Over-dried Earth

The south-west of the United States, together with some parts of Mexico across the Rio Grande, is one of the driest parts of the North American continent. But, over the past two decades, even that expected dryness     1     (take) to the limit. According to Park Williams, who works at Columbia University’s Lamont-Doherty Earth Observatory, the current lack of rainfall in the area constitutes a megadrought of a severity     2    (see) on only four other occasions in the past 1,200 years.

Dr Williams studies the annual growth rings of 1,586 ancient trees, in order to reconstruct soil-moisture patterns going back to 800 A.D. During warm, wet years trees grow fast, producing wide rings. During cold, dry     3     they grow more slowly, producing narrow rings. During a drought, a tree     4     not grow much at all.

    5    they describe in this week’s Science, the team identified dozens of droughts over the centuries in question. But four stood out. They then took the average soil-moisture value for the current drought and compared it with sequential（连续的） 19-year averages with the previous four, one of them     6    (last) nearly a century. This showed that the region is already drier than it was during the first three of the previous megadroughts, and is equivalent to the event of 1575-1603.

In a world     7     human actions are driving temperatures up, Dr Parker and his colleagues wondered how much people are     8    (blame) for this state of affairs. To estimate that, they turned to climate modelling.

Climate models are able to re-run the past with and     9     the warming effects of human activity, offering a way to compare what actually happened with what might have done. In their simulated world in which anthropogenic（人类起源的） emissions had not increased the greenhouse-gas effect, the team found that a drought did indeed still influence the western reaches of North America during the first two decades of the 21st century. But this imaginary dry spell was considerably     10    (severe) than the real one-ranking 11th rather than 2nd in the period under study (see chart).

Can We Eat Meat Without Damaging the Environment?

“I’ve eaten meat my whole life, but the more I learn about our planet, the more I question how we treat it,” says Liz Bonnin at the start of the BBC documentary Meat: A Threat To Our Planet?.

“Unless we do things very differently,” says Liz, “the impact the meat industry has    1    our environment is only going to get worse.    2    demand increases, so do greenhouse gas emissions and pollution. This leads to a very obvious question: should we just stop eating meat?” This question is often asked, and we can’t just use “yes” or “no” to answer it. I’d like to share with you my ideas on    3    to eat meat with the least environmental damage.

We actually need to eat more grass-fed meat, mainly beef and lamb. University of Oxford Professor Myles Allen has recalculated the amount of CH₄ emissions from ruminants(反刍动物). The inference from this new research is that we don’t have to stop    4    （eat）grass-fed cattle or sheep. Instead of demonizing(妖魔化)them, we need to differentiate between the animals that are part of the problem --- namely intensively produced(集中生产的)poultry, pork and dairy products, and    5    that are part of the solution --- namely grass-fed ruminants. At the root of the climate change problem is our fossil fuel(化石燃料)consumption, this is where we need to take    6    （urgent紧急的,急迫的）action.

There are responsible ways of eating meat. You can begin with knowing the farm your animal came from and what kind of life the animal    8    （lead）.The EU’s organic standard for livestock(牲畜), for instance, requires that a farm hold no more than two cows per hectare of land. In the UK, there is labeling available too,    9    will tell you if a meat’s been pasture-raised(牧场放养).

It’s important to ensure pastures are well-managed and not over-grazed(过度放牧). It’s almost possible to eat meat and be environmentally and socially conscious,    10    what we can do at least is to try not to buy meat that is mass-produced.

Deep diving exploration

While most photographers put their cameras away when the night’s dark curtain falls, Zhang Fan gathers his equipment and starts his black water diving adventure.

Blackwater diving involves photographing small, free floating (自动浮动的) ocean creatures that move up to the ocean’s surface (表面) after dark or in any area     1     there is seemingly no bottom.

Still quite new in China, blackwater diving     2    (date) back to 1984 in Hawaii, US. From small eel larva (幼龄鳗鱼) to big, fierce great white sharks, each of Zhang’s underwater photographs has a “wow” factor. But the story behind each photo adds more emotional value to the work     3    .

“It is like meeting an old neighbor,” the 35-year-old photographer recalled, speaking of the touching moment when he returned to a location after a long time only     4    (see) the fish he previously photographed still there.

While the underwater world     5     seem fascinating, it’s not always a fairy tale. Zhang said that he encountered many dangerous moments underwater, including     6    (hit) as a sperm whale (抹香鲸) went by. But     7     fascinated him most is that he can witness big and small changes in the ocean and     8     these changes can tell him about nature.

“Corals are     9     the first indicators of climate change. With the rise in temperature, corals have experienced a process called ‘bleaching’, during which they lose their color and are dying. It is heartbreaking,” he explained.

This risky     10     charming art has helped Zhang attract loads of fans. His Sina Weibo account has more than 430,000 follower. He hopes that his photos and videos can act as a wake-up call to protect our oceans.

Millions Of Baby Olive Ridley Turtles Emerge in Orissa

Nature is full of wonders. In     1     is one of the most breathtaking sights in nature, millions of baby Ridley turtles broke out of their eggshells under the sand at one of their mass nesting grounds in coastal Orissa. The baby turtles started their journey towards the Bay of Bengal     2           3           4     they emerged from their nest in the southern district of Ganjam, about 175 km from Bhubaneshwar.

Orissa is the home to three mass nesting sites of the Oliver turtles, a species     5       (threaten) with extinction, and one of the sites, Gahirmatha,     6     around 70 to 80million turtles lay eggs on the beach every year, is considered one of the world's largest nesting sites.

The female turtles drag     7     up the beach from the sea, dig a nest, lay at least one hundred eggs, cover and conceal their eggs and nest, and then return to the sea. The females never visit the nest again to take care of the eggs that     8     (deposit) in the warm sand.

The baby turtles emerge from the eggs after 45-60 days, then the babies grow without their mother, which is a rare phenomenon in nature. Interestingly, it is on the same beach where they were born     9     the females lay their eggs.

In recent years, sea erosion has led to many turtles’ nest     10     (damage) or destroyed.

Also, some fierce animals such as dogs and birds     11     (reduce) the number of nesting turtles. And man has also had a negative impact     12     using engine-powered fishing boats near the turtles' nesting grounds.

Water on the Moon

NASA has confirmed the presence of water on the moon’s sunlit surface, a breakthrough     1     (suggest) the chemical compound that is vital to life on Earth could be distributed across more parts of the lunar surface than the ice that     2     (find) previously in dark and cold areas.

“We don’t know yet if we can use it as a resource,” NASA Administrator Jim Bridenstine said, but he added that learning more about the water is still crucial.

The discovery comes from the space agency’s Stratospheric Observatory for Infrared Astronomy, or SOFIA — a     3     (modify) Boeing 747 that     4     take telescope high into Earth’s atmosphere,     5     researchers may peer at objects in space with hardly any visual disturbance from water vapor. To detect the molecules, SOFIA also used a special camera to distinguish between water’s specific wavelength of 6.1 microns and that of its close chemical relative hydroxyl, or OH.

The data confirm     6     experts have suspected, that water might exist on the moon’s sunny surface, though the form of it shall be     7     (obvious) to detect. Experts will now try to figure out exactly how the water came to form and why it persists.

“Data from this location reveal water in concentration of 100 to 412 parts per million trapped     8     a cubic meter of soil.” NASA said in a release about the discovery.

“    9     without a thick atmosphere, water on the sunlit lunar surface should just be lost to space,” said Casey Honniball, the lead author of a study about the discovery. “Somehow we’re actually seeing it.”

There are several possible explanations for the water’s presence, including an interesting yet reasonable    10     claiming its origin to the stony micro objects from space. Small balls of glass from that process could trap water, according to the researchers’ paper.