Understanding climate and non-climate decision triggers to minimize Spring rainfall risks in vineyards  

<p>Climate services have travelled a long way, however, the last mile still has to be covered until climate information can be appropriately integrated in the users&#8217; decision making processes. When is the signal offered by a seasonal forecast useful? How and when can forecasts influence users&#8217; choices? How does the use of the forecasts compare with the methods currently in place? The answer can vary across users and even across decisions that the same user may take.</p><p>This work analyses these questions through the decision making process of a wine producer aiming at reducing its exposure to spring rain variability. Spring rain drives risks of fungal disease causing crop loss and increased costs related to plant protection and canopy management. A transdisciplinary approach, including experts from various disciplines and the end user, is used to understand how and when a particular wine producer needs to trigger a decision linked to total Spring rainfall in order to reduce the risk entailed for plant protection and canopy management. Based on close collaboration, we construct a payoff function and simulate the decision driven by the choice of different forecasted probability thresholds and the business-as-usual decision, and we finally compare them to the observation. This exercise is repeated over 23 years to try eliciting the optimal threshold.</p><p>The results show that the optimal decision to avoid climate risks is not always a feasible solution, demonstrating that climate is only one of the variables taken into account in the complex decision making context of a business. This highlights the importance of interpreting seasonal forecasts appropriately according to each user's context and understanding how this information will be integrated in the decision processes.&#160; Finally, it calls attention to the importance of co-creation in climate services and the need for extending the collaboration process up to the delivery phase, the so-called last mile.</p><p>&#160;</p>