Recently, we have already shown that climate change has led to a dramatic increase in storm surge risk in New York City, making devastating events like Hurricane Sandy more likely.

    What can we say about the role of climate change in the unprecedented disaster that is unfolding in Houston with Hurricane Harvey? There are certain climate change-related factors that we can, with great confidence, say worsened the flooding.

    Sea Level rise attributable to climate change-some of which is due to coastal subsidence(下沉) caused by human disturbance such as oil drilling-is more than half a foot(15cm) over the past few decades. That means the storm surge was half a foot higher than it would have been just decades ago, meaning far more flooding and destruction.

    In addition to that, sea surface temperatures in the region have risen about 0.5C(close to 1F) over the past few decades from roughly 30C(86F) to 30.5C(87F), which contributed to the very warm sea surface temperatures(30.5-31C, or 87-88F). There is a simple thermodynamic(热力学的) relationship known as the Clausius-Clapeyron equation that tells us there is a roughly 3% increase in average atmospheric moisture content for each 0.5C of warming. Sea surface temperatures in the area where Harvey intensified were 0.5-1C warmer than current-day average temperatures, which translates to 1-1.5C warmer than “average” temperatures a few decades ago. That means 3-5% more moisture(水分) in the atmosphere. That large amount of moisture creates the potential for much greater rainfalls and greater flooding. The combination of coastal flooding and heavy rainfall is responsible for the devastating flooding that Houston is experiencing.

    Not only are the surface waters of the Gulf of Mexico unusually warm right now, but there is a deep layer of warm water that Harvey was able to feed upon when it intensified at near record pace as it neared the coast. Human-caused warming is penetrating down into the ocean. It's creating deeper layers of warm water in the Gulf and elsewhere. Harvey was almost certainly more intense than it would have been in the absence of human-caused warming, which means stronger winds, more wind damage and a larger storm surge.

    Finally, the more tenuous but potentially relevant climate factors: part of what has made Harvey such a devastating(毁灭性的) storm is the way it has stalled near the coast. It continues to strike Houston and surrounding regions with a seemingly endless flood, which will likely top out at nearly 4ft(1.22m) of rainfall over a days-long period before it is done. The stalling is due to very weak prevailing winds, which are failing to steer the storm off to sea, allowing it to spin around and wobble back and forth. This pattern, in turn, is associated with a greatly expanded subtropical high pressure system over much of the US at the moment, with the jet stream pushed well to the north. This pattern of subtropical expansion is predicted in model simulations of human-caused climate change. More tenuous(微弱的), but possibly relevant still, is the fact that very persistent, nearly “stationary” summer weather patterns of this sort, where weather anomalies(both high-pressure dry hot regions and low-pressure stormy/rainy regions) stay locked in place for many days at a time, appears to be favoured by human-caused climate change.

    In conclusion, while we cannot say climate change “caused” Hurricane Harvey, what we can say is that it exacerbated several characteristics of the storm in a way that greatly increased the risk of damage and loss of life. Climate change worsened the impact of Hurricane Harvey.

    When was the last time you relied on an old-fashioned map to figure out the route to an unfamiliar place? For many, the GPS has revolutionized navigation, making a paper map almost obsolete? So how has this piece of technology developed over its 26 years of existence? On February 14,1989,the first satellite in the US Global Positioning System was sent into space from Cape Canaveral, beginning the start of one of the wonders of the modern world.

    GPS stands for Global Positioning System, which is made of a network of around 30 satellites that move around the earth. The system uses a process called trilateration to find out one's position. By measuring the time it takes for the signal to reach one satellite, the GPS can determine your distance from the satellite, creating a sphere(范围) of possible locations. Measuring your distance from at least three satellites will narrow your location to the place where the three spheres cross one another, to the accuracy(精确) of about less than 1 meter!

    The GPS was first invented during the Cold War by the United States Department of Defense. In 1960, the first system, which was made of just five satellites, was put into place. It was initially created for strictly military(军事的) use; however, in 1983, as a result of faulty navigation technology, a Korean passenger plane mistakenly flew into USSR territory(苏联领土) and was shot down. In order to prevent such bad events, American President Ronald Reagan allowed civilian(民用的) use of the GPS.

    Over the next ten years, the system's accuracy improved as the network was increased to 24 satellites. And during the first Persian Gulf War, the new GPS was finally used by the military. Now scientists use the technology to track animals to better understand their movement and behavior. Parents who may be worried about their children can also use GPS technology to track them.

B

    Researchers say they have created a new super-tough material in the laboratory. It is stronger, lighter and costs less than steel. But the new material is not a product of high technology. It is wood. Researcher Liangbing Hu says that it can compete with some of the world's strongest materials or even replace steel.

    The product is called Super Wood. It doesn't require any special raw, unprocessed material. That means the cost of the product will be relatively low.Hu said, “We can start with very cheap wood, and also very fancy, expensive wood. But in the end, we get very similar performance.”

    Super Wood is made by partially removing a natural polymer called lignin（木质素）. Hu explained, “Lignin is like glue to hold all the parts together in natural wood. To be able to densify（增密）the wood completely, some of the lignin has to be removed. “Strong chemicals are put on the wood to remove about half of its lignin. Then, after being left in extreme heat and pressurized for a day, the treated wood is ready.

    The wood is strong enough to build automobiles, airplanes, wind turbines and more. Researchers are finding many new ways to use wood, including creating batteries and see-through wood and paper.Hu said, “Wood has been existing on Earth for more than a million years. And human beings have been using wood for furniture, construction for more than 10 thousand years. And the more we worked on this material, we realized, we have never fully exhausted the potential of this amazing material.”

    Not many years ago, a wealthy and rather strange old man named Johnson lived alone in a village in the south of England. He had made a lot of money in trading with foreign countries. When he was seventy-five, he gave 12,000$ to the village school to buy land and equipment for a children's playground.

    As a result of his kindness, many people came to visit him. Among them was a newspaperman. During their talk, Johnson said that he was seventy-five and expected to live to be a hundred. The newspaperman asked him how he managed to be healthy at seventy—five. Johnson had a sense of humor. He liked whisky(威士忌)and drank some each day. "I have an injection(注射)in my neck each evening." he told the newspaperman, thinking of his evening glass of whisky. The newspaperman did not understand what Johnson meant. In his newspaper he reported that Johnson was seventy-five and had a daily injection in his neck. Within a week Johnson received thousands of letters from all over Britain asking him for the secret of his daily injection.

    Pyramid of Giza

    One of seven wonders of ancient world also becomes favorite site for astronomers to capture photographs from the orbit. It is not at all visible with naked eyes from space, so astronomers used special cameras for it.

    Grand Canyon

    It surely takes many days to enjoy every site of 277-mile-long Grand Canyon in Arizona. But the astronauts at orbits of Earth are able to see Grand Canyon with their own eyes all at once. The space images of Grand Canyon help the scientists to make surface map of the steep sided Canyon, also to monitor the changes within its surface.

    Ganges River Delta

    Ganges River Delta is 220 miles long; this amazing geographic feature can also seen from orbits of Earth. When the river becomes empty, it becomes the largest remaining habitat of Bengal tiger and other rich wild life.

    Palm Island, Dubai

    Palm Island along with world islands of Dubai can be seen even from space. The Palm Island actually holds two artificial island in shape of palm tree, spreading across in an area of 100,000 square meters. You can meet hundreds of luxury hotels and parks within this man-made wonder.

    One afternoon I toured an art museum while waiting for my husband to finish a business meeting. I was looking forward to a quiet view of the wonderful works.

    A young couple viewing the paintings ahead of me chatted nonstop between themselves. I watched them a moment and decided she was doing all the talking. I admired his patience for tolerating her constant words. Disturbed by their noise, I moved on.

    I encountered them several times as I moved through the various rooms of art. Each time I heard her constant talking, I moved away quickly.

    I was standing at the counter of the museum gift store doing some shopping when the couple approached the exit. Before they left, the man reached into his pocket and pulled out a white object. He turned it into a long cane (手杖) and then tapped his way into the coatroom to get his wife's jacket.

    "He's a brave man," the clerk at the counter said, "Most of us would give up if we were blinded at such a young age. During his recovery, he made a promise that his life wouldn't change. So, as before, he and his wife come in whenever there's a new art show."

    "But what does he get out of the art?" I asked, "He can't see."

    "Can't see! You're wrong. He sees a lot. More than you or I do," the clerk said, "His wife describes each painting so he can see it in his head."

    I learned something about patience, courage and love that day. I saw the patience of a young wife describing paintings to a person without sight and the courage of a husband who would not allow blindness to change his life.

    And I saw the love shared by two people as I watched this couple walk away arm in arm.