To appreciate Dubai, you could start by going skiing. The ski resort, located inside one of the city’s shopping malls, looks from the outside like a silver spaceship. You put on a thick coat, pull on your gloves and then marvel at what strong air-conditioning can do. At the exit, you can buy a souvenir T-shirt. A cartoon thermometer in Celsius announces: “I went from +50 to minus 8!”

Indoor skiing in the desert has become a symbol of Dubai’s status as a wealthy, modem metropolis. This small fishing village, Dubai’s fortunes changed forever with the discovery of oil in the 1960s. Since then. it has evolved to become the largest city. But the rapid growth has come at a price. To power its cars and air-conditioning, the city has produced large amounts of carbon dioxide (CO. ) from fossil fuels. Now it is making some big changes.

To reduce its dependence on cars and lower its emissions, Dubai has invested in solar energy, green buildings, and a comprehensive public transportation system. In addition, all new buildings must meet strict energy regulations.

The most striking development can be found where the city’s suburbs meet the desert. Unlike much of Dubai, the Sustainable City to the south feels more like a close-knit-village community. About five hundred low-rise houses are distributed along attractive, tree-lined streets. They all face north, away from direct sunlight, and are close together to provide natural shade. Each building has reflective windows and wall paint, which reduce the heat absorbed from the sun. Rooftop solar panels and energy-saving lights contribute to the community’s energy efficiency. As a result, residents of the Sustainable City now consume 50 percent less energy than people living in other parts of Dubai.

By 2050, the government intends to obtain 75 percent of the city’s energy from renewable sources-mainly solar. It also wants to have the smallest ecological footprint in the world. The plan is ambitious. But if successful, even guilt-free skiing in the desert could become an reality.

Off the coast of northeastern Queensland, Australia, near Magnetic Island in Florence Bay, the Great Barrier Reef corals (大堡礁珊瑚) are having a baby boom (激增).

“Every year there are more anrd more coral babies,” says Hillary Smith, an ecologist at ames Cook University in Australia.

That’s thanks to a simple but effective strategy for cleaning the region’s coral reefs: “seaweeding”. Like weeding (给……除杂草) a garden, seaweeding involves pulling big handfuls of large algae (水藻) off reefs and taking them away.

Experts say getting climate change under control is key to keeping the world’s reefs healthy. But meanwhile, local efforts such as seaweeding can help corals grow and reduce the effects of climate change.

The health of coral reefs around the world is dire: By 2050, 95 percent of the world’s coral could experience heat stress, according to a 2020 report by the Global Coral Reef Monitoring Network. Algae is a big problem: Already, algae cover has increased on two-thirds of reefs around the world, and one study published in 2021 showed that half the world’s coral reefs have died since the 1950s. Removing seaweed from reefs requires a great deal of work but is not complex, making it a good project for citizen scientists eager to help restore (恢复) reefs.

When the project first began in 2018, Smith says researchers weren’t sure if removing seaweed would benefit the reef or if removal might have the opposite effect in some way. But now, “It’s all looking really positive for the reef,” she says.

Volunteers are ready and waiting to help near Townsville and at other affected Australian reefs, says the Earthwatch Institute’s Fiona Wilson.“We need lots of willing hands to remove seaweed. It takes weeks of time,”she says. “But obviously recovery of the Great Barrier Reef is a passion for many people, so we draw volunteers.”

When athletes at the 2020 Tokyo Olympics collect their medals, they'll not only be wearing something that celebrates their sporting performance, but something that symbolizes lastingness. For both the 2020 Olympics and Paralympics, organizers aim to make all of the gold, silver, and bronze medals out of used electronics. This strong message about how to make use of e-waste has gotten a lot of Japan involved.

Starting in April 2017, the Japanese Olympic Committee began collecting old laptops, digital cameras, smartphones, and other abandoned electronics. The initiative(倡议）has achieved great success. Already, the quantity needed for bronze medals has been met, and they're in the homestretch for silver and gold medals, meaning the collection process can pack up at the end of March.

When looking just at the number of cell phones collected, the amount of waste is shocking. In a period of about 18 months, a little over 5 million smartphones were collected thanks to cooperation with NTT DOCOMO. Japan's largest mobile phone operator allowed the public to turn in phones at their shops, which counted a lot in the project’s success.

After being taken apart and sorted, the small electronics underwent a smelting process to extract(提炼）all the gold, silver，and   bronze elements. Thanks to this initiative, the worldwide struggle with e-waste will have a global platform. According to a study published by the United Nations University—44.7 million metric tons of e-waste were made in 2016. Only 20% of that was actually recycled. Unfortunately, this figure is set to rise significantly in the coming years, moving to 52.2 million metric tons by 2021. So while the Tokyo Olympics initiative might be just a drop in the bucket, it’s a good start in showing what the public can do if they're made more aware of the issue.