Deserts

To-to-to-to-today’s weather, brought to you by Steve corporation: Yes, today will be sunny, dry and hot, as usual. Tomorrow will be dry, sunny and hot. The day after will be hot, sunny and dry, and after that the same, and… the same... - There are areas on earth where it almost never rains and almost never snows. There is no precipitation, and there is hardly any vegetation. This is desert landscape.

How come it’s so dry there? There are various explanations, since a desert can arise in several ways. Let’s have a look at a couple of them. [1.] When the rays of the sun hit the equator, the earth becomes warmer, and so does the air just above the surface. This warm air moves upwards in the atmosphere. More and more air pushes up from below, but it can’t keep going up forever.

Instead, high in the atmosphere it is pushed sideways — to north and south — by more air from below. Gradually, the air cools and becomes heavier again. Then it sinks back down toward the surface of the earth and creates a high air pressure here. And when the air pressure is high, the weather becomes clear, sunny and dry. Rain is unusual.

And so these areas often become deserts. [2.] Here rain clouds move in from the sea over the land. The shape of the land — the topology of the area — forces the clouds to move upwards in the atmosphere. The clouds cool down and condense into precipitation which falls on the mountains, as rain or snow. So, the rain clouds will never reach the area on the other side of the mountain range. There, it hardly ever rains.

There is rain shadow. And a desert develops. A desert landscape consists of sand, rocks, or cliffs. It can be flat or mountainous. Most deserts are very hot during the day.

The sun blazes, and it’s an environment that is really hard for humans to be in. But the temperature varies a lot between day and night, and the night can be really cold. The plants and animals living in the desert have adapted to this extreme climate. The few plants that can survive there have long roots to reach water deep under the surface. Their leaves are small and covered with wax, so as not to give off very much liquid.

Some plants, like cacti, can store water in their stem. Animals that live in the desert must hide from the sun. They seek the shade, or burrow down into the sand. And instead they are mainly active during the night. They can range from insects, scorpions, birds, and snakes, to even a few mammals such as mice and desert foxes.

And there are also a small number of people who have learned to live in the extreme climate of the desert. Traditionally, these ethnic groups have not had settlements. Instead they have moved around with their families and their cattle to places where water can be found. They are nomads. They wear special clothing that protects them from the sun during the day, from the cold during the night, and from the sandstorms that often occur in deserts.

Today there are modern cities built in the desert, such as Dubai in the United Arab Emirates and Las Vegas in the USA. People can live there, in the desert climate, thanks to modern technology, like air conditioning, water conduits and refrigerators. … and the next day sunny, dry and hot. And the next, and the … But weather forecasts, they probably never need.