TIME big data

Google’s Flu Project Shows the Failings of Big Data

Google flu trends

A new study shows that using big data to predict the future isn't as easy as it looks—and that raises questions about how Internet companies gather and use information

Big data: as buzzwords go, it’s inescapable. Gigantic corporations like SAS and IBM tout their big data analytics, while experts promise that big data—our exponentially growing ability to collect and analyze information about anything at all—will transform everything from business to sports to cooking. Big data was—no surprise—one of the major themes coming out of this month’s SXSW Interactive conference. It’s inescapable.

One of the most conspicuous examples of big data in action is Google’s data-aggregating tool Google Flu Trends (GFT). The program is designed to provide real-time monitoring of flu cases around the world based on Google searches that match terms for flu-related activity. Here’s how Google explains it:

We have found a close relationship between how many people search for flu-related topics and how many people actually have flu symptoms. Of course, not every person who searches for “flu” is actually sick, but a pattern emerges when all the flu-related search queries are added together. We compared our query counts with traditional flu surveillance systems and found that many search queries tend to be popular exactly when flu season is happening. By counting how often we see these search queries, we can estimate how much flu is circulating in different countries and regions around the world.

Seems like a perfect use of the 500 million plus Google searches made each day. There’s a reason GFT became the symbol of big data in action, in books like Kenneth Cukier and Viktor Mayer-Schonberger’s Big Data: A Revolution That Will Transform How We Live, Work and Think. But there’s just one problem: as a new article in Science shows, when you compare its results to the real world, GFT doesn’t really work.

GFT overestimated the prevalence of flu in the 2012-2013 and 2011-2012 seasons by more than 50%. From August 2011 to September 2013, GFT over-predicted the prevalence of the flu in 100 out 108 weeks. During the peak flu season last winter, GFT would have had us believe that 11% of the U.S. had influenza, nearly double the CDC numbers of 6%. If you wanted to project current flu prevalence, you would have done much better basing your models off of 3-week-old data on cases from the CDC than you would have been using GFT’s sophisticated big data methods. “It’s a Dewey beats Truman moment for big data,” says David Lazer, a professor of computer science and politics at Northeastern University and one of the authors of the Science article.

Just as the editors of the Chicago Tribune believed it could predict the winner of the close 1948 Presidential election—they were wrong—Google believed that its big data methods alone were capable of producing a more accurate picture of real-time flu trends than old methods of prediction from past data. That’s a form of “automated arrogance,” or big data hubris, and it can be seen in a lot of the hype around big data today. Just because companies like Google can amass an astounding amount of information about the world doesn’t mean they’re always capable of processing that information to produce an accurate picture of what’s going on—especially if turns out they’re gathering the wrong information. Not only did the search terms picked by GFT often not reflect incidences of actual illness—thus repeatedly overestimating just how sick the American public was—it also completely missed unexpected events like the nonseasonal 2009 H1N1-A flu pandemic. “A number of associations in the model were really problematic,” says Lazer. “It was doomed to fail.”

Nor did help that GFT was dependent on Google’s top-secret and always changing search algorithm. Google modifies its search algorithm to provide more accurate results, but also to increase advertising revenue. Recommended searches, based on what other users have searched, can throw off the results for flu trends. While GFT assumes that the relative search volume for different flu terms is based in reality—the more of us are sick, the more of us will search for info about flu as we sniffle above our keyboards—in fact Google itself alters search behavior through that ever-shifting algorithim. If the data isn’t reflecting the world, how can it predict what will happen?

GFT and other big data methods can be useful, but only if they’re paired with what the Science researchers call “small data”—traditional forms of information collection. Put the two together, and you can get an excellent model of the world as it actually is. Of course, if big data is really just one tool of many, not an all-purpose path to omniscience, that would puncture the hype just a bit. You won’t get a SXSW panel with that kind of modesty.

A bigger concern, though, is that much of the data being gathered in “big data”—and the formulas used to analyze it—is controlled by private companies that can be positively opaque. Google has never made the search terms used in GFT public, and there’s no way for researchers to replicate how GFT works. There’s Google Correlate, which allows anyone to find search patterns that purport to map real-life trends, but as the Science researchers wryly note: “Clicking the link titled ‘match the pattern of actual flu actvity (this is how we built Google Flu Trends!)’ will not, ironically, produce a replication of the GFT search terms.” Even in the academic papers on GFT written by Google researchers, there’s no clear contact information, other than a generic Google email address. (Academic papers almost always contain direct contact information for lead authors.)

At its best, science is an open, cooperative and cumulative effort. If companies like Google keep their big data to themselves, they’ll miss out on the chance to improve their models, and make big data worthy of the hype. “To harness the research community, they need to be more transparent,” says Lazer. “The models for collaboration around big data haven’t been built.” It’s scary enough to think that private companies are gathering endless amounts of data on us. It’d be even worse if the conclusions they reach from that data aren’t even right.

TIME climate change

A Tale of Two Winters

Winter ice on Lake Michigan on Chicago
The winter was brutal in Midwestern cities like Chicago Scott Olson/Getty Images

If you lived east of the Rockies, you froze this winter. But the other side of the country experienced unusual warmth—and sometimes record-high temperatures

As I write this in New York, it’s 25 degrees Fahrenheit (-3.9 Celsius)—about 21 F degrees below normal for Mar. 13—and frankly, we’re all sick of this. For much of the eastern half of the country, 2013-14 has been the winter that will never end. And now the numbers are in from the National Oceanic and Atmospheric Administration (NOAA), and we’re mostly right: It’s been very cold. But probably not as cold as you think.

The average temperature for the continental U.S. from December to February was 31.3 F (-0.4 C), 1.0 F (0.55 C) below the 20th century norm. That’s hardly record-breaking—it’s only the 34th coldest winter in recorded U.S. history—but it’s a lot colder than last winter, where the average temperature was 34.3 F (1.3 C), which helps explain why it felt so frigid. Even so, the continental U.S. experienced a colder winter as recently as 2009-2010, well before anyone had heard of the term “polar vortex,” and back when only hurricanes—not snowstorms—were given names.

How cold you were this winter depended largely on where you were in the U.S. If you lived east of the Rockies—home to significantly more than half the U.S. population and sometimes, it seems, virtually all the U.S. media—you experienced below-average temperatures. Midwesterners had it particularly bad—most of the area north of the Ohio River was 7 to 15 F (4 to 8 C) below normal, which helps explain why at their peak in early March 91% of the Great Lakes were frozen over. It was nasty for the Northeast as well, where temperatures were largely cooler than normal, especially in the western regions near the lakes (pity the citizens of Erie, Pennsylvania, where temperatures were nearly 5 F, or 2.75 C, below normal for the winter.) From Washington D.C. to Caribou, Maine, it seems that not a single town in the Northeast had above-normal temperatures this winter.

That wasn’t the case in the West, though. California—already in an incredibly severe drought—had the warmest winter on record, with average temperatures of 48.0 F (8.9 C), some 4.4 F (2.2 C) above the 20th century average and nearly 1 F (0.55 C) hotter than the previous warmest winter, in 1980-81. That’s a reminder of just how big the U.S. is, and how variable weather can be—which brings us to climate change. Scientists are going to have fun figuring out just what was behind phenomena like the polar vortex (one theory is that higher temperatures in the Arctic could impact the jet stream, allowing colder Canadian air to sweep down to the East). But a nasty winter in New York City no more disproves climate change than an all-time hot winter in California clinches the case for global warming. Climate change is a global phenomenon and a long-term one, which is why icy temperatures along the East Coast in January are a lot less important than the fact that the global land and ocean surface average temperature for January was 1.17 F (0.65 C) above the 20th century norm, which made it the fourth-warmest January on record globally.

Barring even weirder weather, winter should finally be giving way to spring even in the coldest states in the U.S.—finally. But with scientists warning of a possible El Nino later this year—which usually brings hotter temperatures—we may end up looking back on the polar vortex with fondness as the dog days of August drag on. Maybe.

TIME energy

Frack, Rattle and Roll: Did Hydraulic Fracturing Play a Role in Ohio Quakes?

Fracking and Ohio quakes
Fracking wells may be triggering seismic activity MLADEN ANTONOV/AFP/Getty Images

Ohio officials shut down several wells after a pair of earthquakes. How much of a role does hydraulic fracturing play in the startling rise of quakes in the middle of the U.S.?

The mystery over the possible connection between hydraulic fracturing and earthquakes deepened on Mar. 10, when the Ohio government ordered a halt to operations at seven oil and gas wells near the Pennsylvania border after two quakes occurred earlier that day. While the quakes in Ohio’s Poland Township were too small to cause damage or injuries—they measured in at 2.6 and 3.0 on the Richter scale—the fact that one of the wells was undergoing fracking at the time of the quakes was enough for the Ohio Department of Natural Resources (ODNR) to suspend drilling operations in the area. “The decision was made out of an abundance of caution after analyzing location and magnitude data provided by the U.S. Geological Services” ODNR spokesman Mark Bruce said in an emailed statement.

Other than that, Ohio officials haven’t been saying much about the possible connection of the quakes to fracking operations—and neither has Hilcorp Energy, the Texas-based company operating in the area, which said in a statement that “we are not aware of any evidence to connect our operations to these events.”

It will take more research to know if fracking at those wells directly led to the small quakes, but it’s not impossible. While there is a stronger connection between earthquakes and deep injection wells—where wastewater left over from fracking is disposed of by being piped at high pressures deep underground—there have been a few instances in which the act of fracking itself seems to have made the earth move. (In case you haven’t been paying attention, fracking involves the fracturing of shale rock thousands of feet below the ground, using millions of gallons of water and chemicals, to free up trapped oil and natural gas.) Quakes in British Columbia, England and south-central Oklahoma have been traced back to fracking—and since Ohio officials say there were no disposal wells in the area where the quakes occurred, it’s definitely possible that fracking could have played a role here as well, as retired Columbia University geology professor John Armbruster told the Columbus Dispatch:

It’s an area which (before 2011) had no history of earthquakes. It looks very, very suspicious.

What’s definitely suspicious is the astounding increase in earthquake activity in parts of the central and eastern U.S.—the same areas that have taken part in the fracking boom, as this chart from the USGS shows:

Nearly 450 earthquakes with a magnitude of 3.0 and larger occurred in the region in the four years from 2010-2013, over 100 per year on average, compared to an average rate of 20 earthquakes per year observed from 1970-2000. Last month, Oklahoma was hit by a wave of more than 150 minor earthquakes over the course of a week, including one that had a magnitude of 3.8, and today 10% of the quakes felt in the U.S. occur in the Sooner State. All of this is happening against the backdrop of the fracking revolution. In Ohio, oil production doubled between 2012 and 2013, and natural gas production increased by two and a half times.

The reason fracking itself does not trigger detectable seismic activity all that often is that the forces involved are relatively weak, and the fragile shale rock tends to fracture before it can build up much strain—which is, after all, the point of fracking. That doesn’t mean it’s impossible, just that it seems to pose less of a risk that deep injection wells, which involve far greater amounts of liquid and which have been known to trigger quakes since the 1960s. Here’s how the USGS put it:

Wastewater injection increases the underground pore pressure, which may, in effect, lubricate nearby faults thereby weakening them. If the pore pressure increases enough, the weakened fault will slip, releasing stored tectonic stress in the form of an earthquake. Even faults that have not moved in millions of years can be made to slip and cause an earthquake if conditions underground are appropriate.

Fracking has boomed across the country, as this excellent map from the Post Carbon Institute shows:

All the wastewater created by those fracked oil and gas wells has to go somewhere—hence the concurrent boom in disposal wells. Ohio has more than 188 such wells, with more being drilled, in part to take wastewater from Pennsylvania fracking after regulators in that state ordered oil and gas companies to stop dumping waste in streams. And while most of the quakes happening in frackland have been small, there have been some bigger ones, including a 5.7 magnitude quake in Nov. 2011 in Prague, Oklahoma that a USGS study this week linked to a disposal well. “The observation that a human-induced earthquake can trigger a cascade of earthquakes, including a larger one, has important implications for reducing the seismic risk from wastewater injection,” the study’s coauthor, USGS seismologist Elizabeth Cochran, said in a statement.

So induced earthquakes are definitely one more reason to worry about the rapid spread of fracking. But like most of the other concerns—potential groundwater contamination, spills and accidents, stress on small town infrastructure—seismic risk should be manageable with the right regulations. The USGS notes that there are some 30,000 wastewater disposal wells around the country, and “very few” seem to have the potential to cause quakes. Geologists know where fault lines are, and if we listen to them, we should be able to ensure that any new wells, whether drilled to get gas and oil or to store wastewater, are well clear of them. But until we do, don’t expect the shaking to stop.

TIME climate change

How Climate Change Drove the Rise of Genghis Khan

Mongol herdsmen
New research suggests that climate change may have helped the rise of the Mongol empire Evin Krajick—Earth Institute, Columbia University

The Mongol warlord built the world's largest land-based empire. But he couldn't have done it without a change in climate

In the late 1100s, the Mongol tribes were split by dissension, a threat to no one but themselves. By the early decades of the 1200s, the tribes had become a united force that rained havoc on its neighbors, expanding in every direction on a wave of horses. Eventually the Mongols would establish the largest land empire in history, ruling over modern Korea, China, Russia, eastern Europe, southeast Asia, Persia, India and parts of the Middle East. To this day the DNA of the Mongols can be found throughout the territories that once made up their empire.

The difference was Genghis Khan, the warlord who united the tribes and launched them on their wave of unstoppable conquest. But the Mongol Empire wasn’t solely the product of Genghis’s will. As a fascinating new study in the Proceedings of the National Academy of Science (PNAS) demonstrates, the rise of the Mongols may have owed just as much to beneficial changes in the climate that made the grasslands of the Mongol steppes green and verdant, fueling the horses that were the backbone of the empire’s military. Climate change helped make the Mongol Empire possible.

The PNAS study came from research done by the tree-ring scientists Neil Pederson at Columbia University’s Lamont-Doherty Earth Observatory and Amy Hessl at West Virginia University. On a research trip to Mongolia in 2010, Pederson, Hessl and their colleagues discovered a stand of stunted Siberian pine trees in the Khangai Mountains. The trees—some of which were still alive—were ancient, some more than 1,100 years old. Old trees provide a living history book of the climate. During warm, wet years, the trees grow more, and the rings inside the trunk that mark those years are wider. The opposite happens during dry years, when the rings would be narrow.

Counting back to the late 1100s, just before the rise of Genghis Khan, the tree-ring data indicated that the Mongol steppes had been in the grip of an intense drought, one that could have helped drive the years of division among the Mongol tribes as they competed for scarce resources. But the tree-rings showed that the years between 1211 and 1225—a period of time that coincided with the meteoric rise of Genghis Khan, who died in 1227—were marked by unusually heavy rainfall and mild temperatures. It didn’t turn Mongolia’s harsh steppes into Maui, but the warmer climate would have stimulated the growth of the grasslands that fed the Mongols’ vital herds of horses and livestock. Given that each Mongol warrior had five or more horses, the energy represented by that additional grass would have helped fuel their astounding rate of expansion.

As Hessl put it in a statement:

The transition from extreme drought to extreme moisture right then strongly suggests that climate played a role in human events. It wasn’t the only thing, but it must have created the ideal conditions for a charismatic leader to emerge out of the chaos, develop an army and concentrate power. Where it’s arid, unusual moisture creates unusual plant productivity, and that translates into horsepower. Genghis was literally able to ride that wave.

Of course, climate change was hardly the only factor in the Mongols’ wave of conquest. Genghis used that supply of horses to form the greatest cavalry force the world had yet seen, one capable of rolling over opposing militaries. But it seems likely that he benefited from that unusual bout of climate change, just as civilizations ranging from the Anasazi in the American Southwest to the Angkor in Southeast Asia were likely laid low by shifts in climate that led to sudden, devastating drought.

In recent decades Mongolia’s climate has been changing even faster than in the rest of the world, with temperatures in parts of the country rising by as much as 4.5 F over the past 40 years. At the same time, the country has been hit by severe summer droughts followed by a dzud, or a long, harsh winter. The same tree rings that revealed the climactic history of the Mongol empire show that the most recent drought, from 2002 to 2009, compares in its severity only to those dry periods in the late 1100s. The droughts and the dzuds have killed millions of animals and ruined the livelihood of Mongolia’s herders, forcing them to more en masse to the swollen capital of Ulaanbaatar. Climate change is still putting Mongolians on the move—but this time, there’s no end in sight.

TIME climate change

Malaria Climbs Mountains as the Climate Warms

Malaria mosquito
Climate change will expand the range of mosquitoes that transmit malaria UIG/Getty Images

New research says that climate change will cause mosquitos to move into previously bug-free high-altitude territory, bringing the debilitating and often deadly disease with them as they climbs up warming hilly terrain

Malaria is one of the most common—and deadly—infectious diseases in the world, sickening more than 300 million people a year and killing over 600,000 people. But because it’s a mosquito-borne disease—the parasite that causes malaria is passed to human beings by mosquito bites—its range has been limited to warmer tropical areas, the so-called “malaria belt.” And even within tropical countries, altitude matters: the disease is much less common in tropical highlands, where colder temperatures slow down both the mosquito and the development of the parasite within it. It’s not for nothing that 19th century British colonists would build hill stations in malaria-prone countries like India, to escape both heat and disease.

So it’s not surprising either that scientists have been trying to find out for years whether climate change might expand the range of malaria, putting millions of people who live in tropical highlands at risk. Warmer temperatures should mean more malaria, but in recent years the number of cases has actually fallen dramatically, largely because of renewed efforts to fight the disease. But now a new study in Science makes a strong case that as the climate warms, malaria will indeed be on the march, expanding its range to previously safe high-altitude territory, putting even more pressure on prevention campaigns—and if those fail, leading to more deaths.

Researchers from the London School of Hygiene and Tropical Medicine and the University of Michigan sifted through regional records in Ethiopia and Colombia, two tropical countries with highland territory, looking at malaria cases from 1990 to 2005 in Colombia and 1993 to 2005 in Ethiopia. They corrected for other factors that might influence malaria cases—mosquito control programs, for example, which lead to fewer of the insects; and rainfall, which leads to more—and found that the median altitude of malaria cases moved higher in warm years, and lower during cooler yields. All else being equal, as the planet warms, it seems likely that malaria will become more dangerous to more people.

“This is indisputable evidence of a climate effect,” said Mercedes Pascual, a disease ecologist at Michigan and one of authors of the Science paper. “Our findings here underscore the size of the problem and emphasize the need for sustained intervention efforts in these regions, especially in Africa.”

One thing that will make the problem worse is that people who live in tropical highlands tend to be much more vulnerable to malaria parasites to begin with because they’ve never been infected before. In an earlier paper, the Science researchers estimated that a 1° C (1.8° F) temperature increase could lead to an additional 3 million malaria cases in Ethiopian children, assuming control methods weren’t strengthened. And that’s the key point. While global warming will put more people around the world at risk for malaria and other tropical diseases, climate is far from the only factor at work. Developed cities like Singapore are well within the malaria belt, but the disease has been virtually eradicated there thanks to stringent control methods. Malaria was rampant in U.S. states like Georgia as late as the 1920s, but it’s long gone now, eliminated by control efforts that led to the creation of the Centers for Disease Control. And even in Africa, malaria incidences have fallen by 31% since 2000— as the climate has warmed—and globally 3.3 million malaria deaths have been avoided thanks to the work of institutions like the Gates Foundation. Malaria, like many infectious diseases, is first and foremost a problem of development and poverty—and when those are addressed, infections fall.

But by expanding the range of malaria, climate change will make a tough challenge all the more difficult. It’s just one more way carbon can kill.

TIME Solar Power

A Bright Year for Solar in the U.S.—But There Are Clouds on the Horizon

The solar industry is growing in the U.S., but a trade war could change that Don Emmert—AFP/Getty Images

Energy harvested from the Sun was the second-biggest source of new electricity generation capacity in 2013, but there are clouds on the horizon as a trade war between the U.S. and China stands to throw a monkey wrench in the works

You don’t get any brighter than the reflecting mirrors at the just-opened Ivanpah Solar Power Facility, in California‘s Mojave desert. When I visited the project back in May, I was warned not to look directly at the mirrors, lest my eyeballs end up as scorched as some of the birds that have flown through the 1,000° F-plus (538° C) heat generated by the solar towers. The picture is almost as bright for solar as a whole in the U.S. According to statistics released today by the Solar Energy Industries Association, a trade group, demand for solar increased by 41% in 2013, with 4.75 gigawatts of photovoltaic panels installed last year. (1 GW is about enough energy to power 750,000 homes.) That made solar the second-biggest source of new generation power in the U.S. after natural gas, which is still benefiting from the shale revolution. By the end of 2013, there were more than 440,000 operating solar electric systems in the U.S., with more than 12 GW of photovoltaic (PV) and nearly 1 GW of concentrated solar power.

While big utility scale plants like Ivanpah, which harnesses the heat of the sun with concentrated solar mirrors, got most of the headlines, it was small-scale residential systems that drove much of the demand last year. Residential projects increased by 60% over 2012 as the price of installing solar fell and as customers took advantage of leasing options—offered by companies like Solarcity, which I wrote about last year—that allowed them to purchase panels with little money up front. The growth was rolling throughout 2013, with residential installations increasing 33% in the last quarter of 2013, and should continue this year. That financing market is growing: Mosaic, an Oakland-based startup launched by the climate activist Billy Parish, just began offering a home solar loan that allows consumers the chance to borrow the cost of a solar system over 20 years. “2013 offered the U.S. solar market the first real glimpse of its path toward mainstream status,” said Shayle Kann, vice president of GTM Research, which follows the clean tech market.

(MORE: The Power—and Beauty—of Solar Energy)

Bright times for solar, indeed—and that’s just in the U.S. Last year China installed at least 12 gigawatts of solar capacity, at least 50% more than any other country had ever built in a single year. But that’s where things get cloudy. The U.S. solar boom has been fueled in part by cheap solar panels from China, which have helped bring down the cost of solar power—now 15% cheaper than it was in 2012. But those same cheap Chinese panels have hurt domestic manufacturers of solar PV, even as they’ve helped installers like Solarcity. Several domestic solar manufacturers—led by SolarWorld, an American arm of a German company—have complained that the Chinese government is unfairly subsidizing national solar PV manufacturers, which allows them to undercut their American competitors.

In response, the U.S. government agreed in 2012 to impose tariffs of 24 to 36% on Chinese PV panels. But that made little difference—Chinese companies just outsourced much of their production to Taiwan. This year, however, SolarWorld brought a new suit in response, pushing the U.S. to extend those tariffs to Chinese panels made in Taiwan. Last month, the U.S. International Trade Commission said it would move forward with an investigation, and is set to issue a preliminary ruling by the end of March. If those tariffs are indeed extended, you can expect solar power in the U.S. to get more expensive, slowing down growth and hitting installers—who employ far more Americans than U.S. solar manufacturers do—very hard, especially since China has already said it would impose retaliatory tariffs. More expensive panels would likely depress demand for solar in the U.S., hurting installers.

There’s some truth to the argument that China may be intentionally driving down the price of solar panels to allow its companies to dominate the industry. But if so, the strategy hasn’t been that effective—a number of Chinese manufacturers have gone bankrupt, including Suntech, which was until recently the world’s biggest panel maker by volume. The U.S. solar industry is at a tipping point, poised to grow its way out of niche status and potentially change the way Americans think—and more importantly, pay for—energy. It’d be a shame if a 21st century industry gets tripped up by 19th century trade politics.

(MORE: Solar Powered Plane Soars Across the U.S.)

TIME Food & Drink

Our Global Diet Is Becoming Increasingly Homogenized—and That’s Risky

Bananas are increasingly popular around the world, but they're vulnerable to a new disease Ronaldo Schemidt—AFP/Getty Images

A new study confirms that worldwide, we're increasingly eating foods from the same small number of staple crops, which makes the global food supply vulnerable to new diseases and pests

All it takes is a trip to the closest Whole Foods to discover how much more varied the offerings of an American grocery store have become in recent years. Organic asparagus from Mexico, papaya from Hawaii, dry scallops from Nantucket Bay—the foodstuffs available to American consumers have never been more diverse. And on a country by country basis, that diversity is growing around the world, as people take advantage of economic growth and urbanization to move away from basic staples like rice and beans, adding meat and dairy and processed foods, while liberalized trade rules have allowed the spread of global food brands. Whether you’re in New York or Nairobi or Nagoya, chances are you have access to a greater variety of food than your parents or your grandparents once did.

But even as the offerings in each individual country become more diverse, the global diet as a whole—what people actually buy and eat—is becoming more homogenized, and that’s a dangerous thing. Those are the conclusions of a new paper published in the Proceedings of the National Academy of Sciences. Researchers from around the world went through 50 years of data gathered by the U.N.’s Food and Agriculture Organization to identify trends in the global menu. They found that human diets have grown increasingly similar—by a global average of around 36%—as a few staple crops like wheat and maize (corn) and soybeans come to play a bigger and bigger part of mealtime, displacing regional crops like cassava and sorghum.

“More people are consuming more calories, protein and fat, and they rely increasingly on a short list of major food crops, like wheat, maize and soybean, along with meat and dairy products, for most of their food,” said Colin Khoury, a scientist at the Colombia-based International Center for Tropical Agriculture (CIAT) and the lead author of the paper, in a statement. “These foods are critical for combating world hunger, but relying on a global diet of such limited diversity obligates us to bolster the nutritional quality of the major crops, as consumption of other nutritious grains and vegetables declines.

(MORE: Whole Food Blues: Why Organic Agriculture May Not Be So Sustainable)

The conclusion shouldn’t be surprising to any world traveler who has noticed that you can get Mexican in Malaysia, sushi in South Africa and McDonalds just about everywhere. On a country by country basis, that can mean more choice and variety—Americans would never have eaten sushi 100 years ago and Japanese weren’t chowing down on hamburgers. But on a global level is all evens out, as the diets of individual countries become more and more similar.

While cheaper wheat and soybeans—much of which is consumed in processed food or in meat by grain-fed animals—has introduced new foods to billions of poor people who used to be dependent on a very limited diet, there are obvious drawbacks. The Westernized diet that’s sweeping the world has contributed to the rise in global obesity, which has nearly doubled since 1980, and the resulting spread of metabolic diseases like diabetes. The carbon footprint of crops like maize and wheat, and especially meat and dairy, is often bigger than that of the foodstuffs they’re displacing, amplifying agriculture’s role in climate change. And just as the homogenization of global culture through Hollywood mega-blockbusters and the spread of English has led to the crowding out of regional identity and language, the homogenization of the global diet could result in the loss of unique crops and obscure delicacies.

But the bigger problem is that a global diet that overwhelmingly depends on just a few staple crops is extremely vulnerable to any new diseases, pests or climatic changes that could threaten those plants. Just look at the banana, which has become the world’s most valuable fruit, with exports that reached 16.5 million metric tons in 2012. Americans alone eat more bananas than apples and oranges put together. But a pair of diseases are ravaging existing banana crops. Black Sigatoka, a disease that blackens bananas and can cut yields in half, is showing resistance to the fungicide that has long been used to control it. Worse, Foc Tropical Race 4, a disease that attacks the ubiquitous Cavendish banana variety, is spreading through Asia and is now threatening Latin America, which produces 70% of the world’s $8.9 billion banana export crop.

The reason Cavendish bananas now make up 99% of the bananas eaten in the developed world is because they could survive an earlier version of the plant disease called Race 1. Over the first half of the 20th century, that pathogen drove what had been the world’s only export banana—the Gros Michel—to virtual extinction. (The losses caused by Race 1 were so great that they inspired the 1922 song “Yes, We Have No Bananas,” which as Homer Simpson once noted, is just so sad.) As Gwynn Guilford writes in Quartz, the damage to the global banana industry could be even worse if “banana HIV,” as some have called Race 4, spreads globally:

And at $8.9 billion, bananas grown for export are only a fraction of the $44.1 billion in annual banana and plantain production—in fact, bananas are the fourth-most valuable global crop after rice, wheat, and milk. Where are the rest of those bananas sold? Nearly nine-tenths of the world’s bananas are eaten in poor countries, where at least 400 million people rely on them for 15-27% of their daily calories. And that’s the really scary part. Since the first Panama disease outbreak, bananas have evolved from snacks into vital sustenance. And this time there’s no back-up banana variety to feed the world with instead.

That’s true for too many of the increasingly narrow number of crops that the world depends on today. A homogenized global diet isn’t just unhealthy and boring; like a stock portfolio with just a few holdings, it’s very, very vulnerable to any kind of disaster.

(MORE: Vital Farms: Raising the Ultra-Organic Egg)

TIME health

Thanks to Climate Change, West Nile Virus Could Be Your New Neighbor

Asian Tiger Mosquito
Asian tiger mosquitoes are a major vector for West Nile virus Getty Images

A new study shows how climate change will contribute to the spread of the mosquito-borne West Nile virus

Invasive species aren’t just species — they can also be pathogens. Such is the case with the West Nile virus. A mosquito-borne virus identified in the West Nile subregion in Uganda in 1937 — hence the name — West Nile wasn’t much of a concern to people elsewhere until it broke out of Africa in 1999. The first U.S. cases were confirmed in New York City in 1999, and it has now spread throughout much of the world. Though 80% of infections are subclinical — meaning they yield no symptoms — those who do get sick can get very sick. The virus can lead to encephalitis — inflammation of the brain and nervous system — and even death, with 286 people dying from West Nile in the U.S. in 2012. There were more than 5,500 cases reported that year, and the scary thing is that as the climate warms, West Nile will continue to spread.

That’s the conclusion of a new study from a team of researchers in the U.S., Britain and Germany, including those at the Center for Tropical Research at UCLA’s Institute of the Environment and Sustainability. In a study published in the journal Global Change Biology, the researchers took climate and species-distribution data, and created models that try to project the spread of the virus as the globe warms. West Nile virus is carried by mosquitoes, and infected insects transmit the virus to human beings with a bite. But birds play a role too — if bitten by an infected mosquito, birds can generate high levels of the virus in their bloodstream, and can then transmit it to uninfected mosquitoes, which in turn can infect people. The biggest indicator of whether West Nile virus will occur is the maximum temperature of the warmest month of the year, which is why the virus has caused the most damage in hot southern states like Texas.

The UCLA model indicates that higher temperatures and lower precipitation will generally lead to more cases of West Nile, as well as the spread of the virus to northern territories that haven’t yet been affected by it. In California alone, for example, more than half of the state will see an increased probability of West Nile in the decades to come, and by 2080 the virus may well be prevalent in parts of southern Canada, and as far north as northern British Columbia, as you can see in this map:

The UCLA model looks only at climate data and doesn’t take into account the kind of control methods that can be used to combat West Nile on the ground, including pesticide spraying and land-use changes that deny mosquitoes the pools of stagnant water they use as breeding sites. That’s important to remember: while climate change can raise the risk of typically tropical diseases like West Nile or malaria, smart control efforts can offset at least some of that danger. (Malaria used to be common throughout much of the South — which is easily warm enough in the summer for the disease — before steps were taken to eliminate it, a process that led to the creation of the Centers for Disease Control and Prevention.) But the UCLA study underscores the fact that climate change operates as a threat multiplier for tropical diseases, one that will allow pathogens to invade new territory — and, ultimately, us.

TIME endangered species

Save the Polar Bear—Today Especially

One of the planet's most charismatic creatures is being driven into the sea—literally. But there are ways to save the species

It’s International Polar Bear today, so if you live within shouting distance of the Arctic Circle, hug the closest polar bear. (Actually do not do that—an adult male polar bear is nearly half a ton of hungry predator and they are extremely dangerous.) Still, the beasts deserve a little tenderness.

The polar bear is now considered a vulnerable species, under threat from the loss of its sea ice habitat. To draw attention to their plight, Google is now offering glimpses of polar bears in their native environment, via its Street View program. Cameras in Cape Churchill and Wapusk National Park in northern Manitoba captured images of polar bears doing their polar bear thing during an annual gathering in the region in October and November. You can see pictures of polar bears sparring, and a mother nursing her cub, all against the flat white and brown background of the Arctic. The footage was taken with Google’s Street View Trekker—15 cameras mounted on a backpack—from aboard the decidedly off-road vehicles known tundra buggies

“It provides an opportunity to document what it looks like now, the potential to document what it looks like next year, five years from now, 10 years from now,” Krista Wright, executive director of the conservation group Polar Bear International, told the CBC.

Many scientists and conservationists fear that there may be far fewer polar bears in even that single-decade time frame, thanks chiefly to the effects of climate change. Polar bears use sea ice as a platform to reach their prey, chiefly seals, and summer sea ice is melting fast. Despite a rebound from a record low in 2012, the extent of Arctic sea ice is generally trending downwards, often dramatically. As the ice vanishes, polar bears are forced to swim longer and longer distances to reach those hunting platforms, which is taking a toll on the species.

Exactly how vulnerable polar bears are is not clear, partially due to the fact that they live in such a forbidding climate and are themselves not exactly friendly. That makes getting a proper count challenging. (Google is helping with this as well: researchers are using Google Earth satellite images to count polar bears from space.) Still, most experts agree that there are about 20,000 to 25,000 polar bears alive, scattered around the Arctic—a perilously small number though some subpopulations have rebounded, in part because of restrictions on hunting. There’s also evidence that polar bears are changing their dietary habits, possibly to adapt to the loss of sea ice, shifting from seals to snow geese, caribou and berries. But polar bear subpopulations are still trending downward in many areas of the Arctic, and if climate change keeps vaporizing sea ice, the pressure on the bears will only increase.

Of course, that’s true of many, many species; in fact, a new study in the journal Nature Climate Change just found that global warming dramatically increases the risk of extinction for amphibians and reptiles. Yet how many other species are so popular that Coca-Cola will change the color of its cans just to draw attention to their plight, as the company did in 2011? Last year a policy paper in Conservation Letters laid out an ambitious plan to save polar bears in the face of global warming, even going so far as to feed starving bears directly—an amazing thought, given the obvious risks. Why go to such great lengths to save the polar bear, and not, say Mexico’s critically endangered pygmy raccoon?

The truth is there’s no perfect reason, but it’s the sort of triage we’ll be doing more and more often in the future as we face down the sixth extinction. (For more on that, check out Elizabeth Kolbert’s excellent new book on the subject.) Which brings us back to Google Street View and those candid shots of polar bears in their element. There is something majestic about a polar bear against the backdrop of the Arctic, something wild and worth saving. And the polar bear dearly needs saving.

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