The Gobi and the Steppes

Deserts are large, extremely dry areas with less than 25 cm of precipitation (rain or snow) a year. They are found on every continent and cover about one-fifth of the Earth's land.

And they are not empty. According to the National Geographic Society, around one billion people (one-eighth of the world's population) live in deserts.

The Gobi lies in Mongolia, with part of it in north China. Mongolia is called the 'Land of the Eternal Blue Sky', because it has 8 to 9 months of sunny weather a year.

But sunshine is not warmth. Winter temperatures can drop to minus 30°C, the climate is harsh and plants are few, so herders move their animals with the seasons to reach pastures fed by underground water.

The same sun and wind are now being put to use: the chapter shows solar panels and windmills in the Gobi.

North of it lie the Eurasian Steppes, stretching over 8,000 km from west to east. A steppe is a large, flat, treeless grassland with hot summers, cold winters and moderate, often seasonal, rain. The nomads of the steppes live in a yurt: the traditional hut of a steppe nomad.

The steppes do something important for the whole planet: this grassland is a carbon sink. It absorbs carbon from the air and stores it underground, which helps reduce the greenhouse effect over time.

It is also a resting place for migratory birds like the Siberian crane, and home to the steppe tortoise, which lives in burrows almost 2 metres deep, hibernates (sleeps through winter) for 2 to 5 months, and two of which were among the first living things from Earth to travel to the moon, in 1968.