1 . A new study by scientists at Utrecht University concludes that about half of global wastewater is treated, rather than the previous estimate of 20%. Despite this promising finding, the authors warn that treatment rates in developing countries are still very low.

Humans and factories produce vast quantities of wastewater per day. If not properly collected and treated, wastewater may severely threaten human health and pollute the environment.

The authors use national statistics to estimate volumes of wastewater production, collection, treatment and reuse. “Globally, about 359 billion cubic metres of wastewater is produced each year, equivalent to 144 million Olympic-sized swimming pools,” says Edward Jones, PhD researcher at Utrecht University. “About 48 percent of that water is currently released untreated. This is much lower than the frequently announced figure of 80%.”

While the results show a more optimistic outlook, the authors stress that many challenges still exist. “We see that particularly in the developing world, where most of the future population growth will likely occur, treatment rates are falling behind,” Jones explains. “In these countries, wastewater production is likely to rise at a faster pace than the current development of collection and treatment basic facilities. This poses serious threats to both human health and the environment.”

The main problem, especially in the developing world, is the lack of financial resources to build basic facilities to collect and treat wastewater. This is particularly the case for advanced treatment technologies, which can be extremely expensive. However, the authors highlight potential opportunities for creative reuse of wastewater streams that could help to finance improved wastewater treatment practices.

“The most obvious reuse of treated wastewater is to increase freshwater water supplies,” Jones states. Treated wastewater reuse is already an important source of irrigation water in many dry countries. However, only 11% of the wastewater produced globally is currently being reused, which shows large opportunities for expansion.

“But freshwater increasing is not the only opportunity,” says Jones. “Wastewater also has large potential as a source of nutrients and energy. Recognition of wastewater as a resource, opposed to as ‘waste’, will be the key to driving improved treatment going forward.”

However, the authors stress the importance of proper monitoring of wastewater treatment factories, accompanied by strong legislation (法律) and regulations, to ensure that the reuse of wastewater is safe. The authors also acknowledge public acceptance as another key barrier towards increasing wastewater reuse.

2 . Have you ever enjoyed a trip to a zoo, but wondered whether it is acceptable for humans to keep so many treasured animals in cages. You are not alone. Many people concerned about the fate of zoo animals and feel conflicted about the very existence of zoos. However, there is no reason to worry.

Most zoos around the world provide the highest level of care and cleanliness for their animal residents. In fact, animals in zoos often experience far healthier lives than they would in the wild due to the access to medical care.

Zoos provide opportunities for people of all ages to view and connect with animal life that they would otherwise not encounter. By interacting with wild life, people can gain a greater appreciation for the animals of the world. Zoos offer educational experiences through which people can learn why it is so important to protect and maintain the diversity of animal life on Earth.

Zoos also function as places where these often rare or endangered animals can be studied. By keeping and raising animals in cages, extensive research can be conducted on the animals to help scientists understand them. This scientific understanding, in turn, contributes to conservation efforts around the world. Because zoos are a safe place for animals to be observed, scientists are able to make important discoveries about their lives.

While it is true that not all zoos are as well maintained and equipped, there is growing international pressure for universal regulations that will ensure the monitoring of all public zoos. This type of legal support will allow the world’s zoos to continue their important research programs, many of which are adjusted toward breeding programs designed to make more endangered species come in. Breeding programs are essential to continue certain species which are nearly wiped out from the wild, and zoos are the ideal place for these programs to promote the increase of the animals. In this manner, zoos contribute to restoring balance in the wilderness by giving endangered species a second-chance at survival.

If you visit a top-ranking zoo, you will enjoy viewing animals in a habitat designed to support their health. You can rest assured that by supporting such zoos as a visitor, you are also supporting valuable science and conservation efforts. Your interactions with the animals and exhibits might educate you further about creatures in parts of the world you haven’t been exposed to.

When people are inspired, they tend to take action more readily, and zoos are an inspiring example of this truth. Zoos provide an unforgettable experience in appreciating animal life and take concrete action towards advocating for their future.

5 . No doubt that humans have widely changed, developed, and exploited (开发) much of the natural world for our own ends. But how much of the land surface remains free of our often-harmful influence?

In a new study, scientists compared figures from four different sets of data using different kinds of methods and classification (分类) systems to answer this question. On average, the researchers say roughly half (48 to 56 percent) of the world’s land shows “low” influence of humans. While the figures may inspire many—stressing the vast expanse of significantly untouched lands that can still be protected through conservation measures—the study also shows just how much of the Earth has already been occupied and used by humans.

In fact, only about a quarter (20 to 34 percent) of the planet’s ice-free land surface shows “very low” signs of human influence, the researchers say, and the parts of the planet that we have left alone up until now constitute (构成) some of the least livable places on Earth. In other words, whether through urbanization, forestry, agriculture or other means, humans have applied the most influence on biodiverse land that presented ripe and easy opportunities for immediate human needs; in contrast, roasting deserts in the world’s hottest places, or frozen wastelands in its coldest spots, have been ignored.

Even so, the researchers say the results shown here give us a strong, clear marker that we can use to help structure existing and future conservation efforts by preventing disturbance on existing low influenced areas, meanwhile, recovering areas for conservation in land that has already been exploited too much.

“The encouraging takeaway from this study is that if we act quickly and decisively (果断地), there is a slim window in which we can still conserve roughly half of the Earth’s land in a relatively untouched state,” says biologist and lead author of the study, Jason Riggio.

There’s a chance, right now, to draw a line in the sand, and say “no more”.

10 . The Terror of the First F5 Tornado

The nonstop high plains wind suddenly fell dead still, leaving the evening air hot and heavy over Lubbock, Texas. Impossibly dark clouds hung low in the sky.

Standing in the yard outside her family’s trailer home, 12-year-old Cindy Keele saw the worry emerge in her grandmother’s face. “Go in and put on your shoes,” Keele’s grandmother said flatly. “We have to get to the storm cellar.”

The girl dashed inside. As soon as the screen door slapped shut behind her, hail (冰雹) began rapping against the roof. Keele yelled to her mother, “Grandma says we have to get to the storm cellar!” Then a hail stone the size of a softball smashed through the kitchen window. Another one punched a hole in the ceiling. And then came the sound: the unmistakable, ear-splitting roar of an approaching tornado.

Cindy Keele’s mother was suddenly on the same page. But getting herself, her three kids, and her mother to safety was no simple matter—the shelter was at the opposite end of the trailer park. If they didn’t drive, they’d never make it.

The five moved quickly to the family car, ducking to avoid hurtling pieces. At last, everyone was in the car.

“My purse!” Keele’s grandmother shouted “My purse is still in there!”

Keele jumped out of the car and ran back into the house. She fetched the purse and dashed back into the maelstrom. She almost made it. “As I ran to the car,” she says, “an enormous hailstone hit me in the back of the neck. I was told it was the size of a soccer ball.” The next few minutes were a blur for the girl. Her next clear memory is of inside the shelter.

“I guess there were 60 of us in there, plus dogs and cats,” Keele says. “The sound outside was deafening. And then, all of a sudden, it got quiet.” Cautiously, the group emerged from underground.

“My mother ran straight for our street. What she found was—nothing.” The place where our house had been were pieces of houses, but not pieces of our house. “I’d never seen my mom cry,” Keele recalls softly. “But she was on her knees. She was broken.”

May 11 marks the 51st anniversary of the 1970 Lubbock tornado, the first such storm ever to be classified F5.