Navigating expert judgment uncertainty in post-event environmental impact assessments for human-made disasters litigation

Environmental litigation stemming from human-made disasters associated with large-scale infrastructure investments is commonly initiated by concerned stakeholders seeking environmental justice. The investigative process involves Post-Event Environmental Impact Assessments (PEEIA), which entail retrospective analyses heavily reliant on expert judgment to establish the causal nexus between the evidence of environmental damage and the alleged tortious conduct. A key concern within PEEIA pertains to effectively screening expert judgment when the scientific basis is in dispute, given that critical determinants in tort litigation revolve around the reliability and relevance of expert judgment. However, these assessments contend with complex ecosystems, along with discrepancies in the scientific knowledge supporting claims of the tortfeasor's liability. Consequently, the principal challenge of PEEIA lies in effectively navigating the inherent uncertainty surrounding expert judgment.Here, we introduce a PEEIA approach aimed at evaluating the reliability of expert judgment and managing disputed scientific knowledge. The approach is grounded in abductive reasoning and counterfactual inference. It operationally integrates axiomatization and decision theory techniques, including Weight of Evidence (WoE), Clairvoyance Analysis (CA), and inductive risk. This approach first formalizes alternative and contested expert judgments as a set of hypotheses concerning the causal nexus between evidence of environmental damage and the alleged tortious conduct. Next, a quantitative metric is employed to ascertain the reliability of each hypothesis and discern the best explanation for the evidence of environmental damage.