Global synthesis indicates widespread occurrence of shifting baseline syndrome.

As environmental degradation continues at local, regional, and global levels, people's accepted norms for natural environmental conditions are likely to decline. This phenomenon, known as shifting baseline syndrome (SBS), is increasingly recognized as a likely major obstacle to addressing global environmental challenges. However, the prevalence of SBS remains uncertain. We conducted an extensive systematic review, synthesizing existing research on people's perceived environmental baselines. Our analysis, based on 73 case studies, suggests that SBS is a widespread global phenomenon, occurring across diverse socioeconomic, environmental, and cultural settings. We observed that younger individuals tend to hold lower environmental baselines across various environmental contexts, including climate change, natural resource depletion, biodiversity loss, and pollution. An upward shift in perceived environmental baselines among younger generations was rarely observed. These results underscore the challenge that SBS poses when policy and management responses to environmental degradation are influenced by perceived natural environmental norms.