TIME

The Seismic Link Between Fracking and Earthquakes

Environmentalists fear that fracking could cause more quakes if it expands to California Photo by David McNew/Getty Images

New research indicates that wastewater disposal wells—and sometimes fracking itself—can induce earthquakes

Ohio regulators did something last month that had never been done before: they drew a tentative link between shale gas fracking and an increase in local earthquakes. As fracking has grown in the U.S., so have the number of earthquakes—there were more than 100 recorded quakes of magnitude 3.0 or larger each year between 2010 and 2013, compared to an average of 21 per year over the preceding three decades. That includes a sudden increase in seismic activity in usually calm states like Kansas, Oklahoma and Ohio—states that have also seen a rapid increase in oil and gas development. Shale gas and oil development is still growing rapidly—more than eightfold between 2007 and 2o12—but if fracking and drilling can lead to dangerous quakes, America’s homegrown energy revolution might be in for an early end.

But seismologists are only now beginning to grapple with the connection between oil and gas development and earthquakes. New research being presented at the annual meeting of the Seismological Society of America this week shows that wastewater disposal wells—deep holes drilled to hold hundreds of millions of gallons of fluid produced by oil and gas wells—may be changing the stress on existing faults, inducing earthquakes that wouldn’t have happened otherwise. Those quakes can occur tens of miles away from the wells themselves, further than scientists had previously believed. And they can be large as well—researchers have now linked two quakes in 2011 with a magnitude greater than 5.0 to wastewater wells.

“This demonstrates there is a significant hazard,” said Justin Rubinstein, a research geophysicist at the U.S. Geological Survey. “We need to address ongoing seismicity.”

Rubinstein was speaking on a teleconference call with three other seismologists who have been researching how oil and gas development might be able to induce quakes. All of them noted that the vast majority of wastewater disposal sites and oil and gas wells weren’t connected to increased quake activity—which is a good thing, since there are more than 30,000 disposal wells alone scattered around the country. But scientists are still trying to figure out which wells might be capable of inducing strong quakes, though the sheer volume of fluid injected into the ground seems to be the driving factor (that’s one reason why hydraulic fracturing itself rarely seems to induce quakes—around 5 million gallons, or 18.9 million L, of fluid is used in fracking, far less than the amount of fluid that ends up in a disposal well).

“There are so many injection operations throughout much of the U.S. now that even though a small fraction might induce quakes, those quakes have contributed dramatically to the seismic hazard, especially east of the Rockies,” said Arthur McGarr, a USGS scientist working on the subject.

What scientists need to do is understand that seismic hazard—especially if oil and gas development in one area might be capable of inducing quakes that could overwhelm structures that were built for a lower quake risk. That’s especially important given that fracking is taking place in many parts of the country—like Oklahoma or Ohio—that haven’t had much experience with earthquakes, and where both buildings and people likely have a low tolerance to temblors. Right now there’s very little regulation regarding how oil and gas development activities should be adjusted to reduce quake risk—and too little data on the danger altogether.

“There’s a very large gap on policy here,” says Gail Atkinson, a seismologist at the University of Western Ontario. “We need extensive databases on the wells that induce seismicity and the ones that don’t.”

So far the quakes that seem to have been induced by oil and gas activity have shaken up people who live near wells, but haven’t yet caused a lot of damage. But that could change if fracking and drilling move to a part of the country that already has clear existing seismic risks—like California, which has an estimated 15 billion barrels of oil in the Monterey Shale formation that could only be accessed through fracking (limited fracking has been done in California, but only in the lightly populated center of the state). Environmentalists who seek to block shale oil development in the Golden State have seized on fears of fracking-induced quakes, and a bill in the state legislature would establish a moratorium on fracking until research shows it can be done safely.

Regulation is slowly beginning to catch up. In Ohio, officials this month established new guidelines that would allow regulators to halt active hydraulic fracturing if seismic monitors detect a quake with a magnitude of 1.0 or higher. But it will ultimately be up to the oil and gas industry to figure out a way to carry out development without making the earth shake.

“I am confident that it is only a matter of time before we figure out how to exercise these technologies in a way that avoids significant quakes,” says Atkinson. Otherwise the fracking revolution may turn out to be short-lived.

TIME

It’s Time to Stop Ignoring the Bad Air We Breathe

Air pollution
Nearly half of Americans breathe unhealthy air Photo by David McNew/Getty Images

A survey shows nearly half of all Americans breathe unhealthy air — but air pollution doesn't get the attention it deserves

Take a look outside your window. Chances are the air you’ll see is far cleaner than it was decades ago. Since 1980 levels of ozone pollution — one of the main ingredients in smog — have fallen by 25% in the U.S., while nitrogen dioxide has fallen by 55% and sulfur dioxide by 78%. The change is visual too — the smog-obscured skies that were once a constant backdrop to cities like Los Angeles in the 1960s and ’70s are far less common. It’s easy to assume that America won the war on air pollution, and to look with pity on developing cities like Beijing and New Delhi where the air is still poisoned.

There’s just one problem with that sense of satisfaction: the data doesn’t back it up. According to a new report from the American Lung Association (ALA), nearly 148 million Americans live in areas where smog and soot particles have led to unhealthy levels of pollution. That means that for almost half of all Americans, simply breathing can be dangerous. Even worse, the report shows that some aspects of air quality have been deteriorating over the past few years in many cities — from 2010 to 2012, ozone worsened in 22 of the 25 biggest metropolitan areas, including cities like New York and Chicago. “Air pollution is not just a nuisance or the haze we see on the horizon; it’s literally putting our health in danger,” Bonnie Holmes-Gen, senior policy director of the ALA in California, told the Los Angeles Times. “We’ve come a long way, but the status quo in not acceptable.”

The news is far from all bad. Thanks in part to the retirement of a number of older coal-fired power plants, levels of particulate pollution — soot, in other words — have been dropping in recent years, with cities like Philadelphia and Indianapolis recording their lowest levels yet. And historically, we’re far better off — as Brad Plumer notes over at Vox, air pollutants as a whole have fallen 72% since the Clean Air Act was passed in 1970, even as the economy, population and energy use have all risen.

But as the ALA report makes clear, some of that progress is being lost, in part thanks to climate change — one environmental challenge we’re very much not meeting. Rising levels of ozone pollution have been linked to warmer temperatures, which will make it that much tougher to fight smog in the future. And the government could have done more — in 2011, President Obama went against the recommendations of the Environmental Protection Agency (EPA) and rejected a proposal that would have tightened the ozone standard to between 60 and 70 parts per billion. (The level is currently at 75 ppb, set by former President George W. Bush, who was not exactly known as an environmental paragon.)

Those regulatory battles matter because it’s becoming increasingly clear that healthy air is a moving target. The more scientists learn about the health impacts of air pollution, the more dangerous it appears — even at comparatively low levels. Last October the World Health Organization (WHO) officially declared air pollution to be a carcinogen, connecting it directly to lung cancer as well as bladder cancer. And bad air doesn’t just hurt the lungs — a raft of studies have connected air pollution, especially soot, to cardiovascular disease, even triggering heart attacks. Even autism has been linked to pollution. In March the WHO estimated that outdoor air pollution caused 3.7 million premature deaths globally in 2012 — nearly three times the number of people who die each year from tuberculosis.

Climate change gets most of the environmental attention, with reason — its effects are already being felt, and it has the potential to radically change our world for the worse. But air pollution is sickening and killing millions of people around the world right now. And unlike global warming, the technological and regulatory solutions to conventional air pollution already exist. That’s why it was good news yesterday when the U.S. Supreme Court upheld the EPA’s ability to control coal-fired power-plant emissions in 28 states. The decision excited greens because it indicates the court will eventually back even more controversial carbon regulations that the Obama White House is busy formulating now, but the regulation that was upheld — the Cross-State Pollution Rule — will prevent an estimated 45,000 deaths a year from conventional air pollution once it’s in place.

Air pollution remains stubbornly difficult to eliminate, in part because of the vagary of the wind itself, which separates the victims of pollution from its source. As Justice Ruth Bader Ginsburg wrote in her decision yesterday, quoting from the Book of John: “The wind bloweth where it listeth, and thou hearest the sound therof, but canst not tell where it cometh, and whither it goeth.” But if we can’t control the air, we can control what we put into it — and protect ourselves.

 

TIME Environment

From ‘Gale’ to ‘Inconceivable,’ Ranking Tornado Strength

Ranking tornado strength
Deadly tornadoes devastated the town of Vilonia, Arkansas on Apr. 27 Mark Wilson/Getty Images

As tornadoes blast across the southeastern U.S., a look at how officials gauge just how powerful a killer twister is

Tornado season began with a crash in the southeastern U.S. this week, where dozens of twisters ripped across Mississippi, Arkansas and Alabama. At least 29 people have died in the storms — and with more tornadoes forecast as the weather system moves further east, that number will almost certainly rise.

It’s the suddenness of tornadoes, as much as their power, that accounts for the lives they take. Meteorologists can forecast when and where storms that can produce tornadoes will appear, but they can rarely give residents more than 15 minutes of warning before a twister touches down. Unlike hurricanes, which meteorologists can now track days in advance with increasing precision, tornadoes remain stubbornly unpredictable, although forecasters at the National Oceanic and Atmospheric Administration (NOAA) are working on ways to extend that warning time.

That unpredictability also makes it harder to assess the destructive power of a tornado in real time. Hurricane categories are based on sustained wind speeds in a storm—a Category 1 storm would have sustained winds 74-95 mph (119-153 kph), while a Category 5 storm would have sustained winds of over 157 mph (252 kmh) (“Sustained wind speeds” means the average wind speed in a storm over 10 minutes). The damage a hurricane can cause doesn’t always conform completely to categories. Superstorm Sandy, for instance, wasn’t even a Category 1 hurricane by the time it made landfall in New Jersey, but still caused more than $60 billion in damage, largely due to the size of its storm surge. But more wind generally means more danger—just ask the people of New Orleans, hit by Category 5 Hurricane Katrina in 2005.

Tornado strength is assessed on a different and slower scale, after the twisters have struck. When tornadoes occur, National Weather Service (NWS) officials are dispatched to survey the damage. They also reconstruct tornadoes’ life cycles, where they touched down—and how strong they were. Tornadoes are ranked on the Enhanced Fujita (EF) Scale, developed by a Japanese-American meteorologist who, not coincidentally, got his start studying the damage caused by the atomic bomb in Hiroshima. The original Fujita scale was based primarily on the damage a tornado did, with wind speed estimated after the fact. The scale ranked tornadoes from a F0 (Gale) to an F5 (Incredible), with an unofficial F6 category that would require winds in excess of 318 mph and which goes by the name Inconceivable—accurate, since no F6 tornadoes have ever been recorded.

The Enhanced Fujita scale was adopted in 2007. It was designed to more accurately reflect the actual damage a tornado had done on the ground. The EF scale uses 28 different damage indicators, ranging from small barns to hardwood trees to shopping malls—and each of those indicators is assessed based on several different points of possible damage. A shopping mall could range from damage that is just barely visible to complete destruction of some or all of the building. There’s a large database of how strong a tornado needs to be to cause certain kinds of structural damage, so meteorologists are able to use the final damage report to go back and estimate the tornado’s wind speed at the time of touchdown. The categories range from EF0—with three-second wind gusts of 65-85 mph (104-137 kph)—to EF5, with three second gusts over 200 mph (321 kph).

We won’t know the full strength of this week’s multiple tornadoes until NWS surveyors have had a chance to measure the damage on-site. But there has already been a pair of EF3 twisters this year, striking Arkansas and North Carolina on Apr. 27, and those tornadoes may be upgraded as full damage assessments are carried out. 2014 had been shaping up to be a quiet year for tornadoes—Apr. 27 marked the end of a string of 159 days without an EF3 or above tornado, and there had been only 93 tornado reports this year through Apr. 24. That changed this week—there were 87 tornado reports on Apr. 28 alone. And while no tornado that’s hit yet looks to be as strong as the EF5 twister that devastated Moore, Oklahoma last year, the season is far from done.

TIME health

Solving the Mystery Flu That Killed 50 Million People

The deadly 1918 flu pandemic
The 1918 flu pandemic killed an estimated 50 million people Photo Researchers via Getty Images

Researchers have wondered for decades why the 1918 flu disproportionately killed so many young people, but a new study in the Proceedings of the National Academy of Sciences suggests the answers are in the pattern of past flu infections

Years ago the environmental historian Alfred Crosby was at Washington State University, where he was teaching at the time, when on a whim he decided to pick up an old almanac from 1917. (This is apparently the kind of thing historians like to do in their spare time.) He looked up the U.S. life expectancy in that year—it was about 51 years. He turned to the 1919 almanac, and found about the same figure. Then Crosby picked up the almanac from 1918. The U.S. life expectancy in 1918 had fallen to 39 years. “What the hell happened?” Crosby told the New York Times writer Gina Kolata in her book Flu: The Story of the Great Influenza Pandemic of 1918. “ The life expectancy had dropped to what it had been fifty years before.”

What happened was the 1918 influenza pandemic. A virus that usually does little more than make people feel awful for a few days killed an estimated 50 million people worldwide, if not far more, with 650,000 people dying in the U.S. alone. The flu killed more people in a year than the bubonic plague killed in a century in the Middle Ages. Worst of all, this flu disproportionately took the lives of men and women in their 20s and 30s, while often sparing the very old and the very young—two population groups that are especially vulnerable to the flu in most years.

This has confounded scientists for almost a century, but a new study in the Proceedings of the National Academy of Sciences (PNAS) puts forward a fresh answer to one of the enduring mysteries of medical science. Researchers led by Michael Worobey of the University of Arizona reconstructed the origins of the 1918 pandemic, concluding that the pathogen arose when an existing human H1 flu virus acquired genetic material from a bird flu virus. That new H1N1 flu virus was able to evade immune systems, which helps explain why it infected more than a quarter of the U.S. population at the time. But it was young adults between the ages of 20 and 40 that died in the greatest number—and Worobey’s study suggests that the unusual death pattern was due as much to flus of the past as it was to the flu of 1918. “Prior immunity, or lack of it, seems to be the decisive factor,” says Worobey.

Flu viruses are constantly changing and mutating, which is why we can’t develop a lifelong vaccine for it the way we can for more stable viruses, like the ones that cause smallpox or the measles. A flu virus has two parts: hemagglutinin and neuraminidase proteins, shortened to HA and NA (and just H and N when naming a virus). It’s the HA protein that seems to drive our immune system response, as Worobey put it in a statement:

Imagine a soccer ball studded with lollipops. The candy part of the lollipop is the globular part of the HA protein, and that is by far the most potent part of the flu virus against which our immune system can make antibodies. If antibodies cover all the lollipop heads, the virus can’t even infect you.

Worobey and his colleagues looked back at the kinds of flu viruses that were in circulation in the decades preceding the 1918 pandemic by examining antibodies found in old blood samples. (Your immune system will produce customized antibodies in response to a flu infection, and those antibodies will remain in your body, which allows scientists to identify the genetic makeup of the virus that led to their creation.) It turns out people born between 1880 and 1900—the generation hit hardest by the 1918 flu—were mostly exposed during childhood to a H3N8 flu virus that began circulating during an earlier pandemic in 1889, but not to an H1 virus, which meant that generation had virtually no antibodies to fight it off.

By reconstructing the genetic origins of the 1918 flu, Worobey found that a version of that H1N1 flu virus was circulating for years before the pandemic began. Because flu strikes most commonly in childhood, those born after 1900 were more likely to have had previous exposure to an H1N1-like flu virus, which would have offered them some protection. Meanwhile those born before 1880 were more likely to have been exposed to the H1N8 flu strain that was prevalent when they were children. In both the very young and the old, having earlier exposure to an H1 flu—even one different from the strain that caused the 1918 pandemic—offered a level of protection not present in those who had never been infected by an H1 strain. That could explain the unusual mortality curve in the 1918 pandemic.

1918 flu mortality curve
The researchers found a remarkable overlap between death rates in various age groups in 1918 and childhood exposure to an H3 flu virus that was mismatched with H1N1 pandemic virus. Credit: Michael Worobey

Thankfully, no flu pandemic since 1918 has been anywhere near as deadly. The 2009 swine flu pandemic killed an estimated 284,000 people worldwide, comparable to flu deaths in a non-pandemic year. But two avian flu viruses — H5N1 and H7N9 — have for years been periodically jumping the species barrier and infecting human beings. And like the 1918 flu, H5N1 and H7N9 are unusually deadly, particularly for the young and elderly, respectively. “Lots of different age groups might be exposed to these viruses, but the virus that kills them is the one that’s mismatched to the virus they encountered as a child,” says Worobey.

The PNAS paper suggests that this might be due to past flu patterns as well, with both groups having been exposed to flu viruses in their youth that offered them little protection against the new pathogens. If either virus were to mutate to the point where it could spread easily in the human population, the results could be catastrophic.

But the PNAS paper offers hope that doctors could begin to design flu vaccination strategies that compensate for the strains that different age groups never experienced as children. Down the line, scientists may even be able to develop a universal flu vaccine that targets parts of the virus that almost never change from strain to strain. “This work is encouraging that possibility,” says Worobey. If we’re smart, the global catastrophe that was the 1918 pandemic will remain confined to the history books.

TIME health

Almost Half of Homeless Men Had a Previous Brain Injury

Homeless people and TBI
Past traumatic brain injuries were correlated with homelessness Getty Images

A new study of homeless men found that 45% of the subjects surveyed had experienced traumatic brain injuries in the past. Brain injuries can cause both cognitive and personality problems that researchers don't yet fully understand

Traumatic brain injuries (TBIs) happen in a moment: a jarring collision while playing sports, an accidental fall, a sudden bomb blast. But their effects can last for a lifetime. Cognition and decisionmaking abilities can be damaged. Mood and behavior can shift suddenly, sometimes resulting in increased aggression or reduced motivation. While most people who suffer a TBI will be able to continue on with their lives unchanged, a subset of victims are never the same. The trajectory of their life is altered permanently.

Just how altered isn’t clear, but a new study published in the journal CMAJ Open offers some sobering data about a possible connection between TBI and homelessness. Jane Topolovec-Vranic, a researcher in trauma and neurosurgery at St. Michael’s Hospital in Toronto, surveyed 111 homeless men recruited from a city shelter to see whether they had suffered a TBI sometime in their past. She found that 45% of them had experienced a traumatic brain injury at some point in their life. (Sadly, most of her subjects’ TBIs resulted from assault.)

“You could see how it would happen,” she says. “You have a concussion, and you can’t concentrate or focus. Their thinking abilities and personalities change. They can’t manage at work, and they may lose their job, and eventually lose their families. And then it’s a negative spiral” — a spiral that, for the men in Topolovec-Vranic’s study, ends up in a homeless shelter. There’s no clear data on how prevalent TBI is in the general population, which makes it difficult to say for sure whether the homeless men in Topolovec-Vranic’s study were injured at an unusually high rate. Hers was also a small study, which limits any larger conclusions about the connection between TBI and homelessness.

But the more we learn about the long-term effects of TBI, the more worrying such injuries become. Another study recently published in the Journal of Adolescent Health found that nearly half of all newly admitted adolescents to the New York penal system had a history of TBI. Studies have also shown that military veterans who suffered a TBI are more likely to commit suicide than those who didn’t.

Our brains are extraordinary machines, and we now know that they continue to change throughout our lives — for the better and, sometimes in the case of TBI, for the worse. Homelessness is sad enough in its own right, but the thought that a single traumatic brain injury could make that fate more likely is truly tragic.

TIME Environment

It’s Hard Out There for a Honeybee

Honeybees
Honeybees still face a variety of health threats Photographer's Choice RF via Getty Images

Honeybees in Kenya are infested with parasites, but they still thrive — unlike their American cousins. Are there lessons for U.S. beekeepers?

Commercial honeybees might be America’s unluckiest laborers. They’re infested with pests like the Varroa destructor mite and the Nosema ceranae parasite; infected with diseases like the Israeli paralytic virus and the tobacco ringspot virus; dosed with pesticides like clothianidin and imidacloprid; starved of nutrition thanks to crop monocultures; shipped around the country to be worked half to death in almond fields and apple orchards; and victimized by a still mysterious malady called colony-collapse disorder (CCD). It’s little surprise that U.S. beekeepers lost about a third of their colonies over the winter of 2012–13, and if early reports from states like Ohio are any indication, this year could be even worse.

But there’s a place where honeybees are apparently doing much better: East Africa. In a study that came out recently in the journal PLOS One, researchers from Kenya and the U.S. surveyed honeybee populations at 24 locations throughout the African country. And the scientists found that while honeybees in Kenya suffered from some of the same problems as their Western counterparts, the African bees remained much more robust. “I was amazed by the lack of manifestation of ill health in the bees,” Elliud Muli, lead author on the paper, told National Geographic.

What’s protected the Kenyan honeybees? African honeybees rarely encounter the sorts of pesticides that are in heavy use on American farms — and which pose a clear danger to American bees. The African bees also generally stay in one place, while the biggest honeybee keepers in the U.S. will move their colonies thousands of miles for major events like the California almond-tree pollination, which requires an astounding 60% of all hives in the U.S. Without those additional stressors, the Kenyan honeybees seem capable of thriving even in the presence of dangerous pests.

That doesn’t mean that pesticides alone are causing CCD — but they sure aren’t helping, as even the Environmental Protection Agency (EPA) has begun to realize. Last year the EPA ordered changes in the labeling of neonicotinoid pesticides, which have been linked to high rates of honeybee deaths and which have been banned in Europe. American honeybees also suffer from a lack of nutrition, as bee-friendly wild spaces are converted into corn or soybean fields that offer them little forage.

A Department of Agriculture program announced this winter will put $3 million toward encouraging farmers and ranchers in the Midwest to plant bee-friendly plants on the edges of their fields. That will help, but far more must be done. As I wrote in our TIME cover story on the subject last year, it’s as if the modern American environment itself is hostile to the health of honeybees. Even the hardest-working members of the animal kingdom can only take so much.

TIME TIME 100

The Green Heroes of the TIME 100

Tom Steyer is on the TIME 100
Steyer is one of several TIME 100 honorees fighting for the planet Harry E. Walker/MCT via Getty Images

Energy, climate, food and the environment—a number of selections from the TIME 100 are fighting for the planet

It’s that time of year again. The TIME 100 list of the most influential people in the world is officially out, and while boldface names like Beyoncé, Pope Francis and Robert Redford will get most of the attention, there’s also a surprising number of figures whose influence extends to the environment. A quick rundown:

  • Tom Steyer: Steyer became a billionaire as a bold hedge-fund trader. Now the San Francisco financier is betting some of his fortune on climate change, spending tens of millions of dollars to support candidates who are willing to act on global warming—and punishing those that won’t. Suddenly the Koch Brothers have competition.
  • Katharine Hayhoe: The bubbly Texas Tech climatologist has been doing work on climate change for years, but she came to the country’s attention earlier this month when she was featured in the premiere episode of Showtime’s global warming documentary Years of Living Dangerously. What sets Hayhoe apart from most climatologists is her faith: She’s an evangelical Christian, and proud of it. She’s made it her mission to bring the facts of climate change to her fellow believers.
  • Alice Waters: Waters all but kicked off the locavore revolution when she opened her Berkeley restaurant Chez Panisse in 1971. But in recent years she’s turned her focus to children, using her pioneering Edible Schoolyard Project to push the idea that kids should be able to learn about food and farming in schools. Waters continues to change the way Americans eat—from the ground up.
  • Yao Chen: Every Chinese knows the air quality in their country is bad and getting worse. But not every Chinese is willing to say that out loud. Yao is the exception. The beloved movie star has more than 66 million followers on Weibo, China’s microblogging network, and she uses that platform to raise concerns about the country’s poisoned air and water.
  • Jack Ma: The founder of the Chinese e-commerce site Alibaba, Ma has become one of China’s richest businessmen. But last year he stepped back from his business to become the chairman of the Nature Conservancy’s China program, taking on his country’s catastrophic pollution.
  • Kathryn Sullivan: NASA may get all the glory, but the National Oceanic and Atmospheric Administration (NOAA) forms the backbone of U.S. climate and weather research. NOAA is led now by Sullivan, part of the first class of female astronauts and a veteran of three space shuttle flights—including the one that deployed the Hubble Space Telescope.

 

TIME Environment

Lead Didn’t Bring Down Ancient Rome—But It’s Still a Modern Menace

Roman aqueducts led to lead contamination
Aqueducts like this one contaminated Roman tap water with lead Moment via Getty Images

Lead levels were high in ancient Rome's tap water—but not high enough to cause the collapse of its civilization

You could fill a book with theories on why the ancient Roman Empire declined and fell—which, in fact, is what the 18th British historian Edward Gibbon did in his magisterial Decline and Fall of the Roman Empire. But if you don’t have time to read the 3,000 or so pages in Gibbon’s full work, here’s one very simple theory: it was lead. Canadian scientist Jerome Nriagu published an influential 1983 paper arguing that high levels of the neurotoxin lead—which contaminated water and other beverages through lead aqueducts and lead cups—caused mental disabilities and erratic behavior among members of Roman high society. Nriagu even reviewed the personalities and habits of Roman emperors between 30 B.C. and 22o A.D.—a list that includes notorious nutjobs like Nero and Caligula—and concluded that two-thirds of them suffered from symptoms of chronic lead poisoning. It’s hard to keep an empire going when your living god of an emperor has been brain-poisoned.

An empire brought down by one of its signature innovations, the aqueduct — it’s a theory that has stuck with the public, although experts have long been skeptical of its merits. It turns out that the theory was half-right: In a new study in the Proceedings of the National Academy of Sciences (PNAS), a group of French and British researchers report that the tap water in ancient Rome was indeed contaminated with lead, with levels up to 100 times higher than those found in local spring water at the time. But while Roman tap water might not have passed modern-day standards, it’s almost certain that the contamination wasn’t extensive enough to be responsible for the collapse of Roman civilization.

As lead author Francis Albarede of Claude Bernard University in Lyon told the Guardian:

Can you really poison an entire civilization with lead? I think it would take more than lead piping in Rome to do that.

Still, any amount of lead can pose a danger to the human brain, especially those of young children, so Rome’s contaminated water couldn’t have helped. In fact, the more researchers learn about lead, the more dangerous it seems—and the more important it becomes to get lead out of the environment. There’s a fascinating body of research, summed up in this excellent piece by Mother Jones‘s Kevin Drumm, that links the drastic drop in violent crime in the U.S. over the past two decades to the phasing out of leaded gasoline in the early 1970s, which greatly reduced lead levels in the environment.

The theory is that children in the 1940s, 50s and 60s were exposed to high levels of lead in leaded gasoline and lead paint. High blood lead levels are directly correlated with a loss of IQ points. But more than that, lead seems to particularly damage the parts of the brain linked to aggression control and executive function. Lead seems to affect boys more—and men, of course, make up the vast majority of violent criminals. When those lead-exposed boys became young adults in the 1970s and 80s, it wasn’t surprising that so many of them fell into violent crime. But once they aged out by the 1990s, that cohort was replaced by a generation of children who largely hadn’t been exposed to high levels of lead, and violent crime dropped.

But while most—though not all—American children are no longer exposed to high levels of lead, it’s still a major problem in poorer countries around the world. NGOs like the Blacksmith Institute are working to clean up lead contamination, though far more needs to be done. Lead may not have brought down the Roman Empire—you’ll need to go back to Gibbon for that—but two thousand years later, it’s still a public health menace.

TIME Environment

The Earth Is Changing Rapidly. Can We Change Too?

Antarctica used to be warm
Moment/Getty Images

On Earth Day, we celebrate a planet that has nurtured human life. But it wasn't always so nice—and as the climate changes, it may get worse

I had the chance to see the Grand Canyon last week for the first time, and I can tell you this: it is really big. So big, in fact, that I led my partner on an endless walk along the rim, searching for the entrance a trail that would take us some of the way down the canyon. It turned out that I misread the map scale just a tiny bit. I think she may have forgiven me by now.

Of course, there’s more to the Grand Canyon than its sheer size: Its exposed rock reveals some 2 billion years of Earth’s geologic history, a span of time that is unfathomable by human beings (our species Homo sapiens is about 0.00005% as old as the oldest rock found in the Canyon). And even that time period covers less than half of the Earth’s age. Our planet is ancient, and the only constant over the course of its 4.54 billion-year history has been change—albeit change on a scale that almost always unfolds far too slow for us to realize it. If the Earth seems as solid as the ground beneath our feet, that’s only because we haven’t been around long enough to see just how unstable it really is.

That’s something to keep in mind as we celebrate the 45th Earth Day. Human civilization has flourished over the past ten thousand or so years largely because our species has been fortunate enough to arise during a Goldilocks (not too warm, not too cold) climatic period known as the Holocene. It’s an age that has proven ideal for agriculture and other activities that now support a human population of 7 billion-plus. But it hasn’t always been this way, as a new study that was published Monday in the Proceedings of the National Academy of Sciences demonstrates.

A team led by Yale University scientists used a new method to determine temperatures in the Earth’s past, measuring concentrations of rare isotopes in ancient fossil shells found in Antarctica. The researchers found that during the Eocene epoch—about 40 to 50 million years ago—temperatures in parts of Antarctica reached as high as 63 F (17 C), with an average of 14 C (57 F). That’s far above the mean annual temperature of Antarctica’s interior today, which registers at a frosty -70 F (-57 C), and closer to the kinds of temperatures you’d see in today’s San Francisco. Seawater around parts of Antarctica was even warmer, a balmy 72 F (22 C)—or about the same temperature as the tropical seas around Florida today.

If there were people living 40 million years ago—there weren’t, FYI—they could have been snorkeling off the coast of Antarctica’s Ross Island.

Why? Carbon dioxide levels in the atmosphere during the Eocene were much, much higher, perhaps as high as 2,000 ppm or more. Even though human beings have been pouring carbon into the atmosphere by the gigaton for decades, that’s still far higher than current levels, which stand at a little above 400 ppm. But even that increase has helped global temperatures rise by about 1.53 F (0.85 C) since 1880, and despite 45 Earth Days since the first in 1970, global carbon emissions just keep on growing, reaching a record 36 billion metric tons in 2013.

As Brad Plumer puts it over at Vox, our chances of keeping global temperature increase below 3.6 F (2 C)—a figure governments around the world have adopted as a climate change red line—seem vanishingly small:

If you look at the current rapid rise in global greenhouse-gas emissions, we’re on pace to blow past the 2°C limit by mid-century — and hit 4°C or more by the end. That’s well above anything once deemed “dangerous.” Getting back on track for 2°C would, at this point, entail the sort of drastic emissions cuts usually associated with economic calamities, like the collapse of the Soviet Union or the 2008 financial crisis. And we’d have to repeat those cuts for decades.

Needless to say, that’s unlikely. Barring some major political or technological revolution, our Earth will likely change more in the decades to come than it has for the entire lifespan of human civilization—and that change almost certainly won’t be for the better. As the PNAS study shows, the climate we think of as stable—the “long summer” of humanity—has been drastically different over the course of Earth’s deep past. The Earth will change. The question for the Earth Days to come is whether we can change, too.

TIME Environment

Portraits of the Planet for Earth Day

Looking at the Icebergs, Near Franklin Island, Ross Sea, Antarctica in 2006.
Looking at the Icebergs, Near Franklin Island, Ross Sea, Antarctica in 2006. Camille Seaman

Google+ and TIME teamed up to find beautiful pictures of our planet. Selections made by TIME's photo editors are featured on the massive NASDAQ billboard in Times Square on Earth Day.

The NASDAQ billboard in Times Square features Google+ users' earth day photos selected by TIME's photo editors.
The NASDAQ billboard in Times Square features Google+ users’ earth day photos selected by TIME’s photo editors. Wesley Houser / Google

Mars is nice and Jupiter has a big red spot, but there’s no more gorgeous planet in the known galaxy than Earth. On a day when we tend focus on the threats to the Earth—which are many—we should also take time to celebrate the varied beauty found throughout our home. Google+ collected photos from around the world tagged with #MyBeautifulEarth, and TIME editors culled through the images to find the very best. The pictures that appear below are visual reminders of the Earth’s diversity, from fathomless oceans to glowing volcanoes to alpine glaciers. The only constants are color—and overwhelming beauty. This planet is a never-ending feast for the eyes, which is one more reason why we should try to take care of it, on Earth Day and every day.

Your browser, Internet Explorer 8 or below, is out of date. It has known security flaws and may not display all features of this and other websites.

Learn how to update your browser