Conservation scientist Kim Williams-Guillen was trying her best to come up with a way to save endangered sea turtles (海龟) from egg thieves when she had an “aha” moment: If she placed a fake (假的) egg containing a GPS tracker in the reptiles’ nests, she might be able to track the thieves.

Williams-Guillen found a flexible plastic material to mimic (仿造) the shell of real eggs. She and colleagues then used a 3D printer to produce the fakes of the same size, weight, and texture and put the smallest GPS tracking devices inside each. The researchers then went to four Costa Rican beaches, where green sea turtle come ashore to make their nests. As mothers laid their eggs under cover of night, the researchers slipped a fake egg into each nest. Once the fakes are covered in sand and mix with the real eggs, it’s very difficult to tell the difference between the two.

Of the 101 fake eggs, 25 were taken by thieves. The farthest moving egg traveled 137 kilometers inland. The fake egg sent its final signal the next day from a residential property, suggesting that the research team had tracked the eggs through “all of the players in the entire chain.”

By understanding that chain, Williams-Guillen says researchers can identify trading hot spots. She emphasizes that the tracker is not a way to catch local thieves, many of them living in poverty, but a tool to better understand their routes, which could help them and eventually law enforcement (执法部门) identify larger players in the chain.

In the meantime, Williams-Guillen and her colleagues are working to get their fake eggs to other sea turtle conservation organizations. Ultimately, though, scientists and nonprofits are going to engage communities with local outreach and education programs to save sea turtles. She says, “The real meat and potatoes of conservation isn’t going to come from deploying (布署) eggs.”

Autumn Peltier is a youth environmentalist who has inspired thousands of students to walk out of class and demand action on climate change.

When Autumn Peltier was just 8 years old, she attended a ceremony at a reservation where she saw a sign warning that the water was poisonous. Growing up on a freshwater island in Wiikwemkoong Unceded Territory in Canada, Peltier says she had never experienced poisonous water. The memory of that sign stayed with her.

Two years later, at the age of 10, Peltier is fighting for water conservation and water rights for everybody. She says she was inspired by her great aunt, Josephine Mandamin, a well-known activist who walked the shores of all five Great Lakes to raise awareness for water conservation.

When she was 12 in 2015, Peltier met Canadian Prime Minister Justin Trudeau, telling him she was unhappy with his policies on debating pipeline projects. Trudeau promised her he would preserve the water. Since 2015, 87 long-term water advisories in Canada have been lifted; 56 water advisories remain.

At middle school, Peltier joined an environmental group at her school and later co-founded the Canadian Youth Water Strike-a Canadian branch of the international movement to conserve water.

Last year, Peltier spoke at the UN about the importance of water conservation and water access, explaining the fundamental role water plays in her culture.

“Many people don’t think water is alive or has a spirit. My people believe this to be true. . . . We believe our water is precious because we are born of water.”

After the speech at the UN, Peltier is joined by a group of teenagers who share similar thoughts. Her friends include Greta Thunberg, a Swedish girl who drew the world attention through the talk at World Economic Forum at Davos, Bruno Rodriguez, an Argentinian boy who joined in the UN Climate Summit, and Mari Copeny, an American girl who is dedicated to the cause of saving water. Peltier and her friends believe that together they can make a big difference.

Undoubtedly, Peltier’s many years of hard work has paid off. She has greatly raised people’s awareness of water conservation and taught people to take specific actions to conserve water.

That’s an impressive list of accomplishments for anyone, let alone a middle schooler.

The production and distribution of food accounts for around a third of the world’s total greenhouse gas emissions (排放). But as a consumer? It’s difficult to measure the climate impact of what you eat.

A Dublin-based startup called Evocco could soon make it much easier. It lets users track and improve the climate impact of your food purchases. Users simply photograph their grocery receipts using the Evocco app, which identifies the food products by reading the printed text and using machine learning. It then calculates the carbon footprint based on the store’s location and by checking the type, weight and origin o£ a food against a database. The database is maintained by Eaternity, a life cycle assessment company based in Switzerland. If the receipt doesn’t contain enough data on a product, it will give an estimate based on similar products and reference points.

The app is available for free on iOS and Android devices, which has been downloaded more than 1,000 times since its launch at the end of last year. As well as the personal shopping app — which Evocco hopes to launch in the United States by the end of this year — the company is developing a digital tool to sell to food storekeepers, e-commerce platforms and delivery apps that will track the climate impact of a product’s journey through the supply chain. The aim is to help storekeepers provide climate impact information directly to consumers, and more importantly, to give Evocco access to product data to improve its app.

The Evocco app is not the only app looking to reach this climate-conscious market. There’s Capture, which estimates monthly CO₂ emissions by asking users a series of questions on diet, transport and other factors, as well as Yayzy and My Carbon Action, which link to a user’s bank account, calculating their footprint from trade.