Algae power and flying robots: Welcome to the skyscraper of tomorrow Skyscrapers of the future will be serviced by flying robots, run on algae and react to inhabitants" moods. A new report has outlined how urban buildings could look in 2050, and each idea, however outlandish it may seem, is in development. Engineering giant Arup, responding to the pressure of an expected 75 per cent of a nine-billion strong global population living in cities within four decades, predicts buildings will no longer be "passive shells, but things that are much more reactive," with their own "brains," "nervous system" and "skin" that allow them to respond to changes in the environment around them and the people who live in them. Josef Hargrave, a consultant in the foresight and innovation team at Arup, a company that has worked on projects from the Pompidou Centre in Paris to the Shard and the Gherkin in London, has sketched out the skyscraper of the future in his report, "It's Alive." The "nervous system," for example, could do anything from responding to weather or a person's mood to reacting to how many people are in a room. Some "modules" that form the building-blocks of the skyscraper could be used for urban food-production sites housing meat, poultry, fish or vegetable farms. Green spaces inside the tower will "turn the concrete jungle into real jungles," Mr Hargrave said. Building facades will become super-complex, changing the way they look throughout the day as well as being environmentally-friendly, by using cement that can absorb carbon dioxide and paint that can harness solar energy. Much of the building's energy needs might be met by biofuel created by algae, while wind turbines could manufacture drinking water from humid air. The algae project is already being worked on by scientists in Berlin. Mr Hargrave's favourite development is the "flying drones that maintain and assemble the buildings." Already robotics experts have teamed up with architects to experiment - a fleet of drones recently built a six-metre tower out of foam bricks, working autonomously. The new buildings will react to changes in society. "I like the idea of new urban communities... remodelling them with more local working, less long-distance travelling, and buildings that offer green spaces," Mr Hargrave said.