of unrest in istanbul. >> there was a lot of back-and-forth fighting with protesters, lots of things, plod things moving through the air and ultimately, of course, the police won that battle. >> woodruff: paul solman reports on people working beyond retirement age, even into their hundreds, and whether having more older workers is a plus for the economy, social security and more. >> ifill: an accused boston mob boss has his day in court, we look at the trial of whitey bulger, charged with involvement in 19 murders carried out by the winter hill crime gang. >> woodruff: and we continue our "food for nine billion" series with a story from singapore. on one farm-owner's bid to get around the lack of open land by taking farming in a new direction. >> land here comes at a premium, forcing people to expand up rather than out. and it's not just office towers and apartment complexes that are reaching skyward: singapore now has one of the world's first commercial vertical farms. >> ifill: that's all ahead on tonight's "newshour." >> major funding for the pbs newshour has been provided by: >> i want to make things more secure. >> i want to treat more dogs. >> our business needs more cases. >> where do you want to take your business? >> i need help selling art. >> from broadband, to web hosting, to mobile apps, small business solutions from a.t.&t. can help get you there. we can show you how a.t.&t. solutions can help your business today. >> more than two years ago, the people of b.p. made a commitment to the gulf. and everyday since, we've worked hard to keep it. today, the beaches and gulf are open for everyone to enjoy. we shared what we've learned so that we can all produce energy more safely. b.p. is also committed to america. we support nearly 250,000 jobs and invest more here than anywhere else. we're working to fuel america for generations to come. our commitment has never been stronger. >> supported by the john d. and catherine t. macarthur foundation. committed to building a more just, verdant and peaceful world. more information at macfound.org >> and with the ongoing support of these institutions and foundations. and... >> this program was made possible by the corporation for public broadcasting. and by contributions to your pbs station from viewers like you. thank you. >> woodruff: for the first time, the man running the national security agency spoke publicly today about extensive surveillance of phone calls and online communications. he defended the efforts and said, "we're trying to protect americans." ray suarez begins our coverage. >> reporter: army general keith alexander came to a senate hearing to discuss cyber- security in general. but the questions quickly turned to surveillance. vermont democrat patrick leahy pressed him to tell what the n.s.a. has to show for its efforts. >> has the intelligence community kept track of how many times phone records obtained through section 215 of the patriot act were critical to the discovery and disruption of terrorist threats? >> i gave an approximate number to them in a classified. >> so what's the number of them... >> but it's dozens of terrorist events that these have helped prevent. >> reporter: others, including oregon democrat jeff merkley, wanted to know more. >> so here i have my verizon phone. my cell phone. what authorized investigation gave you the grounds for acquiring my cell phone data? >> you know i think on the legal standards and stuff, on this part here, i think we need to get department of justice and others, because it is a complex area. i think what we're doing to protect american citizens here is the right thing. our agency takes great pride in protecting this nation and our civil liberties and privacy. >> reporter: alexander said he's bothered by how edward snowden,- an intelligence contractor at n.s.a.-- could learn of the surveillance programs, and then leak them. snowden's last known whereabouts were hong kong. and today, he was heard from again. in an interview with the "south china morning post", he declared: "i am neither traitor nor hero. i'm an american." he insisted he would not flee. instead, he said, "my intention is to ask the courts and people of hong kong to decide my fate." many in congress have condemned snowden and defended the n.s.a.'s activities, which key committees monitored all along. others voiced new concern yesterday as they emerged from closed-door meetings with intelligence officials. democratic congressman brad sherman of california said he was surprised by the scope of the monitoring under the secret fisa court. >> i did not know a billion records a day were coming under the control of the federal executive branch. >> reporter: maryland democrat dutch ruppersberger said it's high time for a full-scale airing of the privacy-versus- security issue. >> congress needs to debate this issue and determine what tools we give to our intelligence community to protect us from terrorist attacks. >> reporter: lawmakers will get to ask more questions tomorrow, behind closed doors, when the house and senate receive separate briefings on the n.s.a.'s surveillance. >> ifill: we'll have more on american's attitudes on balancing privacy and security later in the broadcast; between now and then; calming the unrest in turkey; working beyond retirement age; a notorious alleged mobster goes on trial in boston and farming in a singapore high-rise. but first, with the other news of the day. here's kwame holman. >> holman: a colorado wildfire forced evacuations of more than 7,000 people today, as it burned out of control in record heat and high wind. officials said the big blaze may have destroyed 100 homes so far, with hundreds more in jeopardy, near colorado springs. as the flames spread, more than 900 prisoners had to be moved from a state prison. the fire is burning in an area near last year's waldo canyon fire that wiped out nearly 350 homes. forecasters are keeping an anxious watch on a huge storm system that could affect 75 million americans in 19 states, over the next two days. the national weather service issued its highest alert today for iowa, illinois, indiana, and ohio. the system could bring heavy thunderstorms, tornadoes and even a rare, straight-line wind storm known as a derecho. the u.s. senate wrangled today over how secure the mexican border has to be before immigration reform kicks in. republican charles grassley of iowa, called for full border control for six months, before anyone in the country illegally moves toward citizenship. democrats, including patrick leahy of vermont, objected. it was part of the debate on an immigration bill authored by the so-called "gang of eight" senators. >> the group of eight, say they're open to improving the bill. well, my amendment, now before the senate, does just that. my amendment improves the trigger that jump starts the legalization program. it ensures that the border is secure before one person gets legal status under this act. >> i will oppose efforts that impose unrealistic, excessively costly, overly rigid, inhumane or ineffective border security measures. and i will oppose efforts to modify the triggers in ways that could unduly delay or prevent the earned legalization path we've waited too long already. >> holman: currently the bill calls for improvements to the border fence and other triggers before immigrants are granted new status. in moscow, as many as 15,000 protesters marched today to denounce russian president putin. the demonstrators, including opposition leaders, criticized putin for authoritarian rule and demanded freedom for dissidents arrested at putin's inauguration. the turnout was far below the 100,000 who protested against putin before he won his third term as president last year. former south african president nelson mandela reportedly is responding better to medical treatment today. the 94-year-old mandela has been hospitalized five days with a recurring lung infection. south africa's current president jacob zuma shared news of the improvement in a parliamentary address. >> we are very happy with the progress that he is now making following a difficult few days. we appreciate the messages of support from all over the world. >> holman: mandela spent 27 years in prison under south africa's apartheid regime. in 1994, he became the country's first black president. a 10-year-old pennsylvania girl with cystic fibrosis received a lung transplant today from an adult donor. sarah murnaghan's case drew national attention when a federal judge last week ordered her placed on the adult transplant list, overruling hospital procedures. the judge also added an 11-year- old boy to the list. as more cars let drivers use on wall street, stocks tumbled again over renewed worries over whether the federal reserve will rein in its stimulus efforts. the dow jones industrial average dropped back under 15,000, losing 126 points to close at 14,995. the nasdaq fell 36 points to close at 3,400. those are some of the day's major stories. now, back to judy. >> woodruff: we return now to turkey and the protests against prime minister erdogan that have gripped the country. an uneasy calm held in taksim square at mid-morning in istanbul, riot police rested around a monument to modern turkey's founding father, kemal ataturk, and armored vehicles idled, their water cannons silent. but protesters insisted their resolve was unbroken. >> ( translated ): we do not want to withdraw or to go back one step. there were civil demands and we were all united without any political help from any party. here there is a civil resistance and we will not get back until our demands are fulfilled. >> woodruff: the daytime quiet was perhaps a product more of exhaustion than of any resolution to the near-two-week standoff. and it followed a violent night that left the square littered with debris. clashes between police and protesters raged through the night hours, with water cannon, tear gas fusillades. protesters threw rocks and chunks of sidewalk and launched fireworks at police. it was the most serious confrontation in the square since the sit-in began with environmentalists trying to preserve gezi park-- one thin slice of green space in sprawling, central istanbul. when police assaulted that initial gathering, other groups, with a more pronounced political agenda, joined in. since then, protests have spread to other cities. today, lawyers in the capital, ankara, gathered to decry heavy- handed treatment. >> ( translated ): oppression has been going on for months. they are doing it to their own people and in doing so, the government is exactly like the ones that they have been criticizing. >> woodruff: that's a veiled reference to the syrian regime of bashar al-assad, on turkey's southern border. turkish prime minister reccep tayyip erdogan has become a staunch supporter of syrian rebels seeking to bring down assad. but now the protests here have morphed into the most-serious challenge to erdogan's rule since he first won office ten years ago. turkey's economy, already the trouble has also laid bare long-simmering class and religious tensions, between secular, liberal groups on one side and erdogan and his ruling, islamist justice party on the other. erdogan has bristled at the challenge, seeking to crush the protests, and dismissing the throngs as outside agitators. he's also calling for his supporters to turn out in large numbers later this week. but turkey's other senior leader, president abdullah gul, struck a more conciliatory tone again today, near the black sea in turkey's north, after meeting with schoolchildren. >> ( translated ): i've said since the beginning: peaceful, non-violent demonstrations, displays of opinion, sharing of ideas, these are all democratic rights. and we're proud of that. >> woodruff: meanwhile, in back in ankara, erdogan met with a delegation of 11 activists today, but others in the streets said the group was not representative of the larger movement. and after that meeting came the announcement from erdogan's justice party that a referendum on the park's fate would be considered if the protestors finally leave. joining me now to discuss the protests, the government's reponse and what it all means, is scott peterson of the christian science monitor in istanbul. and soner cagaptay, director of the washington institute's turkish research program. we thank you both for being here let me start with you, scott peterson. the government came down really hard on these demonstrators last night. where do these things stand now? >> well, at the moment-- and, in fact, for most of the day today-- the police have been very, very relaxed. they've certainly been in control of this square. they opened it up this morning after a night full of violence. there was a lot of back-and-forth fighting with protesters, lots of things exploding, things moving through the air and ultimately, of course, the police won that battle and by dawn this morning there was traffic already moving around the square and we saw a very different sense from the police today. they looked very relaxed, had their helmets off, riot shields piled up, although we're not sure what may be happening tonight. some people are expecting there might be a push to try and clear that gezi park. >> woodruff: soner cagaptay, who are these people and what is driving them? >> they are secular middle-class turks, it's not the game of politics where you have islam versus secularism or islamist versus secularist. this is not an ideological protest movement, it's about quality of democracy in curty. this is people makingoutthe government's need to respect freedom of assembly and association. urban space-- hence the demonstrations over the park. it's a sign of a new turkey. turkey has become a wealthy society. the a.k.p. and its leader erdogan, thanks to their success it has become a majority of middle-class society. now they're making middle-class demands saying "we have a right to assembly and if the government is going to build a shopping mall they should ask for our opinion." >> woodruff: scott peterson, the government is saying there are terrorists among the demonstrators. have you seen the makeup of these protests change in the last few days. >> well, they definitely have made a lot of claims about who these protesters are but, in fact, really it's a broader group of turks than you'd expect. certainly those who are manning the front lines during some of the most violent protests during these last two weeks have been mostly young people, some of them have been football hooligans or others truly looking for trouble but i would say the vast majority of the people we've seen here cut across a much broader swath of turkish society. so you've got young people certainly university students but at the same time you've also got their parents who often are there. i've seen last night, for example, during some of the very heated exchanges when there was tear gas all over the place i saw one mother and quite older mother hand in hand with her daughter and they both had their gas masks on and were trying to make a point and we see this in a lot of different places here. so i think it's correct to recognize that really, you know, there are a lot of people who are here and trying to make their point unified really in kind of their anger at how prime minister erdogan has handled his own leadership, feeling that they're very, very much excluded and trying to use this event as a way of getting their voices out there. >> woodruff: soner cagaptay, what about erdogan's response? how do you explain it? >> the response has been heavy handed. obviously he did not reach out for a compromise. the demonstrators are saying the following. they're saying "you may have won the election but listen to us." and erdogan's response has been heavy handed. but today he reached out. there was a suggestion that there will be a referendum hold determine whether this park will be turned into a shopping mall. but i think overall he's trying to build his constituency which is is political right of the turkish spectrum but he will have a challenge which is that the turkish political left and liberals have found a voice that they can demonstrate, do so publicly. >> woodruff: scott peterson, again, do you sense more broadly among the turkish population the support for erdogan? prime minister erdogan says he has? >> well, there's no question that he's got a lot of support that really and probably as he says is 50% of the country. now, we also know, however, that there's some people who are within his own ruling a.k.p. party, there have also been islamists who have been out on the streets here who have been protesting not necessarily at his policies but at the way that the prime minister actually conducts himself and behaves himself and really is sometimes much more confrontational than they themselves would like to see. so there are a lot of things that are mixed up in this dynamic and in people's reaction. of course, no one here expected-- and, in fact, just yesterday the prime minister mentioned in parliament, he said "what did they expect? did they expect that we will kneel down before them?" that's the question he's asking and he's really couched this often in quite divisional and divisive terms but at the same time we've also gotten a sense in the last two days-- especially when he's been make manager speeches in a day, several speeches in a day-- that he almost has kind of started his presidential campaign for next year already and that if this dragged on for a few more days and he was able to point to the other as people who were connected to terrorists or otherwise vandals or marauders than that would only help to solidify his own base and that could only work to his favor. >> woodruff: soner cagaptay, just quickly, what do you expect next? >> what's going on is not a political landscape in turkey. half of the country supports the a.k.p., that's a constant. the other half does not support this party, that's now taking issue with the style of government and telling erdogan to not legislate on issues that infringes on people's liberties and rights such as recent legislation that limits the sale of alcohol, goes into issues of women's rights and people are upset. so we're going to see a new you are the any which the secular middle schrasz found a voice on the street and are going to continue to demonstrate whatever that next issue is and turkey will be unfortunately polarized for the next year between the supporters and the opponents of the government as a country that's almost split in the middle between two large political factions. >> woodruff: watching turkey closely, soner cagaptay, scott peterson, we thank you both. >> ifill: now, the last in our occasional series on america's aging workforce. "newshour" economics correspondent paul solman has reported on a factory where the average age is 74, the graying of academia, senior entrepreneurship and age discrimination. tonight, he considers how working longer could help the economy. it's all part of paul's ongoing reporting: "making sense of financial news." >> you're doing something useful, you're not just sitting and vegetating. >> reporter: at age 101 rosa finnegan is still punching in part-time at small manufacturer vita needle. by working into old age, finnegan and those like her are extending their useful lives and their retirement income. but might they also be a boon to the economy? how much are you paid? >> i don't think i'm allowed to say, am i? >> reporter: you're 100 years old, you can say whatever you want! the reason i asked: this year the gap between u.s. government spending and tax revenues is expected to be over $640 billion. threatening to widen the gap: 32 million americans reaching retirement age in the next 20 years slated to draw social security and medicare while paying zero taxes on income at all. are you slowing down? >> yes, definitely. as long as i don't come to a screeching halt i'll be lucky. >> reporter: but what if americans worked as long as rosa finnegan, whom we interviewed in december? finnegan was coy about her pay but whatever she's making, she's paying taxes: federal and state income, medicare and social security, which vita needle matches. >> i made my first surfboard in 1960, when i was about 12 years old. >> reporter: another older worker we interviewed recently, 66-year-old steve bane. he runs infinity boards, pays himself about $60,000 a year. his yearly tax tab: more than $18,000. and then there was mike grottola, 69, who became a business consultant after trying in vain to get a tech executive job like the one from which he was laid off at 65. >> that big six figure salary that was so great, da-da-da. but at 65, you're not going to make any headway doing that and it was a mistake. let me go on a path that will be way more productive. >> reporter: with his new business up and running, last year grottola paid close to $15,000 in total taxes on income. finally, 71-year-old george mason writing professor don gulear: >> i think this is my 47th year that i'm here. >> reporter: gulear paid about $35,000 in taxes, including his university's social security contribution. he has no plans to retire. >> last semester i had five students come up to me and say it was the best class they ever had, so apparently i'm still good for my students. >> reporter: overall 18% of americans 65 and older are now working and paying taxes, at least $120 billion a year, we figure, on average, a figure that doesn't include state income taxes. moreover, every extra percentage point of the workforce not retiring would mean at least another few billion dollars in revenues toward closing america's annual budget gap. >> it's good for the economy. >> reporter: university of southern california economist julie zissimopoulos thinks older people working longer is an unambiguous good. why? >> for the simple reason that it grows a labor force. how are we going to keep social security solvent? how are we going to keep uh medicare beneficiaries receiving the benefits that they have received in the past? in order to fund these, we need workers, we need people paying taxes. >> reporter: it's a problem economists have worried about for decades. as the population has aged the number of workers supporting retirees has dropped, a trend we reported on back in 1990. >> when social security began paying benefits, for example, payroll taxes were modest, since there were 159 american workers being taxed for every retiree. >> by the late 1940s, we reported back then, 42 workers for every social security recipient. by 1970, only four workers. and looking at the numbers these days, for 2012, for example, there were just 2.9 workers for every beneficiary. social security now pays out more in benefits than it receives in tax revenue. but according to eugene steuerle of the urban institute, if, instead of retiring, more and more people 65 and older continue to work, the picture could change dramatically. rather than just drawing from benefit programs, they'd be contributing to them. >> it's not just social security taxes and medicare taxes, the types of taxes we might think of as necessary to support programs for the elderly, but among the biggest gains for the government as a whole are with respect to income taxes. higher income taxes mean that its easier to support government programs without increasing tax rates. >> reporter: steuerle found that the social security taxes generated if the average american retired five years later than normal would make up better than half of the programs shortfall come 2045. if you factor in income tax revenue, the shortfall would be completely erased. boston colleges alisa manell says there's an even more direct economic benefit to working longer. >> it makes the pie bigger. you have more people out there, working with their capital to produce more stuff. so you get a bigger g.d.p. and everyone is better off. >> reporter: not every economist agrees, of course, boston university's larry kotlikoff. who writes about social security thinks the plusses of working longer are way overblown. >> only a very small share of people over 65 are going to continue to work under the best of circumstances, so it really can't matter much to the macro economy or to our fiscal problems. it's just not a big enough effect. >> reporter: so you don't think this is going to make that much of a difference? >> even if we had another 20% of people in their 60s continue to work through their 70s or 75 it just wouldn't add up to much. it's just not enough people earning enough money, paying enough taxes to matter much. >> reporter: what a surprise, economists disagree! but it's certainly true that many who want to stay in the workforce, simply cant due to poor health, a strenuous job, the need to care for a sick family member, so we just don't know how many will. but says gene steuerle the portion of older people continuing to work has been growing for years. >> the social security administration has consistently underestimated the extent to which older workers will work longer and constantly pushing up that projection. and as larger and larger shares of the population hit these older ages, someone has to produce the goods and services. >> reporter: and, says munnell, that would be a good thing for the older workers, considering that 55-64 year olds have an average of only $120,000 saved for retirement. >> $120,000 may sound like a lot but when you think about taking that out over a 20-30 year retirement you're talking about only a few hundred dollars per month. >> reporter: so you mean if you've saved as much as $120,000 in your late 50s, you're still facing relative poverty? >> people are not going to have very much money if they retire at 64. so my view is the single most important thing they can do is to work as long as they possibly can. >> reporter: marc freedman, the founder of encore.org, says there are major benefits to working longer for the workers themselves, and for the broader economy. >> it's an extraordinary opportunity for individuals to have another chance to do something important, but really for society which is discovering a continent of human resources that's really only comparable to the emergence of women in new roles 30, 40 years ago. now we wouldn't be able to contemplate being competitive globally without that talent pool and i think 20-30 years from now well feel the same way about all these people in their 60s and 70s who are continuing to do important work. >> reporter: a nice thought for the nearly eight million of us who are still working, past traditional retirement age. >> woodruff: our reporting on longer work lives continues online on a brand new site we're calling "new adventures for older workers." again, paul solman explains. >> our working longer website is designed to be an adventure in itself. you can see how you compare to your peers, whether you're planning to retire or work forever, see if you've saved enough for retirement. whether you're 22 or 72, we've got new data, new analysis, and not-so-new people, some of whom "newshour" viewers have met, like 101-year-old manufacturing worker rosa finnegan, or mannequin madness entrepreneur judi townsend, 55. and you'll meet others, like mike kemp, whose health may force him to quit before he'd planned to. at times, scary; at others, inspiring; often interactive; more often, surprising. it's all at our website. >> ifill: now, the long-awaited trial of an alleged mob boss, who once topped the f.b.i.'s most-wanted list gets underway in boston. james "whitey" bulger's day in court finally arrived, with federal prosecutors declaring he was at the center of murder and mayhem in boston for nearly 30 years. he's accused of extortion, racketeering and 19 murders. at the age of 83, he's now pleaded not guilty to all counts. bulger allegedly ran the violent winter hill gang in south boston, and at the same time, prosecutors say, he provided the f.b.i. with information on a rival gang. in 1994, he fled as he was about to be indicted, and managed to evade capture for 16 years. while he was being hunted, his former f.b.i. handler was convicted of tipping him off. >> have you seen this woman? >> ifill: in 2011, agents finally tracked bulger down through his longtime girlfriend, catherine greig, and he was arrested at this rent-controlled apartment in santa monica, california. his trial is expected to last three to four months. for more we turn to kevin cullen, reporter and columnist for the "boston globe," and co- author of the book, "whitey bulger: america's most wanted gangster and the manhunt that brought him to justice." he was in the courtroom today. he was in the courtroom today. this corruption trial that we are following now, kevin, are we talking about something that was individual in his alleged crimes or institutional. >> well, i think the corruption that's at the heart of this, gwen, is absolutely institutional. it's not just one rogue agent and one corrupt supervisor. it goes much deeper than that. and when -- there was a 15-month period in 1981 to 1983 or 1982 into 1983 in which whitey bulger and his criminal partner stephen "the rifle man" flemmi were implicated in four murders and there were discussions at the highest level at the j. edgar hoover building in washington. and at that level there was not a decision to turnbull jer and flemmi over to appropriate authorities. it was a decision to protect them. and it wasn't just a question of the f.b.i. looking the other way. in one very specific case involving the murder of a legitimate businessman roger wheeler in oklahoma, the f.b.i. in boston lied to their colleagues at the f.b.i. office in oklahoma about the whereabouts and the alibis of steve flemmi and whitey bulger. so the corruption at the heart of this goes to the highest levels of the f.b.i. >> ifill: so he was on the run for 16 years, he was found two years ago and the trial begins today. in your opinion the courtroom. give us a sense of the scene. >> well, i mean, it -- obviously it's a pretty subdued setting and, you know, you had three sets of spectators. they were people that were the victims of the family that were directly in back of the -- t prosecution table. then you had bulger's side which frankly, the only people that i saw that were close to whitey bulger was his brother jackie, his politician brother bill bull scer was not there. then you had the media on the other side. so there were three different groups. and brian kelly, the federal prosecutor, gave a very understated sort of "these are the facts, a ma'am" joe friday approach to the indictment against whitey bulger and just spelled it out in detail. but there was one very poignant moment during brian kelly's opening. toward the end of it he just showed -- he read the names of the 19 murder victims one by one pausing between each name while their photograph was shown on an overhead projector shown to the courtroom. and at the end of it, brian kelly said "that, ladies and gentlemen, is what this case is all about." >> ifill: so what is the defense? >> the defense is actually novel because jay carney, who is the lead attorney for whitey bulger, went in there and admitted in open court that his client was a criminal. he said his client was an extortionist, a book maker, and a very big surprise to us, he admitted his client was involved in drug dealing. >> ifill: which he never admitted before, right? >> no, no, no, no, he would never admit particularly that. that was a sore spot. and particularly his apologists in south boston and other places would always say that whitey would never touch drugs whereas the evidence was overwhelming that he made millions by shaking down drug dealers. but the evidence now even more specific that he was involved in actual movement of cocaine. so -- but jay carney, his lawyer admitted to all that. so in some respects they went in there in their opening statement and admitted it to a number of predicate acts that would find him guilty of racketeering, which he is charged. but what's clear by the defense, what jay carney outlined, is whitey bulger is not interested in getting acquitted of everything. he's interested in being acquitted of two very specific charges. someone that he was an informant for the f.b.i. carney said he never was. but the other thing that bulger really wants to change, he doesn't like this part of the narrative, is the killing of the women. of the 19 murders he's charged with killing two women and he cannot abide by that because he spent his entire criminal life creating a narrative of him and that narrative is that he's a good bad guy. he's a criminal with scruples and criminals with scruples do not murder defenseless young women. >> ifill: four to five months you're saying this is going to take. why so long? >> well, part of it is they're only going half days. he's 83 years old. judge denice casper, who is the presiding justice at this, agreed with the defense that it would be asking an awful lot of a man that's going to turn 84 in september to do long days. so right now it's going to be four days a week from 9:00 a.m. to 1:00 p.m. and then thursdays will be a long day that goes to 3:30 so that alone, gwen, would make this trial -- that really pushes it past -- it might have been able to be done in two and a half months but because of the accommodations they're making for mr. bulger it's going go long. i think that's conservative. i think it depends on the cross-examination. we could be doing this come the fall. this might be going on during the harvard-yale game. >> ifill: sounds to me like you'll be watching it fairly closely. kevin cullen, thank you so much. >> i'll be there. thanks, gwen. >> woodruff: next, we resume our week-long look at food security and how climate change is affecting what we produce and how we eat. tonight, special correspondent sam eaton reports from singapore, where the challenge of feeding a growing population is pushing the concept of urban farming to new heights. it's part of our series, "food for 9 billion," in partnership with public radio international's "the world," homeland productions, american public media's "marketplace" and the center for investigative reporting. >> reporter: singapore has one of the highest population densities on the planet. more than five million people crowd into this small wealthy island city. land here comes at a premium, forcing people to expand up rather than out. and it's not just office towers and apartment complexes that are reaching skyward. singapore now has one of the world's first commercial vertical farms. it's called skygreens. >> this is the framework. the greenhouse and also hold our vertical system. >> reporter: 50-year-old entrepreneur, jack ng, an engineer by training, is the farms owner and designer. translucent structures, nearly four stories tall line the property. on the inside automated towers of vegetables rotate like ferris wheels in slow motion between a nutrient-infused bath below and the sun above. ng says each tower is powered by a gravity-fed water wheel. it's an ancient technology with a modern twist. a low-power pump returns the ng says one of the biggest benefits of this closed loop, hydraulic system is how little energy it consumes. >> electricity we use in singapore, it's three dollars per month. >> reporter: that's three dollars a month to run this entire tower, or about the same amount of electricity used in single 60-watt lightbulb. >> you can try the lettuce. okay, it's fresh. >> reporter: eating local, freshly picked greens is a luxury in singapore. with just 250 acres of farmland left, the city grows only seven percent of the produce it consumes. that may be an extreme case, but it represents a looming problem facing cities all over the world, says columbia university ecologist, dickson despommier. >> we're going to reach a tipping point really soon where traditional ag can no longer provide enough food for the people living on the planet. >> reporter: despommier says producing enough food for the three and a half billion people living in cities today requires an amount of land twice the size of south america. >> now that would be okay if we could stabilize our population at seven billion. but that's not going to happen. >> reporter: despommier believes that 80% of the world's population will be living in cities by 2050, making today's challenges seem trivial by comparison. >> so the question arises, can we supply enough food for everybody on the planet including a growing urban population. and i think we can. and i think we can do it by empowering people in the cities to grow food right there. >> reporter: skygreens' vertical farm offers one example of how that may be possible, not just technically but also economically. the system is ten times more productive per square foot than conventional farming. it also takes a lot less water, labor and chemical inputs. doctor lee sing kong directs singapore's national institute of education. >> i think eventually urban factories for vegetable production would take place in place of electronic factories in singapore. >> reporter: but lee says visit any singapore restaurant and you can see just how far the country is from being self-sufficient. >> if you look at the plate of food on the table, say vegetables, it could come from china, it could come from the neighboring countries of indonesia or malaysia or it could come in terms of salad greens, as far off as the u.s. and the european countries like holland or australia. >> reporter: maintaining that supply of food from so many foreign sources is a monumental task. every night hundreds of trucks enter singapore from malaysia and beyond, unloading their cargo of fruit and vegetables at this central wholesale market. from here the food is loaded onto smaller trucks and delivered throughout the city before sunrise. more than 90% of the food in singapore's grocery stores like this one comes from foreign countries. that makes local, urban produce like skygreens a premium novelty for customers. but to some it's much more than that. it's an insurance policy. >> reporter: supermarkets buy food from dozens of other countries as a defense against climate-related disruptions in the global food chain. but the national institute of education's lee sing kong, says that even that may not be enough to guarantee a steady food supply in the future. >> we do anticipate that the need for our own production to a certain level of self- sufficiency. i think the government has set a target, initial target of 10% to 20% of our need and if we can achieve that i think there will be a great feat that we have attained. >> reporter: singapore recently invested $20 million in a fund to boost domestic food production through new farming technologies like skygreens. but lee says incentives alone aren't enough. first, he says, high rise farming needs to be cost competitive. >> whatever we produce in singapore must compete with the prices of vegetables coming in singapore. so that's why the government in singapore is now encouraging models of urban farming that can really not just increase productivity but also lowering cost of production. >> reporter: skygreens owner jack ng says he's confident he can compete. three years into his experiment, he says his operating costs are only a quarter of what it would cost to run a conventional farm. and since he's local, his transportation costs are also minimal, making his fresh lettuce and chinese cabbage price-competitive with mass- produced, cheap imports. but most importantly, ng says they taste better. he says the same day freshness of his greens is a real selling point. >> so far my customers keep on asking us, "can you produce more, can you supply more?" >> reporter: ng has raised $28 million in public and private money to more than quadruple his capacity over the next year and a half. and in fast rising singapore, that seems like a smart investment. >> ifill: you can find a photo essay about singapore's towering vegetable gardens on our website. tomorrow, we look at how california's dairy industry is changing global trade. >> woodruff: finally tonight, we look at a question getting more attention in the wake of the surveillance stories: just how much information we routinely disclose about ourselves online and our own attitudes about the use of that data. jeffrey brown has our conversation. >> brown: and for that, we're joined by viktor mayer- schoneberger is co-author of the new book-- "big data: a revolution that will transform how we live, work, and think." kashmir hill is a senior online editor and writes the technology and privacy column, "not-so private parts" at forbes.com and jules polonetsky is director of the future of privacy forum, a think tank that promotes responsible data practices. >> well, viktor mayer, i want to start with you. before we get to the n.s.a. explicitly, i want to describe briefly the world of big data you've been writing about. what does it mean? how and where does it affect all of us? >> well, big data is our ability to really see at a large scale what we couldn't see at a small scale. and big data is all around us. if we search online with google, that's big data. if we ask alps on our iphone, that's big data. the video recommendations on net flex, that's big data. if bing travel tells us whether or not a ticket price goes up or down most likely over the next couple of days, that's big data. but it goes beyond the internet companies. we see it when airlines that make predictive repair and maintenance on their jet engines or when inflation rates are being announced almost in realtime not by government officials but by a startup company out of boston that monitors online price data points. so big data is ally everywhere. >> brown: so kashmir hill, we've talked on the show several times about the privacy issue in the context of facebook, google, various times. how much do you think people are aware of this big data world that that we're talking about? >> i think people are thinking about this a lot these days and privacy has become something very interesting to people in part i think because they're on facebook and they're sharing so much information and everyone has a smart phone and they're downloading apps that are sharing a lot of information about them from where they are, their location information to who their contacts are. so i think people are thinking about it a lot. but a lot of people are also aware of the benefits of big data. so i think people are often giving up that information knowing that they're going to get something in return. so there's a lot to think about right now in terms of if the tradeoffs are worth it and when it's too private invasive for people. >> brown: jules polonetsky, pick up on that. there are pluses and minuses. have you seen an evolution in how much people are aware and responding to what's around them? >> people are clearly aware but they don't always think about in the terms of data or privacy. all they know is amazon recommended a book and it turns out it seems to be based on what other people are buying and they kind of like that. they like that netflix can recommend and make their queue easier and smarter. but when you sit back and say "well, do you like it that everybody knows everything about you?" well, that sounds scary. so i think the challenge is how do we get the benefits? how do we solve diseases because we're better able to analyze lots of health data? how do we figure out what schools are really working by analyzing what actually works for a particular student? all of those things are going to perhaps make our planet smarter the way i.b.m. starts argues, smarter planet. >> brown: in the best of all worlds. >> but each of those things can come with a big negative. whether people profile you, discriminate against you? have l the government predict that you're going to be a way that -- be a criminal in a way that frightens you. so we have to get this balance right or we're in for a lot of debates. >> brown: well, viktor mayer-schonberger, we see this polling data right afterward that at least suggests a pa majority of americans are relatively comfortable with what's going on. how do you fit that into the kinds of concerns we're talking about? >> well, i think we don't know all the facts yet and i think the american public is just making up its mind right now. a significant portion may be comfortable now but as more information becomes available that might shift. the situation is still fluid and i've seen a survey that said that about 40% of the people in the united states uncomfortable. what really this points towards is that this is early days in what we need to have is a public debate about the pros and cons, as jules said, and that public debate could be the positive outcome of that n.s.a. situation. >> brown: just to stay with you for a moment, you've been looking at this for many years. are you sanguine, are you concerned? are you coming out on one side or the other? >> i am quite concerned but i'm not so much concerned about the civilians aspect than about how big data can be abused for predictions, predictions about future behavior. and if we use these predictions to then punish people, to penalize them, not for what they have done but what they're only predicted to do, then we are on a slippery slope towards "minority report" and that keeps me up at night. >> brown: "minority report" meaning the old movie that showed data coming into our lives, right? kashmir, let me ask you: how much of this do you think is generational? it's often talked about younger people are coming up in a world where they just live on line and they're very comfortable giving out a lot of data. >> one thing that's been interesting to see that has plays out, there's all these different polls and some say that young people care less about privacy and others say they care more. but what's been interesting about what we're learning about the n.s.a. is some people are shocked by it but some people have been told for so long that everything we do is tracked, we're giving out all of this information and the way that we live today when we walk around with a smart phone tracking us all the time and these dossiers about ourselves on face fwhook it seems some people are just used to this and aren't as surprised but they thought it was happening already. so it's interesting kind of what happens in terms of expectation of privacy as you tell people over and over again they have no privacy and then when it's confirmed they're not surprised by it. >> brown: well, that's an interesting way of thinking about it, jules polonetsky. is there a difference when it's national security as opposed to amazon telling me what book i might want? >> the same solution, frankly, is needed in both these areas. >>, and that's transparn city. companies say "trust us, we want to sell you stuff, you have nothing to worry about." the government says "trust us, we want to catch terrorists." but this is too important to just trust. so we need transparency. we need to know that someone is watching the watchers. finally the civil liberties board has been appointed and they're going to be taking a look into this. the obama administration has a bunch of open cheap privacy officer roles that need to be filled at the department of justice, at homeland security. we need to know that if data is being collected for terrorism or if it's being collected to invent the next great new product that there are people scrutinizing-- humans, not just predicting who the next criminal is-- but scrutinizing and making sure that the risks are being minimized and avoided. >> brown: do you see any signs that the public is -- where things are going? publish pushing back against privacy concerns or getting more comfortable? >> i think we've been seeing -- you know, this is a great explosion but we've seen pushback when facebook has made moves that the public didn't like. when amazon has made moves. when apple's made moves. we haven't seen this giant uprising of people debating and calling congress but i think consumers in this day and age have the tools to make quick decisions and if companies aren't careful, they'll be making them. >> woodruff: just briefly from you viktor mayer-schonberger, do you see any beginnings of a pushback or people getting more comfortable? >> well, just a here is fact google and facebook and microsoft were so quickly reacting to this situation by announcing that they want the federal government to permit them to make public the numbers -- the number of times they had given access to government agencies shows that these companies really care about consumer trust and they care about losing that. they're afraid of losing that. and this shows to me that trust is brittle. and if it is not maintained, if it is not cared for, it may erode very quickly. >> brown: viktor mayer-schonberger, jules polonetsky and kashmir hill, thank you all three. >> ifill: again, the major developments of the day: the army general running the national security agency defended extensive surveillance of phone calls and online communications. and the c.i.a.'s deputy director, michael morell, announced he'll retire. he drew criticism for defending harsh interrogation techniques and for the response to the attack in benghazi, libya. >> woodruff: online, snowboarding on mars. kwame holman explains. >> holman: scientists have found dry ice can cut steep gullies across the martian landscape, creating something akin to ski slopes. watch that video on our science wednesday post. all that and more is on our website newshour.pbs.org. gwen? >> ifill: and that's the "newshour" for tonight. i'm gwen ifill >> woodruff: and i'm judy woodruff. we'll see you online and again here tomorrow evening. thank you and good night. >> major funding for the pbs newshour has been provided by: ♪ ♪ moving our economy for 160 years. bnsf, the engine that connects us. >> support also comes from carnegie corporation of new york, a foundation created to do what andrew carnegie called "real and permanent good." celebrating 100 years of philanthropy at carnegie.org. >> and with the ongoing support of these institutions and foundations. and... >> this program was made possible by the corporation for public broadcasting. and by contributions to your pbs station from viewers like you. thank you. captioning sponsored by macneil/lehrer productions captioned by media access group at wgbh access.wgbh.org