Intolerance of Uncertainty and Eco-anxiety: a Systematic Literature Review (2001-2005)

Abstract

The declining climate conditions have introduced various forms of uncertainty in human
society, leading to increased risks of environment-related anxiety known as eco-anxiety.
This review aims to examine the relationship between intolerance of uncertainty (IU)
and eco-anxiety. In line with the PRISMA 2020 guidelines, a search was conducted on 4
databases: Google Scholar, PubMed, Arxiv and Scispace for empirical research
published between 2021 and 2025. The search yielded 179 unique records, which were
screened by their abstracts. The review cut across different regions and population
groups and selected seven primary empirical studies, which met the inclusion criteria.
The evidence from these studies demonstrates a positive association between IU and eco-
anxiety, with Positive IU playing an important role, as it is characterised by proactive
information seeking, whereas inhibitory IU leads to paralysis and appears more
peripheral. Intolerance of Uncertainty also plays a mediating role in the relationship
between eco-anxiety and mental wellbeing. Using the ROBINS-1 assessment to assess
the risk of bias, the result indicated a moderate overall bias across all included studies,
particularly due to the cross-sectional nature of the data, which limits causal inference.
Limited geographical diversity, absence of longitudinal designs and reliance on
convenience samples were identified as significant gaps in the literature. Future research
should prioritise prospective studies to establish temporal precedence and examine
intervention targets for reducing maladaptive climate-related distress.