1 . The organic foods have gained a lot of popularity as they are being considered as healthier and tastier. A fair number of people advocate a large-scale shift to organic farming from conventional agriculture. But this might not seem well-founded.

Since the mid-19th century, conventional industrial agriculture has become incredibly efficient on a simple land to food basis. Conventional farming gets more and more crop per square foot of land, which can mean less wilderness needs to be transformed to farmland.

To make farming more efficient, conventional agriculture uses a significant amount of synthetic fertilizer each year, and all that nitrogen(氮) enables much faster plant growth.   However, the cost is paid in vast polluted dead zones at the months of many of the world’s rivers, because much of the nitrogen ends up running off the soil and into the oceans. This also makes conventional farming one of the major threats to the environment.

To weaken the environmental impact of agriculture, improve soil quality as well as produce healthier foods, some farmers have turned to organic farming. Environmentalists have also   welcomed organic food as better for the planet than the food produced by agricultural corporations. Organic practices—refusing artificial fertilizers and chemical pesticides—are considered far more sustainable. Sales of organic food rose 7.7% in 2010, up to $26.7 billion—and people are making those purchases for their moral senses as much as their tongues.

Yet a new meta-analysis in Nature does the math and comes to a hard conclusion: organic farming produces 25% fewer crops on average than conventional agriculture. This is definitely a downside of organic farming, especially when global population is still growing rapidly.

In the Nature analysis, scientists performed an analysis of 66 studies comparing conventional and organic methods across 34 different crop species, from fruits to grains. They found that organic farming delivered a lower output for every crop type, though the difference varied widely. For crops like fruit trees, organic trailed(落后于) conventional agriculture by just 5%. Yet for major grain crops and vegetables—all of which provide the world’s main calories—conventional agriculture outperformed organics by more than 25%.

What that means is that while organic farming may be more sustainable than conventional agriculture, there are trade-offs(此消彼长)with each. So an ideal global agriculture system may borrow the best from both systems rather than upholding merely organic or conventional practices.

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2 . Every year on April 22,Earth Day marks the anniversary of the birth of the modern environmental movement in 1970.It gave a voice to an emerging public consciousness about the state of our planet.The founder was Gaylord Nelson.

What moved Gaylord Nelson to action was the1969massive oil spill（溢出）in California,the largest oil spill in the United States at that time.The spill proved to be an environmental nightmare as it had a strong impact on marine life,killing an estimated3,500sea birds,as well as marine animals such as dolphins,elephant seals and sea lions.Inspired by the student antiwar movement at that period of time,Nelson found it was a right time to channel the energy of the students towards a fight for environmental protection.He decided that it was time to educate the Americans on the need to protect the environment.Thus,Earth Day was born in1970,and public environmental consciousness took centre stage.

On 22nd April 1970,millions of Americans took to the streets to demonstrate for a healthy,sustainable environment and thousands of students marched in protest of the terrible situation of the environment.Businesses were forced to follow environmental standards if they wanted to continue their operations.The year1990 saw Earth Day reach out to many more countries around the world.It helped pave the way for the 1992 United Nations Earth Summit in Rio de Janeiro,bringing together many nations,for a joint effort towards protecting the environment.In 2009,the United Nations decided to officially set April 22 as Earth Day.

For his role as founder of Earth Day,Gaylord Nelson was awarded the Presidential Medal of Freedom（1995）,the highest honour given to civilians in the United States.We honor the man,as the fight for a cleaner environment continues.

3 . The need to feed a growing population is putting much pressure on the world’s supply of water. With 97% of the world’s water too salty to be drunk or used in agriculture, the worldwide supply of water needs careful management, especially in agriculture. Although the idea of a water shortage seems strange to someone fortunate enough to live in a high rainfall country, many of the world’s agricultural industries experience constant water shortages .

Although dams can be built to store water for agricultural use in dry areas and dry seasons, the costs of water redistribution(重新分配) are very high. Not only is there the cost of the engineering itself, but there is also an environmental cost to be considered. Where valleys are flooded to create dams, houses are lost and wildlife homes destroyed. Besides, water may flow easily through pipes to fields, but it cannot be transported from one side of the world to the other. Each country must therefore rely on the management of its own water to supply its farming requirements.

This is particularly troubling for countries with agricultural industries in areas dependent on irrigation(灌溉). In Texas, farmers’ overuse of irrigation water has resulted in a 25% reduction of the water stores. In the Central Valley area of southwestern USA, a huge water engineering project provided water for farming in dry valleys, but much of the water use has been poorly managed.

Saudi Arabia’s attempts to grow wheat in desert areas have seen the pumping of huge quantities of irrigation water from underground reserves. Because there is no rainfall in these areas, such reserves can only decrease, and it is believed that fifty years of pumping will see them run dry.

4 . Have you ever had the feeling that you can’t think when there is too much noise around Did you ever think a fish could experience that feeling too? A recent published paper, combined over10,000 scientific papers, confirms that undersea life knows that exact same feeling, more often than not. Anthropogentic ocean noise, also known as underwater noise pollution, has created a huge impact on sea life due to “human-caused” activity within and neighboring our oceans.

The film Finding Nemo educated us about the ocean, and specifically within the ordinary world of a clown fish. A fact many may not know is that clown fish spend the first part of their lives as larvae (幼虫),moving slowly with the current of the ocean until they become strong enough to swim against it. Once they are powerful and strong, they head home in sheltered coral reefs. There is only one drawback—the fish can’t physically see the reef, but they can hear it. The only problem is, if they can’t hear it, will they ever make it home?

Our ocean noise, such as cargo ships, ship and boat propellers (螺旋桨),surfing, deep sea mining, etc. are causing destruction of sea life. Some researches found that sound is the sensory signal that travels the farthest through the ocean. The ocean noise drowns out the natural soundscapes, putting sea life under great stress. Altogether, this stress then affects their general health, disturb their behavior, reproduction and, in extreme cases causes death. Marine life can adapt to noise pollution, however, only if they can escape it. This only causes further complications of straying（使偏离）species from their traditional breeding regions or separating them from their families.

Now, what if we told you there is already a solution? Multiple ways, ideas and designs are currently in the works or already exist to remove the damage of the ocean noise. As the previous research explains, from wind-powered ships to noise-reducing propellers, a great many solutions are already available and in some cases, cost-effective. The authors of the paper hope it will catch the attention form the society.

5 . Many cities in the world are benefiting from the night activities of a group of people who call themselves guerrilla (游击队) gardeners. Armed with trowels, spades and a van full of flowers and plants, guerrilla gardeners turn abandoned urban land into a blaze of color. In city centre locations where there was mud, weeds and empty plastic bottles, residents often wake up to find that the wasted area has been transformed overnight with brightly-colored bedding plants.

In most British cities, local governments and police turn a blind eye to the effort of the gardeners, whose activities are always carried out under cover of nightfall. And so far, there has been nothing but praise from the astonished and delighted local residents when they find their neighborhood transformed in such a striking fashion.

Not only do the guerrilla gardeners beautify ignored places, they also return regularly to water the plants and weed the flower beds. They also make sure that at least some of the plants they bring are evergreens, which means that the area doesn't look depressing in the winter months.

The first guerrilla gardener in London was Richard Reynolds, whose day job is at an advertising agency. Mr. Reynolds, a graduate of Oxford University, began his efforts two years ago when he moved to a flat in tower block in South London. From his balcony, he could see several empty concrete pots, placed by the local governments to contain plants but never used. He went out after midnight and filled the pots with plants, and then planted more flowers in the path leading to the entrance to the block.

He then set up a website to explain his plan and called upon more gardeners to join him. Cash donations flooded in and, more importantly, volunteers rushed to be part of the movement. Within six months, there were five hundred people in London prepared to come out at very short notice to restore neglected parts of the urban landscape. There are now unofficial but carefully-organized groups in many cities in Britain and North America and there is also a website where would-be urban gardeners can find out the location of the next expedition.

10 . In 2016, the world’s population cast aside 49 million tons of electronic waste, known as e-waste.

It has been calculated that this number will grow to more than 60 million tons by 2021.

What is causing the upsurge ( 激增 ) in e-waste? Technology is becoming more and more widespread, covering almost every aspect of our lives. Meanwhile, the lifespan of devices is getting shorter---many products will be thrown away once their batteries die, to be replaced by new devices. Companies intentionally plan the obsolescence ( 过时 ) of their goods by updating the design or software and discontinuing support for older models, so that now it is usually cheaper and easier to buy a new product than to repair an old one. Since prices are falling, electronic devices are in demand around the world.

As more people buy electronic equipment, manufacturers ( 制造商 ) are beginning to face shortages of the raw materials needed to make their products, so recycling and reusing materials from discarded products and waste makes economic and environmental sense.

Recycling e-waste is practiced both formally and informally. Proper or formal e-waste recycling usually involves taking apart the electronics, separating and sorting through the materials and cleaning them. Companies must obey health and safety rules to reduce the health and environmental hazards of handling e-waste by using pollution-control technologies. All this makes formal recycling expensive. Informal recycling is typically unlicensed and uncontrolled. At informal recycling workshops, men and women recover valuable materials by burning devices to melt away non-valuable materials. Usually they do not wear protective equipment and lack any awareness that they are handling dangerous materials.

With the amount of e-waste growing around the world, recycling alone will not be enough to solve the problem. In order to reduce e-waste, manufacturers need to design electronics that are safer, and more durable, repairable and recyclable. The best thing you can do is resist buying a new device until you really need it. Try to get your old product repaired if possible and, if it can’t be fixed, resell or recycle it responsibly. Before you recycle your device, put any broken parts in separate containers and close these tightly to prevent chemicals from leaking. Wear latex gloves and a mask if you’re handling something that’s broken.