1 . The streets and roofs of cities all absorb heat, making some urban areas hotter than rural ones. These “urban heat islands” can also develop underground as city heat spreads downward, and subway tracks and other subsurface infrastructure (基础设施)  also constantly radiate warmth into the surrounding earth.

A new study of downtown Chicago shows underground hotspots may threaten the very same structures that give off the heat in the first place. “Without anyone realizing it, the city of Chicago’s downtown was deforming,” says study author Rotta Loria, an environmental engineer.

Humans aren’t the only potentially affected. “For a lot of things in the subsurface, it’s kind of ‘out of sight, out of mind’,” says Grant Ferguson, a geologist. But the underground world is full of creatures that have adapted to subsurface existence such as insects and snails. As the temperature rises because of climate change and underground urban development, scientists are keeping eyes on the potential implications for underground ecosystems.

But the question of how underground hotspots could affect infrastructure has gone largely unstudied. Because materials expand and contract with temperature change, Rotta suspected that heat coming from underground could be contributing to wear and tear on various structures. To understand how underground temperature difference has affected the ground’s physical properties, he used a computer model to simulate (模拟)  the underground environment from the 1950s to now—and then to 2050. He found that by the middle of this century, some areas may lift upward by as much as 0.50 inch or settle by as much as 0.32 inch, depending on the soil makeup of the area involved. Though these may sound like small displacements, Rotta says they could cause cracks in the foundations of some buildings, causing buildings to fall.

Kathrin Menberg, a geoscientist in Germany, says these displacement predictions are far beyond her guesses and could be linked to the soft, clay-heavy soils. “Clay material is particularly sensitive,” she says, “It would be a big issue in all cities worldwide that are built on such material.”

Like climate change above the surface, underground changes occur gradually. “These effects took decades to develop,” Ferguson says, adding that increased underground temperatures would likewise take a long time to dissipate on their own. “We could basically turn everything off, and it’s going to remain there, the temperature signal, for quite a while.”

But Ferguson says this wasted heat energy could also be reused, presenting an opportunity to both cool the subsurface and save on energy costs. Still, this assumption could fail as aboveground climate change continues to boost underground warming. However slowly, this heat will gather beneath our feet. “It’s like climate change,” Rotta Loria says. “Maybe we don’t see it always, but it’s happening.”

2 . The idea that aging reduces adults’ ability to imagine, a common theme in children’s literature, is contradicted by psychological research. While children are often portrayed as more imaginative, research indicates that adults not only keep this ability but sometimes surpass children in imaginative thinking.

Children are frequently celebrated for boundless imagination. Yet, research reveals that their make-believe games often center around realistic scenarios, such as cooking and cleaning, as demonstrated in a 2020 study published in Journal of Cognition and Development. Another study, lasting for four decades, also suggests that children are not naturally more imaginative than adults; their limitations result from a lack of knowledge and expertise to effectively use their imaginative capacity as adults.

Imagination may have evolved for considering alternatives to reality, but we use it most naturally to explore close alternatives, like preparing a different meal, rather than far alternatives, like riding on clouds. When we use imagination to envision far alternatives — to innovate or invent — we’re not digging into an inborn appreciation of the extraordinary; we’re using a tool designed to explore the ordinary. When considering alternatives to reality, we fix our attention on possibilities that are physically reasonable, statistically probable, socially conventional and morally permissible. When told about possibilities that violate such regularities, we usually deny they could happen. Generally speaking, our ideas about what could happen are firmly rooted in what we expect to happen.

This mindset is also particularly apparent in young children. In a 2018 study I co-designed with psychologist Jonathan Phillips, 4-year-olds were asked to help a distressed girl who disliked going to school due to missing her mother. Among all the solutions given, they perceived the only possible solution was for her mother to do something special after school to ease her concerns. Unexpected alternatives, such as snapping fingers and making it Saturday, wearing pajamas to school or lying about school being closed, were all regarded impossible. From this, we can conclude that children’s earliest intuitions (直觉力) about possibility confuse what could happen with what should happen.

Historically, the improbable event of traveling faster than a horse was considered impossible, as was traveling by air or traveling into space. Before the arrival of trains and planes, there were good reasons to think that people could travel only so far and only so fast. But these reasons were empirical (经验主义的), not logical. Imagination, on its own, lumps the improbable with the impossible, but we can combine imagination with other abilities — namely, knowledge and reflection — to separate the two. While imagination in children often subjects to expectation, adults can control their imaginative capacity for innovation by integrating it with accumulated knowledge and reflective thinking.

3 . The California sea otter (海獭), once hunted to the edge of extinction, has staged a thrilling comeback in the last century. Now, scientists have discovered that the otters’ success story has led to something just as remarkable: the restoration of their declining coastal marsh (沼泽) habitat.

Elkhorn Slough, a coastal marsh within Monterey Bay, had been experiencing severe damage. The root cause was a growing population of shore crabs, which fed heavily on the marsh plants, weakening the structural integrity of the habitat. Coastal marshes like these are not only natural defenses against storm waves but also serve as important carbon storage areas and water-cleaning systems.

The conservation-driven comeback of the sea otter has been crucial. California’s coastlines were once alive with sea otters. Sadly, they were nearly wiped out at the hands of fur traders. In the 1980s, conservation efforts aided these otters in re-occupying large areas of their former range. Now, Elkhorn Slough has the highest concentration of sea otters in California, with a population of about 100. By naturally feasting on crabs, the otters have helped a significant regrowth of plant life. Brent Hughes, a scientist working alongside Angelini, led a three-year study. Their findings were clear: in areas with sea otters, crab numbers fell markedly. This led to a resurgence in plant growth, which in turn stabilized the soil and lowered the rate of soil washing away.

As the sea otter population continues to restore, their positive impact on coastal ecosystems is likely to increase. It not only showcases the sea otter as a central species—a species that has a significant effect on its natural environment—but also highlights the essential nature of top predators (捕食者) in preserving ecological harmony. “My honest reaction was—this could become a classic in the literature,” says scientist Lekelia Jenkins. She reveals marsh restoration also helps people by reducing flooding. “Suddenly, sea otters go from just cute things we like to something that can protect our livelihoods and our properties.”

4 . Humans have long gained pleasure from the smells of the natural world. For the most part, though, human beings are not their target market. For plants, fragrances are a way to interact with insects and other animals. Their attraction for people happens simply by chance.

In chemical terms, most natural fragrances are made up of volatiles — so called because of their tendency to change states suddenly. Volatiles evaporate easily, drifting into noses. In plants’ reproductive processes, smelly volatiles attract pollinators (授粉昆虫). But their natural applications are much more varied. If an insect chews through the leaves of some Bursera plants, out shoots a sticky, smelly liquid to trap it. Coyote tobacco plants are even more crafty: upon sensing the smell of hungry caterpillars, they produce volatiles that attract predators to kill the pests.

What is truly amazing is just how wily plants can be in using their scents for reproduction. White flowers often emit their scent at night to attract nocturnal pollinators such as moths. They produce a dilute nectar (稀释的花蜜) that encourages moths to keep moving, rather than linger at a single bloom—all the better to increase pollination. Other flowers change their fragrance after being successfully pollinated, as a signal for insects to go elsewhere.

But though “Scent” is a story of plants’ cleverness, it is also a tale of the human kind. People have long used fragrances for their own purposes, particularly for use in religious ceremonies: perfume recipes on the walls of an Egyptian temple in Edfu demonstrate just how long ingredients have been mixed in pursuit of the best blend. So highly prized were some scents that, to scare off competitors, Arab traders spread a legend about giant eagles that guarded cinnamon.

Eventually scientists no longer needed natural sources for fragrances. In 1866 a fragrance molecule was produced for the first time. Sixteen years later, Houbigant Parfum released Fougère Royale, the first “modern fantasy perfume” that creates an imaginary scent rather than copying a natural one. Nowadays fragrance–making is dominated by man–made compounds, which can be reliably and affordably produced in large quantities.

That has led to the mass production of smelly products, from toilet paper to toothpaste. Scent is accordingly big business. It is said that a world–famous fragrance and flavour manufacturer that claims people interact with its products up to 30 times a day, had sales of €3.8bn last year.

5 . It is an uncomfortable fact that civilized society is almost completely dependent upon fossil fuels in nearly every aspect. Whether you believe there are hundreds of years or just a few decades left of this resource, the fact remains that it is a limited resource. At some point, fossil fuels are going to either be gone or become too expensive to realistically use. That is, when fossil fuels become too expensive to use, people will just start using something else. Though this may work well in theory, actually shifting from fossil fuels is not the same as shifting from one brand of shampoo to another.

This is entirely due to the fact that humans rely so much on the infrastructure (基础设施) they have developed, which is entirely dependent upon this resource, accounting for 85% of the United State's energy use. If the world were entirely dependent upon solar energy, that would be fine because sunlight is a continuing resource. However, at the current state of things, humans are in a dangerous position owing to its complete dependence upon one single limited input.

Fossil fuels are also responsible for a significant amount of land, water, and air pollution beyond their carbon dioxide (二氧化碳) production. For example, coal mining brings solid wastes to the surface that would normally remain underground and the areas around a mine can remain barren (贫瘠的) for generations due to the lack of proper topsoil. The burning of coal for energy also produces many different types of particulate (微粒的) matter that pollutes the air. Compared with fossil fuels, renewable energy is far more environmentally friendly.

There exists an argument that renewable energy options are not as efficient as fossil fuels because the deployment (部署) of renewable energy equipment like the wind turbine (风力涡轮机) costs a lot of money. However, when factors such as pollution and climate change are considered, renewable energy is actually far more efficient than fossil fuels. And fossil fuels will be surely replaced by renewable energy whether it is your generation or your grandchildren's.

6 . I was 16 years old the day I skipped school for the first time. It was easily done: Both my parents left for work before my school bus arrived, so when it showed up at my house on that cold winter morning, I simply did not get on. The perfect crime!

And what did I do with myself on that glorious stolen day, with no adult in charge and no limits on my activities? Did I get high? Hit the mall for shopping?

Nope. I built a warm fire in the wood stove, prepared a bowl of popcorn, grabbed a blanket, and read. I was thrilled and transported by a book — it was Hemingway’s The Sun Also Rises—and I just needed to be alone with it for a little while. I ached to know what would happen to Jake Barnes and Lady Brett Ashley and Robert Cohn. I couldn’t bear the thought of sitting in a classroom taking another biology exam when I could be traveling through Spain in the 1920s with a bunch of expatriates (异乡客).

I spent that day lost in words. Time fell away, as the room around me turned to mist, and my role — as a daughter, sister, teenager, and student — in the world no longer had any meaning. I had accidentally come across the key to perfect happiness: I had become completely absorbed in something I loved.

Looking back on it now, I can see that some subtle things were happening to my mind and to my life while I was in that state of absorption. Hemingway’s language was quietly braiding itself into my imagination. I was downloading information about how to create simple and elegant sentences, a good and solid plot. In other words, I was learning how to write. Without realizing it, I was on the trail of my own fate. Writing now absorbs me the way reading once did and happiness is their generous side effect.

7 . Steven Stein likes to follow garbage trucks. His strange habit makes sense when you consider that he’s an environmental scientist who studies how to reduce litter, including things that fall off garbage trucks as they drive down the road. What is even more interesting is that one of Stein’s jobs is defending an industry behind the plastic shopping bags.

Americans use more than 100 billion thin film plastic bags every year. So many end up in tree branches or along highways that a growing number of cities do not allow them at checkouts(收银台). The bags are prohibited in some 90 cities in California, including Los Angeles. Eyeing these headwinds, plastic-bag makers are hiring scientists like Stein to make the case that their products are not as bad for the planet as most people assume.

Among the bag makers’ argument: many cities with bans still allow shoppers to purchase paper bags, which are easily recycled but require more energy to produce and transport. And while plastic bags may be ugly to look at, they represent a small percentage of all garbage on the ground today.

The industry has also taken aim at the product that has appeared as its replacement: reusable shopping bags. The stronger a reusable bag is, the longer its life and the more plastic-bag use it cancels out. However, longer-lasting reusable bags often require more energy to make. One study found that a cotton bag must be used at least 131 times to be better for the planet than plastic.

Environmentalists don’t dispute(质疑) these points. They hope paper bags will be banned someday too and want shoppers to use the same reusable bags for years.

What does the word “headwinds” in paragraph 2 refer to?

8 . Steven Stein likes to follow garbage trucks. His strange habit makes sense when you consider that he’s an environmental scientist who studies how to reduce litter, including things that fall off garbage trucks as they drive down the road. What is even more interesting is that one of Stein’s jobs is defending an industry behind the plastic shopping bags.

Americans use more than 100 billion thin film plastic bags every year. So many end up in tree branches or along highways that a growing number of cities do not allow them at checkouts(收银台). The bags are prohibited in some 90 cities in California, including Los Angeles. Eyeing these headwinds, plastic-bag makers are hiring scientists like Stein to make the case that their products are not as bad for the planet as most people assume.

Among the bag makers’ argument: many cities with bans still allow shoppers to purchase paper bags, which are easily recycled but require more energy to produce and transport. And while plastic bags may be ugly to look at, they represent a small percentage of all garbage on the ground today.

The industry has also taken aim at the product that has appeared as its replacement: reusable shopping bags. The stronger a reusable bag is, the longer its life and the more plastic-bag use it cancels out. However, longer-lasting reusable bags often require more energy to make. One study found that a cotton bag must be used at least 131 times to be better for the planet than plastic.

Environmentalists don’t dispute(质疑) these points. They hope paper bags will be banned someday too and want shoppers to use the same reusable bags for years.