The 2020 summer Olympics will be held in Tokyo next year. Japan has made 5,000 medals for the winners. But this Olympic medals are more special than most----they are made entirely out of recycled electronics.

One new focus of the Tokyo Olympics is to make them “sustainable”----to avoid using too many natural resources, so that the games are environmentally friendly. As part of this goal, the organizers decided to make all of the Olympic medals out of metal recycled from old electronics. They needed gold for first place medals, silver for second, and bronze for third. You might not know it, but almost all electronics are made with small amounts of “precious” metals, like gold and silver. But collecting enough of these metals to make 5,000 medals is a huge challenge. That's because the amount of metal in each device is tiny. It would take about 20,000 cell phones to get just 2. 2 pounds (1kilogram) of gold.

Beginning in April 2017, organizers placed collection boxes around the country, and asked people to turn in their old electronic devices for the Olympic medals. Soon people began to fill up the boxes, turning in smart phones, digital cameras and laptops. By the end, 1,621 local governments had helped out with the collection process. The Japanese mobile phone company NTT Docomo collected 6.21 million used cell phones. In all, around 158,000,000 pounds (71,667,660 kilograms) of electronics were collected.

Then came the job of breaking those phones down into smaller pieces. This is a difficult job. It's also dangerous, because some of the metals and other things that go into electronics aren't safe for people to touch or breathe. That's why it's not a good idea to try something like this at home. Once the devices were broken down, the metals had to be carefully separated out. By the end of March, the organizers had hit their targets. The opening ceremony for the 2020 summer Olympics will take place in Tokyo on July 24,020.

Recently, the most heated topic of “which is the right bin for my garbage” has swept China.

Shanghai is among China’ s first cities to introduce garbage classification (垃圾分类) and also the country’s most serious in its performing. Since July 1,2019, Shanghai residents have been required by law to sort garbage into four different categories, or they could face fines. Individuals, including tourists, can be fined 200 yuan for failing to sort their waste properly, while companies and institutions can be fined up to 50,000 yuan.

The government has set up online apps to handle sorting questions, and announced guidelines to address the “one-size-fits-all” method. The country is about to invest over 21 billion yuan in the construction of garbage processing facilities to meet demands. Now it’s introducing artificial intelligence into its waste management system, by setting up little cameras in many sets of bins.

However, not every face can be recognized by the smart dustbin until you register for the system. Once registration is complete, users will scan a QR code on the bin, which then opens it up to allow for garbage disposal (处理). Now, each household gets one special QR code for throwing out waste. Here, the intelligent bins don’t just calculate garbage weight, they also help residents gain rewards by collecting points through the special app.

China is stepping into the age of compulsory garbage sorting with its cities revising laws on garbage classification. For Shanghai, sixty percent of the city is expected to carry out garbage sorting by the end of 2019, and 90 percent by 2020. Garbage sorting is, without doubt, a costly but worthwhile endeavor. It is good for the environment and important for the country’s sustainable development (可持续发展), and may finally turn out to be a promising industry as well.

Half of the world’s beaches could disappear by 2100, a study published in the journal Nature Climate Change suggests.

Michalis Vousdoukas, of the European Union’s Joint Research Center in Ispra, Italy, was the lead researcher. “Tourist areas which have sandy beaches as their main selling point will probably face strong consequences.” he said. Aside from economic value, beaches play an important environmental role. “Sandy beaches are important habitats supporting a wide range of species. They also protect the coast from the effects of storms, so without sandy beaches other inland environments can be affected by the effects of waves and saltwater entering,”Vousdoukas added.

The main causes are rising sea-level and erosion (侵蚀) from storms, the study says, which warned of the near-disappearance of almost half of the world’s sandy beaches by the end of the century. Beaches in the United States will be “greatly affected”, as will shorelines in Canada, Mexico, China and Chile. In the U.S., beaches along the East Coast and the Gulf Coast will experience the most erosion.

Michalis Vousdoukas and other researchers used satellite images to track the way beaches have changed over the past 30 years and patterned how global warming might affect them in the future. They found that West Africa will see some of the worst losses, where more than 60% of sandy coastline may be lost in countries such as The Gambia and Guinea-Bissau. Australia will also take a hit: when the total length of sandy beach projected to be lost is analyzed Australia would be hit the hardest, with more than 7,000 miles at risk.