståelse, formidling og beslutningstaking. De vil danne grunnlaget for et langsiktig samarbeid med ledende klimaforskere. Designprosessen vil involvere ulike interessenter på flere stadier. Visualiseringene skal kunne stå alene, men samtidig bidra til en helhetlig fortelling som introduserer begrepet Overshoot og dets implikasjoner – og dermed legge til rette for de neste steg i pågående kommunikasjonsutfordring. Artikkelen “Overshoot: A Conceptual Review of Exceeding and Returning to Global Warming of 1.5°C” presenterer: - 8 viktige innsikter, - 4 fremtidige utfordringer, og - 5 figurer som illustrerer de klimamessige, teknologiske, økonomiske og politiske konsekvensene av ulike scenarier for overskridelse av 1,5 °C global oppvarming. Studien er skrevet av Andy Reisinger, Jan S. Fuglestvedt, Anna Pirani, Oliver Geden, Chris D. Jones, Shobha Maharaj, Elvira Poloczanska, Angela Morelli, Tom Gabriel Johansen, Carolina Adler, Richard A. Betts og Sonia I. Seneviratne. Den er publisert i Annual Review of Environment and Resources 2025, Volume 50, sider 1.1–1.33. Les artikkelen her: https://doi.org/10.1146/annurev-environ-111523-102029 En digital plattform utviklet i samarbeid med CMCC bygger videre på innsikten i artikkelen og tilbyr en lettfattelig fremstilling av dette komplekse temaet. Plattformen kobler sammen vitenskap, politikk, miljø, samfunn og økonomi, og vil være viktig i fremtidige klimadiskusjoner. Besøk plattformen her: https://overshoot.cmcc.it

The overshoot concept is important to understand as a key policy challenge with far-reaching implications for global climate adaptation and mitigation strategies. - An international research team presents a comprehensive framing of the concept to understand different warming futures, the related mitigation options to bring temperatures down, how the Earth system responds to climate-related risk, as well as the adaptation needs and feasibility. - 8 key takeaways, 4 future challenges, and 5 figures that portray the climate, technological, economic, and policy implications of various overshoot pathways. The results are presented in the paper “Overshoot: a conceptual review of exceeding and returning to global warming of 1.5°C”, Andy Reisinger, Jan S. Fuglestvedt, Anna Pirani, Oliver Geden, Chris D. Jones, Shobha Maharaj, Elvira Poloczanska, Angela Morelli, Tom Gabriel Johansen, Carolina Adler, Richard A. Betts, Sonia I. Seneviratne. https://doi.org/10.1146/annurev-environ-111523-102029 - A digital information platform hosted by CMCC expands on the paper’s insights, offering a plain language narrative to navigate this complex issue - one that will shape climate discussions in the years to come, bridging science, policy, environment, society, and economics. https://overshoot.cmcc.it/ An International, multidisciplinary team of renowned scientists and experts The team behind this research is composed of high-profile experts from top institutions around the world. Several authors served or are serving as vice-chairs of one of the IPCC’s Working Groups, while others served as authors of a range of IPCC reports. CMCC’s Anna Pirani, one of the paper's authors, also has an extensive background in the IPCC, including being the Head of the Working Group I Technical Support Unit of AR6 and now the alternate IPCC Focal Point for Italy. The team includes contributors from prestigious institutions such as CICERO in Norway, the German Institute for International and Security Affairs, the Met Office in the UK, the University of Bristol, the University of Fiji, the Institute for Small Islands, the Alfred Wegener Institute for Polar and Marine Research, the Mountain Research Initiative, the University of Bern, the Global Systems Institute at the University of Exeter, and ETH Zurich. The paper’s graphical material was co-designed with the team of authors, led by Angela Morelli and Tom Gabriel Johansen of Info Design Lab.

Current insufficient global action on reducing greenhouse gas emissions makes it almost certain that global warming will exceed 1.5°C within the next decade. Limiting warming to 1.5°C long-term is still possible if we prepare for a temporary exceedance, known as 'overshoot,' and take actions to stabilise and eventually reduce global temperatures. Deciding whether to overshoot and then reduce to 1.5°C, or to stabilise above 1.5°C, will depend on clear information about the climate-related impacts and risks avoided, and the additional mitigation options and efforts needed. It is crucial for researchers and policymakers to start discussing these scenarios and what they mean for immediate action. Effective communication of this topic is essential to align global actions. The purpose is to co-design the toolkit in a participatory way through a multi-stakeholder approach, aiming to provide a very specific audience of scientists to efficiently engage into a much-needed conversation to be had. A multidisciplinary team of leading scientists, information designers, and communication experts will leverage their previous experience and groundbreaking work on co-designing communication tools for decision-making to create a solid foundation for the proposed project. Co-design encapsulates a way of approaching data visualisation that ensures a deep and shared understanding between those creating the visuals and the audience, with the goal of staying rigorous to the science while meeting the audience’s needs through engagement, clarity, and beauty. When such a human-centred methodology is at the heart of the design activities, the design process flows across different deliverables and teams. This means milestones and plans can be achieved, ensuring maximum participation of all stakeholders. The work is characterised by inclusiveness, with the ability to break down barriers across disciplines and to ensure the collaboration and knowledge-sharing across the project's ecosystem.