Why Stronger Environmental Policy Alone Is Not Enough: Convergent Evidence from Three Disciplines for Constitutional Biosphere Protection

This article argues that the persistent insufficiency of environmental policy reflects not merely weak political will or regulatory ambition, but a structural mismatch between planetary risks and modern decision architectures. It synthesises evidence from three methodologically independent fields: Earth System Science, cognitive and decision psychology, and environmental history. Each points to the same problem: planetary risks unfold across long time-scales, cross borders, involve thresholds and irreversibility, and exceed the motivational range of ordinary political attention. The article's central claim is that biospheric integrity is not an external policy sector, but a material precondition of legal, political, and economic order. It does not propose a full constitutional design. It identifies functions any adequate institutional response must secure: temporal durability, cross-border binding force, threshold-based precaution, and protection from ordinary political reversal. It concludes that stronger environmental policy remains necessary, but insufficient without constitutional protection of biospheric integrity. Preprint, not peer-reviewed. Manuscript completed in April 2026. Its argument was subsequently developed into the Declaration for an Earth Constitution, version 1.6.