Improvement of Integrated Assessment Models in support of climate policies Actions should improve the state-of-the-art of IAMs by tackling their existing weaknesses and lack of/limited capabilities of the current generation of models in order to provide robust, credible and transparent evidence-base in support of design and evaluation of multiscale (global, European, national, regional) mitigation policies at various time horizons.An important goal of this call is to address multiple challenges in a coherent and consistent manner using an integrated framework. To achieve this goal, it is not compulsory to incorporate all issues into a single IAM. Combinations of hard linking, soft linking and other ways of insuring a coherent approach between models and experts can be considered.Actions should address developments and improvements, such as:Sectorial detail and (transformative/structural) changes across various sectors of the economy such as those resulting from increased circularity and digitalisation.Temporal resolution and technological detail.Spatial resolution with outputs suitable for national/regional level analysis.Behavioural and lifestyle changes.Distributional and equity effects of climate policies.Interactions with the relevant sustainable development goals (such as co-benefits due to avoided impacts and trade-offs in areas such as health, biodiversity, food security etc.).Climate change impacts, including the extent to which they can be avoided through mitigation action, synergies and trade-offs between climate mitigation and adaptation policies.Financial sector and investment needs, including information in support of investment risk-reduction strategies to mobilise capital to finance the transition towards a climate-neutral economy.Uncertainties and risk-management strategies for supporting mitigation policies. The above list is non-exhaustive and actions also may propose new avenues of research, while duly justifying their choice and keeping in mind the impact on IAMs’ relevance and adequacy as a decision-support tool. Actions should also explore options for making models more capable of responding to external shocks such as the COVID-19 pandemic or similar. While addressing the improvements, actions should take into account the modelling requirements and learnings resulting from the COVID-19 crisis.Actions should build on the knowledge base developed by previous initiatives and are encouraged to establish links with other relevant projects financed from this work programme (e.g. circular economy, climate adaptation modelling) and by Horizon 2020. In order to avoid duplication of efforts, proposals should clearly demonstrate how they will go beyond the modelling state of art.Actions are encouraged to explore alternative approaches to the mainstream economic assumptions typically underlying the models (such as fully functioning markets and perfect information) and aim at striking the right balance between model complexity and usability. In order to maximise the impact, active involvement of the end-users (policy makers, business, civil society) in the co-design of models and validation of the outputs should be considered. Applicants should investigate and apply communication tools and strategies for improved interaction with stakeholders and dissemination of model results, duly accounting for the needs of non-technical audiences. They should further develop the thinking around the best ways to apply modelling insights to policies, including by building on the learnings from the COVID-19 pandemic. Consortia should also explore ways for better bridging the gap between modelling theory and practical applications, including in support of behavioural change and societal transformation.It is recommended to include capacity-building efforts to lower the entrance barriers to the established IAM community by involving research teams in EU Member States and Associated Countries that are less advanced in terms of modelling capabilities. When dealing with models, actions should promote the highest standards of transparency and openness, as much as possible going well beyond documentation and extending to aspects such as assumptions, code and data that is managed in compliance with the FAIR principles[[FAIR (Findable, Accessible, Interoperable, Reusable). Further information: https://www.go-fair.org/fair-principles/; and Final Report and Action Plan from the European Commission Expert Group on FAIR Data, “TURNING FAIR INTO REALITY” (https://ec.europa.eu/info/sites/info/files/turning_fair_into_reality_0.pdf) ]]. In particular, beneficiaries are strongly encouraged to publish results data in open access databases and/or as annexes to publications. In addition, full openness of any new modules, models or tools developed from scratch or substantially improved with the use of EU funding is expected.This topic requires the effective contribution of SSH disciplines and the involvement of SSH experts, institutions as well as the inclusion of relevant SSH expertise, in order to produce meaningful and significant effects enhancing the societal impact of the related research activities.