The Climate-Resilience Ledger: Reinterpreting the Indus Script as an Ecological Survival Technology

Traditional scholarship on the undeciphered Indus Valley script treats its seals and clay taggings primarily as commercial identifiers, elite lineage markers, or religious amulets. In this paper, we propose and test a functional paradigm shift: the script as a Climate- Resilience Ledger. We argue that during the severe ecological instability of the Mature to Late Harappan transition—specifically the 4.2 ka mega-drought—the standardized script functioned as an administrative technology to manage severe scarcity, track hydrological cycles, mobilize civic labor, and strictly ration grain and water. Utilizing the Interactive Corpus of Indus Texts (ICIT), we empirically evaluate the geographic distribution of a critical sign pattern associated with rationing (the “Jar + Numeral” motif) across 2,543 in- scribed objects. We find a consistent 1.4× to 1.8× urban enrichment in major capital cities (Mohenjo-daro and Harappa) but demonstrate through rigorous post-hoc Monte Carlo power analysis that the current rural corpus is severely underpowered (10.0% to 29.4%), resulting in a 70.6% to 90.0% chance of a Type II error. Furthermore, we challenge the dominant “clan-based” epigraphical paradigm by analyzing the near-universal distribution of Harap- pan sanitation infrastructure, proving that an egalitarian civic commonwealth model is far more compatible with the material evidence than exclusionary, competing clans. Finally, we model how environmental stress, work-for-grain supply chains, and eventual rural migration led to the logical, non-violent obsoletion and sudden disappearance of the script. Keywords: Indus Script, 4.2 ka Mega-Drought, Climate Adaptation, Rationing Ledger, Post-Hoc Power Analysis, Egalitarian Commonwealth.