Environmental Affairs

Lesson 7: Deserts never sleep

General overview of deserts and drylands

Deserts, seen as arid regions, generally receive less than 25cm of precipitation a year, or they are regions where the potential evaporation rate is twice as great as the precipitation. The world's deserts are divided into four categories.

Subtropical deserts are the hottest, with parched terrain and rapid evaporation. Although cool coastal deserts are located within the same latitudes as subtropical deserts, the average temperature is much cooler because of frigid offshore ocean currents. Cold winter deserts are marked by stark temperature differences from season to season, ranging from 100° F (38° C) in the summer to 10° F (–12° C) in the winter. Polar regions are also considered to be deserts because nearly all moisture in these areas is locked up in the form of ice.

There is no single definition that sufficiently describes all features of desertification. In different places, desertification means different things to different people. Scientifically, deserts, also called arid regions, characteristically receive less than 10 inches of precipitation a year. In some deserts, the amount of evaporation is greater than the amount of rainfall. Semiarid regions average 10 to 20 inches of annual precipitation. Is it possible to identify a cycle of issues that are of relevance to most, maybe even all contexts of desertification? Arguably there are important linkages between the processes of desertification and other environmental concerns. Many may not appear obvious and further examination is clearly necessary to elucidate inter-relationships. Clearly, there are many questions to ask:

- does desertification go hand-in-hand with the loss of bio-diversity? - can a cause-and- effect chain be established between climate change and desertification? - what are the implications of increased human activity (especially residential) in semi- and even arid zones for the world’s fresh water deposits and reserves? - To what degree is desertification induced and accelerated by human actions? - Are there suitable and effective methods and remedies available to inhibit, slow or reverse desertification trends?

One can agree that “today it appears that desertification is not the result of a relentless, inexorable advance of the desert. Rather, the course it takes is determined by specific local conditions in arid and semi-arid areas-areas that vary greatly in terms of their microclimatic and socioeconomic conditions" (1).

As there is such a variety of influencing conditions, management responses to desertification are necessarily complex. A tentative set of central issues can be listed in order to gain an overview of how broad yet managerial specific policy, management and project activities need to be.

The issue list relates to:

a. Indigenous Peoples / Sustainable livelihoods b. Animals, Agriculture/Cultivation c. Water d. Energy e. Advanced land use and urban development f. Intensive Natural Resource Management (NRM) use, economic activities g. Conservation and non-use of desert areas h. Information/Knowledge management i. Alternative usages of deserts/drylands.

In the next section, drought management will be explored from a non-popular perspective.