Farmers preparing a field for the planting season outside Wonsan, North Korea, in the shadow of a denuded hillside.

Inside North Korea's Environmental Collapse

<p>
 North Korea has been hiding something. Something beyond its prison camps, its nuclear facilities, its pervasive poverty, its aching famine, its lack of energy—electrical, fossil, or otherwise. What the hermit kingdom has been covering up is perhaps more fundamental than all of those: an environmental collapse so severe it could destabilize the entire country. Or at least, it was hiding it.
</p>
<p>
 Before ecologist Margaret Palmer visited North Korea, she didn’t know what to expect, but what she saw was beyond belief. From river’s edge to the tops of hills, the entire landscape was lifeless and barren. Villages were little more than hastily constructed shantytowns where residents wore camouflage netting, presumably in preparation for a foreign invasion they feared to be imminent. Emaciated looking farmers tilled the earth with plows pulled by oxen and trudged through half-frozen streams to collect nutrient-rich sediments for their fields. “We went to a national park where we saw maybe one or two birds, but other than that you don’t see any wildlife,” Palmer says.
</p>
<div class="related"></div>
<p>
 “The landscape is just basically dead,” adds Dutch soil scientist Joris van der Kamp. “It’s a difficult condition to live in, to survive.”
</p>
<p>
 Palmer and Van der Kamp were part of an international delegation of scientists invited by the government of North Korea and funded by the American Association for the Advancement of Science to attend a recent conference on ecological restoration in the long-isolated country. Through site visits and presentations by North Korean scientists they witnessed a barren landscape that is teetering on collapse, ravaged by decades of environmental degradation.
</p>
<p>
 “There are no branches of trees on the ground,” Van der Kamp says. “Everything is collected for food or fuel or animal food, almost nothing is left for the soil. We saw people mining clay material from the rivers in areas that had been polished by ice and warming their hands along the roadside by small fires from the small amounts of organic bits they could find.”
</p>
<figure class="richtext-image full-width">
<img alt="Farmers carrying supplies in North Korea" class="richtext-image full-width" src="https://www.pbs.org/wgbh/nova/media/images/dprk-wonsan-farmers.width-990_MXexNT2.jpg"/>
<figcaption>Farmers carrying supplies on foot in North Korea.
        
    </figcaption>
</figure>
<p>
 The country’s ecological ruin is partially responsible for the disastrous famine in the 1990s, when massive flooding washed away crops and destroyed stored grain. Today, it continues to undermine the country’s economy and threaten national stability. Yet as dire as the current situation is, it’s neither unprecedented nor irreversible. And the sooner environmental conditions can be improved, the better things will be for either the current regime or whoever is left to pick up the pieces.
</p>
<div class="ad"></div>
<h2>
 A Broken Landscape
</h2>
<p>
 For Palle Madsen, visiting North Korea was a bit like going back in time 150 years. “At that time the forest was nearly completely gone here in Denmark,” says Madsen, a forester at the Danish Center for Forest Landscape and Planning at the University of Copenhagen. “There wasn’t a totalitarian regime, but we had a similarly overexploited and degraded landscape. It influences the entire microclimate when you remove all of the trees,” Madsen says.
</p>
<p>
 During a three-day conference in Pyongyang, the nation’s capital, North Korean scientists spoke frankly to delegation members about problems related to deforestation and overexploitation of the soil. Mountains make up much of the country’s landscape leaving only 15 percent of land available for agriculture. Erosion, lack of nutrients, and acidification of the soil have had a devastating effect on crop yields, according to presentations by members of North Korea’s Academy of Sciences.
</p>
<p>
 North Korea’s isolation means detailed data on environmental conditions are hard to come by. However, a 2004 study by the Korea Environment Institute based in Seoul, South Korea, reports that forest cover in North Korea dropped by 17 percent from the 1970s to the late 1990s. Following the collapse of the Soviet Union, which provided oil to its communist ally at a discounted “friendship price,” oil imports dropped by 60 percent. Unsurprisingly, the use of firewood for heating more than doubled.
</p>
<figure class="richtext-image full-width">
<img alt="North Korean soldiers hauling firewood" class="richtext-image full-width" src="https://www.pbs.org/wgbh/nova/media/images/dprk-army-firewood.width-990_PYPvKLD.jpg"/>
<figcaption>North Korean soldiers hauling firewood back to base. Fuel for heating is scarce, so many rely on what wood they can find, including, apparently, the normally well-supplied Korean People's Army.
        
    </figcaption>
</figure>
<p>
 What resulted was an increasingly barren landscape. Even saplings are felled for fuel, stripping forests of their ability to regenerate. “They don’t have trees to hold the soil,” says Jinsuk Byun of Sookmyung Women’s University in Seoul. Byun was not a part of the recent delegation but has closely followed environmental conditions in the country. “When it rains the soil washes into the river, landslides occur and rivers flood. It triggers a really serious disaster.”
</p>
<figure class="richtext-image full-width">
<img alt="Damage from a flash flood near South Hamgyong, North Korea" class="richtext-image full-width" src="https://www.pbs.org/wgbh/nova/media/images/dprk-south-hamgyong-flash-flood-damage.width-990_rT019CQ.jpg"/>
<figcaption>Damage from a July 2012 flash flood near South Hamgyong, North Korea.
        
    </figcaption>
</figure>
<p>
 Conditions in North Korea appear to be little better now than during the famine of the 1990s. In Pyongyang, generally considered to be the most well-off city in the country, delegation members saw bonfires burning on apartment balconies at night, presumably lit by residents to keep warm. Other basic utilities were lacking, too. “I saw a woman lifting a bucket of water with a rope up ten stories to her apartment,” Palmer says.
</p>
<h2>
 Looming Famine?
</h2>
<p>
 Such glimpses of reality in North Korea are seldom seen but often rumored. “Guided tours are designed not to show you poverty,” says Barbara Demick, author of
 <i>
  Nothing To Envy
 </i>
 , a book about the lives of ordinary North Koreans who later defected. She says living conditions for the vast majority of those living in the country are likely much worse than what the researchers saw on their tour. “Up to 10 percent of the country perished from starvation in the 1990s. It’s a cold mountainous country, and there is very little arable land. North Korea is highly dependent on artificial fertilization and irrigation and when they ran out of electricity, everything spiraled downhill.”
</p>
<p>
 The lack of birds and other small animals noted by the scientists on their recent visit are a direct result of the famine in the 1990s, Demick says. “The frogs disappeared because everyone caught the frogs,” Demick says. “You see many fewer birds and small animals in North Korea than other countries. People living near the sea ate seaweed but that also ran out.” Ongoing food scarcity continues to take its toll.. A United Nations
 <a href="http://www.wfp.org/sites/default/files/DPRK%20Overview%20Of%20Needs%20And%20Assistance%202012.pdf">
  report
 </a>
 released in May 2012 estimated that two-thirds of North Korea’s 24 million people continue to suffer from chronic food shortages and malnutrition.
</p>
<p>
 Similar famines occurred throughout Europe in the 1800s due to over-exploitation of the land, says Madsen, the Danish forestry expert. What turned things around in Europe was the development of artificial fertilizers, the capacity to breed better crops, emigration to North America, and above all, land reform. “The feudal system of old Europe was still in existence,” he says. “It’s a different system in North Korea, much worse than the feudal system of Europe, but allowing farmers to own their own land is what changed things here.”
</p>
<figure class="richtext-image full-width">
<img alt="Red soil in North Korea" class="richtext-image full-width" src="https://www.pbs.org/wgbh/nova/media/images/dprk-red-soil.width-990_3QET38G.jpg"/>
<figcaption>The reddish hue of exposed soil in North Korea indicates a lack of organic matter, which is vital for farming.
        
    </figcaption>
</figure>
<p>
 Small-scale land reform has begun in North Korea, but such policy changes may be making matters worse instead of better. In recent years, the government has allowed individual households to cultivate their own private vegetable gardens. But that has lead to the cutting down and cultivation of forested hillsides.
</p>
<div class="newsletter"></div>
<p>
 “They are farming every inch of the land,” says delegation member Keith Bowers, president of Biohabitats, an ecological restoration consultancy based in Baltimore, Maryland. “From the rivers to the hillsides, there is no vegetation on this landscape that provides any of the types of ecosystem services in terms of stabilizing soils, filtering air, attenuating flood flows, or controlling against erosion.” Flooding in North Korea left more than 212,000 people homeless last year according to recent news reports. “You have whole towns being buried in mud because they’ve terraced around the town,” Demick says.
</p>
<h2>
 Costs of Reunification
</h2>
<p>
 North Korean scientists told the delegates that they would like to reforest hillsides with trees, including the Japanese chestnut, black chokeberry, and Korean pine, that could both stabilize the soil and provide edible fruits and seeds. But funding for such reforestation appears tight. During their week-long visit the foreign scientists were taken to a tree nursery that is part of the country’s current reforestation effort. The automated potting machinery was inoperable either due to a lack of fuel or spare parts, delegates report, and its greenhouse stood empty. Even if the nurseries were running at full capacity, North Korea would still have a long road ahead of it. Bowers estimates that reforesting even half the country would cost around $46 billion, an amount that exceeds the nation’s annual gross domestic product by $6 billion.
</p>
<p>
 Despite the bleak outlook, many in South Korea view reunification with the north and absorbing the costs of retooling the country as inevitable. Estimates for the cost of reunification run from the hundreds of billions to trillions of dollars. Byun, of Sookmyung Women’s University in Seoul, has studied the German reunification as a possible model for Korea. In the 1990s, Germany spent the equivalent of approximately $450 billion in today’s dollars to reduce air and water pollution from factories, waste treatment systems, and inefficient power plants, Byun says.
</p>
<figure class="richtext-image full-width">
<img alt="Fertilizer factory in North Korea" class="richtext-image full-width" src="https://www.pbs.org/wgbh/nova/media/images/dprk-fertilizer-factory.width-990_ewycltO.jpg"/>
<figcaption>A woman operates a machine inside a fertilizer plant in North Korea.
        
    </figcaption>
</figure>
<p>
 But reunifying Korea would be a more daunting challenge, in part because of the heavily depleted soils. North Korean farmers are heavily reliant on nitrogen-based fertilizers, which in certain formulations can paradoxically drain the soil of nutrients. “It’s a very unbalanced fertilizer, lacking in magnesium, calcium, potassium, and phosphorus,” says Dutch soil scientist Van der Kamp of the fertilizer predominantly used in North Korea. “When you don’t replace those minerals you basically mine the soil for these other nutrients, so the soils in general are very acidic, with very low organic matter content and low microbial activity.”
</p>
<p>
 In 2012 the United Nations planned to distribute 2,000 metric tons of fertilizer containing each of the above-mentioned minerals to 260 collective farms as part of a $14 million agricultural aid package. But that aid is likely a drop in the bucket in terms of what is needed.
</p>
<h2>
 Hope For Collaboration
</h2>
<p>
 Rather, delegation members would like to see ongoing collaborations with the scientists they met during their trip. The idea is that a more informed scientific community in North Korea could help the country recover from its environmental collapse in a more sustainable fashion, one not reliant on infusions of aid.
</p>
<p>
 Bowers, of U.S. company Biohabitat, is working with the Society of Ecological Restoration to set up a chapter in China to exchange technological information with North Korean scientists. “If we are looking at any kind of regime change in next 25 to 40 years in North Korea, I think that doing whatever we can from an ecology restoration perspective will only enhance people’s ability to effect a positive regime change,” he says. Madsen, the Danish soil scientist, is currently looking for funding to host North Korean scientists to study in Europe.
</p>
<p>
 “It was pretty hard to have good interactions with our colleagues there, but you could feel some of the people were both smart, and you felt they really wanted increased cooperation and interaction with us,” Madsen says. “It’s encouraging to proceed to try to raise some funding to do something for them. We can only hope changes will happen in that country, good changes in the near future, so we can have something to build on with these colleagues when it does.”
</p>
<p>
 Photo of flood damage courtesy
 <a href="http://www.flickr.com/photos/69583224@N05/8163462018/">
  EU Humanitarian Aid and Civil Protection
 </a>
 (CC-BY-SA).
</p>
<p>
 All other photos courtesy
 <a href="http://www.flickr.com/photos/josephferris76/">
  Joseph A Ferris III
 </a>
 (CC-BY-NC-ND).
</p>

<p>Scientists who recently visited the hermit nation report the situation is dire.</p>

"A thief with knowledge of my social security number, address, birthdate, and mother’s maiden name succeeded in changing the contact information associated with my credit card," says NOVA Next contributor Phil McKenna.

My Identity Was Stolen. Here’s How They Did It

<p>
 I recently received a call that I’d hoped would never come. My bank informed me that a thief with knowledge of my social security number, address, birthdate, and mother’s maiden name had succeeded in changing the contact information associated with my credit card. The representative I spoke with told me we were dealing with a professional identity thief and that I should assume all of my personal information had been compromised.
</p>
<p>
 The representative continued, instructing me on what I should do immediately to try to control the damage. I tried taking notes but I was reeling. Life as I knew it, or so I told myself, would never be the same.
</p>
<p>
 Each year 13 million Americans, or 5% of the entire U.S. adult population, are victims of identity theft. Fraudulent transactions, including purchases made on existing credit cards, opening new lines of credit, and wiring money from victims’ bank accounts, cost financial institutions and individuals more than $20 billion each year, according to a recent study by financial analysts at Javelin Strategy &amp; Research. But how are identities stolen, how do banks like mine detect fraudulent use, and what, if anything, can we do to protect ourselves?
</p>
<h2>
 A Numbers Game
</h2>
<p>
 Try to guess an individual’s social security number and you’ll quickly realize that the nine-digit code provides the apparent anonymity of roughly 1 billion different number combinations. It’s enough to keep a den of thieves guessing from here to eternity, right? Not so says Alessandro Acquisti, professor of information technology and public policy at Carnegie Mellon University.
</p>
<p>
 In 2009, Acquisti showed that, with some basic demographic information and a general understanding of how the federal government assigns social security numbers, miscreants could predict individuals’ numbers with an alarmingly high degree of accuracy.
</p>
<div class="ad"></div>
<p>
 Combing through millions of publicly available records of deceased individuals’ social security numbers, Acquisti and his colleagues were able to reconstruct how such numbers are assigned. Given an individual’s birthdate and the state they were born in, the researchers could, in some cases, predict the first five digits of an individual’s social security number with more than 90% accuracy.
</p>
<div class="pullquote">
<p>
 “Thieves are not going after one identity but thousands or millions of them.”
</p>
</div>
<p>
 All of this assumes that a thief knows the date and location of your birth, facts which some of your friends may not even know. But chances are this information is hiding in plain sight. Using a webcam and commercially available image recognition software, Acquisti’s team was able to identify by name 30% of students on a North American college campus simply by taking their picture and matching it to a database of publically available images downloaded from Facebook. In many cases the Facebook accounts provided the dates and locations of students’ births. Using this information, the team could then predict the first five digits of a student’s social security numbers in four attempts with 28% accuracy.
</p>
<p>
 Guessing the remaining four digits is relatively easy. “If you assume a brute force attack where you try combinations of one thousand different social security numbers, then the probability of successfully getting the right number for certain states and years of birth can be disturbingly high,” Acquisti says. “You can start with something as anonymous as a face in a crowd and end up with very sensitive information about that person.”
</p>
<figure class="richtext-image full-width">
<img alt="" class="richtext-image full-width" src="https://www.pbs.org/wgbh/nova/media/images/credit-card.width-990_W7iaLiH.jpg"/>
<figcaption>ID thieves have gone well beyond nabbing old credit cards from your trash.
        
    </figcaption>
</figure>
<p>
 Acquisti’s research offers a proof of concept, though it’s unclear whether identity thieves actually take such a circuitous route to acquire information. Easier targets are the data centers of financial institutions and credit bureaus that aggregate consumer information.
</p>
<p>
 Last month, online security expert Brian Krebs revealed that an underground identity theft service which illegally sold Social Security numbers had obtained much of its data by conning Experian, one of the three major credit bureaus, into selling it to them. “Secured databases are a much more concentrated target,” says Cormac Herley, a security expert with Microsoft Research. “Thieves are not going after one identity but thousands or millions of them.”
</p>
<h2>
 A Call From Somewhere
</h2>
<p>
 Once an individual’s identity has been stolen, thieves, as I recently discovered, often target call centers. “There are three ways to rob a bank,” says Vijay Balasubramaniyan, CEO of Pindrop Security. “You can walk in with guns, you can hack into their online systems, or you can call in using a phone. Fraudsters always move to the weakest link, and the phone channel has quickly become the weakest link.”
</p>
<p>
 What makes phones weak, Balasubramaniyan says, is a fraudster’s ability to manipulate individuals on the other end. “A computer is emotionless,” he points out. “It won’t react to you differently based on what you say. But if you have a human on the other end, you can start figuring out what their weaknesses are and start using that to your benefit.”
</p>
<div class="related"></div>
<p>
 Balasubramaniyan gives examples of two highly successful types of thieves his company is monitoring. One begins shouting when he doesn’t get the information he wants. He claims to have been a customer for years and threatens to report the representative to his or her supervisor if he or she don’t provide the information he seeks. Another, he says, “kills with kindness,” calling representatives “Sir” or “Madam” and complementing female representatives on the sound of their voice.
</p>
<p>
 In the past, many such attempts were thwarted when the accent of a foreign fraudster gave them away. “What if I’m a Russian hacker and I’ve stolen a US credit card?” asks Daniel Cohen, a cybersecurity strategist with RSA Security LLC. “If I call a call center, they will pick up on my accent.” RSA has seen a growing trend in recent years of underground, online marketplaces that provide identity thieves with “professional callers” who mimic the identity theft victim’s gender, age and accent. “Say I’ve stolen someone’s identity from Mississippi, I could then ask for someone with a southern accent—it’s that developed,” Cohen says.
</p>
<p>
 To prevent such call center fraud, financial institutions rely on something known as knowledge based authentication or KBA. Long the gold standard for call center security, KBA is a series of questions and answers related to things like prior residences and financial information that only the consumer should know.
</p>
<p>
 Depending on how far back the questions go, however, consumers often don’t recall the correct answers. In fact, identity thieves who obtain an individual’s credit information can often answer the questions better than the victim they are impersonating.
</p>
<figure class="richtext-image full-width">
<img alt="" class="richtext-image full-width" src="https://www.pbs.org/wgbh/nova/media/images/usa-call-service.width-990_cyKBHFG.jpg"/>
<figcaption>Black market sites offer services that help thieves profit from stolen identities, including making calls to banks, stores, and more by people with native accents.
        
    </figcaption>
</figure>
<p>
 If fraudsters gain access to an individual’s KBA information, as likely occurred in my case, the consequences can be far worse than simply having one’s credit card information or social security number compromised. “It’s pretty much the worst thing that can happen to you from a financial data perspective,” says Avivah Litan an analyst with information technology firm Gartner, Inc.
</p>
<p>
 It’s possible that the thief had obtained my KBA information through a massive breach of KBA data uncovered on September 25 by Krebs, the security expert who revealed the recent breach at Experian. He found that hackers had entered computer servers at LexisNexis, one of the largest providers of KBA information to financial institutions. Hackers placed a “tiny unauthorized program called ‘nbc.exe’ on the company’s servers,” Krebs writes, likely placed there either by exploiting a weakness in the servers’ configuration or through a malicious email. The program was designed to open an encrypted channel of communication between LexisNexis’s internal computers and botnets, private computers infected with malicious software, that were controlled over the internet by the identity thieves. It’s unclear what data the thieves gained from the breach, though they may have acquired the KBA data of millions of Americans. “They have always been compromised,” Litan says of KBA data, “but now they are massively compromised.”
</p>
<div class="pullquote">
<p>
 “I have half a dozen apps on my smartphone that can spoof your number.”
</p>
</div>
<p>
 To fill the void of compromised KBA data, banks have started to rely on something known as “phoneprinting,” or the ability to verify the origin of a call. Such verification is now needed because the profusion of online and mobile phone technology in recent years has made it increasingly difficult to tell where a call is really coming from. Thieves use this to add another layer of credibility to their fraud, making it seem as though a call was originated from your number even if the caller is halfway around the world.
</p>
<p>
 “I have half a dozen apps on my smartphone that can spoof your number,” Pindrop’s Balasubramaniyan tells me when at a recent conference. To prove it, he opens an app called callerID Faker. Before I know it, the caller ID on my phone tells me I have an incoming call from my own office number.
</p>
<p>
 Balasubramaniyan has these apps on his phone for a good reason—his company offers call centers a way to verify the source of a call. By analyzing different aspects of the sound quality in a call, Pindrop’s software can quickly determine whether the call originates from a cell phone in Cincinnati or from a Skype call in Siberia. “Imagine 15 seconds into a call, your bank gets an alert saying this is not Phil McKenna,” Balasubramaniyan says.
</p>
<p>
 Pindrop’s software analyzes 147 different aspect of sound quality. It then creates a database of unique “phoneprints” for calls made from different locations using different networks and phone types.
</p>
<figure class="richtext-image full-width">
<img alt="" class="richtext-image full-width" src="https://www.pbs.org/wgbh/nova/media/images/pindrop-analysis.width-990_VYQque8.jpg"/>
<figcaption>A Pindrop analysis of calls in a string of identity theft cases revealed the top 200 numbers connected to the thief's actual phone number (middle).
        
    </figcaption>
</figure>
<p>
 For example, Voice Over Internet Protocol (VoIP) calls such as those made on Skype contain something known as packet loss, or small breaks in the audio signal as a result of how the digital information is transmitted across these networks. The breaks are only milliseconds long, too short to be detected by a human ear, but contain a wealth of information. “I can look at the length of the break and tell you which company—Skype, Google Voice, or magicJack—the caller is using,” Balasubramaniyan says.
</p>
<p>
 Pindrop can also identify which network a caller is using by the background noise. Prior to the digitization of phone networks, calls made on analog telecommunication systems all broadcast a slight hiss that let you know the line was live on other end. When phone companies moved to digital transmission, there was no ambient noise. To ease the transition for users, companies recreated it, calling it “comfort noise.” “Each network did it in a different way, so it allows us to identify the network by the characteristics of their comfort noise,” Balasubramaniyan says.
</p>
<p>
 The various measures Pindrop uses allows them to correctly identify the provenance of a call, including phone type, network used, and rough geographic location, with over 90% accuracy.
</p>
<p>
 The company recently exposed a fraudster in Eastern Europe who had been using stolen KBA information. Once Pindrop’s software revealed the identity thief wasn’t who he claimed to be, it was obvious he was using stolen information. “When he was asked ‘what is your mother’s maiden name,’ we could actually hear him flipping through his notes,” Balasubramaniyan says.
</p>
<h2>
 What Can You Do?
</h2>
<p>
 For every breach in security new technologies emerge to try to prevent fraud, technologies that in turn will likely be thwarted at some point in the future. It’s a seemingly endless arms race between financial institutions and identity thieves. Still, I can’t help feeling like the recent theft of my information was somehow my fault.
</p>
<p>
 Not that I hadn’t taken precautions. I was careful with my personal information. I shredded documents and used strong online passwords. I didn’t fall for obvious phishing scams like pleas from wealthy Nigerians seeking to transfer large sums of money. But perhaps I should have changed passwords more frequently, added additional verification measures, or shared less on social media.
</p>
<p>
 Vern Paxson, a computer security expert at the University of California, Berkeley, absolves me of any such guilt. “Not only is there is nothing you did wrong but probably nothing you could have done differently,” he says. The problem, he says, is massive breaches at data centers like the recent ones by Experian and LexisNexis. Professional identity thieves don’t have time to weed through individuals—they’d rather exploit the richest resource, the central databases.
</p>
<p>
 No system is perfectly secure, but there are relatively easy steps that financial institutions could take now that would help prevent such breaches from occurring. Simply requiring organizations to establish security policies on how they safeguard consumer information would go a long way, says David Thaw, a professor at the University of Connecticut School of Law. In a recent study of health care and financial industries, Thaw found that institutions that had such policies were four times better at preventing security breaches than those that didn’t.
</p>
<div class="pullquote">
<p>
 “Fraud is as old as our species.”
</p>
</div>
<p>
 Acquisti, who showed it is possible to predict social security numbers, suggests we do away with the numbers entirely. The problem, he says, is that they are used for both identification and verification. It’s the equivalent of giving out your phone number to people so they can call you and then using that same number as the pass code for your voicemail. “No sane person would do that,” he says.
</p>
<p>
 Still, Acquisti concedes that gutting social security numbers may be prohibitively expensive. “As a whole, these costs, borne by different parties from identity theft, may be less than changing to an entirely new system,” he says. And even if we did change systems, it’s unlikely that the replacement would succeed in stopping identity theft for very long. “Fraud is as old as our species,” says Bruce Schneier, a security expert at the Berkman Center for Internet and Society at Harvard University. “The crime rate will never be zero in society. The trick is to make it manageable.”
</p>
<p>
 Schneier dismisses the severity of recent data center breaches, saying similar events have occurred on a regular basis for years. The key metric, he says, is how quickly identity theft is identified and corrected after it occurs. “A few years ago it was an absolute disaster,” Schneier says, adding that if my identity had been stolen at that time, I may well have been out $50,000 and spent years restoring my credit. In my case, my credit card company thwarted my identity thieves before they made a single charge.
</p>
<p>
 I did, however, lose several days of my life trying to shore up my compromised identity. After getting off the phone with my credit card company, I alerted the three major credit bureaus of the theft and reviewed my credit report to rule out any further damage. I then called every financial institution that I have an account with to set up a new, unique verbal password that they will ask me each time I call. Two banks required that I visit one of their local branches to set up the password in person. Another institution initially failed to set up my new password correctly. They continued to ask only for my social security number and mother’s maiden name until I escalated my case to a call center supervisor.
</p>
<div class="newsletter"></div>
<p>
 After setting up these initial protections, I then submitted an affidavit to the Federal Trade Commission and visited my local police station to fill out a report. The latter allowed me to put a five-year freeze on my credit report with all three credit bureaus. I’ll have to jump through some additional hoops the next time I want a new credit card, but the freeze should make it much harder for a thief to open a new line of credit in my name.
</p>
<p>
 The time that millions of identity theft victims like me spend recovering from such cases each year isn’t insignificant. Microsoft’s Herley estimates that the time US consumers lose each year to simply maintaining existing passwords and other security measures runs in the billions of dollars.
</p>
<p>
 Yet, as inconvenient as it was, Schneier says my experience is, in fact, proof that the system works. “They caught it before anything bad happened. What more do you want?”
</p>
<p>
 Photo credits: Laura Ellis,
 <a href="http://www.flickr.com/photos/barsen/3714941137/">
  barsen/Flickr (CC-BY-NC)
 </a>
 and Pindrop Security
</p>

<p>Thieves employ sophisticated techniques to steal identities, from phone number spoofing to database hacking.</p>

Melting one pound of ice takes 144 times more energy than raising the temperature of one pound of water 1˚ F.

Melting to Keep Cool

<p>
 As the afternoon sun streams into a once abandoned warehouse in South Boston, the building’s interior walls begin to melt. It’s no design flaw; embedded within the walls is a thin layer of microencapsulated paraffin wax that turns from solid to liquid as the building warms.
</p>
<p>
 “For high efficiency buildings, you need to start thinking in dynamic ways,” says Jan Kosny, head of building enclosure research at the Fraunhofer Center for Sustainable Energy Systems. “Mother Nature is so generous, giving us tons of free energy. But we aren’t using it. Instead we are blocking it with insulation, reflective coatings, and cool roofs. Instead of fighting with Mother Nature, we can collaborate. We can use that sun, absorbing the heat when it is warm and releasing it when it is cool.”
</p>
<div class="related"></div>
<p>
 The solution, Kosny says, are phase-change materials, also known as PCMs—things that change between solid, liquid, or vapor depending on their temperature. What makes them so desirable for use in building materials is their ability to absorb or emit massive amounts of energy while maintaining a near constant temperature.
</p>
<p>
 “To cool one pound of water from 33˚ F to 32˚ F takes 1 BTU of energy,” says Mark MacCracken CEO of CALMAC Manufacturing Corporation, whose company sells ice-based air conditioning systems. “Taking that same one pound from 32˚ F water to 32˚ F ice takes 144 BTUs as it changes from a liquid to solid. By freezing instead of simply cooling the water, you are storing 144 times as much energy.”
</p>
<p>
 The incredible energy density of PCMs is a result of something known as the heat of fusion. In the case of melting ice, thermal energy is required to break hydrogen bonds between individual molecules. When water freezes, thermal energy is released as new bonds form.
</p>
<p>
 “There are slightly different processes [for] different types of PCMs, but in general it is breaking and reforming of bonds between molecules as the material changes phase that requires or releases a significant amount of energy,” Kosny says.
</p>
<p>
 In recent years, research on PCMs has moved beyond water and ice to a vast number of new materials with a wide array of melting temperatures and applications. Some of the new materials will help keep us cool, while others will store energy at temperatures so high they would make us melt. Collectively, they will help us use existing energy supplies more efficiently, which may ultimately keep the entire planet from overheating.
</p>
<div class="ad"></div>
<h2>
 Slimmer, Lighter, and Cooler
</h2>
<p>
 Kosny oversaw installation of the encapsulated wax at Fraunhofer’s new South Boston location as part of a comprehensive energy efficiency retrofit before moving into the converted warehouse earlier this year. As the PCM melts, it absorbs energy while maintaining a near steady temperature. The change in phase, which sucks up the energy from a hot day, helps keep the building’s interior cool while using significantly less air conditioning than would otherwise be required.
</p>
<p>
 When the sun sets and the building cools, the wax in the walls radiates heat as it slowly solidifies, ready to absorb heat the following day. It’s a concept that has been used for thousands of years in warm climates where stone or thick adobe walls absorb thermal energy during the daytime and release it at night. Using PCMs, however, allows for significantly thinner, lighter weight building materials better suited for today’s glass and steel architecture. One half inch of phase-change building materials has the thermal capacity of roughly three inches of concrete, Kosny says.
</p>
<div class="pullquote">
<p>
 “There is no one best material for all applications.”
</p>
</div>
<p>
 Kosny first started looking at phase-change materials as a way to store heat from the sun as a PhD student in Poland in the early 1980s. Resources in the communist country were scarce at the time, and the only material he could find to work with was beeswax. Today he is one of the world’s leading experts on PCMs. His clients include leading building materials manufactures, the aerospace industry, and the U.S. Department of Defense. Working first at the U.S. Department of Energy’s Oak Ridge National Lab in Tennessee and now for Fraunhofer in Boston, he has assembled a library of hundreds of different phase-change materials, each with their own unique thermal properties.
</p>
<p>
 In a tour of his lab, Kosny shows me thick gels ensconced in what looks like bubble wrap—macroencapsulated PCMs, some of which are soft to the touch while others remain frozen solid at room temperature. Next to the gels are samples of drywall with tiny droplets of microencapsulated phase-change materials mixed directly into the building material. The larger gel packs can absorb more thermal energy but have to be covered by conventional drywall and are susceptible to leakage if punctured by screws or nails.
</p>
<figure class="richtext-image full-width">
<img alt="" class="richtext-image full-width" src="https://www.pbs.org/wgbh/nova/media/images/pcm-pellets.width-990_nAImXSs.jpg"/>
<figcaption>PCM pellets created in a Fraunhofer lab
        
    </figcaption>
</figure>
<p>
 In walls around the Kosny’s lab, Fraunhofer uses a slightly different building material, a microencapsulated PCM surrounded by shape stabilizing polymers and sealed with aluminum foil to aide thermal conductivity. “There is no one best material for all applications,” Kosny says.
</p>
<p>
 The building, one of only about two dozen nationwide to incorporate PCMs into its physical structure, uses the material sparingly as part of a showcase of advanced building materials that reduce heating and cooling requirements. In rooms at the Fraunhofer facility where PCMs are used, they cut cooling needs by 10 to 15%, Kosny says.
</p>
<p>
 But when liberally applied to a building’s rooftop, Kosny has demonstrated that phase-change materials can reduce a roof’s peak hour thermal load—the amount of heat conducted into the building during the hottest part of the day—by 95%. By absorbing heat in the middle of the day and radiating it back out later, Kosny says phase-change materials can easily reduce a building’s overall cooling requirements by 25 to 30%.
</p>
<h2>
 Cool as Ice
</h2>
<p>
 When it comes to reducing peak energy demand and keeping buildings cool, there may be an even simpler solution: ice. Some of the world’s largest ice cubes can be found in the basements of Manhattan skyscrapers. Inside Rockefeller Center alone, dozens of massive ice blocks, each the size of a small SUV, melt and refreeze each day. From Wall Street to Times Square, space constraints and high daytime electricity prices are pushing New Yorkers to increasingly embrace one of the oldest yet most efficient forms of air conditioning to keep cool.
</p>
<p>
 “In a place like Manhattan, you need to store a lot of cooling in as little space as possible,” says MacCracken, whose company has installed its IceBank system in thousands of locations around the globe. “Cold water tanks take up 10 times as much volume as ice storage.”
</p>
<figure class="richtext-image full-width">
<img alt="" class="richtext-image full-width" src="https://www.pbs.org/wgbh/nova/media/images/icebank-tanks.width-990_zgzYJKk.jpg"/>
<figcaption>IceBank storage tanks in the basement of a building
        
    </figcaption>
</figure>
<p>
 From the outside, an IceBank storage tank looks much like an oversized water heater. Inside, however, coolant circulating through several miles of polyethylene tubing turns the water inside the tank into an eight-ton block of ice. During the day the system runs in reverse; the ice cools warm fluid pumped through tubes in the tank that is then used to cool the building.
</p>
<p>
 Running chillers at night saves money because electricity is dramatically less expensive then—roughly 70% cheaper than during peak daytime hours, MacCracken says. In effect, CALMAC’s ice blocks—which belong to a class of devices industry officials call “thermal storage”—are simply a way to store energy, much like a giant battery, until it is needed.
</p>
<p>
 Freezing ice the night before it’s needed also allows building managers to use smaller, less expensive chillers than would normally be required of a conventional air conditioning system, which has to provide all the cooling at the time it’s needed. MacCracken likens his system to buying ice prior to hosting a cocktail party, albeit on a much larger scale. “Would you ever consider making the ice cubes for a party when your guests start arriving?” he asks. “Of course you wouldn’t. If it’s laughable to wait to until you need ice for a cocktail party, why is it not absurd that we wait to cool an entire building?”
</p>
<div class="pullquote">
<p>
 “Would you consider making ice cubes for a party when your guests start arriving? Of course you wouldn’t.”
</p>
</div>
<p>
 In addition to saving money, thermal storage also offers significant savings in energy efficiency, but not where you might expect it. At the building scale, ice-based air conditioning is slightly less efficient than conventional air conditioning, which doesn’t require the freezing and melting of ice. On a grid scale, however, the use of such thermal storage is significantly more efficient because electricity generated at night comes from base load power plants. These large, efficient plants operate continuously, as opposed to “peaking plants” which only operate during periods of high demand and are inherently less efficient. “By shifting to nighttime, you may use 5 to 10% more electricity, but power plants are 20 to 30% more efficient at night,” MacCracken says.
</p>
<p>
 As thermal storage gains traction, utility operators are taking notice. In June, the California Public Utilities Commission set a goal of developing 1.3 gigawatts of energy storage by the end of the decade. The target—equivalent to the output of a large nuclear power plant—includes incentives for technologies like ice based thermal storage that shift the energy requirements of buildings away from periods of peak demand.
</p>
<p>
 Even without the incentives, thermal storage is a promising option for grid operators, according to Steven Minnihan, an analyst at Lux Research. “When you look at thermal storage, the cost is substantially less than a fuel cell or any kind of emerging battery technology,” he says.
</p>
<h2>
 Storing the Sun
</h2>
<p>
 In addition to keeping buildings cool, phase-change materials may soon store excess solar power until it is needed. One form of solar power, concentrated solar, uses sunlight to generate steam that is used to produce electricity. In that way, they are similar to conventional power plants. The concentrated solar plants work well so long as the sun is shining, but they have a hard time delivering energy at night or when the clouds roll in. If excess heat not needed for immediate electricity generation could be stored, it could be tapped and used at a later time.
</p>
<p>
 Researchers from the German Aerospace Center recently tested what they say is the world’s largest high-temperature PCM storage module in Carboneras, Spain. At 26 feet tall and filled with 15 tons of salt, the insulated, steel reinforced tower is something akin to a giant saltshaker wrapped in a large tea cozy. It isn’t hooked up to a concentrated solar plant today, but a future version could be.
</p>
<figure class="richtext-image full-width">
<img alt="" class="richtext-image full-width" src="https://www.pbs.org/wgbh/nova/media/images/carboneras-solar.width-990_Ks6sv3r.jpg"/>
<figcaption>The German Aerospace Center's test PCM facility in Carboneras, Spain
        
    </figcaption>
</figure>
<p>
 To charge the module, superheated steam from an adjoining coal-fired power plant is piped through a network of finned tubes that heats the sodium nitrate salt to its melting point of 581˚ F. The liquid salt can then retain its stored thermal energy for up to 24 hours. To discharge the heat, operators essentially run the system in reverse, pumping water through the finned tubes to turn it back into steam, which goes on to spin the turbines that produce electricity.
</p>
<p>
 Until now, solar thermal power plants have either gone without thermal storage or relied on molten salts that remain liquid throughout their charging and discharging cycles. By keeping the salts liquid, though, the system is not taking advantage of the efficiencies inherent in phase change. “You need five times the volume with molten salt storage,” says Doerte Laing, head of thermal process technology at the German Aerospace Center’s Institute of Technical Thermodynamics. “Your storage cost would be roughly five times lower with phase-change salts.” The reduced cost could help stored solar power compete with conventional gas and coal fired power plants for reliable base load power.
</p>
<p>
 The International Energy Agency predicts that concentrated solar power will become cost competitive with conventional fossil fuel power as early as 2025 and, along with photovoltaic solar power, could provide up to 25% of global electricity production by 2050.
</p>
<figure class="richtext-image full-width">
<img alt="" class="richtext-image full-width" src="https://www.pbs.org/wgbh/nova/media/images/solar-tower.width-990_gbsA7qb.jpg"/>
<figcaption>Traditional solar thermal power plants don't use phase change to store energy, but they may soon.
        
    </figcaption>
</figure>
<p>
 Meanwhile, changes in electricity pricing could soon make ice blocks and melting walls much more commonplace. Utility companies in Texas recently began offering free electricity at night in an effort to get residential users to reduce their energy requirements during peak daytime hours.
</p>
<p>
 Until now the manufacturers of ice storage and PCM building materials have focused on large commercial applications, but if the difference between nighttime and daytime residential rates continues to widen, things could change quickly. “In another decade or two we may all have a block of ice in our homes like we did in the [early] 1900s,” MacCracken says.
</p>
<div class="newsletter"></div>
<p>
 Photos by
 <a href="http://www.flickr.com/photos/jariceiii/5012344135/">
  jariceiii/Flickr (CC-BY)
 </a>
 , Fraunhofer-Gesellschaft, CALMAC,
 <a href="http://www.dlr.de/dlr/en/desktopdefault.aspx/tabid-10200/449_read-746#gallery/1507">
  DLR (CC-BY)
 </a>
 , and
 <a href="http://www.flickr.com/photos/mpcevat/6163109139/">
  mpcevat/Flickr (CC-BY)
 </a>
</p>

<p>By exploiting thermodynamics, phase-change materials like ice, salt, and wax save energy and help keep us cool.</p>

Purifying the Dirtiest Waters

<p>
 In the break room of a South Boston research center, a gleaming fish tank stands next to shelves of Cheez-It crackers. Inside angelfish, catfish, and minnows swim around brightly colored plastic seaweed. The only sign of the water’s polluted past is a small jar of tar-black liquid—wastewater from hydraulic fracturing—sitting on top of the tank.
</p>
<p>
 “When oil and gas water comes to the surface, they take the hydrocarbons off and we bring it all the way to potable water,” says Jim Matheson, CEO of Oasys Water.
</p>
<p>
 Oasys Water is one of a number of companies that are taking decades old water purification technology known as reverse osmosis and turning it on its head. The new approach, called forward osmosis, can treat far dirtier water, often using significantly less energy than existing purification methods. The new technique now treats some of the most challenging industrial wastewaters, provides emergency hydration, and could soon bring relief to many of the world’s most water scarce regions.
</p>
<p>
 When reverse osmosis was first developed in the 1960s, it dramatically reduced the amount of energy and cost required to extract freshwater from the sea. Previously, seawater had to be boiled, turned to steam and then re-condensed to separate freshwater from the salts that made it undrinkable. Reverse osmosis cut the cost of desalination by forcing seawater through a semi-permeable membrane that allows freshwater to pass but blocks salt and other impurities.
</p>
<div class="related"></div>
<p>
 Today, 21 billions gallons of fresh water—enough to meet the needs of 300 million people—is desalinated worldwide each day. The vast majority of that water comes from reverse osmosis. Yet to coax freshwater through membranes in reverse osmosis, the seawater has to be pressurized, a process that still requires a significant amount of energy.
</p>
<p>
 This is where forward osmosis comes in. Instead of pressurizing water and pushing it through a membrane, forward osmosis relies on the natural tendency of water to flow through a semi-permeable membrane from concentrated to less concentrated solutions, eventually equilibrating the two. “Instead of using pressure, we are letting nature do it’s job,” Matheson says. “It’s the way your body uses osmosis to move water for cellular processes.”
</p>
<h2>
 The Draw
</h2>
<p>
 Suppose you want to use forward osmosis to purify water. You’d start with two mixtures of water, one on each side of a semi-permeable membrane. The first solution, for example the hydraulic fracturing wastewater that Oasys Water wanted to clean, is called the feed solution. The second, on the other side of the membrane, is the draw solution. It has a higher salinity than the feed solution and pulls or draws water across the membrane through osmosis. At this point you’ve drawn freshwater out of dirty wastewater but have moved it into another solution that is even saltier than what you started with.
</p>
<div class="ad"></div>
<p>
 The key to Oasys’s approach is the salt they use in their draw solution, ammonium bicarbonate, turns into carbon dioxide and ammonia gas when heated. “If you warm it up a little bit, to 80˚ C, you vaporize it.” Matheson says.
</p>
<p>
 Oasys treated tens of thousands of gallons of hydraulic fracturing wastewater from the Marcellus and Permian basins of Pennsylvania and Texas in pilot tests starting in 2011. Hydraulic fracturing or fracking involves injecting water, sand, and a cocktail of often undisclosed chemicals deep underground to release oil and natural gas trapped in shale formations. Water that surfaces with the gas is typically several times more saline than seawater and often includes heavy metals and radioactive material.
</p>
<figure class="richtext-image full-width">
<img alt="" class="richtext-image full-width" src="https://www.pbs.org/wgbh/nova/media/images/img_3286.width-990_9xlRVxG.jpg"/>
<figcaption>Membranes in this Oasys Water system will clean 4,000 barrels of fracking wastewater per day.
        
    </figcaption>
</figure>
<p>
 Using forward osmosis, Oasys was able to turn roughly 60% of the wastewater into freshwater that met or exceeded drinking water standards set by the EPA. The water is too saline to treat with conventional reverse osmosis—the water pressure required to overcome such high salinity would cause its membranes to shred. The only option previously available to purify such wastewater was thermal evaporation, a process that uses 25–50% more energy than forward osmosis, according to Matheson.
</p>
<div class="pullquote">
<p>
 The bigger prize for developers of forward osmosis is the multi-billion dollar global market for seawater desalination.
</p>
</div>
<p>
 In 2013, Oasys partnered with oil and gas equipment supplier National Oilwell Varco to sell a forward osmosis system that can turn up to 4,000 barrels of wastewater into fresh water each day.
</p>
<p>
 The bigger prize for developers of forward osmosis, however, is the multi-billion dollar global market for seawater desalination. In 2011, Oasys’s founders, executives who are no longer with the company, claimed they could produce fresh water from the sea using one-tenth the fuel or electricity required by reverse osmosis. Their claims, however, rested on the presumption that they could harness “waste heat” from power plants at little or no cost.
</p>
<p>
 Power plants and other industrial facilities often release low-grade heat in the form of steam or hot water. Oasys needs heat to “regenerate” their draw solution or remove the ammonium bicarbonate salt to unlock the freshwater that remains. But harnessing this heat proved difficult.
</p>
<p>
 “Waste heat is very seldom free,” says Brent Giles, a water analyst with Lux Research. “The barrier they ran into was you had to build a cathedral to tap enough waste heat out of typical low grade source.”
</p>
<p>
</p>
<div class="newsletter"></div>
<p>
 To reduce energy requirements of forward osmosis, researchers are now pursuing a number of novel techniques, including nanoparticles that can be filtered out, metallic salts that can be drawn out with a magnetic field, and oil based salts that can be skimmed off the top of the water column, to remove salt from their draw solution. “A ridiculous number of solutions have been tried,” Giles says. “It’s really hard to find a good one.”
</p>
<h2>
 Finding a Focus
</h2>
<p>
 A 2014 study by researchers at the Massachusetts Institute of Technology concluded that the energy requirements of forward osmosis will always be greater than those of reverse osmosis for seawater desalination. “In forward osmosis you are moving water into something more concentrated,” says study co-author Ronan McGovern, a postdoc at MIT. “It will always require more energy than reverse osmosis.”
</p>
<p>
 At the same time, the scale up of reverse osmosis desalination has made it a very inexpensive method of water purification. “You can get 1,000 liters of water for less than $1 using reverse osmosis,” says Menachem Elimelech, a professor of environmental engineering at Yale University and one of the researchers behind the initial development of Oasys Water’s technology. “It’s very difficult at this stage to beat that.”
</p>
<p>
 The MIT study recommended that developers of forward osmosis focus on the treatment of exceptionally dirty or salty water where reverse osmosis can’t compete or where the draw solution doesn’t need to be regenerated.
</p>
<p>
 One consumer application that meets both of these requirements is a line of hydration packs developed by Hydration Technology Innovations, a startup company based in Albany, Oregon. Plastic pouches filled with a sugary syrup that acts like a highly saline solution draws freshwater from any source across a forward osmosis membrane to provide a single use, emergency hydration drink. The technology was developed through a U.S. Department of Defense Advanced Research Projects Agency (DARPA) grant for soldier hydration. It is now also marketed for use by hikers, boaters, and wilderness first responders.
</p>
<figure class="richtext-image full-width">
<img alt="" class="richtext-image full-width" src="https://www.pbs.org/wgbh/nova/media/images/modern_water_fo_plant_al_khaluf_oman.width-990_3TIjO05.jpg"/>
<figcaption>A forward osmosis plant built by Modern Water in Al Khaluf, Oman
        
    </figcaption>
</figure>
<p>
 Another application that avoids the need to regenerate the draw solution is fertilizer-driven forward osmosis. A 2011 study by researchers at the University of Technology in Sydney, Australia showed that 2.2 pounds of highly concentrated chemical fertilizers can draw can draw up to eight gallons of freshwater that can then be applied on agricultural fields. The concept is currently being developed by Danish startup Aquaporin.
</p>
<p>
 Other companies are pairing forward osmosis with other technologies to extend its capacity for desalination. Trevi Systems, a company based in Petaluma, California, is coupling forward osmosis with solar power to desalinate seawater. The company is building a pilot plant in the United Arab Emirates that will use solar thermal energy to heat and regenerate its draw solution. The system will be completed in May and will have an output of 1,760 cubic feet of freshwater per day, according to Trevi CEO John Webley. “It will be the first renewable-powered forward osmosis system in the world,” he says.
</p>
<p>
 One of the earliest adopters of forward osmosis, U.K.-based Modern Water, completed its first commercial seawater desalination plant in Oman in 2009 and a second in 2012. Seawater in the region has a higher salinity as well as higher concentrations of algae and other suspended solids that make it more prone to fouling in reverse osmosis than seawater from other regions. Modern Water uses forward osmosis to pretreat the water before using reverse osmosis, a combination that reduces fouling.
</p>
<p>
 “In reverse osmosis, all the stuff in seawater is being pushed toward the membrane,” Giles says. “With forward osmosis, water has an attraction to the other side of the membrane that other materials don’t have. You aren’t pushing material against the membrane, you are letting it draw through.”
</p>
<h2>
 Zero Waste
</h2>
<p>
 Oasys meanwhile is pursuing something called “zero liquid discharge” a process that that could reduce the environmental impact of desalination. Desalination as it is most commonly done today takes seawater and turns it into two products, freshwater that we drink and brine that is roughly twice as saline as seawater. The later is typically dumped back into the sea in a process that increases ocean salinity in the immediate vicinity. As desalination increases worldwide the environmental impact on ocean water is becoming more of a concern.
</p>
<p>
 “If you have a glass of water and keep adding a tablespoon of salt every day, you are eventually gonna get pretty damn salty,” Matheson says. Oasys is currently running a pilot desalination plant near the Bohai Sea in northern China. Their system takes brine wastewater from an existing desalination facility and extracts more freshwater from the brine. Oasys’s goal is to draw all of the water from the brine leaving only dry salt.
</p>
<p>
 “There is significant dialogue in China, especially in the Bohai Sea, because there is a lot of industrial discharge and very little water movement,” Matheson says. “There is pending regulation that discharge in the Bohai Sea, or potentially all of China, may go to zero liquid discharge.”
</p>
<p>
 Oasys’s demonstration plant currently draws 80% of the water from the brine. The company is now completing a commercial-scale zero-liquid-discharge wastewater treatment system at a coal-fired plant elsewhere in the country. The facility will use forward osmosis to draw 90% of the freshwater from the salt. The remaining brine will be heated until only dry salt remains.
</p>
<div class="pullquote">
<p>
 “Potentially all of China may go to zero liquid discharge.”
</p>
</div>
<p>
 At the same time Oasys is pursuing inland desalination, treating brackish water from underground aquifers far from the sea. Such aquifers offer a vast water resource that is difficult for reverse osmosis to treat. Though the water is less saline than seawater, it often contains other minerals including silica, calcium, and magnesium that would foul the membranes used in reverse osmosis.
</p>
<figure class="richtext-image full-width">
<img alt="" class="richtext-image full-width" src="https://www.pbs.org/wgbh/nova/media/images/room-2.width-990_Scf15D0.jpg"/>
<figcaption>Engineers complete the installation of an Oasys Water system at the Hua Neng Changxing coal-fired power plant near Hangzhou, where it will clean wastewater produced by flue gas scrubbers.
        
    </figcaption>
</figure>
<p>
 “It would open up an entirely new capability,” Matheson say. “If you look at California today, it could be a significant game changer for the Central Valley. India, China, the Middle East all have significant sources of brackish water. If you could clean that up, you could bring a significant localized freshwater resource.”
</p>
<p>
 Giles agrees saying the capacity to treat brackish water could have immediate applications in California and elsewhere, but cautions that Oasys Water still has some challenges to work out. “They need waste heat or at least heat, and it’s not immediately obvious where they will find that in the olive fields.”
</p>
<p>
 New developments in conventional reverse osmosis could also provide a competing solution, Giles says. Desalitech, a Newton, Massachusetts, startup is already treating brackish water in California and Israel by running conventional reverse osmosis in a small batch process that allows the company to flush salt and minerals from its membranes as it accumulates.
</p>
<p>
 In South Boston, the ground floor of Oasys’s research facility is littered with plastic totes containing brackish water from the American Southwest, Europe, China, the Middle East, and Australia. Lab benches overflowing with a dizzying array of plastic tubing, custom-built membranes, and novel draw solutions test the mineral rich waters.
</p>
<p>
 As Matheson describes these brackish waters, he rubs his fingers together suggesting a grittiness you can feel in your hand. Standing amongst the totes you get the feeling that major changes in desalination are close at hand, so close that you can almost feel it.
</p>
<p>
 Photo credits: Toa55/iStockphoto, Oasys Water,
 <a href="http://commons.wikimedia.org/wiki/File:Modern_Water_FO_Plant_Al_Khaluf_Oman.jpg">
  Starsend/Wikimedia Commons (CC BY-SA)
 </a>
</p>

<p>Inspired by our body’s own cells, forward osmosis technology can clean the world’s most toxic waters.</p>

The powerful earthquake that struck Nepal on April 25, 2015, opened this large crack in a roadway. Image Credit: Stéphane Brûlé, Krish Dulal/Wikimedia Commons (CC BY-SA), NOAA

Cloaking Buildings from Earthquakes and Tsunamis

<div class="related"></div>
<p></p><p>In August 2012, civil engineers from the French firm Menard drilled three rows of shallow holes into the soft clay soil at the base of the Alps near Grenoble. Each hole was roughly the depth and diameter of what a utility company might dig to secure the base of a telephone pole.</p><p>Then, on one side of the boreholes, they lowered a vibrating probe several feet into the soil. On the surface, they placed a network of sensors to record vibrations. By the time the waves reached the second row of boreholes, a distance of 11 feet, their signal, which would typically travel through 160 feet of soil, hardly registered. The holes had stopped the vibrations in their tracks.</p>
<figure class="richtext-image full-width">
<img alt="First experiment - Grenoble" class="richtext-image full-width" src="https://www.pbs.org/wgbh/nova/media/images/first-experiment-grenoble.width-990_4emK7wN.jpg"/>
<figcaption>Sensors sitting atop concrete blocks monitor seismic waves near the boreholes drilled as a seismic cloak.
        
    </figcaption>
</figure>
<p>For more than 2,000 years people living in earthquake zones have tried to keep the shaking beneath their feet from destroying their buildings. In his history of ancient Greece, Pliny the Elder describes how a temple’s foundation included a layer of sheepskin to allow the ground to slip and slide without damaging the building above. The state of the art for earthquake protection today, including bearings, springs, moveable pads, and other “base isolation” systems, works in much the same way as those employed by the ancient Greeks.</p><p>Now, simple rows of boreholes like those drilled in the field could make all of that obsolete. They appear to work as a “seismic cloak” that could hide a building—or perhaps an entire city—from an earthquake’s deadly waves. “If we drill holes around the building, forget about all your earthquake protections inside the building. We don’t need them anymore,” says Sébastien Guenneau, the originator of the idea and a physicist at the Fresnel Institute in Marseille, France.</p><p>Guenneau compares the effect to that of what we see in a mirage when light, which typically travels in a straight line, is bent by low density, hot air immediately above the surface of the earth. “Instead of having a ray of light that goes straight to the Earth, now it is curved, which is why if you are looking at a mirage, you don’t see the soil but you see the sky,” Guenneau says. “The same thing happens to seismic waves when you change the density of the soil by drilling boreholes. Instead of bending a ray of light, you are bending a seismic wave.”</p><h2>From Microscopic to Massive</h2><p>Guenneau’s efforts at seismic cloaking stem from recent efforts to cloak or hide objects from light. In 2006, John Pendry, a physicist at Imperial College in London, along with researchers from Duke University, showed it was theoretically possible to bend light around an object, effectively making it invisible. Later the same year the group made a partial cloak for microwaves, whose frequencies are slightly larger than those of visible light.</p><p>But cloaking the foundation of an entire building from seismic waves would likely be a much greater challenge. “I was a bit wowed by the daring of this paper,” Pendry says. “But when you think about it, it’s a reasonable proposition. Earthquakes are waves—or those are the things which do the damage—and they propagate along the surface of the Earth. If you’re smart enough, presumably you can deflect them to go different places.”</p><p>Though Pendry doesn’t say it, he likely presumes Geunneau is smart enough. Before Pendry made headlines around the world for his invisibility cloak, Guenneau spent over a year working for him as a postdoc on a Defense Advanced Research Projects Agency (DARPA) project for the U.S. Department of Defense. Guenneau can’t say exactly what all the project entailed, in part because the work he did was basic research and he says he doesn’t know what DARPA did with it. He does add, however that “they are very interested in invisibility cloaks.”</p><p>For more than a decade since, Guenneau has continued to work on metamaterials, artificial materials that have properties not found in nature, such as the ability to bend waves in directions they wouldn’t normally go. The vast majority of people working in the field, Pendry included, work in optics, trying to bend light to create things like cloaks and “super lenses” that have incredibly high resolution. Largely as a way to distinguish himself in an increasingly crowded field, Gueunneau started thinking on a completely different scale, much to the amusement of many of his colleagues.</p><p>“They were just laughing, to be honest,” Guenneau says when he first told coworkers about his plans for a seismic cloak. They ticked off a laundry list of problems, including the fact that soil is viscoelastic—both viscous and elastic, complicating how it reacts to forces—and maddeningly heterogeneous in its composition. “There have been people working on soil structure for many years,” he says his colleagues told him. “And you think you will make a revolution?”</p><p>Guenneau hasn’t sparked a revolution just yet, but the results he and his colleagues have obtained are compelling. Their goal is a true cloak, a circle of boreholes that bends seismic waves around the holes, like water flowing around a boulder in a stream. What they demonstrated in Grenoble was a good first step. There, rows of boreholes caused seismic waves to reflect backwards, like light hitting a mirror. The reflections, however, created seismic waves in front of the boreholes that had twice the strength as those initially generated by the probe. Such an approach could prove catastrophic in real world applications.</p><p>“Behind the mirror, you may have protected your nuclear plant, but in front of your mirror, you have a hospital or a school that gets destroyed,” Guenneau says. The group now hopes to conduct a follow up study that demonstrates their ability to create a true cloak.</p><p>Guenneau is aiming to protect high value—and potentially highly vulnerable—facilities like nuclear power plants.</p><p>For all its daring, creating a seismic cloak may actually be easier than constructing an invisibility cloak for light waves, Pendry says. For metamaterials to work, they have to be smaller than the length of the wave they cloak. Visible light requires nanometer scale metamaterials, devices that are proving incredibly difficult to create. Seismic waves, by contrast, require meter-scale metamaterials like the boreholes used in Grenoble. Yet even if the group is able to hide a building from seismic waves, Pendry questions how widely applicable their approach will be.</p><p>“I don’t think this technology is anything that is going to work in a place like San Francisco because the cloaks tend to be the same size as object you are hiding,” he says. “In a dense city, you wouldn’t be able to excavate the area around buildings without knocking down their neighbors.”</p><p>Guenneau says they aim to protect high value—and potentially highly vulnerable—facilities like nuclear power plants with a sufficient amount of undeveloped land surrounding them where they could drill their holes.</p><p>Still, others say the recent study does little to show that the approach will work at all. “The mechanism of earthquake shaking is very different than a single discrete source that is very close to the boreholes,” says Youssef Hashash a civil engineering professor at the University of Illinois in Urbana-Champaign. “It comes from underneath you. Some from the surface, but a lot of it comes from below these boreholes, and the technique they have doesn’t affect anything underneath you.”</p><p>Jeroen Tromp, a geologist at Princeton University, disagrees, saying surface waves are typically more powerful and do more damage than waves coming up from below. “Surface waves spread in two dimensions as opposed to subsurface waves that spread in three dimensions,” Tromp says. “The energy is distributed over a surface rather than a volume, so they are much more destructive.”</p><p>Tromp cautions, however, that there is no one-size fits all approach to seismic protection. Smaller structures like single-family homes resonate, or shake, at higher frequencies, making them more prone to damage from the less powerful but higher frequency waves coming from underground.</p><p>Hashash adds that the vibrating probe used in the study only tested a single, 50 Hz frequency, while the most damaging surface waves typically occur across a wider and lower range of frequencies between 0.1–10 Hz. “You cannot produce the richness of waves that an earthquake produces with that device,” Hashash says.</p><p>Stéphane Brûlé, a seismologist and geotechnical engineer with Menard and lead author of the Grenoble study, says the initial experiment was a proof of concept to show that boreholes can alter the path of seismic waves similar to how prior studies altered microwaves. Brûlé and his colleagues completed a second experiment several months after the initial test that used significantly wider holes that were seven feet in diameter. This time they dropped a mass of 21 tons from a height of 164 feet to simulate an earthquake. Shaking in the immediate area registered between 2.0 and 3.0 on the Richter scale, and, perhaps more importantly, created waves in the 3 to 12 Hz range, similar to those seen in an actual earthquake.</p>
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<h2>Taming Tsunamis</h2><p>At the same time, Guenneau is moving forward with cloaking techniques to protect against entirely different, yet equally destructive waves. In 2008, he and colleagues from Liverpool University in the U.K. and the Fresnel Institute in France showed how a series of rods arranged in concentric rings could redirect liquid waves, similar to what Pendry and others had shown for microwaves.</p><p>“Tsunami waves and surface waves for earthquakes are pretty much the same in terms of the mathematical equations,” Guenneau says. “You can have a huge storm, you can have waves of very high amplitude, but in center of the cloak you will have calm water.”</p><p>The initial experiment was conducted with an eight-inch diameter disk, a scale so small that the group had to use methoxynonafluorobutane, a compound similar to Freon once used in refrigerators, instead of water because of water’s high viscosity at such a small scale.</p>
<figure class="richtext-image full-width">
<img alt="" class="richtext-image full-width" src="https://www.pbs.org/wgbh/nova/media/images/680_20110311-tsunamiwaveheight.width-990_6zoL1ET.jpg"/>
<figcaption>Waves produced by the March 11, 2011, earthquake off the coast of Sendai, Japan, reached across the Pacific Ocean.
        
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<p>In February 2015, Guenneau and a team of French researchers published a follow up study for an “invisibility carpet,” a significantly larger rectangular pad with several rows of rods jutting out of the water. In wave tank testing, the carpet reflected the waves, which would otherwise have washed over a small seawall, back in the direction from which they came.</p><p>Guenneau says he is now working with a private company to develop a larger scale prototype. “The cost would remain quite affordable compared to the cost of a nuclear plant which is destroyed or a city which is devastated,” Guenneau says. “You prefer to have a carpet which costs perhaps 10 or 20 million euros than have 50,000 human beings wiped from the surface of the earth.”</p><p>Pendry, however, questions whether such a carpet could withstand a tsunami. “I’d be very, very skeptical just because of the enormous forces involved,” Pendry says. “It would involve a very large, very expensive structure, and maybe one that you couldn’t even find the materials to build in the first place.”</p><h2>Protective Forests</h2><p>Whether or not columns sticking out of the sea could provide adequate protection against a tsunami, similar structures on land may already be absorbing earthquake waves.</p><p>In 2014, researchers in France found that a forest of long aluminum rods extending vertically from a horizontal plate canceled out vibration waves. The rods didn’t cause the waves to reflect as if bouncing off a mirror nor bend around a protected area like a cloak. Rather, each rod acted as a resonator absorbing a small fraction of the wave’s energy. Collectively, the rods canceled the wave entirely.</p><p>The finding made the researchers wonder if an actual forest would have a similar effect on seismic waves. In a yet-unpublished study, researchers in Grenoble recorded ambient vibrations in the ground using a pair of seismometers, one located within a small wooded area and one located just outside the wood’s western border. Both instruments detected vibrations from road construction roughly 100 yards away to the north. Vibrations inside the wooded area were six times weaker than those outside.</p><p>“If you have many trees close to each other you can completely cancel the incoming wave,” says Philippe Roux, director of research for the National Center for Scientific Research in Grenoble and co-author on both papers.</p>
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<img alt="" class="richtext-image full-width" src="https://www.pbs.org/wgbh/nova/media/images/mg_0665menard_givors_100109.width-990_hSBjleJ.jpg"/>
<figcaption>This massive weight is dropped by the crane to simulate the waves produced by an earthquake.
        
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<p>Trees, however, have their limitations. Like the metal rods, they only resonate, or absorb wave energy at certain frequencies based on their height. The 33–66 foot pine trees that damped the construction vibrations resonate at 30–45 Hz, a significantly higher frequency than the most dangerous seismic waves that are less than 10 Hz.</p><p>To absorb energy from the most destructive waves, Roux says structures 260 to 330 feet tall would be required. Instead of using trees, we might someday design cities so that a forest of skyscrapers or other tall structures neutralize seismic waves, Roux says.</p><p>Ping Sheng, a physicist at Hong Kong University of Science and Technology, says the energy absorbed from seismic waves could then be converted to electricity. In a recent paper Sheng demonstrated it is possible to convert energy from acoustic waves into electricity, suggesting the same could be done for seismic waves. “If you could have a large-scale dissipative mechanism, then you may be able to lower the effective Richter scale by one while simultaneously converting a lot of energy,” Sheng says. “That would be huge.”</p><p>Cloaking buildings from earthquakes and tsunamis or converting the energy of seismic waves into electricity may seem far-fetched, but probably no more so than it once did to isolate marble temples from the ground with a layer of sheepskins. Researchers will have to continue testing their cloaks and resonators in increasingly complex, real-word settings against a number of different seismic waves before we’ll know just how effective they will be. But in certain applications they might just work. “We are at the stage when people stop laughing,” Guenneau says.</p>
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<p data-block-key="oft86">A simple yet apparently effective metamaterial could save vital buildings from earthquakes’ destructive waves.</p>

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Through-wall radar, like this Cambridge Consultants Prism 200 device, has grown more capable in recent years.

X-Ray Vision is Here

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<p>
 Dina Katabi isn’t faster than a speeding bullet. Her physical strength pales in comparison to that of a locomotive. As for leaping over buildings, the diminutive electrical engineer prefers to take the stairs. Like Superman, however, Katabi possesses an uncanny ability to see through walls.
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 Her super power is on display inside MIT’s Stata Center, a monument to architectural fantasia that itself seems to have sprung from the pages of a comic book.
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 The device is able to zero in on changes so subtle that I wouldn’t be able to see them with my own eyes.
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 Near the base of the shiny, yellow cylinder at the heart of the Stata Center, Fadel Adib, a PhD student in Katabi’s lab, leads me through their latest creation. Sprawling across the top of a humble AV cart sit a jumble of circuit boards, signal processors, and high-precision clocks. Adib explains their individual functions as I dutifully nod my head with only the vaguest of understanding. He then walks to a nearby wall where the cables terminate at a pair of antennas, each of which bear a striking resemblance to the plastic fins or “flights” at the end of a dart on a dart board.
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 Adib walks past the antennas through a doorway to an adjoining room. As he closes the door behind him, the antennas beam radio signals through the wall that track his every move. The device is able to zero in on changes so subtle that I wouldn’t be able to see them with my own eyes even if Adib were still standing right in front of me.
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 Taking a seat next to Hongzi Mao, another student in Katabi’s lab, I watch a computer monitor plot a sine wave that crests and troughs at regular intervals. “Fadel, can you hold your breath?” Mao shouts to his lab mate on the other side of the wall.
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 Before Mao can finish his request the wave on the screen flatlines. “That was his breath,” Mao says of the waves as he pantomimes an exaggerated expansion and contraction of his own chest. Then, Mao points to smaller squiggles that continue to punctuate the otherwise flat line. “This is his heartbeat,” he says.
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<h2>
 Seeing Through It All
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 Drywall, cement block, even solid concrete are no longer impenetrable barriers to what we can see. Recent advances using radio signals to track movement allow researchers to peer not only through walls but also through human flesh with such clarity that they can actually monitor the movement of one’s heart as it beats. Such “X-ray vision,” once the province of superheroes, has obvious military applications for urban combat. Other unexpected uses, however, are emerging with technology that surpasses even the most advanced warfighter capabilities.
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 In 2011, a study funded by the United States Air Force showed it was possible to peer through concrete or cinder block walls to monitor the movements of people on the other side. “It was strictly a military problem,” says former MIT researcher Gregory Charvat who led the study. “We were in these conflicts in Iraq and Afghanistan where there was a lot of searching of buildings.” If, before entering a building, U.S. soldiers could see who was inside and what they were doing, it would give them a tremendous tactical advantage.
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 Using a powerful radar, Charvat and colleagues could see how many people were on the other side of walls and could track their movements. “It could help in the searching of buildings—you may not even have to [physically] search the buildings,” Charvat says.
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 Using radar to see through walls works much like conventional radar: a transmitter emits a radio signal in a certain direction and then an antenna records what bounces back. The time and strength of the signal that returns allows the device to infer how far away and how big an object is. Imaging through walls, however, requires a bit more finesse. Unlike visible light, the shorter wavelength “microwaves” used in radar imaging, can pass through solid walls, but just barely
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 “Only about 0.005 of the original signal makes it through the wall and back again.”
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 When Charvat and colleagues pointed their radar at a four-inch-thick concrete wall less than one percent of the signal made it to the intended targets on the other side. When the remaining signal bounced off the target back toward the radar more than 99 percent of this already weakened signal was again lost before making it back to the radar. “Only about 0.005 of the original signal makes it through the wall and back again,” Charvat says. Still, the returning signal allowed them to monitor in real time the movements of four people on the other side.
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 And that’s not all their radar could see. Radar imaging can tell if a person on the other side of a wall is carrying a large weapon like an AK-47 or a rocket propelled grenade launcher, according to a 2009 study by the United States Army Research Laboratory. In 2013, a study by the Air Force Institute of Technology found the technology could also determine, with more than 95% accuracy, whether individuals on the other side of a wall were children or adults.
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 Over the past decade the U.S. Department of Defense spent millions developing technology that could peer through walls. From 2005 to 2012, the Defense Advanced Research Projects Agency, known as DARPA, alone spent over $60 million on Visibuilding, a program whose goal was to “detect personnel within buildings, determine building layouts, and locate weapons caches.”
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 Then in 2013 the Department of Defense cut all funding for Visibuilding. The same year the US Army terminated its Sense Through The Wall program after determining it “was not mature enough to meet user needs and soldier’s requirements.”
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 One reason was likely researchers’ inability to generate anything more than a very crude approximation of individuals on the opposite side of the wall. As Charvat describes it, all you could see were “blobs.”
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<img alt="" class="richtext-image full-width" src="https://www.pbs.org/wgbh/nova/media/images/radar-images.width-990_OphppvQ.jpg"/>
<figcaption>These images show what through-wall radar imagery looks like. The outlines are the people, walls, and objects in the room (overlaid for context), while the heat map is the intensity of radar reflectance.
        
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 “When I see blobs I think, ‘Wow, that is amazing!’ ” Charvat says. “But when you take it to an end user they may not think it is that great. If you need a PhD electromagnetics person to interpret the data for you, it is not going to be used. There are some real limitations with the data.”
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 Another problem was accuracy. Moeness Amin, director of the Center for Advanced Communications at Villanova University in Pennsylvania, says proponents of through wall imaging promised more than the technology could deliver. “They were very ambitious in terms of what the physics could actually allow,” he says. “Most assumptions from the lab were unfortunately invalid because the real world is very complicated. When a frequency goes through a wall it hits not only you but the chair, the ceiling, the filing cabinets, the interior walls. There is a lot of clutter and the radar hits all of this.”
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 The bouncing of signals from object to object tended to have a multiplier effect on the results. “Instead of you showing up as one, you show up as four,” Amin says. “It generates ghosts.”
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<h2>
 Slimming Down
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<p>
 Katabi can work with blobs and ghosts, but to meet her needs, the imaging equipment had to get a lot smaller. “Typically radar is very big, heavy, and expensive,” she says. “One and a half years ago, the state of the art had to be mounted on a truck. We want something you can attach to your baby monitor.”
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 In June 2013 Katabi showed it was possible to track people through walls using conventional Wi-Fi, the ubiquitous radio signals used to connect computers and other electronic devices to the Internet. Like conventional radar, the technique emitted radio signals that passed through a wall, reflected off objects on the other side, and passed back through the wall to a receiver antenna. Unlike military radar, however, the Wi-Fi signals were offset in such a way that reflections from static objects—things like walls, tables, and chairs—cancelled each other out. The only signals that made it back to Wi-Fi device were those from moving objects; people.
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 “If you need a PhD electromagnetics person to interpret the data for you, it is not going to be used.”
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 By focusing on moving things, Katabi was able to use significantly less power and a single receiver antenna instead of the vast antenna arrays typically used in military pilot studies. Instead of blasting an entire room with radio waves to get a detailed image of everything inside, Wi-Fi could shine a spotlight on only the moving objects.
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 The new technique, however, had its problems. Wi-Fi, it turned out, wasn’t ideal for pinpointing an individual’s exact location. And when people stood still, they often disappeared. “Wi-Fi signals are incapable of providing high resolution because they were not intended for localization to start with.” Katabi says. “There are so many other things going on, like the actual communication that the signal was intended for.”
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 Katabi took the Wi-Fi signal and modified it, increasing the frequency of its radio waves to better pinpoint individuals. She also developed more robust algorythms to better interpret the signals that made their way back through the wall. The changes not only allowed her to zero in on an individual’s exact location. They also allowed her to penetrate an individual’s chest cavity and record the very beating of his or her heart.
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 Her newest iteration, WiTrack, isn’t strong enough to peer through thick concrete walls, but the lower power signal it transmits, 100 times less powerful than Wi-Fi, would likely preclude any safety concerns about its use in consumer electronics.
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 It will likely be years before WiTrack appears in any household gadgets. Current prototypes still gets confused when more than one person enters a room. But, if Katabi and her labmates can make the system more robust, the potential applications, including infant monitors, fall detectors for the elderly, and interactive gaming consoles that allow users to hide behind furniture and walls, are limitless, she says. “Can I, for example, do EKGs remotely without anything on the person themselves?” What began as a failed military research project may have a promising future in health care and other consumer applications.
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<h2>
 Just the Beginning
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 Long before the Stata Center’s shiny cylinders and leaning towers loomed over the MIT campus, researchers developed military radar on the site in a building known as the Radiation Laboratory. Toward the end of World War II, one of the researchers on the project noticed a candy bar in his pocket melted when he got too close to an active radar device. The “Radarange,” now better known as the microwave, was born.
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 Sitting in her office high above the former Rad Lab, Katabi says her recent experiments in radio wave sensing are just the beginning. “We can create a very smart environment that can help us as humans without interfering with our lives,” she says.
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 Image credits: Cambridge Consultants, US Army
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<p>New devices—which could be on the market soon—will let you see who&#x27;s behind a wall. And that&#x27;s just the beginning.</p>

Phil McKenna

Articles