After years of debate, gray wolves were reintroduced to Yellowstone National Park. Fourteen wolves were caught in Canada and moved to the park. By 2016, the Yellowstone wolf population had grown to more than 170.

Gray wolves once were seen here and there in the Yellowstone area and other parks of the United States, but they were gradually displaced by human development. By the 1920s, wolves had disappeared from the Yellowstone area. They went farther north into the deep forests of Canada, where there were fewer humans around. The disappearance of the wolves had many unexpected results. Deer and elk populations — major food sources (来源) for the wolf — grew rapidly. These animals ate large amounts of plants, which reduced plant diversity in the park. With the disappearance of gray wolves, coyote (草原狼) populations also grew quickly. The coyotes killed a great number of red foxes in the park, and completely drove away the park’s beavers (河狸).

As early as 1966, biologists asked the government to consider reintroducing wolves to Yellowstone Park. They hoped that wolves would be able to control the elk and coyote problems. Many farmers were against the plan because they feared that wolves would kill their farm animals or pets.

The government spent nearly 30 years coming up with a plan to reintroduce the wolves. The U. S. Fish and Wildlife Service carefully monitors and manages the wolf packs in Yellowstone. Today, the debate continues over how well the gray wolf is fitting in at Yellowstone. Elk, deer, and coyote populations are down, while beavers and red foxes have made a comeback. The Yellowstone wolf project has been a valuable experiment to help biologists decide whether to reintroduce wolves to other parts of the country as well.

We are all aware of the effect greenhouse gas emissions is having on our planet and the efforts needed to do with climate change. Most of us are doing our bit to minimise our impact on the environment, but despite our collective effort, are we doing enough to achieve net zero by 2050?

Net zero means not adding to the amount of greenhouse gases in the atmosphere. Many countries are doing their bit by changing how they generate and use power, thereby cutting carbon dioxide output. And they announced what further steps they were going to take at the recent COP26 summit in Glasgow.

In the UK, the government has been setting out its plans to achieve net zero by 2050. It's recently announced an end date for the sale of gas boilers, which are used for heating homes. The idea is to replace them with heat pumps. It's offering homeowners grants of up to £ 5,000 to get them installed. Another initiative in the UK is a big push towards electric vehicles. There are to be financial encouragements for car manufacturers, and more charging points are to be installed in streets. And there's to be a ban on the sale of new petrol and diesel cars by 2030.

But not all emissions can be reduced to zero, so those remaining will have to be made up for.

One way to do this is to plant thousands of trees, which are good at absorbing carbon dioxide, The UK government has guaranteed to plant 30,000 hectares of trees a year by 2025. There are other ideas too, but what's certain is this will cost money. The CBI's Tom Thackray told the BBC that“those costs have to be weighed up against the cost of inaction(不作为).”

Whether the UK, or anyone else, reaches net zero remains to be seen. And there's some doubt about how this can be accurately measured anyway. But it's generally recognised that a global effort is needed to tackle climate change. Therefore, net zero targets only make sense if every other country is moving in the same direction.

At the age of seven, while his friends were spending their allowance on things like candy and toys, Jose Adolfo Quisocola was busy saving money for basic purchases. To try to get his peers (同龄人) to do the same, the boy from Peru came up with the idea of an eco-bank, the Bartselana Student Bank, which allows kids of all ages to become financially independent while also helping the environment.

Set up in 2012, the bank is the world’s first bank for kids. To become a member, a kid has to bring in at least 5 kilograms of solid waste and set a savings goal. Once accepted all bank “partners” are required to deposit at least one additional kilogram of recyclables on a monthly basis and observe other requirements, such as attending financial education and environmental management workshops.

The waste accumulated is sold to local recycling companies, which, thanks to Jose’s efforts, pay a higher-than-market rate for everything brought in by the bank members. The money received is placed in the personal account where they collect until the savings goal is reached. The account holder can then withdraw the money, or choose to leave it and make it continue to grow for a bigger target. “At the beginning, my teachers thought I was crazy or that a child could not undertake this type of project,” Jose recalls. “They did not understand that we are not the future of the country but its present. Luckily, I had the support of the school headmaster and an assistant in my class.”

The boy’s efforts paid off, and by 2013, the bank had over 200 members, who brought in one ton of recyclable waste. Today, the eco-bank, which now has the support of several local institutions, boasts ten educational centers. They are designed to teach over 3,000 students, aged 10 to 18, to become financially independent, use their money wisely, and help the environment.

Not surprisingly, Jose’s efforts have earned him several national and international awards. On November 20. 2018, Jose won Children’s Climate Prize, which comes with a medal and $5.500 in prize money and is given to a child or youth who has accomplished an extraordinary achievement for the climate or environment.