Agriculture is a major contributor to the economic development of modern as well as ancient India and largely depends on the rainfall in the monsoon season. In order to understand the impact of climate variability on cultural changes in the Indian subcontinent, high resolution centennial to millennial scale middle Holocene Indian summer monsoon (ISM) variability was reconstructed from Bednikund lake, located in an alpine meadow of the Pindar basin, Chamoli, Central Himalaya. Increased ISM precipitations were found during similar to 5930-3950 (mid-Holocene climate optimum), similar to 3380-2830 (Minoan Warm Period), similar to 2610-1860 (Roman Warm Period), similar to 1050-760 (Medieval Climate Anomaly), and similar to 320 cal yr BP to Present (Current Warm Period). The decreased ISM strengths were found during similar to 3950-3380, similar to 2830 -2610, similar to 1860-1050 (Dark Ages Cold Period), similar to 760-580, and similar to 500-320 cal yr BP (Little Ice Age). The covariance between our records of precipitation change and total solar irradiance for the middle to late Holocene and with Northern hemisphere (NH) temperature for the past two millennia suggested solar insolation as a primary forcing mechanism of ISM variability. The reconstructed paleoclimate combined with archaeology and historical records indicated that ancient Indian civilizations e.g., the Indus Valley (similar to 5200-3300 cal yr BP) and Vedic (similar to 3400-2400 cal yr BP) had established and thrived during periods of strengthened ISM precipitation, whereas their collapse closely corresponded to the decreased strength in ISM. From similar to 2400 to 200 cal yr BP, the Indian subcontinent witnessed the rise and fall of various Kingdoms/dynasties. This period saw an exponential expansion/growth in agriculture, economy, population, languages, architecture, and religions in the Indian subcontinent. The agrarian-based economy showed little or no impact of monsoon weakening after similar to 2400 cal yr BP possibly due to development and reforms in administrative policies, construction of irrigation systems such as dams, lakes and canals, use of technology for irrigation such as waterwheel, knowledge of double cropping, production of cash crops. The ancient civilizations of India were directly impacted by the strengthening and weakening of ISM, whereas for the later periods, civilizations were able to adapt to climate change. (C) 2021 Elsevier Ltd. All rights reserved.
Rawat, V; Rawat, S; Srivastava, P; Negi, PS; Prakasam, M; Kotlia, BS
Middle Holocene Indian summer monsoon variability and its impact on cultural changes in the Indian subcontinent
Quaternary Science Reviews