 fellows and guests. Many thanks for all of you coming this evening. I hope to do justice to what is in many ways a very large topic and a topic that has involved very many people. I'm not necessarily going to thank them individually, but I've put the names of quite a number of my colleagues and collaborators at the bottom of this image, and the fact that there's a whole host of shields at the bottom should reflect the fact that much of what I will talk about in the second half of the lecture very much reflects a collaboration between myself and several other academics and students at the University of Cambridge, several other institutions within the UK, and also a wide number of other academics and institutions in India as well. But in terms of what I'm going to speak about, primarily I'm going to be focusing on the Indus civilization, and I'm in order to sort of give you all a bit of an update on the current state of affairs, I'm going to go back over some things that many of you may already know and hopefully give you some insight into some things that some of you won't know, and then bring on the evidence that we've got to explain where we are in terms of understanding the relationship between climate and environment and the Indus civilization. Now I always find it's easiest to make sure that everyone's oriented correctly by showing a map as soon as possible. When speaking about the Indus civilization I'm very much speaking about quite a specific geographical region of the world, focusing on this particular area of the northwest of the South Asian subcontinent, and I'll explain in a moment roughly where we're speaking in terms of chronological range. But we're talking about one of these early old world civilizations that develops more or less in the Bronze Age, and also I'm going to touch a little bit on what happened subsequently, because in South Asia there are two early phases of urbanism. The Indus civilization which is effectively a Bronze Age phase of urbanism, this undergoes a decline when we see the deterioration of the largest Indus cities, and we have a subsequent sort of second urbanization in what's called the early historic period, and these two processes happen in slightly different locations. But the reasoning for explaining this will hopefully become clear during the lecture. In terms of chronology, what we're talking about when people often refer to the Indus civilization it's not entirely clear where we're speaking in terms of chronological development. What I show here is three separate chronological schemes that show the chronological relationships between the Indus valley on the left-hand side, Mesopotamia in the center, and Egypt. What we have with the Indus civilization per say is the development over many centuries and millennia of a sort of highly complex early urbanized civilization. What we see around 2500 BC is the appearance of relatively large urban centers and quite complex interaction networks and systems. Then we have a subsequent period of decline when these large urban centers are no longer present and then we have a sort of re-urbanization in subsequent periods. The phase of the Indus civilization here stretches from around say 2500 to around 1900 BC and this broadly correlates with developments in complex societies in ancient Mesopotamia. So it broadly overlaps with the end of the early dynastic period in Mesopotamia, the rise of the Akkadian empire and it also corresponds with different parts of the Old Kingdom in Egypt and the Middle Kingdom as well. So what we have with the Indus civilization is one of these major Old World civilizations but in many respects it's probably the least well known of these Old World civilizations. We know much more about ancient Egypt and much more about ancient Mesopotamia and there's various reasons for that. Part of some of the questions that we have about the Indus civilization come about because of the nature of its material culture. It's often been mentioned that the Indus civilization is effectively a faceless civilization. We lack monumental sculpture, we lack monumental reliefs, we don't have clear personalities or portraits or individuals that can be identified. This particular image shows a sculpture that's about 18 centimetres tall, so this is blown up to about 600 times its actual size. This is one of the largest and most spectacular pieces of Indus sculptural art. It's often regarded as a priest king and various sorts of other appellations but realistically we have relatively limited understanding of precisely who this individual is. So the term faceless civilization is probably a little bit inappropriate, it's probably more a lack of sort of obvious individuals. Many questions that come about because of the Indus civilization relate to the sort of lack of easy access and insight into what's actually going on in the Indus societies. As a result of there being a whole range of questions what we end up with is what I often refer to as a sort of a National Geographic presentation of what the Indus civilization was. This is an artistic reconstruction of the entrance to an Indus city which has appeared in National Geographic magazine about five or six years ago. What you can see here is in some ways a completely artificial construct of little pieces of archaeological evidence in the form of monumental walls and structures, all sorts of bits and pieces of material culture such as masks and beads and other items, elements of carts and things that we can reconstruct from the different pieces of evidence that we know. But by and large what we see in terms of people's reconstructions is a sort of adaptation of what we see in modern India and Pakistan and grabbing out all of the interesting and exotic elements and melding them together into a picture of what the ancient Indus civilization's life might have been like. There are a whole range of pieces of information that we do know. What we see here is a distribution map that shows the location of all of the known Indus civilization settlements here. So just to orient you, the yellow lines are the borders of modern Pakistan. We have Indus settlements extensively throughout the area which is probably best referred to as the Indus, the area of the Isht Plains or the Indus Valley. But we have an abundance of settlements located in adjacent areas in Baluchistan, many of which were discovered by the fellow Beatrice Takari who is here with me. We also have a large number of Indus settlements that were discovered after independence and partition between India and Pakistan. There was considerable amount of survey focus in the northwestern parts of India, discovering literally hundreds of Indus settlements and also areas of Gujarat here. So we now know that the Indus civilization spreads across both India and Pakistan and also parts of Afghanistan as well. It's quite the best known Indus civilization settlements are the sites of Mahendadara which is a large urban settlement located here and the site of Harappa which is located up here to the north. For many decades it was long believed that these were the twin capitals of the Indus civilization. What we now know is that these are two of a relatively small number of very large urban settlements. These sites are between say 100 and 200 hectares in size. We have a reasonably newly excavated site called Dolavira which is located down here in Gujarat. We have a site called Ganweriwala which is located in the deserts of Cholistan and a settlement called Rakhigari which is located up here in northwest India which I'll speak more of in a moment. We know that these urban settlements in many ways are different to what we see in ancient Mesopotamia. What we know of in places in Mesopotamia is that they have large urban centres that exist within 20, 30, 40 kilometres of each other. These large Indus settlements are 250 kilometres apart or more. The closest to a 250, Harappa and Mahendadara are close to 500 kilometres apart. We're talking about a very different type of urban landscape to what we see in other parts of the old world. Part of the pieces of the puzzle that might explain this difference come from the existence of these smaller settlements that I've shown circled in blue. We see sites that are around say 10 hectares up to 20 hectares in size. Settlements show all sorts of attributes but they're very, very small in comparison. So the nature of political organisation and social organisation appears to be obviously different. Some of the questions that we sort of forced to ask come around to how we understand issues of how people feed themselves and the nature of social and economic and political relationships. It's long been assumed that the Indus civilisation developed on the back of wheat and barley domestication and cattle sheep and goats. More or less following a sort of pattern of development that originated in the ancient Near East and then went on and developed in this world. I'll show in the lecture the picture of what was actually happening in the Indus civilisation is gradually changing. Other questions that we're particularly interested in are related to the nature of political control and the relationships that these large urban centres might have. Do these large urban centres act as capitals of states? Are we talking about an enormous area where populations are integrated? Are the smaller centres subsidiary or independent? We're left with many, many questions about the nature of Indus economics and politics and society. Looking briefly at one of these major centres, this is the city of Mahenjidara which was first excavated in the early part of the 20th century by Sir John Marshall. This is probably the most famous Indus civilisation settlement. Its area is possibly as large as 250 hectares in size. The traditional view was that it was broken up into two separate parts. There was an upper Citadel area here and a lower town, in some ways conforming to a sort of very classical definition of an acropolis versus a lower city. It's often been stated that Mahenjidara has evidence for urban planning and that it was created in a sort of flourish of urban construction and activity. Part of this comes from the existence of widespread evidence for drainage, buildings being made out of fire brick or mud brick, lots and lots of wells and a general interest in water. There's a general element of difference when it comes to comprehending what happens in Indus cities. There's often a claim that the material culture that's used is very homogenous and similar. I'll show you some examples of that in a moment. Another point that's often made is that there's a lack of monumental and elite architecture. This goes with, in some respects, the lack of obvious individuals that are being identified through sculpture or other sorts of means. Some of our ideas are, however, changing. This is coming from scholars in the last four or five years actually reassessing the excavated evidence from these sites, particularly in the area of the upper part of Mahenjidara, which is called the Stupa Mound, or the Great Bath Mound, and also in one of these lower areas, which is referred to as the HR area. On the upper mound, we've long known of the existence of a structure which is referred to as the Great Bath. This is often referred to as being enigmatic and appears to be what is in effect a relatively large swimming pool with staircases at either end, and presumably involved with certain types of ritual activities. Adjacent to this building is a structure that, since it was first excavated, has been referred to as a stupa. A stupa is a religious monument that dates to the early historic period, about 1,500 or 2,000 years later than the other remains at Mahenjidara. What is now clear, however, is that this particular structure is very potentially not a stupa at all, but it is actually possibly an in this period structure of some importance. This is the structure that sits on the highest part of the mound at Mahenjidara. Unfortunately, you can't see it here, but it's actually just off to the right of this photograph. What we're seeing is the identification of buildings which we've long known were ritual structures, and also the reinterpretation of buildings which were previously given other interpretations. In many ways, our ideas about what constitutes the inter-civilisation are constantly changing. Other elements that are changing come down to looking at the details of the urban fabric of the city. This is a plan of one of these exposed areas at Mahenjidara. In blue you see what is traditionally regarded as being the largest Indus house in blue. In orange are examples of buildings that have been referred to as temples, largely because they're built of very substantial fire brick architecture, not because of any artefacts, not because of any texts, but mostly because of the architectural remains. In 2010 it was proposed that rather than being made up of a whole hodgepodge of small buildings, if you look closely you can see a wide number of numbers that have been added to this. Each one of these numbers refers to an individual building in inverted commas that was identified by the excavators. It's subsequently been proposed that rather than being made up of many different buildings, this is possibly an entire palatial structure at Mahenjidara. The adjacent to this structure is a small version of the Great Bath. This reinterpretation of this area at Mahenjidara in many ways throws open all sorts of new ideas about how social organisation and even potentially political organisation within the settlement may have existed. What we've seen is that the realisation that we have large numbers of these limestone column bases that were discovered in this large palace and also the recognition that in various bits and pieces of iconography there seems to be examples of these limestone columns that seem to have been stacked together as some sort of monumental entrance way to a structure. So all of a sudden, possibly rather than a simple explanation, we possibly have the existence of a palace in the lower town and we possibly also have an existence of a smaller scale emulation or a copy of this Great Bath also existing in the lower town. So the arguments that are beginning to be put forward about the industrialisation is that rather than maybe looking at major settlements that are dominated by an upper mound having control over a lower mound, possibly what we may be seeing is different areas within an urban city whereby we have different groups of elites, multiple centres of control, multiple groups that have power and groups possibly existing in some sort of heterarchical relationship rather than one that's hierarchical. Other elements that we know about the industrialisation relate to its material culture. We know that in this crafts people engage in the manufacture and production of all sorts of exotic material using raw material that are obtained from all sorts of different areas. And the widespread distribution of this material leads to the suggestion that we have a sort of a homogeneity of material culture. For example, we see these long Carnelian beads which are found throughout Indus settlements but are also found in Mesopotamia. We have cubical weights which provide indications of control structures and mechanisms which are similarly found throughout the Indus world but also in the Persian Gulf. And more enigmatically we have these square shaped Indus seals which display elements of iconography. But again these seals are usually less than say five centimetres on a side. So we're not talking about massive scale art. These seals also show at the top here examples of what's referred to as the Indus script. But this is in many ways problematic. We have a script that exists but it's made up of inscriptions that are usually less than about five or six signs in length. And it's at present untranslated. So in many respects the presumption is that the Indus civilization is broadly literate but we can't actually work out what it is that they were saying. In terms of understanding how this big picture civilization fits together it's useful to sort of give some examples of how the populations in different regions were interacting. This is some two maps that I've proved from publications by an American scholar called Randall Law who conducted his PhD research looking at the distribution and redistribution of exotic raw materials. On the left hand side all of the coloured dots on the map indicate sources of raw materials that were being accessed by Indus civilization craftspeople. The red dots here for example represent the sources of carnelian. Blue dot in the top here is the location of the sources of lapis lazuli in Barakshan. We have all sorts of different types of church used to make very, very specialised stone tools. Different types of limestone and steatite. All types of material being used to manufacture very, very specific and visually recognisable material culture. More or less as you can see here. What we see is that the Indus populations living out on the panes exist that are relatively isolated. They don't have an abundance of these exotic raw materials but they have, they establish over time, they establish networks that enable them to draw these raw materials into the urban centres and production centres and that material is then converted into more elaborate craft products and then redistributed across the landscape. This is the network that we see working at the site of Harappa. So we see that the populations at Harappa are able to draw material from the full range of areas within the Indus civilization zone and we also see other settlements are involved in this network as well. So during the period where we have these Indus urban settlements we have a very vibrant and active population engaging in long distance interaction. There's cities that are engaging in trade and interaction with each other spread over at least 500 kilometres apart. They're engaging in all sorts of other exchange of finished products, trade and exchange of raw materials and various sorts of other elements. And in addition to that sort of pattern we also know that the ancient Indus populations were also living in a connected world. People are starting to use the phrase globalisation in this particular context. So we know in the third millennium BC we have very clear evidence for Indus populations engaging in probably indirect trade with populations in Mesopotamia and that trade is being managed by intermediaries living in different parts of the Persian Gulf. We also have clear evidence that there's connections up into different parts of Central Asia and a whole range of different types of products and materials moving around in this particular period. What we see however is a point at which all of this changes. And as far as we can tell this seems to happen at some point around 2000 BC or 1900 BC. What we see in the material record is the general breakdown of the urban fabric. We see occupation at these large urban centres deteriorates and declines. Several of these large urban centres are abandoned and we also see the breakdown of these elaborate craft technologies and the sort of rate related elements that appear with them. So we see the cessation of the production of these Indus seals. We see the disappearance of the use of Indus cubicle weights. We see the cessation of the production of Indus long beads and various sorts of other things. And by and large we see a dispersal of the population that was living in these urban centres. As you can imagine this is a particularly compelling instance of civilisation collapse and decline and people have been speculating about what caused the collapse of the Indus civilisation or the decline of the Indus civilisation since it was first discovered. And there's been a whole range of possible causes that have been put forward to explain that. Usually these causes are divided into natural causes or human causes. And this very much has become a sort of topic that is in terms of being tying into current issues with relationships to the impact of climate change and the role of humans in driving climate change or responding to climate change. So some of the examples of instances of the causes of the decline of the Indus civilisation come from things like declining rainfall, desiccation, the exhaustion of resources, for example, in the production of bricks, social changes that have, you know, as a result of the increases in population. Changes in the causes of rivers is a particularly important example and I'll talk about that more in a moment. And there's also a whole range of other sort of more human human changes that have been invoked. Going all the way back to the suggestions in the early part of the 20th century, that there were Aryan invasions that resulted in wiping out of the populations of these urban centres, to more sort of reflective, modern interpretations that suggest that there was some degree of social evolution that took place over time and possibly social evolution that took place over time and possibly social evolution that took change in response to changes in the natural context within which these Indus settlements existed. What we see in terms of the archaeology is quite interesting. We see areas that had been previously quite intensively occupied in areas of the modern state of Sindh and the Punjab appear to be broadly abandoned and we see increases in the density of settlements in this area of West India and also the area down here to South. So we see a shift away from what was in many respects the heartland of the Indus civilization. What we see generally though is that we see an increase in the number of settlements but a decrease in the size of those settlements and we're left in many respects with trying to understand why this process has taken place. And in many respects the sort of decline or collapse or probably more correctly transformation of the Indus civilization is bedeviled academic debate for many decades in many respects left with substantial gaps in the evidence that might actually enable us to answer this question. This partly comes from the fact that when people focus their research on the Indus civilization, they focus on the urban period. They're interested in all of these elaborate craft products. They're interested in the rise of an urban city. We don't necessarily have a lot of information about the decline of the urban city. This is complicated by the fact we don't have very, very good dating evidence to work out precisely when this process took place. And understanding the role of the environment and climate is also made very, very difficult because we have in general for the subcontinent we have a lack of directly relevant climatic evidence. And we also have a lack of detailed study on the ancient environment. So we can't necessarily understand the processes that face these ancient inhabitants. And in some ways the key piece that's missing and the bit that archeology is really perfectly set up to contribute to is how humans interacted with and responded to their environment. And this is a sort of question of something that's becoming a part of modern or more recent scientific heavy or science heavy archeology whereby we start to look at different categories of evidence that were previously not being assessed. One of the things that we know now about the region across which the Indus civilization was distributed is that it's a very, very complex environmental zone. This is a map produced by the Lake Gregory Purcell showing what he defined as domains or culture geographic regions that exist within the Indus civilization. The previous maps I showed you had large colored blobs on the map showing you where Indus civilization settlements were. This is a map that shows different shades of colored blobs. We don't see a lot of people, we're just seeing colored blobs at the moment. But what we have is that an attempt to highlight the geographical differences across this enormous area, it's often been repeated many times that the Indus civilization was covered an area of as much as one million square kilometers. I think that's a slight over exaggeration but what we have is populations living across a very, very large area that we're using broadly similar raw, sorry, broadly similar material culture at one level but different material culture at another level. So we seem to have what looks like a veneer of similarity that ties all of this population together but underlying that veneer, we have very, very clear differences in terms of the environment and the landscape. And this is something that has really become clear in recent years to sort of highlight the nature of the difference in the Indus landscape and she's going to have a look at, this is a map that shows climate zones. What you can see here is the course of the Indus River here and the rivers of the Punjab here and the Ganges and the Yamuna River over here. By and large, the majority of Indus settlements are distributed in this yellow area which is referred to as effectively an arid area. We have a semi-arid zone here that encompasses parts of the Punjab and in somewhat surprisingly large areas of Rajasthan and also Gujarat and we have more temperate zones up here to the north in the foothills of the Himalaya. So we can see that we have Indus populations living in a variety of different climatic zones and this produces different sorts of environmental zones. The reasons for this variation in climate are explained when we look at the rainfall patterns in this area. We know that this particular part of the globe is benefits from sitting right at the point where we have summer rainfall and winter rainfall zones overlapping with each other. So what we see here is the edge of the winter rainfall front, effectively rainfall falling in November, December and January, the northern hemisphere winter which is critical for the growing of wheat and barley and we see that while we don't have, this is modern rainfall data that's been reconstructed. While we don't, a great deal of rainfall falling in these sort of arid zones out here on the plain. What we do see is rainfall falling in the watershed of all of these rivers. So we see a rainfall pattern that provides water in this zone, in particular areas that enables the growing of wheat and barley at the right time of year. What is in some ways more surprising to some is the pattern of summer rainfall. What we see here is the pattern caused by the distribution of the Indian summer monsoon which falls June, July, August and has an incredible intense rainfall in areas of the north here. We're seeing the 800 millimetre isohyd up in the foothills of the Himalaya and 900 millimetre isohyd here in this area of central India. And what we see here is a very steep rainfall gradient but we do nonetheless see monsoon rain falling on this area up in the northwest and also in the areas of Gujarat. And even some monsoon rain falling out in the arid zones out in the center here. Monsoon rain in some ways in modern India and Pakistan, monsoon rain is critical for the growing of millet and rice and other types of summer crops. So we have an environment in some ways that's predisposed to double cropping systems and being very adaptive to different rainfall. In terms of understanding the climate in this area, what you can see on this map is the orange line which shows where inter-civilization settlements are distributed and in red you see the locations of paleoclimatic data that exists at the moment. We have a number of climatic sequences that exist in the area called the Ta desert which is one of the driest parts of the subcontinent. But we have no evidence for climatic patterns within the Indus zone itself. What we can reconstruct is that there seems to have been periods of wetness and dryness during the long Holocene. So after the last ice save we had a period of increased wetness followed by around 6000 BC of a period of intense aridity followed by another period of wetness and then a period of increased drying that appears to have accompanied the rise of the Indus urban centers. What we don't know however is what impact the climate may have had on the Indus civilization itself. If we have a look at the chronological chart you can see here on the left hand side the period that the Indus civilization existed corresponds with a period for which we have no climate data for this particular part of the subcontinent. So whether or not climate plate a factor is a big question that we really can't answer. That's hopefully what we shall get to in the rest of the talk. Now I mentioned in the beginning why focusing on, why mention these two different phases of early, sorry early urbanism. And it's very much an area in the northwest of India where it's particularly interesting to have a look at this particular zone where we have an overlap between the Indus urban phase and the early historic urban phase in terms of its regional developments. This is an area in the northwest. But there's a specific reason why this particular region is interesting. And this comes back to the fact that it is in this area that it's long been suggested since the middle of the 19th century that there was a dry river or a lost river that is often related to the mythical Sarasvati River that's referred to in a variety of Indian mythological texts. And early explorers in the middle of the 19th century had identified what appears to be a paleo channel that spanned across this part of the landscape. And they traditionally assumed that there was a relationship between this apparently dry river and what was being referred to in various mythological texts. But what we have, what we now see on the ground in this particular part of northwest India is quite interesting and enigmatic evidence for what's happening. We see, this is a satellite image that shows the courses of the modern rivers. And in green it emphasizes areas that have intensive vegetation. What you can see on this map is the very, very northern edge of the Tar Desert here, which is sort of in yellow and purple here, and a sort of green linear feature which stretches across the landscape. This is what was being investigated in the 19th century revisited by a whole raft of other scholars in the middle of the mid to late 20th century as well. What we see in this particular area is an area that is the zone between two different water systems. We have the Punjab here in the west and the Ganges and Yamuna rivers, area between those two river systems which seems to be characterized by a dry river. The reason that this river has become important is because we have lots and lots of Indus settlement in this particular area. So the questions that we're interested in as a project is what is the role of climate? It seems as though we know that Indus cities decline around 2000 or 1900, and there's a shift in settlement. But is this correct? Why did this particular thing happen and was climate a factor? And this brings us around to the focus on the project. There is a lot of skepticism about the impact and possible impact of climate and climate change. What we do know is that in this particular part of the world, minor variations in climate can have massive and dramatic effects. In 2010, there was a slightly intense monsoon rainfall in the Himalayas and the foothills around northern Pakistan. This resulted in the submergence of one-fifth of the state of modern Pakistan underwater and the displacement of 21 million people. This is an area where monsoon rainfall can be quite variable and it can have quite dramatic impact. The question is that we can ask, was climate playing a role in this factor? We can't necessarily know, but we can at least try and understand it. So in terms of making a big summary of what I've just spent quite a long time describing, in general, we have a poor understanding of a lot of parameters related to climate and the environment. We have a poor understanding of things like this dried river channel. What we don't know about that river channel, for example, is when water actually flowed in it. We don't have dates until now. We don't precisely know where the water was coming from either. And in terms of the archaeological evidence, we don't know how the people living in certain areas were relating to their environment. And this stems from problems with not really understanding why settlements are abandoned and different factors about chronology and other sorts of things. So in terms of trying to take on this whole big raft of questions, I'm in some way standing as a figurehead of a relatively large project that's trying to look at whether or not climate played a role in these sorts of changes. What we're trying to understand is, was there a change in the hydrology in the water of this part of Northwestern India? Were those changes as a result of climate change and did they have an impact on Indus urbanism? So in some ways, one big question, but three interrelated questions. As you might imagine, in terms of trying to address a collapse of the civilization and the interaction of environment and climate and river systems, it takes lots of people. It also takes lots of funding from lots of different bodies. So I've shown an example, sort of all of the collaborators in this project. And I've also shown some examples, the groups that have funded the first phase of the project, which is primarily what I'm going to be speaking about in the remainder of the lecture. So the project was in receipt of funding from the British Council, the UK India Education Research Initiative, which is also sponsored by the British Council. Elements of BAHRC, the British Academy, the Isaac Newton Trust and the McDonald Institute in Cambridge. None of the work that we've actually been able to undertake would have been possible without the Express Authorization and Commission of the Archaeological Survey of India and actually the collaboration of them as well. What this land, water and settlement project has attempted to do is to take an integrated approach to look at how humans interact with their environment and to try and understand that environment. We're doing three separate strands of evidence and we're trying to combine all of this evidence together to give ourselves a coherent picture. We're looking at this dried up river and trying to work out when it flowed and when it stopped flowing. We're looking at various different paleo lakes in different parts of this area of Northwest India to try and get local climate data to try and understand what type of climate existed and how that climate changed over time. And tying all of those things together, we're trying to understand where people lived and when they lived in those locations. It all sounds relatively simple and straightforward or obvious, maybe I should say. What the drilling exploration that's been taking place has been focusing in different locations along this channel that we can see here. This is another satellite image that shows a discoloration stretching out of the Himalaya here adjacent to the course of the modern Sitaledge River. You can see there's a trace of a river visible on the ground. Coring in these separate loads has shown that there's an ancient river that's buried about 10 meters below the modern ground surface. My colleagues are working based in Imperial College and one of the Indian Institutes of Technology in Kanpur, Dr. Sanjeev Gupta and Dr. Rajiv Singh Haralini, the project they've managed to reconstruct the course of this river. They suggest at some point probably as much as 16,000 years ago there was a river that flowed along this course. Then there was some sort of evolution, possibly produced by an unusually high monsoon rainfall that caused the river to jump out of its bed here and to change its course. What's interesting is that although it's been speculated that this river may well have played a key role in the decline of the Indus civilization, it now appears that this river had not been a river for at least 10,000 years before the Indus civilization developed. So it throws up a lot of interesting possibilities in terms of how we understand things. Our project has also been engaged in paleoclimate reconstruction as well. This is the location of the previous or the existing climates data sources out here in the TARDesit. What our project has attempted to do is to date new plier lakes much, much closer to where the Indus settlements lie. Then what we see, by looking at these plier lakes, we're basically trying to locate on the ground dried up lakes that have dried up at a certain point in time, taking centimeter by centimeter samples from these lakes that can then be studied isotopically to establish whether or not they're getting increased rainfall, decreased rainfall, and other sorts of things. What we're seeing is evidence for very clear periods of climate change. It appears that though we have one point of climate change happening at around 8.2,000 years ago, that's about 6,000 BC, and another one at about 4.1, 4.2,000 years ago, or around 2,000 BC, which is when we know roughly the Indus urban settlements start to decline. And this is an example of these isotopic results. Here you can see we've got evidence of the lake being a deep lake, a shallow lake, and then at around 4,000 BC, the lake dries up. This appears to be evidence that there was a dramatic change in the quantity of monsoon rainfall about this point in time. What's unclear at the moment is whether the monsoon ever came back to where it had been previously. All of this analysis is being based on looking at very, very small gastropods. This is one millimeter here. This is a small shells of about five millimeters in size, but also looking at ostracod species. These are a sub-millimeter size, very, very small mollusks. And what we can see is that there's a shift. We have freshwater mollusks, mollusks, these ostracods that operate in saline conditions, and then these ostracods disappear completely. So we can see that there's changes in the lake systems, and this is suggesting changes in the quantities of the rainfall. And this broadly, this change that we see all the way down here at the bottom, broadly corresponds with what we see in climate records from a whole range of different locations in the world. So areas looking at dolomite concentrations in the Gulf of Oman, former Nifera in the Arabian Sea, even peaks in ice cores in the Kilimanjaro in Africa, all suggest that there was actually a point around 4.2, 4.1,000 years ago when there was a shift in the Indian summer monsoon. So we seem to have a river that wasn't flowing and evidence for climate change. How do we understand the archeology? One of the things in terms of trying to understand the archeology is that it became obvious through very, very brief reconnaissance that there was a whole series of problems with our understanding of the archeology. There was large numbers of errors in the locations of sites. There were relatively small numbers of sites that were actually located along this river anyway. And it appeared to be quite clear that although there were lots of sites that were recorded, there were also literally hundreds of sites that had not been recorded. And what we could see on the ground is that the evidence that we had for where settlements existed was based almost entirely on where people had looked rather than where the settlements actually were, if that makes any sense. So very, very detailed surveys have produced an abundance of archeological evidence for sites. To try and solve some of these problems, our archeological project has been engaged in quite extensive survey and excavation work in a variety of different regions. Thus far, we've carried out surveys in these five areas of Northwest India. I'm not gonna talk about all of them in detail. Please, sir. The main area that I'm gonna sort of focus on is this area here around the ancient site of Rakhigari. Now Rakhigari is one of these large Indus settlements. We know it's at least 80 hectares in size. It's recently been published in the Indian media that this is actually possibly 400 hectares in size. I'm not sure that that's actually fully justified, but some of you may have become aware of it. We've excavated small village sites in the hinterland of this large urban center. And what we've seen has been very, very interesting. These small village sites seem to be engaging in a very, very mixed economy. Rather than just relying solely on wheat and barley, what we're seeing is people living in these settlements were also using rice and millet. And they were using this mixed crop economy from the early Harappan period onwards. So it shows that populations living in this particular area were already adapted to an unusual environment. They're used to getting monsoon rain, they're used to getting winter rain, and they adjust their crop patterns accordingly. This sounds very, very obvious in many respects, but it's actually a novel suggestion when it comes to understanding Indus subsisted strategies. The other thing that sort of changed with our project is understanding the relationship and the development of urban centers. What we see here is the location of Rappi Gari and the knowledge that we had before our surveys of the distribution of settlements in its hinterland. The green dots were the known sites. We conducted a relatively intensive survey and after our survey we changed the map quite considerably. This is the distribution of all sites of all periods. But what we found was we literally doubled the number of sites and then some within this particular zone. And in many ways revolutionized what we understand about the rise and fall of urban settlement in this particular area. So this is the distribution of, as we now know at the distribution of these settlements that existed before Rappi Gari was an urban center, they appear to be relatively sparsely distributed across the landscape and they appear to be lined up with a degree of linearity, which is an interesting question. Was there a river? Was there a canal? Question mark, something else to investigate further. What we see when Rappi Gari becomes an urban settlement is that we have an abandonment of large numbers of these settlements in its hinterland and presumably the consolidation of the population into this large urban center. When we look at the post-urban period, we have an abandonment of the large urban center and actually the reoccupation of many of the sites that had been occupied earlier. And the only area where new sites appear is this zone down here to the south, which is interesting. So this in many ways says, okay, do we seem to have evidence or for an impact of change in hydrology, change in climate? It's not exactly clear. What we really see is the change that happens in the subsequent period, way after the Indus civilization has moved on. And we see a whole series of dynamics. We see large parts, the plains abandoned in a period which is referred to as the painted grayware period, areas of intensive settlement here. And then if we move on into the early historic period, we see a different type of settlement, populations living in all areas of the plain, settling large areas that had never been occupied before and settling them with very, very large settlements. So it seems clear that although we do have change over time, we don't ever run into the situation where this area becomes unviable for settlement. And it's also interesting to see that we see, we don't necessarily see an increase in population in the late Harappan period. It's many, many slides ago I showed you that there seems to be this evidence for a decline in the core area of the Indus civilization and an intensification of settlement up here in the Northwest. This isn't reflected in what we see at Raqqigari and at Tintiland. What we really see is almost a flat line across settlement distribution there, a decrease and then a subsequent steep increase. So very, very different evidence, different sorts of patterns. Another area that we've investigated further north is just quickly looking at this area along the Gaga River. And this is the Gaga River here visible on a satellite image. This is this paleo channel that's about 10 meters down that you can see even that results in the growth of fertile vegetation in this zone. Again, there was long speculation that there was an abundance of settlements along this river. In actual fact, there's not that many settlements along this river. But this is the known settlement distribution before our work. After our work, the known settlement distribution changes quite dramatically. Eyes of sites, of sites and all sorts of things also change quite dramatically. If we have a look at the evidence for this early Harappan period, we can see that there are settlements that are distributed on the end of this channel. But they're all very, very small farm village settlements. The big sites are located at some distance away. When we move to the urban period, we see something quite surprising. This particular area is almost entirely abandoned. We're left with much smaller number of settlements. And that pattern seems to continue into the post-urban period. So rather than again seeing an increase in settlement in the post-urban period in this part of India, we're seeing is actually a decline. So the general perception is not at all matched by the work that we've been doing in this Northwestern area. But what we do see is after the Indus period, again, a different pattern. We see a different thing also to what we see in Raki Gauri. We see an increase in the numbers of these painted greyware settlements and a massive increase in the early historic period, including the establishment of a 100 hectare city that had previously not been recorded and several other cities up here. So the pattern again is in actual fact, in the Indus period, we see relatively low numbers of settlement and not a steep increase in the late Harappan but a steep increase in the subsequent periods. Now, just in terms of putting it all this into perspective and seeing how the nature of our archaeological knowledge of this is changing in terms of what the work other people are doing, I'm just going to briefly show you one example of the impact that a PhD student can have on a field. This is the work done by a PhD scholar from Rottak University in Northwest India. This is the relatively well-known Indus site called Kalibangang, which sits along the course of this river, this river channel, and this is the known settlements of all different periods. Vikas Parwar's PhD, however, has changed that quite dramatically. He discovered 500 new sites, primarily because he looked in areas where nobody had bothered to look before. What's clear from his evidence is that there is obvious focus of settlement along this channel, but there's also settlements and people living in the desert margins, in all sorts of other environments that were not expected before. So what this new research is really doing is forcing us to rethink how we understand Indus populations lived and how they lived in their environment as well. And this sort of shows, this is the overall impact of our project in general, in terms of the general view that we have of, there's Indus settlements and other settlements located along this river channel, and there's an increase in settlement in this particular zone. If you add all of the work that we've produced onto that, the map changes quite dramatically. Unfortunately, what we've done is highlight what happens when you focus on particular limits of the survey area, because we don't know what's going on outside those areas as of yet. But what we're doing, we have some nice hearty gaps for future surveys which will hopefully change the picture in a more positive way. So in general, in order to sort of bring all this sort of broad sweeping discussion to, what we know about our, as a result of our survey work, particularly is have a massive underestimation of density of settlement in this particular part of Northwestern India. And this actually makes it very, very difficult to draw coherent conclusions about what's actually going on. What we can say, however, is that it's quite clear that the ancient populations all the way back from the beginnings of village settlements up to the medieval period, people were living in all sorts of different environments in this zone. They were living in arid environments, semi-arid environments, and temperate environments. They were living in areas where they had access to regular water and where they didn't have access to water at all. So it seems quite clear that the populations living in this area were no doubt very, very well informed about their environment and very clever in ways of how to use and how to exploit it. What this suggests is that the Indus agricultural system was very, very diverse and it was by no means homogenous, but it was adapted to the local conditions. This seems like one of the most obvious things to say in the world, but it's actually not something that's appeared in the literature very much. So the final thing is to draw the whole extra to a close rather than to just focus on the results of the survey. And now it appears to be quite clear that we have good evidence that there are changes in the climate in Northwest India. What's difficult to work out is what the impact of this was upon the population. We can see that there's changes in where people were living in different periods. What we really want to understand is how it changed from the day-to-day lives of the people living in these sites. Did they change the way that they lived? Did they change the way that their houses were constructed? The types of crops that they actually focused on? We know rice and millet, but did they start using more rice and more millet or less rice and less millet? And how did that sort of change in relationship to these rainfall pattern changes? What seems clear also is that although it's often that the Indus civilization's name comes from the Indus River, and it's usually regarded as being a river in civilization, a civilization that focuses on rivers and whereby water is the critical element. But in actual fact, it seems like populations were living in a whole range of different environments where water was not necessarily a reliable resource. So what we really need to know now is that how populations may have used the different water sources that were available at different times of the year, and really how the agricultural systems were adapted to this variable environment, but an environment that was also variable within each individual years. So the next step for the project is very much looking at issues of resilience and response to these sorts of parameters that we can identify quite clearly. And what we're trying to do, just to give you a bit of an insight as to where we're trying to go next, is this, I'll just sneakily put two slides on up again that show the distribution of Indus settlements in this particular area in the urban phase. So this looks like we have a nice coherent pattern of settlement distribution and we can possibly build arguments and debates. This includes all of our own survey data. But what you see, if we look at the late Harappan period, this period where we have this intensification of settlement in this particular area, what you can see is that you see the distribution of sites actually conforms quite neatly to the boundaries of the districts and the tessals that make up the administrative areas of this part of North India. There's some parts of the Punjab here which lies square in the temperate zone, which should be perfect for living in, which seem to have about five settlements in them. Obviously our existing settlement data has huge holes whereby in some of these areas there's just unexplained gaps. We just need to start filling in these gaps and doing some more work to try and really explain how people were living in this environment. We also have nice evidence for the climate environment as it existed on this zone, right at the edge of the arid area. What we don't know is what's happening up here in the foothills of the Himalaya at all. So effectively what I've described to you is stage one of what I am now afraid is going to be much more of a long-term project than I hoped when I started it. Thank you very much.