60cm sediment core explains how ancient societies in central India adapted to climate change | Pune News

Pune: Deep inside the forests of Bandhavgarh in Madhya Pradesh, scientists found a long and surprising story written in the soil. The narrow core of sediment, just 60cm long, led researchers to trace how climate influenced people in this region for nearly 2,600 years. Their findings challenge the common belief that climate change automatically leads to the collapse of societies. The research, published recently in the Holocene journal, was conducted to understand how people and nature worked together over a long time.The research was carried out by scientists and historians from Birbal Sahni Institute of Palaeosciences, Ashoka University, Agharkar Research Institute, Indian Institute of Tropical Meteorology, and Academy of Scientific and Innovative Research.

The paper said, “Today, Bandhavgarh is famous as a tiger reserve. But long before it became a protected forest, it was home to people who lived, farmed, built caves and temples, and managed water through centuries of changing rainfall. The study shows that while climate shifts shaped the environment, they did not decide human destiny.”Nayanjot Lahiri of Ashoka University’s Centre for Interdisciplinary Archaeological Research, one of the co-authors of the study, said, “Despite climate shifts, the one constant here is the expansion of human occupation from the ancient to the medieval. Even with changing ecological conditions, the impression of a larger-than-life human presence is striking.”The team used five scientific methods: mineral magnetism, grain-size analysis, diatoms (tiny water plants), pollen analysis, and elemental chemistry.Using the data, the researchers identified five major climate phases from around 525 BCE to the present. Importantly, they first mapped climate changes independently and only later compared them with archaeological history.The earliest phase, between about 2,700 and 2,400 years ago, saw frequent swings between wet and dry conditions. Stone tools show hunter-gatherers were present, while cereal pollen suggests that farming had already begun. During wetter times, moist deciduous forests expanded across the region.The second phase, from about 2,400 to 1,700 years ago, became drier. Water levels dropped, and plants showed signs of stress. Yet this was also when large-scale rock-cut caves began to appear. Human activity did not decline, it changed.A return of stronger monsoon rains between about 1,700 and 1,300 years ago supported healthy sal forests and stable wetlands. Cave use expanded further, showing continuity in settlement, the study stated.The toughest test came during the fourth phase, roughly 1,300 to 400 years ago, when Bandhavgarh experienced its driest conditions. Instead of abandoning the area, rulers of the Kalachuri dynasty responded by building temples, tanks, and water-harvesting systems.Diatom studies revealed that even when the monsoon weakened, Bandhavgarh’s local geography helped retain water. “We could see large-scale catchment activity based on the diatom record, where the disturbance in the catchment was reflected by a shift in the diatom community,” co-author Karthick Balasubramanian of Agharkar Research Institute said. This local stability allowed people to survive and even thrive.