SPEAKER_05: Amazing, fascinating stories of inventions, ideas and innovations. Yes, this is the podcast about the things that have helped to shape our lives. Podcasts from the BBC World Service are supported by advertising.
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SPEAKER_06: for three month plan required. Taxes and fees extra. Additional restrictions apply. See Mint mobile.com for full terms. 50 things that made the modern economy with Tim Harford.
SPEAKER_01: Not far from Cairo stands a remarkable dam, the Saad el-Kafara. It is more than 100 metres long and 14 metres high and could store about half a million cubic metres of water. These statistics are modest by modern standards, but the Saad el-Kafara is not a modern dam. It is nearly 5,000 years old and it was a spectacular failure. Archaeologists believe the dam burst almost immediately. One cannot fault the ancient Egyptians for trying. Water was scarce and rainfall uneven. A sudden storm would have delivered a valuable resource free of charge, literally falling from the sky. A dam would have allowed water to be stored until needed. Ancient Egypt isn't the only place to have found itself trying to deal with uneven rainfall. Much of the world's population lives in places where the availability of water is seasonal or increasingly unpredictable. The plentiful year round water we have come to expect in developed countries often relies on a system of dams and reservoirs. Where such a system is lacking, the effects can be brutal. Kenya lost more than 10% of its economic output to drought in the late 1990s, followed by an even larger economic loss because of flooding. With dams offering the potential to manage both droughts and floods, small wonder they've been tempting projects for millennia. As a bonus, dams can include hydroelectric power stations. Hydroelectricity is a bigger energy source than nuclear, solar, wind or tidal. What's not to like? The citizens of Henan province in central China could tell you. They live downstream of the Banqiao Dam, which was built in the 1950s and immediately showed signs of cracking. After reinforcement, it was dubbed the Iron Dam and declared unbreakable. In August 1975, it broke. Locals describe the event as the coming of the river dragon. It was a wave several metres high and eventually 12 kilometres wide. Tens of thousands of people died. Some estimates suggest almost a quarter of a million. The tragedy was a state secret in China for many years. Nevertheless, it didn't stop the Chinese government from deciding to replace the dam. Even in wealthy countries, dams have been responsible for some of the deadliest man-made disasters. Large reservoirs weigh over 100,000 million tonnes when full, enough to cause earthquakes, and much smaller ones can still cause deadly landslides. The Malpassé Dam in France cracked in 1959 when the land at one edge of the curved concrete shell slipped under the pressure of the water. 423 people died. Four years later, the new Viont Dam in Italy was overwhelmed by an inland tsunami when the weight of its slowly-filling reservoir caused a landslide. Nearly 2,000 people died. Military attacks on dams are now regarded as war crimes, and with good reason. And the dam doesn't have to be destroyed to be a weapon. The Itaipu Dam, on the border of Brazil and Paraguay, lies upstream of Argentina's capital, Buenos Aires. If the sluice gates were all opened at once, the city would be flooded. Yet it's not the risk of catastrophe that gives the modern dam its uneasy reputation. It's the harm done as the dam reshapes the ecosystem, both up and downstream. The poster child for this harm has long been the High Aswan Dam in Egypt. The High Aswan holds back the River Nile, creating a reservoir 500 kilometres long. The Economist magazine gives a checklist
SPEAKER_01: of the consequences. An explosion of water hyacinth, outbreaks of bilharzia, polluted irrigation channels, and a build-up of sediment in land that would otherwise compensate for coastal erosion from Egypt to Lebanon. That doesn't even mention the fact that ancient Nubian temples were flooded or moved in their entirety. And it wasn't just the temples that were displaced. More than 100,000 people were forced to move. But some experts argue that despite all the costs, the project has been an overwhelming success. The High Aswan allows predictable irrigation. It paid for itself within two years and shielded Egypt from what would have been a disastrous drought throughout the 1980s, followed by potentially catastrophic floods in 1988. All dams create winners and losers and tensions that need to be managed. The only two women to win the Nobel Memorial Prize in economics both studied dams. Eleanor Ostrom showed how dams in Nepal destabilised traditional bargains between upstream and downstream communities about sharing water and sharing effort. Esther Duflo found that large dams in India benefited some communities through irrigation but increased poverty in others. The losers from dams often live in other countries, which makes the tensions international. The latest example is the Ethiopian Renaissance Dam, which will be Africa's largest hydroelectric project when completed in 2022. It's upstream from the High Aswan and has the potential to restrict the flow of the Nile towards Egypt. Egypt is not happy. But compensating the losers is not always a priority for politicians. They're more often interested in the symbolism. You can see why. From the early Soviet Union's Dneprostroi to modern China's Three Gorges Dam, which vies with the Itaipu for the title of the world's largest power station, political leaders have wanted successful dams to stand testament to their grand strategic vision. Some believe the enduring bad reputation of the High Aswan dates from Cold War propaganda. When Egypt's President Nasser couldn't get backing for the dam from the United States, he turned to the Soviet Union and nationalised the Suez Canal to help pay for it. That led to the Suez Crisis. No wonder Western leaders didn't want Nasser to get a public relations boost. Dams reshape economies in complex ways. Many may be worth it overall only if the benefits can be equitably shared with those who lose out. But this messy reality is easy to overlook when dams are seen as symbols of national virility. When India's first Prime Minister Nehru spoke to villagers displaced by the colossal Hirukud Dam project in 1948, he may have spoken more plainly than he intended. If you are to suffer, you should suffer in the interest of the country. It is not clear anyone found that comforting.
SPEAKER_03: Norman Smith describes the Saard al-Kafara in his book, A History of Dams.
SPEAKER_06: For a full list of our sources, please see bbcworldservice.com slash 50 things.
SPEAKER_04: The Compass is the BBC World Service podcast that explores big ideas. We have a tendency
SPEAKER_00: in science when we talk about the intelligence of animals to go for things that we are good at. So we are good at language. If you have a talking ape, people are extremely impressed or a talking parrot for that matter. But other skills we don't care much about. And how those big ideas
SPEAKER_04: shape the world around us. Animals are more or less a symbol of an economic system that has a
SPEAKER_02: dead end. That it's all focused on production and consumption. Animals are suffering and we do not take care of each other anymore. The Compass podcast from the BBC World Service. She's an
SPEAKER_04: intelligent, social, autonomous being. She needs her freedom. Search for The Compass wherever you get your podcasts.
