village in georgia where warm water is now on tap thanks to the sun. in ecuador, entrepreneurs are developing ways to make shrimp farming more environmentally friendly. and we go to california to meet a woman who, despite having a job, can't afford her own four

walls. with a gdp of over $19 trillion, the u.s. was the world's strongest economy in 2017. it's a country where dishwashers can become millionaires -- according to the american dream, at least. but is that dream today little more than a myth? according to official figures, around 40 million americans now live in poverty. and at the same time, the cost of living keeps on rising. the average monthly rent in the u.s. is $1500. and in major urban centers, that number climbs to $2500. those who can't afford such rents often end up on the streets. last year, over half a million people in the u.s. were homeless. reporter: when night falls, ellen penney's car turns into her bedroom. everything she needs is folded

neatly away here in the back. she sleeps in her car almost every night, even though she has a full-time job. she works as a lecturer, teaching english literature at a state university. it's her dream job. she proudly completed her master's degree at age 50, but her studies landed her with nearly insurmountable debts. ellen: once i got in and found out how little i make and how much work it takes -- and i have a strong work ethic, i was raised that way. and now, being in a position living in the car? no, i'm not happy. no, i didn't think it was going to be like this. reporter: living in a car presents a number of challenges. ellen has to find public washrooms, places to charge her cell phone and laptop, and parking spaces she won't get chased away from.

she feels let down by society's attitude towards her. ellen: they don't want to know, they don't want to see. not their problem. that, that angers me, frustrates me, disappoints me in humanity in this area. and they don't know how well they have it. reporter: san francisco is a well-heeled metropolis. the city used to be a magnet for counter-culture, but that counter-culture has turned corporate. silicon valley is home to some of the world's richest tech companies. but not everyone in the bay area is living the dream. many people here are falling by the wayside, including the middle classes. extortionate rent prices are forcing professionals out to the cheaper, far away suburbs. some even live in motor homes, entire streets of them. these people have literally been kicked to the curb. among them is the roiz family, with three children and another

on the way. the mother has been cleaning other wealthier people's homes for 15 years. the family had to move out of their apartment three years ago. the monthly rent was $3000 for a two-bedroom apartment. they just couldn't afford it. delmi: we're staying here because my husband has a good job nearby. we can't move because we don't have any savings. what can we do without money? reporter: they improvise with the small space they have, barely getting by while the people they work for earn six-figure salaries, plus shares and bonuses. the enormous gap between supply and demand is driving prices up in the housing sector here, and normal earners don't stand a chance. lenny: no matter how fast you run, you always end up in the same place. and because our companies are doing so well, google's hiring, linkedin's hiring, intuit's hiring, symantec's hiring. all these companies are hiring,

they're hiring at a faster rate than we can get housing built, and get affordable housing built. reporter: ellen isn't alone. six years ago she married jim, who recently retired. but then he found out his pension wasn't enough to cover his rent. both of them sleep in their cars. jim is reaching the end of his tether. jim: this is not something that provides you with a lot of self worth and dignity. you appear ok, but inside it's eating at you. i've broken down i think two or three times now, where it just wears on you to the point you go into tears, because you're asking yourself, how could this happen to someone who's honest, hard-working, dedicated. and you know, i'm not the only one. i'm not the only one.

reporter: for real estate agents like gary herbert, the housing shortage has been a goldmine. gary: so here we have a two-bedroom, two-bath house, on an 11,000 square foot lot in central los altos. reporter: demand has caused property prices to skyrocket. this two-bedroom house is expected to sell for more than $3 million. gary: this house will probably be torn down and a new one built. reporter: so they're basically buying a lot for $3 million? gary: yes. it's a big, beautiful lot, it's in a great location, it's easy to build on, there's no trees in the way or things that can inhibit the building. so they can build their dream home here. reporter: and this is how the other half lives. ellen shows us where they keep their possessions that don't fit in the car. everything valuable or important is in storage, in hopes of better times. some things have too much

sentimental value to be discarded, like the christmas decorations that ellen inherited from her mother. ellen: my mom died in my arms when i was 21. that was back when i had a home. got to keep something, don't have them anymore. i don't have the farm. sorry. reporter: ellen is making notes for tomorrow's lecture. her car also has to serve as her workspace. the affordable housing crisis has been especially severe on the west coast of the u.s. california has the highest rate of unsheltered homelessness in the country. ellen: i've got to keep going, i don't have time to really be

afraid. if i do that, then i'll just become static. reporter: people like ellen are locked in a daily struggle for survival. here in the shadow of silicon valley, at the heart of america's digital revolution, people are becoming invisible. >> i am -- >> -- a global teen. justin: hi, my name is justin bosman. i live in hillbra neighborhood in johannesburg, and i'm 16 years old.

i normally go visit friends, but now they stay too far, so i'd rather stay at home. i mostly play chess at home. i listen to khalid's music at the moment. he's an r&b and rapper. his songs, at the moment, i feel i can relate to. one day when i grow up, i would like to be a lawyer. but at the moment, i'm rethinking that because i'm thinking of becoming an english teacher. because i see the inspiration in my teacher's eyes when she teaches me. i want to feel that way, i want to help people. because without teachers, do you

think the great lawyers of today would be living, the great doctors? no, they wouldn't be there without them. a day out with friends, playing chess, or walking around in the parks, having funny jokes. my fear is that, one day, we will go into world war because the way we're living at the moment isn't the best way you could live. we live to fight instead of living to love. host: mangrove forests are highly biodiverse ecosystems found in tropical and sub-tropical coastal areas and along river estuaries. in the 1980's, scientists estimated that mangroves covered a total area of 200,000 square kilometers worldwide. now, around half of them have

been destroyed. if deforestation continues at the current rate, experts fear that in 100 years the trees will have disappeared completely. they blame the growing global population and the booming shrimp industry. reporter: the southern coast of ecuador is dotted with countless shrimp farms. around two-thirds of the mangrove forests that once lined the shore here have been destroyed to make way for them. to make the animals grow quickly, the shrimp farmers feed them two to three times a day. wilian: you have to fertilize, and treat the water and the ground. then around 60% of the shrimp survive. that's a very good result. but for that, you need fertile ground and good water. reporter: shrimp need saltwater, so the ponds have to be filled with water from the sea that's replaced regularly.

the farms cause serious environmental damage. to prevent possible disease, the farmers give their shrimp heavy doses of prophylactic medication. when the pond water drains into the sea, it's taken up in the marine food chain. studies show aquaculture is increasing the worldwide danger of antibiotic resistance. wilian: the medications are in the food that the shrimp eat. it contains a wide range of different substances. but we only use antibiotics when the shrimp grow sick and the disease shows signs of spreading. reporter: in the last few decades, ecuador has become one of the world's largest producers of shrimp. ponds are harvested every three months, and business is booming. along with petroleum and bananas, the crustaceans have become one of the country's top exports. last year, just under 450,000 tons were sent abroad, bringing

in $3 billion. and exports are expected to expand this year. diesel-powered aeration systems help keep oxygen levels in the ponds high. exhaust from the generators pollutes the air. now, not far from the old ponds, shrimp farmers are testing a new method developed in singapore. in it, the ponds are placed inland rather than at the shore. that gives farmers much more control over conditions. the ponds are smaller, but yields are much higher. after 25 years as an agricultural engineer, guillermo pina andrase turned a chapter. now he's pursuing a new career as a shrimp farmer. guillermo: our breeding method is much healthier than traditional methods. you don't need nearly as many

antibiotics. and because of the roofs that cover the ponds, you can control temperatures better. also, because the water isn't changed, you have more control over pathogens. reporter: a pond like this yields around 80 to 100 shrimp per square meter of surface area, a lot more than traditional breeding methods. that's largely down to the fact that more creatures survive, and grow larger as well, significantly increasing their value on the hard-fought global market. guillermo: people who try them have told me that the consistency of the flesh is firmer, so it's better. and they say that the taste is exactly the same. reporter: and that, even though the shrimp are being raised in

freshwater rather than saltwater, an innovation that allows farms to be set up practically anywhere, rather than only along the coast. but it t the animals a while to get accustomed to the different conditions. guillermo: this is where we put them when they come out of the lab. depending on the salinity, they stay here five to eight days. then we take them out and we put them in this tank. it has lower salinity levels. they stay in there for another eight days. after that, we put them out in the pond. reporter: a modern system like this costs around 200,000 euros to set up. the water is reused again and again, and the system is powered by solar energy. guillermo pina andrase is still testing it out. and soon he'll be selling his first harvest of shrimp.

host: this week in our global ideas series, we're off to the caucasus. our reporter, maria lesser, headed to georgia to meet the resourceful residents of one small village. now they've begun using solar energy to heat water, which has a knock-on effect. it protects local forests. wate like she does every, nana rabanidze tcmorning.t the cow's udder has to be cleaned before milking. a little later, as well as the family's breakfast, she makes cheese.it requires. she can tell the cheese is ready when the consistency is just right. everything here runs like clockwor with no te for

breaks. nana: as a housewife i have a lot of work to d i clean, me the foodmilk the co. there's always something to do. reporter: nana gurabanidze is 60, and was a nurse for 30 years. she lives with her husband, son, daughter-in-law, and grandchildren. nana: i always need hot water, i'm glad we have this system. report: they receive solar-powered water heater from a local energy cooperative. nana: we saved up a bit of money and sold a few things. it was my husband who really wanted this. it's quite expensive, but it is manageable.

reporter: was he trying to make her daily work easier? nana: i think it was mainly about saving electricity. but i can't say for sure. when we had the wood stove he had to go out collecting firewood and make sure we had enough. so maybe that had a lot to do with it. reporter: the cheese is ready. nana gurabanidze is going to take it to the market. people here bring produce they grow or ke at homelike vetables, frt, herbs, and cheese. mrs. nana s barelynpacked befors the lot. depending on the type of cheese, she ys betweenne euro 50nd two euros 50 a kilo.

nana: you n't get mu. but you live ugally, yo get by. we try tget by oit. reporter: liza bachilava is also in charge of the housework in her home, plus the farm and the grandchildren. she ill heats ter the traditional y on wood-burning stove in the living room. she needs a lot of h water, and therefe a lot ofood. her annual wood supply costs between 200 and 240 ros. in georgia, average income is under 3500 euros a year. liza: we save money so we can afford the wood. but sadly, there are lot of families who don't manage. we're doing better than some. we can pay for firewood. the poor families can't.

reporter: the men collect wood from high up in the forests of the caucasus mountains. they're still allowed to fell trees here. gogita chikjladze is 27. he comes here regularly. gogita eimates thaeach and ery house his area nsumes about two to three truckloads of wood every year. gogita eimates thaeach and gogita: if we cut down trees eranywhere else we could cause rock slides, which are dangerous for the residents. reporter: the forest might seem lush, but deforestation is rife across georgia. the number of trees being cut has to be limited to ensure long-term sustainability. currently over 12 times that number is being felled.

the work of these two mechanics is helping to solve the problem. they're cutting solar panels. the mache dates ba to worldwar. they're part of the energy cooperative. the systems they produce here should help to reduce wood buing, andherefore cbon dioxide emissions. the cooperative has provided solar-powered water heaters to more than 100 homes in the village. marietta letodiani is a 39-year the system is being installed here today. marietta: local residents know about the hot water systems, and they know that banksre providg loans fothem.

weon't havto go fr door to doo. ople whore interted cometo us. providg loans fothem. repoer: marita has bnor to doo. usg the syem herse, and she's impressed. marietta: of course, i've had one at home for three years already. it's great. it saves money and makes the housework easier. reporter: nana gurabanidze is back from the market, and the r safter e children.law are at worno time for a break.e. nana: i'm 60 years old, and i think my life is almost over. i'd do anything to give my children and grandchildren a better future. i hope they have a better life. reporter: and hot water straight from the tap is a good place to start.

host: this week on global snack, we visit a very special fast-food joint in berlin. reporter: kreuzberg, berlin's melting pot, and traditionally, a bastion of subculture. it's also home to an exciting food scene. there's a lore to than kebab shops. now open for nine months, goldies has become a popular local haunt. its specialty is fries -- fries with a difference. vladislav: we fry them either in beef fat or peanut oil. guests can choose. if they order a vegetarian dish, they're done in peanut oil. if they order a meat dish, they get beef fat. regulars who eat meat get beef fat without asking. reporter: vladislav gachyn and

kajo hiesl hit on the idea of deluxe fries while training as chefs. the fact that their eatery se 14 different sauces isn't the only evidence that they learned their craft in starred restaurants. kajo: this is our peking duck. it's pulled duck. we marinate duck legs in salt and sugar for 12 hours to make the meat as juicy as possible. then we braise it in the oven. we turn the skin into a crumble and then we shred the meat, so there are no bones or fat. we serve it with a hoisin-plum mayonnaise. and we fry the crispy skin in fat. reporter: guests love it. goldies goes through a ton of potatoes a week. along with peking duck, its most

popular dish is fries with black truffle sauce. >> i'm dutch, so i have high standards when it comes to fries. i miss them in berlin. they're just aren't as good here. this is the only place where the fries are better than in holland or belgium. reporter: a portion costs between 5 and 10 euros. and of course, takeout is also an option. vladislav: we love chips, but it's not like we would kill for chips. we just wanted to fill a gap in the market. kajo: that's right. usually you just get chips on the side when you order a curry sausage or a burger. but we were thinking about things that berlin doesn't have, and we decided it was chips. reporter: and for the really diehard fry-fans, there's even video art devoted to these deep

as ever, we love hearing from you, so drop us a line, global3000@dw.com, and take a peek at our facebook page, dw global society. see you next time. till then, take care. ♪ [captioning performed by the national captioning institute, which is responsible for its caption content and accuracy.

narrator: on this episode of "earth focus," climate change is forcing people to migrate in search of food and shelter, altering traditional lifestyles across the globe. in tijuana, mexico, haitians fleeing devastation are building a neighborhood as their dreams of entering the united states dwindle. while in mongolia, the traditional herding lifestyle is threatened as drought forces a new generation to the capital in search of opportunities.