字幕表 動画を再生する 英語字幕をプリント Welcome to ExplainingTheFuture.com This time, I'm going to talk about future cities. A modern city can be thought of as gigantic creature that depends on resources fed to it from around the planet. However, in the future, such global supplies cannot be guaranteed. Cities have evolved into sophisticated cybernetic machines for keeping civilization alive. In some aspects, cities are therefore humanity's greatest achievement. Nevertheless, most cities would decend into anarchy in only 48 hours without a constant supply or food, energy and clean water. The Industrial Revolution saw a mass migration of people from the country side. Those who remained on the land then had to develop increasingly intensive farming methods to meet the food requirements of urban dwellers who could not feed themselves. Canals, railways and roads allowed the first industrial cities to be supplied with their daily nutrition. However, this resulted in a food chain dependant not just on the complex transport infrastruture, but also fuel and modern fertilizers. As a consequence, today, every calorie we eat also requires the consumption of 10 calories of oil. And within a few decades at best, this addiction of the modern city to petroleum will no longer be sustainable. There are, however, possibilities that the farm may migrate from the countryside. So called 'vertical farming' could involve multi-tiered city farms in future glass skyscrapers or pyramids. Such stacks of artificial fields would allow city dwellers to harvest crops all year round in areas without available land. They would also significantly reduce the energy required for food transportation, would lower crop loss associated with shipping and storage, could recycle their own water, and, within their sealed environments, may even use fewer pesticides. One vertical farm could potentially feed 50,000 people. However, even before the construction of such massive projects, laws could be passed requiring all new buildings in large cities to have at least some space dedicated to food production. For example, new apartment blocks could be required to include hydroponical lodgements on the roof. In addition to food, all cities currenly require significant natural resources to meet their raw energy needs. However, alternative technologies, including solar cells, rooftop wind turbines, ground source heat pumps, and methane power plants fuelled from domestic rubbish could see future cities becoming at least partly energy sufficient. Micro power generation may even extend to piezo-electric paving slabs to generate electricity from our footsteps, as well as hydraulic plates in road surfaces that would generate power as vehicles drive over them. In addition to producing at least some of their own food and power, future cities will also have to use fresh water far more efficiently. In part this is because treating and transporting fresh water is energy intensive. However, half of the world's population now live in countries where the water table is falling. Future cities will therefore need to capture and recycle water whenever this is possible. Future food, energy and water supplies are at best uncertain. The global population of city dwellers also continues to increase. Future cities will there have to become leaner and more self-sufficient. For more information, please see ExplainingTheFuture.com. But now that's it for another video. And remember, the future is in your hands.