Uncertainty in Island-based Ecosystem Services and Climate Change

Small and medium-sized islands are acutely exposed to climate change and ecosystem degradation, yet the extent to which uncertainty is systematically addressed in scientific assessments of their ecosystem services remains poorly understood. This study revisits 226 peer-reviewed articles drawn from two global systematic reviews on island ecosystem services and climate change, applying a structured post hoc analysis to evaluate how uncertainty is treated across methods, service categories, ecosystem realms, and decision contexts. Studies were classified according to whether uncertainty was explicitly analysed, just mentioned, or ignored. Only 30 percent of studies incorporated uncertainty explicitly, while more than half did not address it at all. Scenario-based approaches dominated uncertainty assessment, whereas probabilistic and ensemble-based frameworks remained limited. Cultural ecosystem services and extreme climate impacts exhibited the lowest levels of uncertainty integration, and few studies connected uncertainty treatment to policy relevant decision frameworks. Weak or absent treatment of uncertainty emerges as a structural challenge in island systems, where narrow ecological thresholds, strong land-sea coupling, limited spatial buffers, and reduced institutional redundancy amplify the consequences of decision-making under incomplete knowledge. Systematic mapping of how uncertainty is framed, operationalised, or neglected reveals persistent methodological and conceptual gaps and informs concrete directions for strengthening uncertainty integration in future island-focused ecosystem service and climate assessments. Embedding uncertainty more robustly into modelling practices, participatory processes, and policy tools is essential for enhancing scientific credibility, governance relevance, and adaptive capacity in insular socio-ecological systems.

💡 Research Summary

This paper conducts a systematic post‑hoc analysis of 226 peer‑reviewed studies that assess ecosystem services (ES) on small and medium‑sized islands under climate change (CC). Drawing on two recent global systematic reviews (2025), the authors re‑examined each article to determine how uncertainty was treated, classifying papers into three categories: (1) Explicit – uncertainty quantified or modeled using probabilistic, sensitivity, ensemble, or scenario‑based methods; (2) Mentioned – uncertainty acknowledged narratively but not analytically; and (3) Ignored – no reference to uncertainty. Only 30 % (68 papers) fell into the Explicit group, 16 % (37) merely Mentioned it, and a majority of 54 % (121) ignored uncertainty altogether.

The analysis was stratified by ES category (provisioning, regulating, cultural, supporting), climate impact type (temperature, precipitation, sea‑level rise, ocean acidification, extreme events), ecosystem realm (terrestrial, marine, freshwater), and geographic region (Pacific, Atlantic, Indian, Mediterranean, polar, global). Marine‑focused studies showed the highest proportion of explicit uncertainty treatment, whereas terrestrial studies were most likely to ignore it. Provisioning services such as food, raw materials, freshwater, and climate modulation were more frequently linked to explicit uncertainty analysis, while cultural, aesthetic, and tourism services were overwhelmingly in the Ignored or Mentioned groups. Similarly, basic climate variables (temperature, precipitation) attracted more rigorous uncertainty handling than high‑impact drivers like sea‑level rise, acidification, or extreme events.

Temporal trends were explored using binary logistic regression with publication year as a predictor, both in simple year‑only models and in multivariate models that controlled for study type, ecosystem realm, and region. Neither model revealed a clear increase or decrease in uncertainty treatment over time, suggesting that despite growing awareness, systematic integration of uncertainty has not become routine.

The authors argue that the pervasive neglect of uncertainty constitutes a structural vulnerability for islands, which are characterized by limited spatial buffers, strong land‑sea coupling, and reduced institutional redundancy. Decision‑making under incomplete knowledge can thus lead to maladaptive policies and heightened exposure to climate risks.

Based on the identified gaps, the paper recommends: (1) broader adoption of probabilistic and statistical techniques (e.g., Bayesian inference, confidence intervals) to move beyond scenario storytelling; (2) development of mixed‑methods frameworks that capture qualitative uncertainty for cultural and relational services, incorporating stakeholder perceptions through participatory workshops; (3) implementation of multi‑model ensembles and scenario portfolios for high‑impact climate drivers such as sea‑level rise and extreme events; and (4) explicit linkage of uncertainty outputs to decision‑support tools such as cost‑benefit analysis, adaptive management pathways, and policy scenario planning.

By highlighting methodological blind spots and offering concrete pathways for integrating uncertainty, the study aims to enhance the scientific credibility, governance relevance, and adaptive capacity of island‑focused ES and climate assessments.