By Neal Lineback and Mandy Lineback Gritzner, Geography in the NewsTM
The Strange Namib Desert of Africa
Africa seems to always be in the news covering conflict and disease across the continent. Its wonderful physical diversity, however, provides a background that is often overlooked by the casual reader. The Namib Desert is just one of those fascinating physical regions.
While fall is quickly approaching in the United States, the Namib Desert of southern Africa is almost ready for spring. Climatically, the Namib Desert is strange. Though it receives on average less than 0.4 inches (10 mm) of rain a year, the air is often at or near its saturation point and fog is common. The Namib is often called one of the world’s “foggy” deserts.
The Namib (nah-MEEB) Desert is located along the Atlantic coast of Africa from Luanda, Angola, through the entire length of Namibia to the mouth of the Orange River in the Cape Province of South Africa. It stretches 1,200 miles (1,900 km), but its width is very narrow, rarely exceeding 100 miles (161 km) and averaging only about 70 miles (113 km). The Namib covers approximately 19,300 square miles (50,000 sq. km) and gradually merges in the south with the Kalahari Desert of Africa’s interior. They differ considerably in their temperatures and seasonality.
Some desert environments are tropical dry, existing between 20 and 30 degrees latitude. Others are middle latitude deserts situated in the interiors of large continents and have cold winters. Although the Namib Desert is located in the tropics, geographers and climatologists label it a coastal desert, whose year-round temperatures are anything but tropical.
Research shows that arid or semi-arid conditions have existed in the region of the Namib Desert for more than 80 million years, making it the oldest continuous desert on earth. Located along the coast, its odd climate is created by the Atlantic Ocean’s cold Benguela Current, which flows northward along the coast. Cool, moist air from over the Benguela Current pushes onto the coast producing a cool coastal fog. As the air pushes inland, however, the air gets warmer over the tropical land, the fog evaporates and relative humidity drops rapidly. Hardly any precipitation falls because the air is warming rather than cooling.
Average daily temperatures in the Namib range between about 64 F (18 C) in the warm season (December) and 50 F (10 C) in the cool season (July). Coolest nighttime temperatures may drop into the low 40s F, while highest daytime temperatures can reach into the 80s F (approx. 7 to 30 C), making the climate very temperate for a tropical location.
Strangely enough, humidity on the coast stays at 100 percent on an average of 19 hours a day during summer days and 11 hours a day during the winter. Further inland, more continental conditions prevail and temperatures vary more between seasons. Other foggy coastal deserts include the Atacama in Chile and Peru and the Moroccan deserts of Northwest Africa, both of which have cold ocean currents along their tropical coasts.
The Namib Desert’s most famous landforms are its sand dunes, which are some of the oldest in the world. Scientists estimate that they are approximately 30 million years old and they cover about 12,500 square miles (32,400 sq km). Coastal winds in the Namib create the tallest sand dunes in the world, with some reaching heights of 980 feet (300 m). Many of the dunes are bright orange. The color is created by iron oxidizing in the sand over time. Therefore, the oldest dunes are brighter in color than the younger ones. Near the coast, the sand dunes tend to taper off leaving lagoons, wetlands and mudflats that are homes to hundreds of thousands of birds and other animals.
For the most part, however, the Namib Desert is relatively barren. Large areas, especially the gravel flats, the bedrock platform and the dunes, are nearly devoid of any vegetation. In the zone of heaviest fog near the coast, especially in the south, however, low succulent bushes can be found growing sporadically. Along the eastern border of the desert, a thin to moderate cover of annual grasses appears in most years. These grasses can support a variety of ostrich, zebra, antelopes and their predators for a short time during the year.
Of all the animals that make the Namib their home, however, none is more unexpected than the herds of elephants. They make a strange images as they roam the dunes in search of occasional succulent vegetation and water sources.
Though very few settlements exist in the Namib, the area is important for the mining of diamonds, tungsten, zinc, tin and salt. A few ports, including Walvis Bay and Luderitz are Namibia’s principal entry ports, while settlements exist in the interior desert solely for the extraction of mineral resources. Although some cattle and goats are grazed on the scarce grasses, cultivated agriculture is limited to a few irrigated areas and elephants often harass farming communities as they search for green vegetation.
In general though, the beautiful and remarkably old Namib Desert remains a place livable for only the hardiest Namibians and desert animals. As one of the world’s driest deserts, the Namib stands out for its temperate climate and the moist fog that shrouds its shores.
And that is Geography in the News.
Sources: GITN #866 “The Strange Namib Desert,” Maps.com, Jan. 5, 2007; http://www.greatestplaces.org/notes/namib.htm; http://www.worldbiomes.com/biomes_desert.htm; and “Inside the Cover Image,” Journal of Geography, Volume 105, No. 3, National Council for Geographic Education, May/June 2006.
Co-authors are Neal Lineback, Appalachian State University Professor Emeritus of Geography, and Geographer Mandy Lineback Gritzner. University News Director Jane Nicholson serves as technical editor. Geography in the NewsTM is solely owned and operated by Neal Lineback for the purpose of providing geographic education to readers worldwide.