When 62-year-old fisherman Kpana Charlie finished the day’s catch, he liked to settle into a wooden chair, thinking about his childhood. Back then, his life on Sierra Leone’s Nyangai Island seemed excellent. He spent endless hours playing with his friends on the island’s white beaches. Whenever he wanted to avoid having to do his housework, he could simply disappear into the forest that covered much of the island. He remembers as recently as ten years ago, it still measured some 2, 300 feet from end to end.

Today, Nyangai is disappearing before his very eyes, covered by the endless sea. The forests are gone. And the land on which Charlie’s family home once stood, has long since disappeared beneath the waves.

In fact, the local government has responded to the sharp increase of sea level by building a concrete (混凝土制的) seawall along the length of the town. But in the many smaller coastal towns and villages in the area, there simply aren’t the resources. Then, the government made a project to protect some of the settlements by planting trees, but this has had limited success. With the population relying on woods for building and smoking-fish, few trees lived longer than the project, which ended in 2021.

Sierra Leone has been identified as one of the world’s most weak countries to the effects of climate change, despite having little influence on global CO₂ emissions (排放). “Weak countries should be getting some support from wealthy nations to strengthen their climate defenses (防御),” says Gabriel Kpaka, the head of the country’s Meteorological Agency. “But we’re not really seeing that.”

With global sea level expected to rise by anywhere between 1 and 3 feet by the end of the century, along with an increase in extreme weather events, the experience of this West African island offers an understanding of the possible future of countless other low-lying areas around the world.

Imagine living on the edge of a vast desert, which is moving quietly closer to your village every day and covering your fields. The desert is on the move. This is called desertification (沙漠化).

Desertification occurs in regions close to an already existing desert. It generally arises from two related causes. The first is over-use of water in the area. There is not enough water in any case, and if it is not carefully used, disaster can follow. As time goes on, water shortages make farming more and more difficult. In some places, locals can remember local lakes and marshes which were once the homes for all kinds of fish and birds. They have been completely buried by the sand now. Farmers leave the land, and fields are replaced by deserts.

The second cause is misuse or over-use of the land. This means that the wrong crops are planted, and need more water than is available (可获得的). Ploughing (耕种) large fields and removing bushes and trees means that the wind will blow away the soil. Once the soil is lost, it is hard to replace, and if there is rain, it has nowhere to go, and brings no benefit.

It is not only the farmers and villagers who suffer. Every spring, the skies over some of cities, thousands of kilometers away from the deserts, can be darkened by sandstorms. Dust from deserts can have a great effect on weather systems. While desertification is perhaps being partly caused by global warming, these sandstorms can make global warming worse by adding to what is known as the greenhouse effect.

What can be done to slow down or stop the process of desertification? A great deal of work is already under way. Obviously the first step is to find new water sources. Tree planting can also help, by providing barriers (屏障) between desert and rich field. Some types of grass also hold the soil together, and stop the wind taking it. Without these efforts, it will be harder and harder to stop the world’s deserts in their tracks, and more and more farmers will give up and head for cities. The lesson to be learnt lies beneath (在……下面) the sand.