i'm cnn's rachel crane. over the next half-hour we'll take you around the globe to cities preparing for the future, using technology that's change how we live. and force us to ask the question. is the city of tomorrow already here? the high cost energy, crime, choking air pollution, around the globe, these 21st century challenges are all being met with real innovation. in england, wind energy from the atlantic is powering london homes. police in los angeles are crunching big data to solve every day crime. and in seattle, one building is redefining what it means to be green. real solutions. but the challenges only grow bigger. according to the u.n., the world's population will reach 8.3 billion by 2030. in that same time greenhouse gases are expected to increase by 25%. the world's trash nearly doubled. while half the world will live in areas threatened by lack of water. what does that mean for cities? 60% of us will live in one bifrl 2050, 70%. the demand for clean air, water, energy, and yes, convenience, w

cnn's rachel crane takes a look at why black boxes are so crucial to an investigation after a plane goesfollowing a plane crash, the search for survivors always comes first. but just as important is the search for answers. the why and the how. often those answers are found in the black box. ♪ since the '60s, all commercial airplanes have been required to have one on board. now the name is a little misleading because they're actually orange. when we're talking about a black box, we're talking about two different boxes. one being the cockpit voice recorder, the other being the flight data recorder. together they weigh anywhere between 20 to 30 pounds. and they have to be crash proof. black boxes can survive just about anything. temperatures up to 2,000 figures fahrenheit for an hour. forces that 3,400 g's. that's 3,400 times the force of gravity. they're waterproof and they can save data for two years. and it's a lot of data. the cockpit voice recorder records the crew's conversation and background noise. by listening to the ambient sounds in the cockpit before a crash, experts can determi

i'm cnn's rachel crane. over the next half-hour we'll take you around the globe to cities that are preparing for the future using technologies that change how we live and force us to ask the question. is the city of tomorrow already here? the high cost of energy, crime, choking air pollution. around the globe these 21st century challenges are being met with real innovation. in england, wind energy from the atlantic is powering homes. police in los angeles are crunching big data to solve every day crime. and in seattle, one building is redefining what it means to be green. real solutions. but the challenges only grow bigger. according to the u.n., the world population will reach 8.3 billion by 2030. in the same time, greenhouse gases are expected to increase by 25%. the world's trash nearly doubled. while half the world will live in areas threatened by lack of water. what does that mean for cities? 60% of us will live in one. and by 2050, 70%. and the demand for clean air, water, energy, and yes, convenience,

cnn's rachel crane says london is already doing something about it. >> reporter: this is the london arrayit's the world's largest offshore wind farm. and this is what it helps power. the farm has 175 giant wind turbines, capable of generating enough electricity to power half a million homes. and it's white possibly the answer to london's growing energy needs. >> we expect about 900,000 tons of carbon dioxide that otherwise would have been put into the atmosphere. that is equivalent to 300,000 cars a year taken off the road. >> reporter: approximately 8.3 million people live here. and by 2031, that number is expected to climb to 10 million. a growing population that means a growing need for energy. london, one of the most historic cities in the world, knows that in order to keep up with future energy demands, they need to update and diversify their energy portfolio. >> it's really bad. how do we get to more cleaner future reliable energy source and that's really what the london array is about, is moving from that old, coal gas nuclear to more renewable and offshore winds. >> reporter: the

rachel crane has the story in today's "city of tomorrow." >> reporter: this is the london array.s largest offshore wind farm. and this is what it helps power. the farm has 175 giant wind turbines, capable of generating enough electricity to power half a million homes. and it's quite possibly the answer to london's growing energy needs. >> we expect about 900,000 tons of carbon dioxide to be saved a year that would have otherwise be put into the atmosphere. the equivalent of 300,000 cars a year taken off the road. >> reporter: approximately 8.3 million people live here. and by 2031, that number is expected to climb to 10 million. a growing population means a growing need for energy. london, one of the most historic cities in the world, knows that in order to keep up with future energy demands, they need to update and diversify their energy portfolio. >> it's really about how do we get to a cleaner future, reliable energy source? and that's really what the london array is about, is moving from that old, coal, gas nuclear to more renewable and offshore winds. >> reporter: the uk is

. >> catherine: rachel crane has the story. ---------------------------- >> reporter: this seems thetiment was and then there and done that. naso is setting its sights on a new target. the perfect castro it but let to catch on. and study it it is called the astronaut redirect mission. >> reporter: and robotic space mission to do sell nasa has come up with two options options a and option be which will break off a boulder for a much larger astroid. astronauts will then visit it using the same system that would transport humans to mars. the budget for this mission is approximately $1.2 billion. now why would the u.s. want to spend all this money to capture and store it? ast reoid >> reporter: how about what happened to the dinosaurs? we're thinking if we changed the airstrike we can chat would protect ourselves to another one collapsing into earth. >> reporter: so it may have been a giant leap for mankind but are we over the moon? all signs kind of 0.2 yes. point to yes >> reporter: people behaving badly not tonight at 8! >> reporter: one of the downside still living in the bay area, w

rachel crane gives us a preview of what is popping up. >> reporter: what if you could build the perfectnswer the questions what it would look like. in south korea 80s a smart city that uses magnetic tubes to transport trash. in awe bu dhabi it recycles 80% its water and replacing cars with electric pots. in japan, a 592 million dollar town will soon have smart street lights with motion sensors that create an invisible security network. each house will also be solar powered and the capability to stay off the grid for up to three days. many of these massive projects have been government-funded but increasingly money is coming from private organizations. fuji is powered by panasonic. the answer is mixed so far. 33,000 have moved into here and fuji sawwa will build only a hundred homes. they have recorded economic and scientists teaming to built a satellite campus. the hope is the masses will follow the brains. in each case, these custom built towns seem to be more laboratory than final project and each looking into the future to see what tomorrow's generation will need. one thing seems cle

i'm cnn's rachel crane. we'll take you around the globe to cities preparing for the future, usin