The Sixth Extinction (灭绝)

Extinctions, where entire species are wiped out, are not unusual in our Earth’s history. In fact, over 90 percent of all species that ever lived are now extinct. In the last 500 million years, there have been five times when life on Earth has almost ended. These include the third mass extinction, known as the “Great Dying”, which killed 90% to 96% of all species. And the fifth event, which occurred 66 million years ago, caused the death of the dinosaurs. The reasons for extinctions are varied. According to scientists, they include volcanic eruptions, asteroids (小行星) hitting the Earth from space, changes in sea levels, the decrease of the oxygen content of the sea and global warming. Many scientists say we are now entering the Earth’s sixth mass extinction. This time, human activity will be to blame.

Although it is not unusual for species to die out naturally, the rate at which this is now happening is cause for concern. A 2015 study by scientists who were based at Brown University and Duke University in the US, looked at how quickly species die out due to natural causes, that is, the “background extinction rate”. They found that human activity is causing species to die out 1, 000 times faster than normal. There is a long list of reasons why so many species are dying out: air and water pollution, forests being destroyed, factory farming and overfishing. It is clear that human activity has negatively affected all other species on Earth, including animals and plants.

If a sixth mass extinction occurs, scientists who have studied the issue believe that up to three quarters of all species on Earth could die out. Of course, as we humans depend on so many species for our survival, we would also be at risk of dying out. Our world and our lives depend on the balance in nature between animals and plants. Without forests, we would have no air to breathe and without clean water we would be unable to survive.

Can a sixth extinction be avoided? Experts say that it is not yet too late, if we take action now. If we want to survive, we need to stop destroying the planet that we live on and start to protect it.

Calling for the protection of our environment

World Environment Day, falling on the fifth, June, is around the corner.

5 . You don’t need to travel long distances to find pleasure in nature

The Greek historian Herodotus is said to have made one of the earliest lists of seven wonders of the world. These were man-made structures, including the still mysterious feat of ancient horticulture known as the Hanging Gardens of Babylon. More recent times saw natural alternatives to these marvels of classical architecture proposed: waterfalls, mountains, canyons, reefs.     1    

As environmental consciousness has risen in the west, attitudes to such sightseeing have changed. Yes, it is thrilling to visit remote forests or spot rare species. But travelling to far-flung destinations is carbon-intensive when flights or long road journeys are involved, and conservation can be made more difficult as well as assisted by sightseers. There is a balance to be struck, and ethical governments and businesses around the world try to maximize the benefits while minimizing the harms.     2    

Most of us, in the rich countries where people take most holidays, understand better than ever that there are costs as well as benefits associated with exploring. One of the six pledges proposed by an environmental campaign launched last month, The Jump, is to “holiday local”, taking short-haul flights once every three years and long-haul flights very rarely. Fortunately, the UK’s 15 national parks, 86 areas of outstanding natural beauty （known in Scotland as national scenic areas）, and countless other landscapes that are without formal status, but beloved nonetheless, mean that there is no shortage of special places for domestic nature tourists to visit—while a host of European beauty spots are accessible by rail.

One recent survey found that Windsor Great Park and Kew have become Britain’s most popular attractions, while Covid has created difficulties for indoor spaces which do not apply to outdoor ones.     3     Some companies that formerly ran foreign trips have adapted to the pandemic by taking people to watch dolphins and other marine life off British coasts instead.

    4     Sewage outflows are out of control due to failed water industry regulation. The owners of a popular rewilded estate in West Sussex—Knepp—have warned that plans to build 3,500 homes next to their land would be catastrophic for the species that live there. But as we confront an environmental emergency that grows ever more dangerous, it is essential to cultivate appreciation for the nature that surrounds us. In a small way, holiday outings to watch dragonflies, kingfishers or seals, or be surrounded by trees that are coming into leaf, could help us to focus on what matters.

6 . Trees are symbols of hope, life and transformation. They are also increasingly labeled as a straightforward, relatively inexpensive, and best solution to climate change. Lately, society has been putting a lot of pressure on trees to get the whole world out of the climate change emergency. Accordingly, enthusiasm is worldwide popular among governments, businesses and individuals for ambitious projects to plant billions, even a trillion more, so as to help cut current emission (排放).

“Trees are having a bit of a moment right now,” says Joe Fargione, an ecologist with The Nature Conservancy based in Minneapolis. “There’s no anti-tree lobby. Trees have lots of benefits for people. Not only do they store carbon, they help provide clean air, prevent soil erosion, shade and shelter homes to reduce energy costs and give people a sense of well-being.”

Yet, as global eagerness for adding more trees grows, some scientists are urging caution. Before moving forward, they say, such massive tree projects must address a range of scientific, social and economic concerns. Poorly designed projects that don’t address these issues could do more harm than good, the researchers say, wasting money as well as public goodwill. “There’s a real feeling that forests and trees are just the idea we can use to get some unspeakable support for many, perhaps more complicated, types of landscape restoration initiatives”, says ecologist Joseph Veldmanan.

The concerns are myriad: There’s too much focus on numbers of seedlings planted, and too little time spent on how to keep the trees alive in the long term, or in working with local communities. And there’s not enough emphasis on how different types of forests store very different amounts of carbon. There’s too much talk about trees, and not enough about other carbon-storing ecosystems. And over the last decade, a diverse garden of tree-centric proposal has spread across the globe. That can lead to all kinds of problems, Joseph adds. “For me, the devil is in the details.”

Caring for the Environment Starts from Ourselves

9 . U.N. Report Warns Nature Crisis

A new U.N. report focuses on the negative effects of human activity on nature. It says one million plant and animal species on land, in the seas and in the sky are now in danger of extinction.

    1     It draws on the work of 450 scientists from dozens of countries. The Earth has always suffered from human activity, it says. However, these scratches (划伤) have become deep scars (伤疤) over the past 50 years. Species are going extinct several hundred times faster than the average rate during the past ten million years. It’s something that has never happened before in human history.

    2     Since 1970, the human population has doubled. The global economy has grown by four times. To feed, clothe and give energy to this fast-changing world, lots of forests have been cut down. Between 1980 and 2000, one million square kilometers of tropical (热带的) forest were lost. Furthermore, hunting, overfishing and pollution have also been killing species in great numbers.

The problem can be fixed, the report says.     3     The amount of land and sea that is under protection needs to increase rapidly. The report suggests governments move away from using GDP as a key measure of development. Long-term effects must be considered, too.

Professor Eduardo Brondizio of Indiana University is an author of the report. He says, “We all know what needs to be done. The knowledge is there.     4    ”

10 . We use a huge amount of single-use plastic each year-we buy one million plastic bottles each minute around the world.Plastic waste,a material that can take centuries or more to disappear, is causing great damage to the planet.However,plastic waste produced in many countries typically ends up in open, uncontrolled landfills(垃圾填埋池），most of which finally enters the ocean either by wind or through waterways.

Now,Nzambi Matee,a 29-year-old woman from Nairobi,Kenya,is dealing with this global, crisis by recycling bags,containers, and other waste products into bricks(砖头）used for construction projects.Before founding her company -Gjenge Makers,Matee worked as an oil-industry engineer.After seeing plastic waste along Nairobi's streets,she decided to quit her job and built a small lab,testing sand and plastic combinations(结合）Matee managed to study in the materials lab at the University of Colorado Boulder, where she in the end developed a machine that produces the new bricks.

Made from a combination of plastic and sand,the bricks have a melting point higher than 350℃ and can be used for a longer time than traditional bricks. Matee and her team gain much of the raw product from factories and recyclers, and sometimes it's free, which allows the company to reduce the price point on the product and make it more affordable for schools and homeowners.

“There is waste that recyclers cannot deal with anymore. That is what we get,”Matee said. Her factory produces 1,500 bricks each day,made from a mix of different kinds of plastic.These are polyethylene(聚乙烯）used for milk bottles,sandwich bags, and ropes. But she does not work with polyethylene terephthalate or PET,commonly used for plastic bottles,which can be made into the same form easily again and again.

The plastic waste is mixed with sand,heated and then pressed into bricks, which are sold at different prices,depending on thickness and colour.