Hot Deserts

• What is a desert?

  A desert is a landscape where little precipitation (less than 250mm of rainfall) occurs and, consequently, living conditions create unique biomes and ecosystems
• Where are hot deserts found?

  Between 15 and 30 degrees N and S of the equator. At the equator, warm air rises and condenses meaning it loses water and is perfect for rainforests. As the warm air hits the stratosphere it travels north and south and sinks as dry, waterless air through Hadley Cells
• What are hot deserts like?

  Have a very hot climate. Very dry, less than 250mm of rain. Two distinct seasons; summer and winter. Little to no biodiversity because of the harsh climate. Plants and animals which survive have adapted. Soils are thin, sandy, rocky and generally grey in colour. It is so hot water is drawn up to the surface of the soil by evaporation. The water evaporates and salts are left behind on the surface of the soil.
• Plant adaptations in the desert

  Cactus - Have spines instead of leaves as they lose less water than leaves so are efficient in hot climates while also protecting the cactus from animals

  Succulents - store water in their stems and also have a thick waxy skin so that they lose less water by transpiration
• Desert Opportunities

  Mining - the desert has valuable reserves of minerals. Las Vegas is a site for mining

  Farming - Long hours of sunshine make favourable conditions for growing crops

  Tourism - Tourism is the region's most important economic activity also its an important source of income and creates many jobs for local people.
• Desert Challenges

  Water - With only 120-240 mm of rain falling per year in the desert, water must be used sensibly and sustainably. Humans will find it harder to survive.

  Inaccessibility - Most of the desert is inaccessible due to the extreme environmental conditions and poor infrastructure. A large proportion of roads are unsurfaced.

  Extreme Temperatures - High temperatures lead to rapid evaporation and a shortage of water. Makes it very challenging for people, such as farmers, to work outside.
• What is desertification?

  The process of land turning into desert as the quality of the soil declines over time.
• Desertification causes

  Overgrazing - Farmers let their livestock graze in one area before moving on once the soil quality becomes poor. This leaves the soil exposed to erosion.

  Deforestation - When the land is cleared of trees, the roots of the trees no longer hold the soil together so it is more vulnerable to soil erosion.

  Climate Change - In desert regions conditions are not only getting warmer but drier too. On average there is less rain now in desert regions than there was 50 years ago.
• Strategies to reduce desertification

  Afforestation - The roots of trees hold the soil together and help to reduce soil erosion from wind and rain

  Improving soil quality - Can be managed by encouraging people to reduce the number of grazing animals they have and grow crops instead.