Meeting User Needs for Sea Level Rise Information: A Decision Analysis Perspective

Abstract

Despite widespread efforts to implement climate services, there is almost no literature that systematically analyzes users' needs. This paper addresses this gap by applying a decision analysis perspective to identify what kind of mean sea level rise (SLR) information is needed for local coastal adaptation decisions. We first characterize these decisions, then identify suitable decision analysis approaches and the sea level information required, and finally discuss if and how these information needs can be met given the state of the art of sea level science. We find that four types of information are needed: (i) probabilistic predictions for short‐term decisions when users are uncertainty tolerant; (ii) high‐end and low‐end SLR scenarios chosen for different levels of uncertainty tolerance; (iii) upper bounds of SLR for users with a low uncertainty tolerance; and (iv) learning scenarios derived from estimating what knowledge will plausibly emerge about SLR over time. Probabilistic predictions can only be attained for the near term (i.e., 2030–2050) before SLR significantly diverges between low and high emission scenarios, for locations for which modes of climate variability are well understood and the vertical land movement contribution to local sea levels is small. Meaningful SLR upper bounds cannot be defined unambiguously from a physical perspective. Low‐ to high‐end scenarios for different levels of uncertainty tolerance and learning scenarios can be produced, but this involves both expert and user judgments. The decision analysis procedure elaborated here can be applied to other types of climate information that are required for mitigation and adaptation purposes.

The Role of Climate Sensitivity in Upper‐Tail Sea Level Rise Projections

“…Here we demonstrated a similar sensitivity to different plausible ranges of ECS, including important effects on SLR time horizons and regional projections. Results can help inform SLR uncertainty and are adaptable to regional assessments relevant to stakeholder and decision maker needs, such as robust decision making which accounts for deep uncertainties and trade‐offs in investment decision strategies (see, e.g., Garner & Keller, 2018; Hinkel et al, 2019; Sriver et al, 2018; Stammer et al, 2019).…”

Framework for High‐End Estimates of Sea Level Rise for Stakeholder Applications

“…Probabilistic sea level predictions, independent from external assumptions such as Representative Concentration Pathway (RCP) scenarios (see Figure 2). (note that there are no known example of such predictions in the current published literature, Hinkel et al, 2019) High-end scenarios based on the selection of thresholds in the upper tail of probabilistic sea level prediction (e.g., 0.1%, 1%, 5%; e.g., see method in Jevrejeva et al, 2014) The upper tail of the distributions are currently considered too poorly constrained to define precise high-end scenarios Le Cozannet, Manceau, & Rohmer, 2017). Existing probabilistic projections do not yet combine all RCP scenarios (see Figure 2)…”

“…High-end scenarios based on the selection of thresholds in the upper tail of a probability distribution conditioned to RCP8.5 (e.g., Jevrejeva et al, 2014) It is unsure that RCP8.5 is the most appropriate assumption for defining high-end scenarios applicable for coastal adaptation (e.g., Hinkel et al, 2019).…”

“…Despite the difficulties to specify high-end sea level rise from a physical modeling perspective, stakeholders have a strong desire for information about the high-end sea level rise tails of the distribution outside the specified likely IPCC range (Hinkel et al, 2015;Hinkel et al, 2019;Le Cozannet, Manceau, et al, 2017). In addition, many stakeholders and decision makers have a strong need for regional to local relative sea level (RSL) information, including vertical land movement.…”

Adaptation to uncertain sea-level rise; how uncertainty in Antarctic mass-loss impacts the coastal adaptation strategy of the Netherlands

“…The large range of potential future sea levels poses, however, the question: 'When and how much to adapt? ' To deal with uncertainties about the future and to minimize regret of investment decisions as the future unfolds, decision makers are urged to take an adaptive approach [6][7][8][9]. Over the last years several frameworks have been put forward to design adaptive strategies, including robust decision making [10,11], adaptive policy making [12,13], dynamic adaptive policy pathways [9,14] and engineering options analysis [15,16].…”