announcer: coming up on "21st century," today a special focus on climate change. india takes on air pollution; in the united states, changing houses to heal the planet; and in morocco, women sowing the seeds for a better future. [car horns honking] sunita narain: there is enough evidence acrososs the worlrld to show that t air pollution is a killer, , that therere is epidemiological studies to s shw what is the impact of air

pollution on your lungs, on your respiratory system. jyotsna pandit: i believe ththat it's up to the yoyounger generatition to think about thte future, ththink about what we''e gonna do w when all ththe resous are e being depleted. it startrted when i cocoughed a. i used t to cough in t the morn. i used to cougugh at night. i id to couough connunuously, andnd y mothther and father used to wake up w with me at night trtrying o hehelp me prevt t the coughihin, but nonothing realally helped.

narrator: : according g to a 207 uniteded nations report, ovevera million people die prematurely inin india each year bececause f toxic particles in the air, a 50% increase since 1995. jyotsna pandit is a 17-year-old studenent at delhi's prestigious sasanskrititi school.. pandit: so finally, we went to the doctor, and he told us that i have this condition. it's an allergy which h is aggravavatedy dust and other particulate pollutants in the air. narrator: last november as pollution levels spiked to their highest in 17 years, the govevernment shut down schools across the city. panditit: there was thisis peri, this 10-0--10-day peperiod in nonovember 2016 when thehere waa great smog that covevered entire dedelhi, and the pollutatant les were so hihigh that ththey justt off chartsts. i thoughght that e

i have a firsthand experience of what children go through when they're subjejected to o pollutd air, to dust partiticles, particiculate matter, why don''i take an initiative do to something for the environment? narrator: concerned that adults were not doing enough, jyotsna, along with two high-achieving schohool friendsds, decided d te her own initiative and entered a competition sponsored by the un, schools, a and industry to findd sosolutions to air polollution. on the national scale, india's biggest climimate challenge ar coal powower plants and heavyy industryry; road traraffic, especially diesel engines; and d the burning of trashsh and crop rididues, but sincnce ratifyining the unid nationons' pararis climatete ac, the governme h has made aa sisignificant t start, closing a major coalal pla in n delhi andd plannining to refufurbish other,

plananning the halve t n numbeof vehicles on ththe road and to tighteten emisonon standards b y 202020, and the governmentnt iso rereduce crop p burning..... but india's central dilemma remains how to couple climate action with reducing massive and widespread poverty. jairam ramesh: ultimately, you know, , people wanant jobs. pepe want projects.s. people want factorieies. i mean, those are e visible signs of progress, riright? narrator: former minister of the environment jairam ramesh says that many in india still believe that pollution is a price the country has to pay. ramesh: pollution is seen to be, you know, "ok. we cough a little"--[cough cough]--"you know, but that's something that we need to do or we have to do in order to industrialize and urbanize, but i think as public awareness incrcreases, as s civc

movements gather apace, i think a lot of governments will have to be sensitive to these issues. narrator: a sign of that new public awareness is visible on delhi's streets, where groups like help delhi breathe protest against what they see as the governmement's s slow and ineffective action on climate. narain: wewe he an urgent t need to addreress the issue of pollution. it is a public health emergency, and we need a sense of urgenency, and so my frustration today is, i don't see that urgency. narrrrator: sunita narain n is e direrector of f the centre foror science and d environment and a wewell-known c climate actctivi. narain: ththere is enough evevie across t the world to show thaht aiair pollutioion is a killer, t there is epidemiological studies to show what is ththe impact o f air pollution on your lulungs, n your respiratory system, on also now heart attatacks. narrator: as an individual,

jyototsna is doing all she can o improve e the environment around her anand her school. pandit: if we can't afford complex technologies, then we can at least plant trees bececae that's what they're doing. they're taking inin carbon dioxe and coconverting it into oxygen. narrator: but the task of purifying a whole country's air is truly d dauntining. [c[car horns h honking over the past year, car manufacturers in india sold nearly 30 million cars. in d delhi alonene, 10 million s traversed the city's streets last year... but the problems of big cities like delhi aren't just because of what happens in delhi.

dr. harminder sindhu r runs a non-profit focused on rural development. part of his work is to try and persuade farmers to not burn their rice paddy before planting t their next t crop--w. the smoke accocounts for one quarter of d delhi's pollution, but even though the e government isis promising a subsidydy for equipment that c can sow crops without burning rice, it's hard to persuade this farmer, pargat singh, to chchange his approach.

narrator: despite these struggles, former r environment mininister jairaram ramesh s stl sees s some posititive trends,st least the plunging cososts of solar energy and india''s huge commitment to dedevelop it. rameshsh: when i was ministeter, solar would costst about 20 rups a unit, , and today solar is costining less than 3 rupeeses a ununit. i mean, it is a a drama- nuclear cocosts are gogoing up.l coststs are going up, , but solr costs s are plummemeting, and di thinink thatat works to our advantage. that gets reflected in this commitmentnt that we hae madede that by 2030, we will h e 40% of our electricity from non-fossil-fuel sources. i don't think that's an unreasonable target, i mean, because already we are knocking onon 30%. narrator: and sunita naraiain, evenen as she calls for greater urgency, says that india is stilill setting g an example foe world on climamate change.

narain: at''s nonot geing ouou about dia and poution is the factct that we are begininning o act onon it, andnd i, therefore, feel that that''s the message that neeeeds to go o out to thee worlrld, that we a are serioioud we will find solutions, and those solutions will actually force the rest o othe world d to reinvent the way they do things. nanarrator: experts like sunita narain believe that the need to tackle air pollution could galvanize the country into taking on the even lararger problem of climate change asas india looks to meet its commitments under the paris climimate accord. back at the sanskriti i school, jyotsna pandndit and her classmates won a prize for designing a new air purifier. pandit: when the dust collects inside thehe filter bags, itit s a a thick barrrrier which h furr

improves t the efficieiency of e filtratition process. narratator: they b believe thaht actionons like t this can makeka smsmall but signgnificant and prpractical contributionon. pandit: i believe that it's up to the younger generation to thinink about ththe future, , tk about t what we'reonna d do when all l the resources are beining depleted. let's starart contributing. let's work together. it's about humanity. it's about conserving the earth. zack sempke: silently around us, all of our buildings are burning energy, and that is a big part of the climate problem. sloan ritchie: you kind of have one opportunity to really fix the energy c consumption of f te house, and you lock in that energy consumption for a hundred years.

loic chappoz: the passive housee movementnt is reallyly taking of across the norththeast and acros the united states. sempke: in the united states, our building are responsible for over 40% of carbon emissions. people aren't aware of this. you know, we think about our cars and other things as the things that are producing carbon emissions, but silently around us, all of our buildings--our homes, our office buildings, schools, hospital--they're all burning energy, and that is a big part of the climate problem. narrator: in the united states, local governments, busininesses, and indidividuals are working on inventive ways to curb carbon emissions in an often-overlooked place--our homes. zack sempke works at nk architects, a compmpany that specializes in a cutting-edge, energy-efficient building technology called passive house. sempke: i'm a very active

proponent, i guess, of passive house because it's s just clearo me that it's a veryry powerful y to transform buildings into a form o of climate action. in the clean-energy space, we're seeing solar panels and wind just plummet in cost and perfrformance rising really rapidly. we need to take a cue from that and harness science, essentially, to build d better buildings, and that's what passive house does. in order to meet the paris accord targets, we need to flatten n out emissions by 2020 and then see emissions reduced by half every dedecade afterwar. narrator: the paris climate agreement pledges s to limit the rise in global t temperature t o will below two degrees celsius. this ambitious goal will require a lot of cooperation, determination, and innovation. reducing energy use in buildings will plalay a major r part in t.

accordining to the u united nats environmental progogram, buildings s use about t 40% of globobal energy.y. anantonio guterres: the moral imperative for action is cleara. all of us--governments, businesses, consumers--will have to make changes. more than that, we will have to be the change. narrator: but how does t this trtranslate into real lilife? in seattle, washington, the ritchie family has built a passive e house for themselves using advanced technology to drastically cut their energy use. ritchie: it blocks the sun... i am an environmentalist. i was an engineer for about 10 years. i have been now in construction for about 10 or 11 years. i like to work with m my hands, and i like--i like construction a lot and wanted to take it to sort of another level toto really dodo something meaningful in the community. once you build a house, hopefully, it's gonna

last for a very long time, and you kind of have one opportunity to really fix the energy consumption of the house, and you lock in that energy consumption for a hundred years, and so, for me, that was a very compelling idea, so we decided to do this house that way. as you can see, this windowsill is probably deeper than most windowsills. this windowsill is probably about maybe 10, 11 inches deep, and that's because the entire wall is 16 inches thick, so this is a fairly deep wall assembly, much deeper than on a traditionalal house. narrrrator: the typical l housen the united states has exterior walls around 10 inches thick. ritchie: so it is an airtight house, and so we have continuous ventilation so we're delivering fresh air to the house all thehe time. narrator: a passivive house uses what's called a building envelope to heavily control the air that gets in and out of a building. that means a super thick layer of insulation everywhere.

ritchie: might be a little challenging to film in here. so this is the heat recovery ventilator. it's bringing in incoming fresh air from outside, and it's filtering that air, so this is delivering fresh air to the house continually. jennnnifer: having continuouslsy filtered fresh air takes the allergens out of the air, takes toxins out of the air, and i think the other part of it is, it's much more cocomfortable. like, in our old homes in the winter, you know, you would be running the heat pretty, you know, constantly, and you would be bundled up, and so for us, we can just have on a t-shirt and, you know, a pair of jeans and flip-flops in our housuse all yr round. narrator: on average, a passive house coststs around 3 3% to 5%e than a conventional building yet reduces energy use by up to 90%. in pennsylvania, the state's

housing agency has begun to incentivize passive house technology by giving builders a competitive edge in their affordable housing bids if they use it. laura nettleton: the biggest threat that we face is climate change. i've alwayays ved d our planet. i love nature. i love our world. i see it slowly being eroded away on a whole variety of fronts, and it alarms me. narrator: laura nettleton--an architect in pittsburgh, pennsylvania--has recently been focusing on restoring old buildings to passive house standards. nettleton: we were called in to mckeesport. this particular neighborhood, because of the reduction in steel production here, this community has kind of emptied out. this ymca turned into a homeless shelter, and there were 72 residedents living there, and the building was dilapidated and in poor condition. the ideal way to do

retrofits is to put a sweater on the outside ofof the building--d that sweater's made of insulation--and a new skin. the best way to think about it is, if i was asking you if y you wanted to stand outside on a 15-degree day all day and i offered you two pieces of clothing--i gave you a snowsuit that went over your head andnd d mittens s built in and went ovor your bootsts or if i offered yoa wool coat, and we both know which one you would tatake--you would take the snowsuit, and the snowsuit's designed to keep the cold air out, the same principle as the passive house. narrator: and the same protection from a cold climate provides energrgy conservation n a hot one, as well, reducing the need for air conditioning when temperatatures run high. nettleton: if you wrap your building in insulation carefully, then you can really conserve a lot of heat. we save 68% of the energy from the origininal facility, so ththat a hugege reduction in energy.

chappoz: the passisive house momovement is s really takakingf acroross the norortheast andnd s the united states. narrator: loic chappoz works onn conservation for multifamily buildings at nyserda, new york state's s energygy agency. chappoz: so the first piece of the equation for me is really reducing the energy we consume. once you reduce the energy you consume in anyny old building by 50%, 60%, 7070%, then it becomes much easieier and possible to mt that energy demandnd with renewable energy, be it solar, be it wind farms. what we are doing here in new york, we're trying to create a market to do very deep retrofits of existing buildings, learning a lot from a successful programam that has be implemented in the netherlands calllled energiesprong. narrator: : the energiesprprong program m takes an existsting buililding; puts a newew, well-i-insulateded shell around; and prprepares the roof f for sr panels. the energy-efficiency principles behehind it, like a super tight bubuilding enveleloe

and continually circulating fresh air, are similar to passive house. nyserda is currently studying how w to implemement a system le enenergiesprong or passive house on a scale large enough to execute statewide, and in an effort to extend the reach of this technology, the passive house institute of the united states has begun working with their counterparts in chinina ad japan n foster sustainable architecture on a global level. sempke: there's a real possibility that passive house could scale up quick enough to create a zero-net-cacarbon-built environmenent by 2050, which is what we e need to dodo. ritchie: i''m sure it was ththe same thing when the first houses had to be plumbed and have electricity. "oh, this is a stupid idea, and we're never gonna be able to-- it's too expensive," you know, right? i mean, it's the same thing. it's just, we're working on how to make the energy more sensible.

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