Major Causes of Droughts

Atmospheric interaction, method of cultivation, selection of cropping pattern, inappropriate land use, and deforestation are important issues in the context of Ethiopian drought.

Atmospheric Interaction

Droughts in Ethiopia occur mainly due to rainfall variability. Seasonal and annual rainfall variations in Ethiopia are associated with the macro-scale pressure systems and monsoon flows related to the changes in the pressure systems (NMSA,1996b). The interactions between the pressure systems are extremely complicated and to date are poorly understood (WMO, 1975a, 1975b, 1983, 1993). However, if any one of the rain-producing systems in any season weakens, there will be an abnormal rainfall behavior during that season. A recent study (Engida, 1999) indicates that the area with stable rainfall activity has decreased, while the area with highly variable rainfall has substantially increased. As a result, the frequency of droughts has increased.

Soil Erosion

Ethiopian farmers are still continuing unsustainable methods of cultivation, and winds and rains have eroded the topsoil. Due to the erosion, water does not percolate into the soil and is wasted as runoff. Therefore, the soil cannot maintain the required amount of soil moisture. As a result of the depletion of soil moisture and soil nutrients, the soils do not sustain plant growth. The Ethiopian Highland Reclamation Study (Constable and Belshaw, 1989) estimated that more than half of the highlands (270,000 km2) are already eroded significantly, of which about 100 tons/ha of soil are eroded every year primarily because of the erosive cropping practices. The annual soil loss due to erosion is estimated at 1.9-3.5 billion tons. According to Hurni (1986), soil loss on cultivated land is estimated to be 4-10 times higher than on grazing land, and 80% of the recorded annual soil loss occurs during the month of plowing and the following month. The reclamation study further stressed that the condition of land before sowing during the short rainy season or during the first month of growth is important for averting soil erosion.

Deforestation

Deforestation is another important factor that contributes to drought in Ethiopia. Historical sources indicate that dense forests that might have covered about 35-40% of the total area of Ethiopia have now been reduced to 2.7%. It is estimated that these resources are vanishing at an alarming rate—150,000-200,000 ha/year (IUCN, 1990; EFAP, 1994; EARO, 1999).

Overgrazing

Ethiopia has one of the largest livestock populations in Africa, with 30 million cattle, 22 million sheep, 17 million goats, 7 million equines, and 1 million camels (CSA, 1999). Approximately 70-80% of these livestock are found in the highlands (Alemneh, 1990). Ethiopian rangelands account for almost 90% of desertified lands (Mabbutt, 1984). Overgrazing of these rangelands by livestock has caused degradation of vegetation and the compaction and erosion of the soil by wind and water.

Population Growth

Growing demand of land for crop production and fuel wood, due to population growth, also contributes to land degradation and drought. Ethiopia has a total area of 1.24 million km2 with a population of about 60 million people and an estimated 3-4% growth rate. Agriculture has always been the backbone of the country (CSA, 1998). Without a major fertility decline, Ethiopia will have to feed a population expected to double by 2030. These are frightening figures to consider because the land cannot support even the present population. Future farming practices will involve intensive cultivation, which will further result in a loss of soil fertility and drought resistance.

Land Ownership

Another important factor contributing to drought recurrence is the problem of land ownership. Investment decisions about land are affected by tenure security (Place and Hazell, 1993; Gavain and Fafchamps, 1996). Communal ownership is believed to lead to mismanagement, particularly, overgrazing and inefficient removal of wood for fuel (Hudson, 1981). The ability to transfer land sales and leasing also allows lands to be used by farmers who earn the highest return from it through mobility of draft animals, farm implements, and labor (Pender, 1998). The system of land tenure in Ethiopia has had varying and significant impacts on land management. From a historical perspective, it is believed that Ethiopia's small holders are uncertain about the security of rights to the land. This has led to cultivation for short-term needs rather than long-term yield. Accordingly, no long-term investments (e.g., soil and water conservation measures) are made that would maintain or boost yields, and this has resulted in ecological damage, which has become almost impossible to reverse (Lakew et al., 2000).

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