Variable monsoons and human adaptations: Archaeological and palaeoenvironmental records during the last 1400 years in north-western India

We present the first systematic evaluation of the relationship between the archaeological and palaeoclimatic record from north-western India during the past millennium, from the urban site of Chandravati. The rarity of Medieval sites, systematic excavations and multi-disciplinary work in the subcontinent obscure the impact of two distinct climate anomalies − the ‘Medieval Warm Period’ (‘MWP’, 740 − 1150 CE), followed by the ‘Little Ice Age’ (‘LIA’, 1350 − 1850 CE). The finds from the archaeological site indicate the presence of winter and summer crops, suggesting the region was likely warm and mild humid during pre-Medieval period (ca. 600 − 800 CE). During Medieval times (between ca. 800 − 1300 CE), a diversification of the crop assemblage suggests that the region was under a warm and humid climate, corresponding to the ‘MWP’, driving increased monsoon precipitation. During the post-Medieval period (ca. 1350 − 1800 CE), drought-resistant millets and other summer pulse crops indicate the region probably experienced weak SW monsoon precipitation coinciding with globally recognised ‘LIA’. These interpretations are supported through phytolith data from the archaeological deposit broadly indicating two phases, the first being a period of diversified agricultural/anthropogenic activity (ca. 600 − 1350 CE), followed by a period dominated by drought-resistant crops (ca. 1350 − 1800 CE). Pollen data from a proximal lake corroborate the warm and humid phase ca. 800 − 1400 CE, with strong representation of warm−humid favouring tropical forest taxa, followed by non-arboreal indicators of a drier more open landscape ca. 1500 − 1800 CE. These environmental changes may have combined with other historic and institutional factors that led to the ultimate abandonment of the city. These changing cropping patterns, vegetation and cultural developments provide insight into past human response to climate change as well as important lessons for modern societies in exploring sustainable agricultural strategies to future climate change.