Hot Desert Case Study: Namib Desert

Namib Desert Climate

• Max Diurnal Range = 9°C (Jun/Jul) (larger inland)
• Annual Mean Range = 5°C
• Mean Max Temp = 22°C (Dec-March)
• Mean Min Temp= 18°C (August) i.e. some seasonal variation as near Tropic of Capricorn and not on Equator.
• Annual Rainfall – 35mm/yr
• COLD OCEAN CURRENT = Benguela Current: a) makes desert cooler than Sahara desert b) creates fog
• Region experiences very little rain but air is often near saturation point = fog
• Fog essential for life. As wind blows east across the cold ocean current it cools the air and water vapor condenses to form fog. The cool air is trapped by the warmer air above it (temperature inversion) resulting in a fog bank forming. Can be up to 20 km wide and forms along the coastal desert.
• Desert is next to the sea = smaller annual range in temp. than Sahara due to the warming effect in winter and cooling effect in summer
• More rain falls inland over the Great Escarpment but water in these streams flowing west into the desert evaporates before it can reach far
• Rain is very rare (only falls on 16 days a year) It can only fall over the Namib Desert when warm, moist air is blown onto the eastern side of the African subcontinent by southeast trade winds. It is highly seasonal.

Plants

The southern Namib is home to over 600 species of plants, the central Namib 400 species and some 1,000 species in the northern Namibia.

The fennec fox is the smallest of all fox species. They are found in the Sahara Desert and elsewhere in North Africa. They are nocturnal, which helps them deal with the heat of the desert environment. They have also made some physical adaptations to help as well. For example, they:

• have thick fur on feet protecting them from the hot ground;
• have large, bat-like ears radiate body heat and help keep them cool;
• have long, thick hair that insulates them during cold nights and protects them from the hot sun during the day;
• have light coloured fur to reflect sunlight and keep their bodies cools. 

A kangaroo rat is a rodent that is found in desert areas in south-western North America. Desert kangaroo rats live in areas with loose sand, often dune terrain. Kangaroo rats have made several adaptations to enable them to survive in the desert, including:

• getting moisture from their seed diet;
• living in burrows during the day to avoid extreme heat;
• having large back legs that allow them to jump almost 3m to avoid predators;
• having large ears, which enables them to hear approaching predators.

Camels have been domesticated for at least 3500 years and have long been valued as pack animals. They can carry large loads 25 miles a day. Camels have adapted to survive hot deserts because they:

• have humps to store fat which a camel can break down into water and energy when nourishment is not available;
• rarely sweat, even in hot temperatures, so when they do take in fluids, they can conserve them for long periods of time;
• have large, tough lips enable them to pick at dry and thorny desert vegetation;
• have broad, flat, leathery feet to spread their weight and provide protection from hot sand; 
• lose little water through urination and perspiration; and
• have slit-like nostril and two rows of eyelashes to protect themselves from the sand.

RESPONSES:

• The coastal desert was names a World Heritage Site in 2012: “The Namib Sand Sea”
• Much of the rest of the desert has been declared part of one national park or another to protect the land and prevent diamond mining
• the Namibian Programme to Combat Desertification (Napcod) has been promoting awareness of the risk of desertification among rural commercial and subsistence farmers 
• Napcod has also undertaken a major survey of desertification in the country to assess the scale of damage
• Forum for Integrated Resource Management (FIRM) for Namibian farmers to educate on sustainable farming

Land use