Towards impact-ready decadal climate services: The promise of hybrid approaches

In the context of climate change, societal demand for actionable climate information is rapidly increasing. Climate services aim to respond to this demand by providing relevant and usable scientific information. In this framework, pluri-annual to decadal timescales are emerging as particularly critical for stakeholder decision-making. However, uncertainty at these timescales remains large at the regional scale, primarily due to the strong influence of internal climate variability. Decadal climate prediction seeks to reduce this uncertainty, yet several major challenges remain. First, current decadal prediction systems exhibit limited skill for key variables over land, such as precipitation over Europe. Second, addressing uncertainty and supporting adaptation at pluri-annual timescales requires renewed approaches to dialogue and communication with stakeholders. Here, we present a set of actions developed by our group to address these challenges. We show that the first limitation can be partly alleviated through hybrid approaches, several of which are introduced here. We also describe processes for transferring scientific results to stakeholders, illustrated through case studies notably on water management in France and agriculture in Senegal. To conclude, those on-going developments illustrate how combining advances in prediction systems with tailored communication strategies, can more effectively support adaptation decisions in a context of persistent uncertainty.