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Barely Any Land on Earth Is Untouched by Humans

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A new study, published in the journal Proceedings of the National Academy of Sciences (PNAS), suggests that nearly all of the world’s unspoiled nature is entirely gone. In fact, most of it disappeared at least several thousand years ago, thanks to human activity, The Washington Post reports.

Nicole Boivin from the University of Oxford and the Max Planck Institute for the Science of Human History teamed up with scientists from the UK, U.S., and Australia to pore over archaeological, fossil, and ancient DNA data. The researchers concluded that humans began affecting the world’s natural ecosystems long before cars, housing developments, or factories existed. “Pristine’ landscapes simply do not exist and, in most cases, have not existed for millennia,” they said in a release.

The paper outlines the major phases when humans shaped the world and altered our world’s ecosystems: global human expansion during the Late Pleistocene; the Neolithic spread of agriculture; the era of humans colonizing islands; and the emergence of urban trading societies.

Here’s a rough timeline: modern humans arose in Africa roughly 190,000 years ago, and by 50,000–70,000 years ago (some say even earlier) had begun venturing out of the home continent. Human hunting is presumed to have helped drive the extinctions of some types of large or giant animals, called megafauna, in Australia, Tasmania, and later the Americas between 50,000 and 10,000 years ago. One example of our early impact occurred some 20,000 to 23,000 years ago, when humans introduced a new species—a marsupial that lived in New Guinea, now called the northern common cuscus—to Indonesia and other regions in the South Pacific.

Astoundingly enough, all this activity preceded the advent of agricultural societies during the Holocene period, which began about 11,700 years ago. (We still live in the Holocene.) By this time, the human species was widely dispersed throughout the world. Farmers began favoring certain animal, tree, and plant species, which thrive today thanks to our ancestors’ green thumbs. They used fire to burn land for agriculture, and to draw animals out into the open for easier hunting. Humans’ agricultural practices also affected everything from forests (after all, we had to clear land for planting food) to the atmosphere’s greenhouse gas composition. Sometime during this era, livestock and poultry were domesticated and spread from the Near East to across the globe.

Meanwhile, seafaring societies began spreading pests from one island to another, since various species of rats, mice, insects, and lizards stowed away onboard sailors’ boats. As humans colonized these new lands, they also threatened indigenous animals, contributed to deforestation, introduced new crops, generally altered these virgin landscapes for good.

As humanity’s become more advanced, our impact on our environment has grown. During the Industrial Revolution, factory emissions dramatically altered atmospheric carbon dioxide concentrations. In fact, researchers have even argued that these gases mark the end of the Holocene and the beginning of a new geological epoch called the Anthropocene.

In short, humans have a long, long history of affecting and changing the natural world. However, the study’s researchers don’t necessarily think that’s a bad thing. We’ll never be able to undo the damage, but we can mindfully monitor and shape the way we physically impact the world.

“The fact that we’ve been changing the planet for so long, with both positive and negative consequences, suggests that we can try to take control of the transformation, and make it less detrimental,” Boivin told The New Yorker

[h/t The Washington Post]

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Today's Wine Glasses Are Almost Seven Times Larger Than They Were in 1700
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Holiday party season (a.k.a. hangover season) is in full swing. While you likely have no one to blame but yourself for drinking that second (or third) pour at the office soiree, your glassware isn't doing you any favors—especially if you live in the UK. Vino vessels in England are nearly seven times larger today than they were in 1700, according to a new study spotted by Live Science. These findings were recently published in the English medical journal The BMJ.

Researchers at the University of Cambridge measured more than 400 wineglasses from the past three centuries to gauge whether glass size affects how much we drink. They dug deep into the history of parties past, perusing both the collections of the Ashmolean Museum of Art and Archaeology at the University of Oxford and the Royal Household's assemblage of glassware (a new set is commissioned for each monarch). They also scoured a vintage catalog, a modern department store, and eBay for examples.

After measuring these cups, researchers concluded that the average wineglass in 1700 held just 2.2 fluid ounces. For comparison's sake, that's the size of a double shot at a bar. Glasses today hold an average of 15.2 fluid ounces, even though a standard single serving size of wine is just 5 ounces.

BMJ infographic detailing increases in wine glass size from 1700 to 2017
BMJ Publishing group Ltd.

Advances in technology and manufacturing are partly to blame for this increase, as is the wine industry. Marketing campaigns promoted the beverage as it increasingly became more affordable and available for purchase, which in turn prompted aficionados to opt for larger pours. Perhaps not surprisingly, this bigger-is-better mindset was also compounded by American drinking habits: Extra-large wineglasses became popular in the U.S. in the 1990s, prompting overseas manufacturers to follow suit.

Wine consumption in both England and America has risen dramatically since the 1960s [PDF]. Cambridge researchers noted that their study doesn't necessarily prove that the rise of super-sized glassware has led to this increase. But their findings do fit a larger trend: previous studies have found that larger plate size can increase food consumption. This might be because they skew our sense of perception, making us think we're consuming less than we actually are. And in the case of wine, in particular, oversized glasses could also heighten our sensory enjoyment, as they might release more of the drink's aroma.

“We cannot infer that the increase in glass size and the rise in wine consumption in England are causally linked,” the study's authors wrote. “Nor can we infer that reducing glass size would cut drinking. Our observation of increasing size does, however, draw attention to wine glass size as an area to investigate further in the context of population health.”

[h/t Live Science]

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Researchers Pore Over the Physics Behind the Layered Latte
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The layered latte isn't the most widely known espresso drink on coffee-shop menus, but it is a scientific curiosity. Instead of a traditional latte, where steamed milk is poured into a shot (or several) of espresso, the layered latte is made by pouring the espresso into a glass of hot milk. The result is an Instagram-friendly drink that features a gradient of milky coffee colors from pure white on the bottom to dark brown on the top. The effect is odd enough that Princeton University researchers decided to explore the fluid dynamics that make it happen, as The New York Times reports.

In a new study in Nature Communications, Princeton engineering professor Howard Stone and his team explore just what creates the distinct horizontal layers pattern of layered latte. To find out, they injected warm, dyed water into a tank filled with warm salt water, mimicking the process of pouring low-density espresso into higher-density steamed milk.

Four different images of a latte forming layers over time
Xue et al., Nature Communications (2017)

According to the study, the layered look of the latte forms over the course of minutes, and can last for "tens of minutes, or even several hours" if the drink isn't stirred. When the espresso-like dyed water was injected into the salt brine, the downward jet of the dyed water floated up to the top of the tank, because the buoyant force of the low-density liquid encountering the higher-density brine forced it upward. The layers become more visible when the hot drink cools down.

The New York Times explains it succinctly:

When the liquids try to mix, layered patterns form as gradients in temperature cause a portion of the liquid to heat up, become lighter and rise, while another, denser portion sinks. This gives rise to convection cells that trap mixtures of similar densities within layers.

This structure can withstand gentle movement, such as a light stirring or sipping, and can stay stable for as long as a day or more. The layers don't disappear until the liquids cool down to room temperature.

But before you go trying to experiment with layering your own lattes, know that it can be trickier than the study—which refers to the process as "haphazardly pouring espresso into a glass of warm milk"—makes it sound. You may need to experiment several times with the speed and height of your pour and the ratio of espresso to milk before you get the look just right.

[h/t The New York Times]

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