1 . Air pollution is one of the world’s invisible killers. It causes seven million deaths a year, making it the largest single environmental health risk. In cities, air pollution is particularly serious. More than 80% of people live in the areas where pollution levels are beyond WHO limits.

One well-established way to reduce air pollution is to plant trees, as their leaves catch and absorb harmful particulates (微粒). But planting new trees is not always a good choice for lack of enough space. That’s why the “City Tree”, a mobile tree which removes pollutants (污染物) from the air, has been becoming popular in cities around the world, including Oslo, Paris, Brussels and Hong Kong.

Each City Tree is just under 4 meters tall, nearly 3 meters wide and 2.19 meters deep, acting as a chair or a bench. A screen is included for information or advertising. Berlin-based Green City Organization explains that its invention has the environmental benefit of up to 275 actual trees.

But the City Tree isn’t, in fact, a tree at all—it’s a moss culture (青苔培植). “Moss cultures have a much larger leaf surface area than any other plant. That means we can catch more pollutants,” said Zhengliang Wu, co-founder of Green City Organization.

The huge surfaces of moss in each tree can remove dust, NO₂ and O₃ gases from the air. It requires very little care: solar panels provide electricity, while rainwater is collected into a container and then sent into the soil.

To monitor the health of the moss, the City Tree has sensors which measure soil humidity (湿度), temperature and water quality. “We also have pollution sensors inside the “trees, which help monitor the local air quality and tell us how efficient the tree is.” Wu said. Its creators say that each City Tree is able to absorb around 250 grams of particulate matter a day and contributes to removing 480 tons of CO₂ a year.

7 . Lake Victoria is best known to the general public following the introduction of the 2004 documentary Darwin’s Nightmare, which focuses on the environmental and social effects of the Nile perch (河鲈) fishing industry. The Nile perch is the largest freshwater fish, which can grow up to two metres long and weigh 200kg. Its introduction into Lake Victoria in the 1950s and its rapid population growth in the 1960s gradually wiped out the native fish species living in the lake, causing a major ecological disaster. Today, the Nile perch population can be found everywhere but has reduced slightly due to overfishing, allowing some species to partially recover.

What is less well known, and perhaps interacting with the presence of the Nile perch, but equally damaging to the ecosystem, is the general water quality of the lake. “This declined sharply between the 1960s and the 1990s due to eutrophication (富营养化), which is caused by increased inputs of nutrients (营养物) into the water bodies as a result of increased human activities in the catchment area.” explains Alberto Borges, FNRS Research Director at the Laboratory of Chemical Oceanography from the University of Liege.

From 2018 to 2019, a research team led by Alberto Borges, studied the biomass (生物量) and composition of phytoplankton (浮游植物) as well as the nutrient status of the lake during three scientific missions. This study shows that the phytoplankton camass has decreased by about seven times compared to the 1990s.” says the researchers. “and that the species composition has also changed in a subtle way.” What seems to be good news for the environment of Lake Victoria may only be on the surface.

“This means that the current improvement in water quality in Lake Victoria may only be temporary and that conditions could become worse again in the future due to continued climate warming.” says Alberto Borges.

9 . Unless you’ve been faithfully bringing reusable shopping bags to the store, you probably grab the plastic bags waiting for customers at the checkout. You’re not alone.

About 100 billion plastic bags are used in the U. S. each year. Unfortunately, single-use plastic bags have serious consequences once our trip to the store is over. Less than 10% of plastic bags used in the U. S. are recycled, leaving the rest to end up in landfills (垃圾填埋场), and polluting soil, oceans and other natural habitats.

To fight pollution and other environmental problems, major companies are taking steps to get rid of the use of plastic shopping bags. If you’re a frequent customer at Walmart, don’t be surprised if you notice the plastic bags disappearing over the next few months. Last summer, Walmart announced its goal to be a zero-waste company — meaning no more plastic bags.

But Walmart has announced its Beyond the Bag, an initiative (倡议) working to explore reusable options and “reimagine” the plastic bag. Target and CVS are also on board as founding partners of Beyond the Bag, and so far, the three brands have invested $15 million to come up with a brand-new bag design.

The initiative also started the Beyond the Bag challenge, giving innovators (创新者) a chance to share their ideas. The challenge ran throughout the summer of 2020, and nine winners from over 450 submissions were selected. From a station supplying reusable bag in-store to a new and improved paper bag, the winning designs cover a lot of bases. Each product now has the chance to be tested with funding from the initiative.

While a final replacement for plastic bags at Walmart has yet to be decided, there’s a more sustainable future on the horizon. And if you want to start reducing your use of plastic bags right now, check out our list of reusable bags to bring on your next shopping trip.

10 . “I knew that the Just Go Zero project could bring many advantages,” says Emmanoui l Antonios Fotaras, one of 745 residents living on Tilos, a small Greek island located between Rhodes and Kos, “but I didn’t expect its effect would be so powerful.” Now Tilos has become the world’s first zero-waste island.

The changes have been big. Before the project began, the island sent 87 percent of its waste to landfill (垃圾填埋厂); now the project has proved such a success that the island no longer has any rubbish bins and the landfill site has closed completely. In its place is the Centre for Creative Upcycling, where items can either be repaired or reused.

The project was controlled and paid for by Polygreen, a Greek company that specializes in circular economy solutions, but much of their success came through education.

They began by setting up an information center in the port so residents could learn about how to sort their waste. Each household was then given its own zero-waste equipment, including boxes for recyclable and non-recyclable waste and a bag for organic waste. Regular door-to-door collections were then arranged across the island. A smartphone app collected real-time information to show Polygreen how much had been recycled. All waste is taken to the 3K Circular Innovation Centre,which is equipped with high-tech waste handling solutions that can further sort and direct rubbish towards recycling or composting (制成堆肥).

Any visitors to the island have to take part in the project as well. Hotels have special equipment for separating rubbish and tourists can pick up cloth bags for shopping from the Zero Point Information Centre.

“In the beginning, it was tiring,” says Fotaras, “but we all helped each other until we mastered it. I am amazed how old people like the idea of no rubbish and how the project benefits the environment — and that gives me hope and courage to do it.”