Environmental Change and the Indus Civilization

Osada Toshiki RIHN

Onishi Masayuki RIHN

goto Toshifumi Tohoku University kharakwal, Jeewan Singh Rajasthan Vidyapeeth, India mallah, Qasid Shah Abdul Latif University, Pakistan masih, Farzand Punjab University, Pakistan maemoku Hideaki Hiroshima University ohta Shoji Fukui Prefectural University saitou Naruya National Institute of Genetics shinde, Vasant Deccan College, Deemed University, India uno Takao International Research Center for Japanese Studies

The Indus Civilization (2600 BC – 1900 BC) is one of the four great ancient civilizations. It is known for its cultural and technological achievements — its characteristic seals and scripts, fortified settlements and drain systems — and also for its brief tenure. The Indus civilization spread over an area of 680,000 km2 along the Indus and Ghaggar-Hakra rivers and into Gujarat in Western India, but its urban phase lasted only 700 years, much shorter than any of its contemporaries. Drawing on archaeology, Indology, and palaeo-environmental investigation, this project reconstructs the social and environmental histories of several key Indus areas, and attempts to determine whether and how environmental factors contributed to their short life and rapid decline.

Project structure and objectives

This research project examines the social character and environmental context of the Indus civilization and attempts to determine how they are related to the civilization’s short life and rapid decline. In particular, we aim to evaluate the impact of environmental change on the subsistence economy and trade network that sustained the Indus civilization’s urban system. Our research will also provide data on the long-term processes of climate change in South Asia. Such data will help us develop historical perspective on, and practical understanding of, contemporary environmental problems in the region.

As shown in Fig. 1, our project collaborates with several universities and institutes in India and Pakistan as MOU partners. The project is divided into five research groups: (1) the Palaeo-Environmental Research Group (PERG); (2) the Material Culture Research Group (MCRG); (3) the Subsistence System Research Group (SSRG); (4) the Inherited Culture Research Group (ICRG); and (5) the DNA Research Group (DNAG). PERG analyzes palaeo-environmental data obtained from coring and other field study and MCRG works on cultural and biological data collected through archaeological excavations at Farmana (Haryana, India) and Kanmer (Gujarat, India). SSRG conducts both archaeo- and ethno-botanical study, while ICRG analyzes linguistic data obtained from ancient texts and field research. The newly formed DNAG is now conducting analysis of the human and cow bones discovered at the Farmana site. Each of these research groups uses its own methodology to investigate the following important subjects: ancient climate change; avulsion of the Ghaggar River; sea level change in Gujarat; and crop distribution in relation to the environment across the Indus region.

Major achievements

As regards the study of the natural environment surrounding the Indus civilization, PERG has produced a preliminary analysis of the sediment core samples obtained from the Rara Lake in the Lesser-Himalayan region in 2009. The sample reveals the overall monsoon pattern in South Asia in the last 4,500 years (Fig. 3). We wait for the results of further analysis of these data.

PERG has also established through the dating of sand dunes that, contrary to its description in the Rig-Veda text (which was transliterated by ICRG), the Ghaggar was not a large river, but a small one capable of providing water for agriculture only during the monsoon season. This finding indicates that the Indus civilization was not as dependent on large rivers as were the three other great ancient civilizations. MCRG analysis of archaeological artefacts from the Farmana site gives a good description of the resource base, society and economy of this region during the Indus period.

Another PERG team investigating the palaeo-coast of Gujarat has collected geological and topographical field data and analyzed satellite imagery. Their findings coincide with the result of hydro-isostatic modelling, suggesting that sea level in the Indus period was about two meters higher than it is in present-day Gujarat. Thus the ancient seaport of Lotal, Gujarat, an important base for trade with Mesopotamia, would have become inaccessible by the end of the Indus period (Fig. 4). The study of cuneiform texts conducted by ICRG members and archaeological data obtained at the Kanmer site help us establish the local evidence of this historical change.

Excavation at Farmana and Kanmer has now concluded. The MCRG uncovered a number of important structures and artefacts, including three seal-like pendants with Indus scripts (reported in Science in May 2010), as well as many plant and animal remains. Analysis of these data will be published in two volumes in spring 2011 as part of the project’s final report. Botanical research conducted by SCRG and philological research conducted by ICRG has allowed us to gradually reconstruct the ancient environment, subsistence systems and trade network of the Indus civilization, which show enormous diversity. For example, palaeo-botanical research conducted by SCRG established the geographical distribution of cultivated plants during the Indus period. Divided into winter, summer and mixed-crop regions (Fig. 5), the ancient boundaries roughly correspond to the present-day climate zones of South Asia. The ICRG linguists’ subgroup published The Language Atlas of South Asia. A future task is to integrate SCRG’s ethno-botanical data into this work.

Future activities

Major activities of each research group have concluded. The few remaining research tasks, such as the oxygen isotope analysis of otolith and DNA analysis of the human and cow bones, are pending laboratory results. We are now integrating all the findings of individual research groups into a Geographic Information System (GIS) in order to present a comprehensive picture of the Indus civilization and its decline.

Project findings have been consistently published in our Occasional Papers and Manohar Indus series and as many individual books and academic papers. Such publications will continue until the end of the project. PERG will present the outcomes of its palaeo-environmental research in a number of international conferences, including at the European Geosciences Union and as a special session at the American Geophysical Union 2011, and will subsequently publish these findings in major academic journals.