October 30, 2013
In 2013, if you’re someone who cares about the environment, your first and foremost concern is probably climate change. After that, you might worry about things like radioactive contamination, collapsing honeybee colonies and endangered ecosystems, among other contemporary environmental perils that fill recent news headlines.
But a number of researchers in the field are focused on a problem that has faded out of the news cycle: the piles of garbage that are growing around the world.
A recent World Bank report projected that the amount of solid waste generated globally will nearly double by the year 2025, going from 3.5 million tons to 6 million tons per day. But the truly concerning part is that these figures will only keep growing for the foreseeable future. We likely won’t hit peak garbage—the moment when our global trash production hits its highest rate, then levels off—until sometime after the year 2100, the projection indicates, when we produce 11 million tons of trash per day.
Why does this matter? One reason is that much of this waste isn’t handled properly: Millions of plastic fragments flooding the world’s oceans and disrupting marine ecosystems, and plenty of trash in developing countries is either burned in incinerators that generate air pollution or dumped recklessly in urban environments.
Even if we sealed all our waste in sanitary landfills, however, there’d be a much bigger problem with our growing piles of garbage—all the industrial activities and consumption that they represent. “Honestly, I don’t see waste disposal as a huge environmental problem in itself,” explains Daniel Hoornweg, one of the authors of the World Bank report and a professor at the University of Ontario, who authored an article on peak garbage published today in Nature. “But it’s the easiest way to see how the environment is being affected by our lifestyles overall.”
The quantity of garbage we generate reflects the amount of new products we buy, and therefore the energy, resources and upstream waste that are involved in producing those items. As a result, Hoornweg says, “solid waste is the canary in the coal mine. It shows how much of an impact we’re having globally, as a species, on the planet as a whole.”
This is why he and others are concerned about peak garbage and are attempting to project our trash trends decades into the future. To make such estimates, they rely upon projections of population grown along with a number of established trends in waste: People create much more trash when they move to cities (and begin consuming more packaged products) and when they become wealthier (and increase their consumption overall).
Historical data indicate, though, that a certain point, the per capita amount of garbage generated in wealthy societies tends to level off—apparently, there’s only so much a person can consume (and only so much trash they can produce). As a result, in many of the world’s wealthy countries, the average person produces slightly more than 3 pounds of solid waste per day, and that number isn’t estimated to change significantly going forward.
The amount of people moving to cities and consuming more in the rest of the world, however, is projected to surge over the coming century—and even as the resulting waste production finally levels off in East Asia around 2075, it’ll be offset by continuing increases in the growing urban areas of South Asia and Sub-Saharan Africa, the authors of the Nature article note. As a result, unless we significantly reduce the per capita waste production of wealthy city-dwellers,
the world as a whole won’t hit peak garbage until sometime after 2100, when we’re creating three times as much trash as we are right now.
How can we address our population’s growing consumption problem? One of the main things to consider is that it’s largely driven by people in the developing world voluntarily moving to cities and improving their standard of living, both signs of economic progress in their own right. But even if these demographic shifts continue, the projected rates of garbage growth aren’t entirely inevitable, because there are cultural and policy dimensions to waste production.
The average person in Japan, for example, creates about one-third less trash than an American, even though the two countries have similar levels of GDP per person. This is partly because of higher-density living arrangements and higher prices for imported goods, but also because of norms surrounding consumption. In many Japanese municipalities, trash must be disposed in clear bags (to publicly show who isn’t bothering to recycle) and recyclables are routinely sorted into dozens of categories, policies driven by the limited amount of space for landfills in the small country.
Creating policies that give incentive to people to produce less waste elsewhere, therefore, could be a way of tackling the problem. But, because our garbage is just the end result of a host of industrial activities, some reduction measures will be less important than others. Designing recyclable packaging would be a much less useful solution, for instance, than designing products that don’t need to be replaced as often. Even better, as Hoornweg and his coauthors argue in the article, would be accelerating ongoing increases in education and economic development in the developing world, especially Africa, which would cause urban population growth—and also the amount of trash produced per capita—to level off sooner.
Garbage might seem like a passé environmental issue, but it’s a proxy for nearly all the others—so tripling our global rate of garbage production is a particularly bad idea. “The planet is having enough trouble handling the cumulative impacts that we’re subjecting it to today,” Hoornweg says. “So with this projection, we’re basically looking at tripling the total amount of stress that we’re putting the planet under.”
October 17, 2013
In recent years, scientists have discovered that chimpanzees, our closest relatives, are capable of all sorts of human-like behaviors that go far beyond tool use.
They self-medicate, eating roughage to clear their intestines of parasites. Baby chimps use human-like gestures to convey their needs to adults. Studies suggest even that chimps have a seemingly innate sense of fairness and go through mid-life crises.
Now, new research indicates that chimps’ vocalized communications are a bit closer in nature to our own spoken languages as well. A new study published in PLOS ONE shows that, when chimps warn each other about impending danger, the noises they make are much more than the instinctive expression of fear—they’re intentionally produced, exclusively in the presence of other chimps, and cease when these other chimps are safe from danger.
This not might sound like much, but linguists use intentionality as a key hallmark of language. Those who argue that apes aren’t capable of language—and that the apes who’ve been trained in sign language are merely engaging in rote memorization, not true language acquisition—point to a lack of intentionality as one of the reasons why. So the study shows that, in their natural environment, chimps do use vocalizations in a way more similar to language than previously thought.
The researchers, led by Anne Marijke Schel of the University of York, studied a community of 73 chimps that lives in Uganda’s Budongo Forest Reserve. To simulate danger, they used the skin of a dead African Rock Python—one of the chimps’ natural predators—to create a fake python, with fishing line attached to its head so they could make it move realistically.
Over the course of nearly a year in the field, they repeatedly placed this artificial predator in the forest with a camera rolling, waiting for unsuspecting chimps—sometimes alone, sometimes with other chimps—to come upon it so they could closely study their response. Typically, when the chimps saw the snake, they were startled, and made one of two different vocalizations, which the researchers identified as ‘huus’ (softer calls, with less alarm) or ‘waas’ (louder, more alarmed calls).
When the researchers analyzed the specific responses, they found that when other chimps were around, the startled chimps were much more likely to make the ‘waas’ rather than ‘huus.’ Moreover, the chimps clearly observed the location of other chimps and whether they were paying attention, and kept sounding the alarm until the others had fled and were safe from danger. The length of time they sounded the alarm, meanwhile, wasn’t linked with their own distance from the snake, further supporting the idea that the call was an intentional warning to others.
The researchers also took note of the pre-existing relationships among chimps (within the social hierarchy, some are closer than others) and found that closer relationships were more likely to trigger alarms. “It was particularly striking when new individuals who had not seen the snake yet, arrived in the area,” Schel said in a press statement. “If a chimpanzee who had actually seen the snake enjoyed a close friendship with this arriving individual, they would give alarm calls, warning their friend of the danger. It really seemed the chimpanzees directed their alarm calls at specific individuals.”
The authors argue that these characteristics—specifically, the fact that alternate vocalizations were employed in different circumstances, that they were made with the attention of the audience in mind and that they were goal-directed, continuing until they’d successfully warned other chimps so they fled—show that the noises are more than reflections of instinctive fear. Rather, they’re a tactical, intentional form of communication.
This observation, the authors say, may also tell us something about the evolution of human language. Gestural theories on the origin of language contend that spoken language evolved from hand gestures, and cite the fact that non-human primates (a model for primitive hominids) exclusively use gestures for true communication, merely making vocalizations based on engrained instinct, rather than calculated intention.
But this discovery of intentional warnings in chimps seems to upend that idea, suggesting that primitive hominids too were able to communicate via both vocalizations and gestures. This indicates, the researchers say, that spoken language may have evolved from multiple different sources, both gestures and vocal calls.
September 23, 2013
Most people think of history as a series of stories—tales of one army unexpectedly defeating another, or a politician making a memorable speech, or an upstart overthrowing a sitting monarch.
Peter Turchin of the University of Connecticut sees things rather differently. Formally trained as a ecologist, he sees history as a series of equations. Specifically, he wants to bring the types of mathematical models used in fields such as wildlife ecology to explain population trends in a different species: humans.
In a paper published with colleagues today in the Proceedings of the National Academy of Sciences, he presents a mathematical model (shown on the left of the video above) that correlates well with historical data (shown on the right) on the development and spread of large-scale, complex societies (represented as red territories on the green area studied). The simulation runs from 1500 B.C.E. to 1500 C.E.—so it encompasses the growth of societies like Mesopotamia, ancient Egypt and the like—and replicates historical trends with 65 percent accuracy.
This might not sound like a perfect accounting of human history, but that’s not really the goal. Turchin simply wants to apply mathematical analysis to the field of history so that researchers can determine which factors are most influential in affecting the spread of human states and populations, just as ecologists have done when analyzing wildlife population dynamics. Essentially, he wants to answer a simple question: Why did complex societies develop and spread in some areas but not others?
In this study, Turchin’s team found that conflict between societies and the development of military technology as a result of war were the most important elements that predicted which states would develop and expand over the map—with those factors taken away, the model deteriorated, describing actual history with only 16 percent accuracy.
Turchin began thinking about applying math to history in general about 15 years ago. “I always enjoyed history, but I realized then that it was the last major discipline which was not mathematized,” he explains. “But mathematical approaches—modeling, statistics, etc.—are an inherent part of any real science.”
In bringing these sorts of tools into the arena of world history and developing a mathematical model, his team was inspired by a theory called cultural multilevel selection, which predicts that competition between different groups is the main driver of the evolution of large-scale, complex societies. To build that into the model, they divided all of Africa and Eurasia into gridded squares which were each categorized by a few environmental variables (the type of habitat, elevation, and whether it had agriculture in 1500 B.C.E.). They then “seeded” military technology in squares adjacent to the grasslands of central Asia, because the domestication of horses—the dominant military technology of the age—likely arose there initially.
Over time, the model allowed for domesticated horses to spread between adjacent squares. It also simulated conflict between various entities, allowing squares to take over nearby squares, determining victory based on the area each entity controlled, and thus growing the sizes of empires. After plugging in these variables, they let the model simulate 3,000 years of human history, then compared its results to actual data, gleaned from a variety of historical atlases.
Although it’s not perfect, the accuracy of their model—predicting the development and spread of empires in nearly all the right places—surprised even the researchers. “To tell the truth, the success of this enterprise exceeded my wildest expectations,” Turchin says. “Who would have thought that a simple model could explain 65% of variance in a large historical database?”
So why would conflict between societies prove to be such a crucial variable in predicting where empires would form? “To evolve to a large size, societies need special institutions that are necessary for holding them together,” Turchin proposes. “But such institutions have large internal costs, and without constant competition from other societies, they collapse. Only constant competition ensures that ultrasocial norms and institutions will persist and spread.”
The model shows that agriculture is a necessary but not sufficient precondition for a complex society, he says—these states can’t form without farming, but the persistent presence of competition and warfare is necessary to forge farming societies into durable, large-scale empires. Conventional analyses of history could come to this same conclusion, but they wouldn’t be able to demonstrate it in the same mathematically-based way. Using this approach, on the other hand, Turchin’s group could remove the influence of warfare and see the model’s accuracy in describing real historical data plummet.
Of course, there are limitations to viewing history through math—humans are more complicated than numbers. “Differences in culture, environmental factors and thousands of other variables not included in the model all have effect,” Turchin says. “A simple general model should not be able to capture actual history in all its glorious complexity.”
Still, the model is a unique and valuable tool. Going forward, Turchin’s team wants to develop it further—adding more nuance (such as including the quality of agricultural productivity, rather than merely toggling if farming exists in a given area or not) to improve on that 65 percent accuracy. Additionally, they’d like to expand the model, applying it to more recent world history and also pre-Columbian North America, if they can find relevant historical data.
Based on his experiences so far, Turchin thinks they’ll be successful in developing a model that better reflects the the rise and fall of civilizations. “It turns out that there is a lot of quantitative data in history,” he says, “you just have to be creative in looking for it.”
August 21, 2013
As the inane car insurance commercials suggest, ancient humans were smarter than we give them credit for. They created some of the same words we still use today. They even brewed beer.
Now evidence suggests that they had some culinary flair as well. A new analysis of food residue encrusted on millennia-old pottery shards collected from sites in Germany and Denmark shows that prehistoric humans used the spice mustard seed to season the plant and animal staples that made up the bulk of their diet.
As part of the new study, published today in PLOS ONE, researchers from the UK’s University of York and elsewhere chemically analyzed the residue on ancient pieces of pottery that are part of the collections of a trio of museums—the Kalunborg and Holbæk Museums, in Denmark, along with the Schleswig-Holstein Museum in Germany. The artifacts were originally excavated from three different sites in the same two countries which are between 5,750 and 6,100 years old, an era during which people in the area were in the midst of transitioning from hunter-gatherer to nomadic societies.
When analyzing the food gunk encrusted on the pottery, the team looked specifically at phytoliths, microscopic granules of silica that plants produce and store in their cells after absorbing silicic acid from the soil. Different plants produce slightly different types of phytoliths, so by closely examining them, the scientists were able to figure out which sorts of plants had been cooked in the pottery.
They found that the residue from the insides of the pots had much larger quantities of phytoliths than the outsides, confirming that the granules were indicative of cooking use. When they compared the size and shape of the phytoliths to databases of hundreds of modern plant phytoliths, they most closely matched that of mustard seed. The team also found oil residue from both land animals and marine life, and other plant residues that come from starchier plants—suggesting that these prehistoric people were cooking fish, meat and plants in the pots and seasoning them with the mustard seed.
For the scientists, the most surprising aspect of the find is the pots’ age. Until now, the oldest clear evidence for spice use was the discovery of residue from ginger and turmeric in 4,500-year-old cooking pots linked to the Harappa culture, in Northern India. But the new find shows that humans were using spices more than 1,000 years earlier.
In Northern Europe, this was a time soon after domestic animals, such as goats and cattle, were introduced, dramatically remaking these societies’ lifestyles. Still, at this point, crops were not known to have been domesticated—these people were still centuries away from the fully settled agricultural societies that would eventually dominate.
Previously, experts thought that the use of plants in cooking during this era was solely motivated by a need for calories. But the presence of mustard seed, which provides essentially no caloric or nutritional value, indicates that these prehistoric people valued taste as much as we do.
August 12, 2013
Hawaiians knew the value of locally sourced foods decades before the term locavore became a buzzword at every Brooklyn, Portland and Northern California farmer’s market. Because of the 50th state’s isolation, Hawaii has always relied upon its easy access to bountiful local seafood to feed the islands. Seafood-heavy restaurant menus testify to this fact.
Many tourists, it turns out, view these colorful fish-filled menus as a great souvenir of their time in Hawaii. Over the years, thousands of pinched Hawaiian menus have found their way back to the mainland in suitcases and travel bags, only to wind up sitting on an attic shelf or stuffed into a drawer for the next 80-odd years. Kyle Van Houtan, an ecologist at Duke University and leader of NOAA’s Marine Turtle Assessment Program, realized the menus could serve a higher purpose than gathering dust. The stuff of breakfast, lunch and dinner plates, he realized, could potentially fill in gaps of historic records of fish populations by showing what species were around in a given year.
The basic premise is this–if a species of fish can be readily found in large enough numbers, then it’s likely to make it on restaurant menus. Van Houtan and colleagues tracked down 376 such menus from 154 different restaurants in Hawaii, most of which were supplied by private menu collectors.
The team compared the menus, printed between 1928 and 1974, to market surveys of fishermen’s catches in the early 20th century, and also to governmental data collected from around 1950 onward. This allowed the researchers to compare how well the menus reflected the kinds of fishes actually being pulled from the sea.
The menus, their comparative analyses revealed, did indeed closely reflect the varieties and amounts of fish that fishermen were catching during the years that data were available, indicating that the restaurants’ offerings could provide a rough idea of what Hawaii’s fisheries looked like between 1905 and 1950–a period that experienced no official data collection.
Prior to 1940, the researchers report in the journal Frontiers in Ecology and the Environment, reef fish, jacks and bottom fish commonly turned up on menus. These include pink snapper, green snapper and amberjack. But that quickly changed after Hawaii received its statehood in 1959. By then, those once popular fishes appeared on fewer than 10 percent of menus. Some, such as Hawaiian flounder, Hawaiian grouper and Hawaiian barracuda disappeared from menus completely after 1960. In their place, large-bodied pelagic species, or those that live in deep open water such as tuna and swordfish, began to turn up served with a wedge of lemon. By 1970, these large pelagic fishes were on nearly every menu the team examined.
Diners’ changing tastes and preferences may explain part of this shift away from the nearshore and out to the deep sea, but the researchers think there is more to the story than foodie trends alone. Instead, this sudden shift likely reflects a decline in nearshore fish populations. Because both the early and later menus corroborate well with known fisheries data, the 1930s and 40s menus likely represent a boom in nearshore fisheries, with the 1950s menus standing in as a canary in the coal mine signaling the decline of those increasingly gobbled-up populations. “This helps us to fill in a large gap–between 1902 and 1948–in the official fishery records,” Van Houtan said in an email. “But it also shows that by the time Hawaii became a U.S. state, its inshore fish populations and reefs were in steep decline.”
Those species that disappeared from menus more than a century ago are still present today, but their populations around Hawaii remain too low to support targeted commercial fishing. Some of them are considered ecologically extinct, meaning that their abundance is so low that they no longer play a significant role in the environment. While a few of those species have returned to Hawaiian menus recently, they are usually imported from Palau, the Marshall Islands or the Philippines, rather than being fished from Hawaiian waters.
The menu trick can’t work for every animal in the sea. Populations dynamics of some species, such as shrimp and mollusks, cannot be inferred from the menus since those animals mostly came from mainland imports. On the other hand, other species, the researchers know, were fished at that time but are not reflected in the menus. Sea turtles, for example, used to be harvested commercially, but they were butchered and sold at local markets rather than at tourist trap restaurants.
Investigating past populations of turtles was in fact the motivation for this project. “Green turtles here nearly went extinct in the early 1970s, and lots of blame was put on increasing tourism and restaurant demand,” Van Houtan explains. He decided to examine just how much restaurants contributed to that near-miss for the green turtles, so he started collecting menus. However, he says, “we were in for a surprise.”
He and his colleagues first got ahold of 22 menus from the early 1960s, only to find that not a single listed turtle soup, turtle pie, turtle stir-fry or any other turtle-themed recipe. He found another 30, then 25 and then 40 menus. By this time, he was 100 menus deep, and had found only a single mentioning of turtle anything. “By doing much background research on the fishery, we discovered turtles were sold over-the-counter at fishmongers and meat markets in Chinatown and other open air markets in Honolulu,” he says. The restaurants, in other words, were not to blame–at least not for the turtles.
Left with all of these menus, however, the team decided to take a closer look into the marine life listed there. “When I assembled those data, it became a story of its own, helping to fill a significant gap in our official government records,” he says.
Collecting all of those menus, he adds, was no small task. He hustled between appointments with Hawaiiana experts, archivists, publishers, Hawaiian cooking historians, tourism historians, museums and libraries. But some of the more pedestrian venues proved most useful, including eBay collectors who would occasionally invited Van Houtan over to dig through boxes of hoarded menus. “I met a lot of interesting people along the way,” he says.
Scientists often turn to historic documents, media stories, artwork, photographs or footage to infer past events or trends. And while researchers have used menus to track a seafood item’s popularity over time, not many think to use dining data as a proxy for fish population abundance. The most interesting thing about the study, Van Houtan thinks, is “not that we used menus as much as that no one previously thought to.”
That, he says, and a few of the more odd-ball items that turned up on some of the old menus, like magnesium nitrogen health broth. “I have no idea what that was,” he says. “And pineapple fritters with mint sauce doesn’t sound very yummy to me either!”