Karoo Karoo The Karoo ( ; from a Khoikhoi word, possibly "garo" "desert") is a semi desert natural region of South Africa. No exact definition of what constitutes the Karoo is available, so its extent is also not precisely defined. The Karoo is partly defined by its topography, geology and climate, and above all, its low rainfall, arid air, cloudless skies, and extremes of heat and cold. The Karoo also hosted a well-preserved ecosystem hundreds of million years ago which is now represented by many fossils. The Karoo formed an almost impenetrable barrier to the interior from Cape Town, and the
Ryn Desert can drop to a low of . Many small towns are scattered throughout the Ryn Desert, and population density is between 1 and 15 people per square mile. The Ryn lies in a semi-arid climate zone, and receives very little rainfall. High winds sweep across the desert, and in 2001 a dust storm in the Baltic Sea was determined as originating in the Ryn Desert. A study of long-range dust transportation to the Baltic Sea region—by analyzing dust pollution in Scandinavia, showed that aerosol concentrations there were influenced more by the Ryn Desert region than the Sahara Desert in Africa.