Patterns and seasonality in the mid-Holocene hydroclimate of the Thar Desert in northwestern India

Abstract Mid-late Holocene hydroclimate changes in the Thar Desert in northwest India have been linked with the Indus cultural transformation. Regional hydroclimate reconstructions present a spatially heterogeneous picture; in particular, the role of seasonality remains unclear. Here, we use multi-model simulations from the Paleoclimate Modelling Intercomparison Project Phase-4 (PMIP4) to evaluate the seasonality of mid-Holocene precipitation and mechanisms governing spatial moisture variability. Results show strong agreement with proxy data on strengthened summer monsoon across the Thar Desert during the mid-Holocene, with north receiving double the effective precipitation than south, which is synchronous with development of agriculture alongside continued foraging. High winter rainfall changes in the south as compared to north explains the spatial heterogeneity in paleoclimate records and possibly the distinct cropping strategies that emerged across the Indus occupied regions. These findings highlight the critical role of seasonal precipitation contrasts in shaping both environmental conditions and cultural adaptations in climatically sensitive regions.