In the last video, we discussed some examples of ancient instincts that were not about water or sanitation. In this video, we're going to examine some ancient instincts that do relate to water and sanitation. I'm going to look at three historical periods, before our ancestors left Africa, after they left Africa but were still hunters and gatherers, and after they settled down in permanent communities and began to cultivate crops. Again, I want to emphasize that this narrative isn't speculative. We want to try to identify some of the factors from our distant past that may still affect the design and implementation of water policies today. Let's begin then, to think about our ancestors' relationship to water on the African Savanna. Before our ancestors left Africa, the climate fluctuated. From roughly 500,000 years ago to 100,000 years ago, the general trend was toward cooler and drier conditions. Many of our ancestors often relied on waterholes as they scavenged and hunted for game. These waterholes must have been dangerous places for our ancestors, just as they were for the baboons and the antelope in the water holes video that you watched. Our ancestors had to be especially alert for predators around waterholes. There must have been a heightened sense of fear about failing to get access to water, because water for drinking was essential for life. And our predators, of course, knew this. At the same time, as the video of the chimpanzee showed, we also loved access to water for relaxation and aesthetics. Our ancestors needed water to drink. But they also loved water for washing, bathing, and relaxing. In a recent book entitled The Improbable Primate, How Water Shaped Human Evolution, Clive Finlayson analyzes our ancestors' relationship with water before they left Africa. Finlayson has proposed the water optimization hypothesis. He believes that homo sapiens selected environments that fell in an intermediate range of rainfall regimes. Finlayson speculates that our ancestors' favorite landscape had trees, open spaces, and water. The water sources were often highly dispersed, seasonal, and ephemeral. As climate changed and these environments became cooler and drier, adaptations that helped us find waterholes were especially valuable. Our ancestors who could run further and faster to find water, thus had an evolutionary advantage. So we evolved bodies that could run to find both water and game. Finlayson calls our ancestors rain chasers. Other scholars have also speculated about our relationship to water. In her book the Aquatic Ape Hypothesis, Elaine Morgan argues that out ancestors must have spent a long period of evolutionary history in or near water. Once piece of evidence she offers in support of The Aquatic Ape Hypothesis is that we are hairless or mostly hairless, like whales. Another piece of evidence is that infants instinctively hold their breath under water. Elaine Morgan has a TED Talk on The Aquatic Ape Hypothesis, if you'd like to learn more without reading the whole book. I have a hard time reconciling the rain chaser and aquatic ape hypotheses. I'm more inclined towards Finlayson's theory that waterholes would have been dangerous places. But both of these hypothesis suggest that our ancestors were likely to have special, ancient feelings and attachments to water. This is a picture of a public latrine in Kumasi Ghana several years ago that is in the process of being cleaned. You maybe disgusted by the sight of this latrine, but chances are you would react even more strongly if you could smell it. All people today are repulsed at the smell of excrement. This repulsion is so strong and universal that it must have been a very ancient instinct and have served an important evolutionary purpose. Hunter-gatherers who kept their campsites free of feces probably improved their chances of not becoming ill. It would thus seem an evolutionary advantage to be repulsed by the smell of feces and to send individuals away from camp to defecate, even if this exposed them to increased dangers from predators. A repulsion to the smell of feces is so strong and universal that if we see someone who has smeared himself or herself with feces, we assume they're insane, that they're crazy. This is almost, by definition, an act of madness. Human excrement is still dangerous today, so being repulsed by the smell of feces is still an evolutionary advantage. Interestingly, like the fear of snakes, this sometimes needs to be triggered. Infants sometimes do smear themselves with their own feces. A minority of the human population now has water-sealed toilets connected to sewers, which in turn are sometimes connected to sewage treatment plants. So for these people in rich countries, the repulsion at the smell of feces is not all that useful. But it does not cause us any major problems. For people in developing countries who are still defecating in the open, this ancient instinct of being repulsed at the smell of feces will prove useful in crafting solutions to the global sanitation problem, as we will see later in this course. We now turn to the period after the small group of our ancestors left Africa about 60,000 years ago, but were still hunters and gatherers. We will try to spot ancient instincts related to water and sanitation that we carry with us today. Our ancestors departed from the arid landscapes of East Africa, and probably first traveled to other arid regions along the Arabian peninsula, probably following the coastline around the Persian Gulf to the Indian continent. From there, some circled back to Europe and Africa. Others pressed eastward to Southeast Asia and China. Our ancestors proved to be great travellers, reaching Australia about 40,000 years ago and North American perhaps 20,000 years ago. After leaving Africa, humans had to confront several ice ages. And all they could do was retreat before the ice. We adapted genetically to these climate fluctuations. Our ancestors must have had a strong desire to understand the natural environment, including climate and the hydrological cycle. They were probably great storytellers, and their stories and myths must have reflected this interest in water and climate. The study of hunter-gatherer societies that persisted into the modern era suggests that our ancestors were religious. And that water likely played an important role in their cosmology. In my own work on water in low income countries, I've been told about sacred springs, and spirits in rivers and streams. I've worked with a Native American tribe in Arizona called the Hopis. The Hopi Indians have a complex cosmology in which the hydrological cycle plays a major role. The spirits of the Hopis return to their villages with the rains. In both Christianity and Islam, water plays important spiritual and ceremonial functions. Our ancestors were great hunters, managing to drive many large mammals to extinction with sophisticated stone tools and fire. The genetic evidence suggests that their prey also included other humans. Some of our ancestors were cannibals. They were great traders, exchanging flint, obsidian, and shells, probably often for meat and animal skins. But they didn't trade water because it was heavy and hard to carry. Water is what economists call a non-traded good, which means that you cannot trade it over long distances. Because water was difficult to trade, our ancestors probably used it to show hospitality and for gifts. Unlike traded commodities, for most of human history water has not had a monetary price or an exchange value. In many contexts, we continue to have difficulty thinking about or assigning a monetary price to water. In the world's great religions, it often seems ethically and morally wrong to charge for water. In Christianity, one is called to give water to the thirsty as an act of charity. And it is often said that the Quran forbids charging for water. In phase two, our ancestors were great artists, travellers, traders, and storytellers. We have evidence from cave paintings of some extraordinarily talented artists. But during phase two, our ancestors were not great engineers. During the second phase, human communities experienced no sustained growth in per capita income, and as far as we know, developed no water technology. The archaeological evidence does not reveal any water-related technological advances over this 50,000 years of hunting and gathering in phase two. There's no evidence that I know of, that these hunter gatherers had tools to carry water, or any depiction in cave or rock paintings of any water-related technology. Of course, the absence of evidence does not prove that some groups did not have water tools. But innovations such as bows and arrows in the domestication of wolves were so valuable, that they appeared to have spread very quickly. There's no evidence of any water-related technologies following a similar trajectory. By the end of phase two, our ancestors had probably developed a reverence and fascination for nature in general, and water, weather, and climate in particular. I believe that the utilitarian uses of water and the spiritual attitudes must have merged easily together. Water was a non-tradable good with no exchange or monetary value, but was absolutely essential to life. From about 20,000 to 15,000 years ago, our ancestors confronted a period of extreme cold. From 15,000 to about 12,500 years ago, there was a warming period. And then from about 12,500 years ago to 11,500 years ago, there was a second brief period of extreme cold. And then we entered the current era of warm temperatures. Our ancestors started to settle down, gradually settling in the Fertile Crescent in China. We domesticated wild grasses and a few animals. As our ancestors started settling down, they faced three new water and sanitation challenges, contaminated water supply, feces management, and water for agriculture. I want to emphasize that we had to face these challenges with our ancient instincts. We still loved sugar, we were afraid of snakes. We were repulsed by the smell of feces. And we had complex feelings about water. Specifically, we weren't used to trading water or assigning it a monetary value. And we loved water for spiritual, recreational, and aesthetic reasons. New technologies were developed to tackle these three challenges. Many are still in widespread use today. One of the difficulties early settled communities faced was the tension between locating in an easily militarily defensible site, and one with a readily available water source. Three technologies emerged to address this problem. The first was fired pottery. It seems that pottery technology probably developed independently in several locations, perhaps first in Japan about 13,000 BC. Fired pottery spread rapidly throughout the world. And cultures adapted different shapes of pots to meet multiple purposes, including for cooking. Technological innovation in the water sector is slow. But fired pottery was the first disruptive water technology. As an aside, note the patterns on the right of the pottery and on the back of the rattlesnake. It seems that our ancestors were thinking about snakes when they made pottery. Fired pottery is still being used today to carry water. Over the last few decades, fired pottery has been replaced by a standard sized 20-liter jerry can in many rural areas. This is probably one of the main reasons why household water use by rural households, collecting water from sources outside their home, has increased significantly over the last several decades. Even in high income countries, we have remained fascinated with fired pottery into modern times. This slide shows a Hopi potter in the late 19th century, in northern Arizona in the United States. Hopi pottery was one of the first things that Anglos wanted to buy from Hopi villages, and it still is. 19th century pots similar to the ones in this picture sell today for thousands of dollars. The second disruptive technology was lined, dug wells. Dug wells enabled people to have a more reliable, higher quality water supply, and to settle in more defensible locations. Early dug wells have been discovered in the earliest settlements in the Fertile Crescent, and 100s of millions of wells have since been dug all over the world. However, the technology did not exist in ancient times to pump ground water to the surface. Water had to be lifted in a container, sometimes made of fired pottery. This practice is still widespread in some low income countries today. The Green Revolution in the Punjab provided farmers with the increased incomes that led to millions of private, hand-dug wells, and the installation of hand pumps to lift water. In sub-Saharan Africa, one of the most important breakthroughs in the rural water sector over the past couple of decades has been the emergence of Chinese contractors who've been willing to drill wells at much lower prices, making rural water supply investments much more cost effective. So were are still using the this early technology, although we are adapting, adding hand pumps to lift water, and using more complex drilling technologies. The third disruptive technology was covered pipes to transport water and wastewater cheaply and easily. Fired pottery was used to create early sewer pipes in Mesopotamia. The Romans developed lead pipes for carrying water. This example is from the city of Bath in the UK, named for its Roman baths in which these lead pipes were used. And today, our preferences for water for relaxation are not so different. The thermal baths in Bath, England have been restored, and are again extremely popular, just as in Roman times. Wooden pipes were used in Europe until surprisingly recent times. The first water pipelines to houses in London in the 16th century were wooden. In Asia, bamboo pipes are still in use in some places today. As we saw in the first module of this course, pipe networks are often very expensive. As our ancestors settled down to an agriculture life, capital was needed for large water projects. Most of the time, only the rulers and the elite had access to the capital needed for complex pipe networks, especially if they involved long distance water transport. So rulers and elites typically dictated what got built. What this means is that the design of the pipe networks reflects the preferences of the ruler or an elite, not necessarily the majority of the citizens. The Hanging Gardens of Babylon were one of the ancient wonders of the world, but they no longer exist. Stephanie Daley, a professor at Oxford, argues in her new book that the Hanging Gardens of Babylon were in fact real, but they just weren't in Babylon. Wherever they were and whatever they looked liked, the water delivery system was a key reason for their fame. The ancient Babylonians evidently made great efforts to create beautiful urban spaces with water. And the beauty of these efforts is still remembered today. I believe that the results were a manifestation of our love for water for recreation and aesthetic purposes, even though very few people could afford such water luxuries. In other words, large capital expenditures revealed the rulers' ancient water instinct and love for water, for recreation and relaxation. Let me give you another example of our love for water for recreation and aesthetics, this one from contemporary Riyadh in Saudi Arabia. The Wadi Hanifa project is an internationally acclaimed, award-winning urban development project in Riyadh. In 2012, I had the opportunity to see this project firsthand. This is a large urban park built along the wadi, or a stream bed that is often dry when there are only natural flows. The wadi used to look like many other heavily polluted urban drainage systems in developing countries, filled with trash, a place where people did not want to visit. After the restoration, the water for the in-stream flows now comes largely from the collection of urban drainage wastewater, not raw sewage. This wastewater is collected by a system of pipes designed to lower the ground water table in Riyadh, similar to agricultural drains in irrigated areas. Although the water is not sewage, it still needs to be cleaned. This is done using innovative bioremediation facilities located mid-stream in the wadi, as shown in these pictures. Today, tens of thousands of visitors come to Wadi Hanifa to walk, picnic, meet friends, and just enjoy themselves near the water. This new urban park designed around water has been hugely successful, and shows that wastewater can be one of the most promising sources of water for urban designers in the 21st century. But note in the case of Wadi Hanifa, the urban wastewater was unpriced, which was one reason it was affordable and could be used in this restoration project. In summary, in this video I have argued that our ancestors had complicated feelings about water from very ancient times, when we were hunters and gatherers. As our ancestors settled down in permanent settlements and started to cultivate crops and raise livestock, they kept the ancient water and sanitation instincts from their hunter gatherer days. Their fear of losing access to water, their love of water for bathing, recreation, and aesthetic purposes, their repulsion of the smell of feces, and their reluctance to trade or assign a monetary price to water. Settlement in agricultural communities brought new water and sanitation challenges, especially the need for reliable, clean water supplies and feces management. We developed new technologies to help address these challenges, including fired pottery, lined wells and pipe networks. And these ancient technologies are still with us today. In the next video, I'm going to relate these ancient water and sanitation instincts to some of the policy problems we have today in the water and sanitation sector.