4 . When 62-year-old fisherman Kpana Charlie has finished placing the day’s catch in his nets, he likes to sit on his wooden chair and let his mind go back to his childhood. Back then, his home on Sierra Leone’s Nyangai Island seemed like a paradise (天堂).

He spent endless hours playing with his friends on the island’s shining white beaches. He liked to kick around a soccer ball on the sports field in his village, and in mango season, he would shake the trees to collect their colorful fruit. Whenever he wanted to avoid doing his homework, he could simply disappear into the thick forest that covered much of the island.

Today, Nyangai is disappearing, swallowed up by the sea. As recently as ten years ago, it still measured some 2, 300 feet from end to end. What’s left today is a patch of (一片) sand which is 300 feet long and 250 wide. The forests are gone, flooded by saltwater. The soccer field lies under water for 22 hours of the day. And the land on which Charlie’s family home once stood, the home he was born in, has been disappearing under the waves. In as little as two years, Charlie fears, Nyangai may no longer exist at all.

With nearly a third of its population living in coastal areas, and its heavy reliance on agriculture and fishing, Sierra Leone has been treated as one of the world’s most vulnerable countries to the effects of climate (气候) change.

Gabriel Jaka, head of operations for the country’s Meteorological Agency, says the reason for Nyangai’s troubles is clear. “We’re seeing a significant sea-level rise and these people don’t have any proper defenses,” he says. “All they have are sandbags. If we don’t act now, the effects on people are just going to get worse.”

5 . Last summer on the Hawaiian Island of Kauai, Tina Taniguchi worked close to the ground. Her coconut leaf hat covered most of her thick brown hair. Wet soil had gotten on her clothes and her smiling face.

Taniguchi smiles a lot while working on the Hanapepe salt land on the west side of Kauai. It is a piece of land about half a hectare in size with pools of salty water. The salt becomes crystals (晶体)as the water dries.

“The work is tiring, but for me it’s also play,” Taniguchi said with a laugh. Taniguchi’s family is one of 22 families who make salt, following a cultural and spiritual tradition. Hanapepe is one of the last remaining salt lands in Hawaii. Its salt can be traded or given away but must never be sold. Hawaiians use it in cooking, healing, and as protection.

Over the past 10 years, there have been several threats to this field. They encompass development, pollution from a neighboring airfield, damage to the sand from vehicle traffic and waste left by visitors to the nearby beach. In addition, rising sea levels and weather might stop the practice.

The process of turning sea water into salt can be slow. The season begins once the rain stops and water starts to disappear from the salt beds. Ocean water travels underground and enters the wells. Each family has their own well. As water enters the well, so do tiny, red brine shrimp. These small ocean animals give Hanapepe salt its unusual, sweet taste.

The families first clean the salt beds and line them with black clay (陶土). Then they move water from the wells into the beds. There, salt crystals form. The top level, or layer, is the whitest. It is used for table salt. The middle layer is pinkish and is used in cooking, while the bottom layer, which is a deep red color, is used in blessings.

Plogging     1     (refer) to the act of picking up trash while jogging. Ploggers collect trash, such as plastic bottles, waste paper and cans from parks, beaches, and other outdoor areas when they exercise.

The     2     (found) of plogging was Erik Ahlstrom. He used to live in a small town, but later he moved to Stockholm,     3     capital city of Sweden. He could hardly believe     4     he saw there—garbage filled every corner of the city. So, he decided to do something     5     (change) the situation. Every time he went jogging, he would invite some friends to pick up trash with him. This gradually became a habit and inspired more and more people to join in the activity. Some famous sports brands even began to provide     6     (run) shoes for plogging enthusiasts (爱好者). Since then, plogging     7     (become) increasingly popular around the world.

Now, plogging is widely recognized as an     8     (effect) and eco-friendly way to keep healthy and contribute to the environment. Whether you are a fitness enthusiast     9     simply want to do your part to protect the environment, plogging will be a great choice. So, why not give it a try? You might find a new way to stay connected to nature and make the Earth a     10     (good) place to live on.

9 . Sounds from human activity flood across the oceans, causing trouble to ocean creatures. And climate (气候) change may make some places even louder.

Researchers have expected the oceans to get noisier because of increasing human activity. “The more goods you buy, the more shipping you have, so the more noise you have.” says Luca Possenti, a scientist studying sound in the ocean at the Royal Netherlands Institute. But Possenti and his co-worker realized that climate change might also influence how sound travels through the water.

Human-caused climate change is changing ocean temperatures, salt levels and acidity (酸度). So Possenti’s team used computers to model how those factors (因素) influence noise levels across the world’s oceans.

When waters become more acidic, they can’t take in sound at some wavelengths as well, so those sounds can travel further, adding to the noise in some areas. This effect is relatively small. Other changes impact the sound level more, the researchers found. Changes to temperature and salt levels can change how well different layers (层) of the ocean mix, which, in turn, impacts how sound travels.

The team predicted (预测) models of the world in about 70 years if climate change continues. And then they compared them with models of the world now. In the North Atlantic, they saw an increase in sound levels in the upper 125 meters of the ocean. This was caused mostly by ice melting (融化) off of Greenland, forming a cold layer of water near the ocean’s surface. Sound traveling through water tends to go toward the coldest area. As a result, sound waves tended to get stuck in the cold top layer-spreading further out across the water, instead of traveling deeper. That increased the noisiness at this depth in the North Atlantic. The models suggested that a single ship could sound about five times as loud underwater because of this. Considering all the ship traffic between Europe and North America, that may stress animals, many of which communicate, and catch food with sound.

10 . More than 80 percent of global heat is absorbed by the ocean, which has a massive capacity to store and give off heat. High sea-surface temperatures are causing long-term damage to coral reefs (珊瑚礁). Corals are dying. The IPCC (政府间气候变化专门委员会) projects that up to 90 percent of coral reefs could disappear if global warming reaches 1.5℃. Another reason corals are in trouble is because of ocean acidification. Higher carbon dioxide levels have shift ed the chemistry of the ocean, making it more acidic, and corals and sea creatures have trouble growing in acidic conditions.

When ocean water warms, it expands in volume. This is a major cause of the rise in sea levels, along with the water added to the ocean by the melting of land-based glaciers (冰川). The sea level has risen by an average of 20 centimeters since the late 19th century, and the research by scientists studying the last 25 years of satellite data found that the ocean water is rising faster and faster. If it continues at its current rate, the rise in sea level by 2100 will be more than double the current estimates. Sea level rise leads to the destruction of coastal wetlands, flooding and damage to water ecosystems.

Temperature and precipitation (沉淀) are key elements of climate. A warmer climate means that more water rises from both the land and ocean, and a warmer atmosphere holds more of that water. Scientists have noticed that there are more heavy rainfall events. Additionally, higher water temperature in streams, lakes, and rivers lead to lower levels of dissolved oxygen in the water, which impacts the survival and populations of fish and other sea life.

Especially troubling are the extreme weather events that are happening more often around the world. Hurricanes are ramping up in intensity, particularly in North Atlantic. The year 2017 was a busy one for Atlantic hurricanes. Meanwhile, in the western United States, the state of California has had record-setting drought conditions, which began in 2012.