2 . In Denmark, bicycling is one of the primary forms of transportation. In sunshine, rain and snow, you will see cyclists on their way to work, to the grocery store, or to social events. The bike is a Dane’s best friend.

Danish cycling culture is as old as the bicycle itself. Bikes were first introduced to the country in the 1880s, and during the 1920s and 1930s, the bicycle became a widespread symbol of equality and freedom. People of all social classes began biking side by side — in the cities on their way to work and in the countryside on their days off.

The increased prosperity of the late 1950s saw some Danes replacing bikes with motorcycles and automobiles. Just like their colleagues around the world, Danish urban planners believed the future belonged to cars, trucks, and ever-wider highways. In the early 1970s, however, the Mideast oil crisis terminated that development. “Car Free Sundays” were introduced in Copenhagen, and protests demanding Copenhagen to become car-free took place. Over time, concerns about air pollution, climate change, and the need for people to get enough exercise have helped bicycles make a big comeback. Denmark’s heavy taxes on petrol and automobiles are a factor, too.

Today, cycling is an inseparable part of Danish culture. Newcomers who do not know how to cycle are encouraged to learn as soon as they arrive. Danish children usually learn to bike before they begin school at the age of six — and often much earlier. In school, children learn about traffic rules, road safety, and the importance of wearing a helmet as well as good cycling habits. Another alternative for families with children is the cargo bike — a sort of oversized tricycle with a large wooden box on the front. It’s estimated that a quarter of all Copenhagen families with two or more children own one of these cargo bikes for transporting kids, groceries, and other necessities. Danish cargo bikes have also won design awards and become a Danish export success.

Commuting by bike is the fastest, easiest and most environmentally friendly way to get around the cities of Denmark. And the numbers speak for themselves: Residents who cycle in Copenhagen request 1.1 million fewer sick days. Cyclists reduce CO2 emissions by 20, 000 tonnes a year on average.

In a small community located at a suburb of Exeter, a disheartening issue had been troubling the neighborhood for years. The once pleasant surroundings were ruined by piles of waste that seemed to multiply with each passing day. Residents were growing tired of the worsening environment, leading many to abandon their homes in search of cleaner neighborhoods. It was in this terrible situation that two young students, Emma and Mia, decided to take matters into their own hands.

Emma and Mia were classmates and best friends from Phillips Exeter Academy, both passionate about environmental preservation and deeply concerned about the pollution crisis their community was facing. Witnessing more and more neighbors’ leaving, they knew they couldn’t stand by any longer. Determined to bring about a change, they undertook a mission that would soon catch the attention of the entire community.

Their journey began with thorough research and planning. The two girls searched carefully on the Internet for information on environmental initiatives and connected with local environmentalists. They organized meetings with residents to understand the issues at hand, collecting data on the types of waste, the sources, and the areas most affected. Armed with this knowledge, Emma and Mia worked out a comprehensive plan and announced it to ask for opinions from the residents. Surprisingly it was strongly supported.

Their strategy was twofold. First, they initiated a waste classification and recycling program. They distributed recycling bins(回收箱) to every household and educated the community about the importance of responsible waste management. Soon, the streets began to show signs of improvement as the volume of garbage inappropriately thrown away decreased gradually.

The second part of their plan was more ambitious. Emma and Mia gathered volunteers from their school and the neighborhood to take part in a massive clean-up campaign. Armed with gloves and trash(垃圾)bags, they began systematically clearing the waste from the streets, parks, and even the local bodies of water. Their firm commitment and hard work inspired others to join the cause.

Half a year later, the changes were significant.

Emma and Mia received recognition and honors for their work.

5 . The Monarch butterfly (帝王蝶) population has dropped to its second-lowest number on record in Mexican forests this winter. The forests are the insects’ winter home. The population decrease is worrying as the butterfly group is already considered at risk of disappearance.

Mexico’s government and the non-profit World Wildlife Fund (WWF) recently issued findings of their yearly joint study on the butterflies. The research shows that the Monarch butterfly presence has decreased to less than a hectare (公顷) of forest area. In the mid-1990s, Monarch butterflies could be found on around 18 hectares of the forests. The findings represent an almost 60 percent decrease in the Monarch butterfly population compared to last year’s study. It is also the second-lowest population finding since the first study took place more than thirty years ago.

Biologists blame the drop on higher-than-usual temperatures and dry conditions in the northwestern U. S. where the butterflies lay eggs. The weather conditions affect the growth of milkweed, the plant where the butterflies lay their eggs. When the young arrive, milkweed is their food for a time. In one of the planet’s famous wildlife migrations (迁徙), the butterflies travel south as many as 4,500 kilometers from places as far north as Canada. They spend the winter in warmer Mexico, where millions of the insects stay in trees that protect them from the rain and cold.

Monarch butterfly populations change year to year. As recently as 2021, the same study showed a 35 percent increase to cover around 2.8 hectares. Officials and activists called for more action to help the species. Such calls include the need to reduce threats of destroying milkweed and the need to protect forests. “We can’t lower our guard,” Jorge Rickards, head of WWF’s Mexico office, told reporters after releasing the latest data.

6 . A new study says that more than half the world’s ocean area is “becoming greener”, and the trend is connected to human-caused global warming.

It’s not clear what is driving the greening. In some places, it could indicate changes in the amount of plankton or other organic material floating in the water. Plankton are a cornerstone of the ocean food chain, and these kinds of shifts could have ripple effects throughout the entire marine ecosystem.

The study, published on Wednesday in the journal Nature, examines 20 years of satellite data measuring light reflected at the surface of the water all across the globe, subtle changes that aren’t necessarily visible to the naked eye. The research finds that 56 percent of the world’s oceans are shifting in color — and on the whole, they’re growing greener. The trend is especially strong in the lower latitudes, including the subtropics and tropics.

The researchers then used a computer model to find out whether climate change was playing a part. They conducted one set of simulations representing the oceans under a strong climate change scenario, and then compared them with a second set of simulations imagining a world in which climate change didn’t exist. The model suggests that rising global temperatures are to blame.

The exact reasons still require some scientific digging. While climate change seems to be the culprit, the study also indicates that rising ocean temperatures in and of themselves aren’t driving the greening.

There are plenty of other ways global warming is affecting the world’s oceans, by changing the structure and flow of certain currents, for instance. These kinds of changes can affect the growth of phytoplankton and other factors that might be contributing to the greening.

The findings weren’t a surprise to the researchers. They’re consistent with the way researchers expect the global oceans to change as the world keeps on warming.

“I’ve been running simulations that have been telling me for years that these changes in ocean color are going to happen,” study co-author Stephanie Dutkiewicz, a senior research scientist at the Massachusetts Institute of Technology, said in a statement. “To actually see it happening for real is no unexpected, but frightening.”

7 . For years, scientists have debated whether humans or the climate have caused the population of large mammals to decline dramatically over the past several thousand years. A new study from Aarhus University confirms that climate cannot be the explanation.

About 100,000 years ago, the first modern humans migrated out of Africa in large numbers. They were very good at adapting to new habitats, and they settled in almost every kind of landscape — from deserts to jungles to the icy taiga in the far north.

Part of the success was human’s ability to hunt large animals. With clever hunting techniques and specially built weapons, they perfected the art of killing even the most dangerous mammals.

But unfortunately, the great success of our ancestors came at the expense of the other large mammals.

It is well-known that numerous large species went extinct during the time of worldwide colonization by modern humans. Now, new research from Aarhus University reveals that those large mammals that survived also experienced a dramatic decline.

By studying the DNA of 139 living species of large mammals, scientists have been able to show that the abundances of almost all species fell dramatically about 50,000 years ago. This is according to Jens-Christian Svenning, a professor and head of the Danish National Research Foundation’s Center for Ecological Dynamics in a Novel Biosphere (ECONOVO) at Aarhus University and the initiator of the study.

“We’ve studied the evolution of large mammalian populations over the past 750,000 years. For the first 700,000 years, the populations were fairly stable. But 50,000 years ago, the populations fell dramatically and never recovered,” he says, and continues: “For the past 800,000 years, the globe has fluctuated (波动) between ice ages and interglacial periods about every 100,000 years. If the climate was the cause, we should see greater fluctuations when the climate changed 50,000 years earlier.But we don’t. Humans are, therefore, the most likely explanation.”

Light pollution is a serious problem. This became completely obvious when the World Atlas of Artificial Night Sky Brightness, a computer-created map based on thousands of satellite (卫星) photos,     1     (publish) in 2016. The map shows how and where     2    (we) world is lit up at night. Large areas of North America, Europe, and Asia are glowing (发光) with light, while only the most remote (偏远的) places on Earth are in total darkness. Some of the most light-polluted    3     (country) in the world are Singapore, Qatar, and Kuwait.

Sky glow is the brightening of the night sky, mostly over cities, because    4    the electric lights of cars, streetlamps, offices, factories and buildings, turning night into day.

People     5     live in cities with high levels of sky glow have a hard time     6     (see) stars at night. Scientists are     7     (particular) worried about sky glow pollution as it influences their ability     8     (view) space.

According to research, more    9     80% of the world’s population, and 99% of Americans and Europeans, live under sky glow. It sounds pretty, but sky glow    10    (cause) by human activities is one of the most common forms of light pollution.