Co-developing a global hydrological service to support climate change risk assessment and adaptation: providing stakeholder-elicited hazard information processed from uncertain multi-model ensemble output

Successful adaptation to climate change worldwide will require many local climate change risk assessments. To this end, societies need access to usable climate change information to better prepare and adapt to future risks as well as opportunities. Co-produced, user-driven climate services are a recognized means of improving the effective generation and utilization of climate information to inform decision-making and support adaptation to climate change. However, there is a structural lack of appropriate, tailored climate services and tools, particularly in developing countries. In addition, there has been limited evaluation of the process of co-developing climate service products. This study describes and evaluates the steps and methods used to co-develop a global hydrological climate service (in the frame of the CO-MICC project), specifically, a knowledge portal on global freshwater-related hazards of climate change, in a transdisciplinary, participative process jointly with providers, local to regional users, and water experts. This comprised the co-production of (i) the relevant hydrological indicators (to be both user-relevant and scientifically sound concerning the global multi-model information basis), (ii) the integration of uncertainty in the provided visual representations of these indicators, and (iii) the necessary supporting information that guides and enables utilization of the provided hazard information. Participants from seven workshops with stakeholders from focus regions in Europe and Northern Africa included local researchers, experts from meteorological services and decision-makers from regional and national hydrological agencies. Together, we co-produced relevant model output variables and appropriate end-user products encompassing static and dynamically generated information in a web portal. The global-scale information products include interactive maps, diagrams, time series graphs, and suitably co-developed statistics, with appropriate visualization of uncertainty. In addition, the integration of local needs into new co-developed indicators was necessary where standard indicators are not scientifically suitable with respect to the information basis. Specifically based on understanding the underlying need of the stakeholder and the capabilities of the global hydrological model output, an alternative indicator consecutive dry years was co-developed to integrate freshwater deficit information for water managers. Lessons learned will be discussed with a particular focus on the challenges of the participatory process in the context of the climate service co-development. The CO-MICC knowledge portal (www.co-micc.eu) enables access to this information to a broad range of stakeholders from around the world (policy makers, NGOs, the private sector, the research community, the public in general) for their region of interest, enabling them to account for climate change in their risk portfolios. In addition, it provides information on the optimal design and methods of co-development processes.