Algeria - Climate
Algeria is an African and a Mediterranean country covering 2,381,741 km2. Like many of the countries in its region, Algeria is affected by desertification and land degradation. Most of the country is arid or semi- arid. The areas receiving more than 400 mm of rain per year are located in a narrow strip along the coast, not-exceeding 150 km large. Moreover, due to climate changes, yearly average rainfall declined by more than 30% over the past decades.
Northern Algeria is in the temperate zone and enjoys a mild, Mediterranean climate. It lies within approximately the same latitudes as southern California and has somewhat similar climatic conditions. Its broken topography, however, provides sharp local contrasts in both prevailing temperatures and incidence of rainfall. Year-to-year variations in climatic conditions are also common.
In the Tell, temperatures in summer average between 21 °C and 24°C and in winter drop to 10°C to 12°C. Winters are not cold, but the humidity is high and houses are seldom adequately heated. In eastern Algeria, the average temperatures are somewhat lower, and on the steppes of the High Plateaus winter temperatures hover only a few degrees above freezing. A prominent feature of the climate in this region is the sirocco, a dusty, choking south wind blowing off the desert, sometimes at gale force. This wind also occasionally reaches into the coastal Tell.
In Algeria only a relatively small corner of the Sahara lies across the Tropic of Cancer in the torrid zone, but even in winter, midday desert temperatures can be very hot. After sunset, however, the clear, dry air permits rapid loss of heat, and the nights are cool to chilly. Enormous daily ranges in temperature are recorded.
Rainfall is fairly abundant along the coastal part of the Tell, ranging from forty to sixty-seven centimeters annually, the amount of precipitation increasing from west to east. Precipitation is heaviest in the northern part of eastern Algeria, where it reaches as much as 100 centimeters in some years. Farther inland the rainfall is less plentiful. Prevailing winds that are easterly and northeasterly in summer change to westerly and northerly in winter and carry with them a general increase in precipitation from September to December, a decrease in the late winter and spring months, and a near absence of rainfall during the summer months.
In the context of climate change, Algeria is subject to adverse impacts of climate change. Several climate scenarios for Algeria project a substantial rise in temperature already by 2020, along with a significant decrease in rainfall and increased evaporation, leading to increased water shortage and exacerbating people's vulnerability to health risks. But also the forestry sector plays an important role for Algeria. Given that 84% of the country is covered by the Sahara, sustainably managing existing forests is not only a factor for mitigating climate chage, but also important for the biological balance of this fragile ecosystem.
Due to its geographical position and climatic characteristics, Algeria is highly vulnerable to climate change. Even a small rise in temperature would lead to various socio-economic problems that hinder the development of the country. The models predict that rainfall events are less frequent but more intense, while droughts are more common and longer. The spatial and temporal distribution of rainfall will also change.
Parallel to the coastline, mountains act as a barrier and accentuate the climate drought towards the south of the country. Anthropic effects aggravate those caused by geographic characteristics. Indeed, 85 % of the Algerian population lives in the northern part of the country. Moreover, land characteristics reduce the possibilities of carbon capture in Algeria, when compared to countries with a large vegetal coverage.
Algeria is facing extreme climate events recrudescence, which accentuates its vulnerability. In addition, the recurrence of drought cycles, with longer durations, accelerates desertification. In fact, more than 50 million of hectares face highly deteriorated conditions. Rural population -composed mainly of farmers and breeders- is forced into exodus to large cities, for survival. This situation is the direct result of land impoverishment and the decline in water resources.
Important programs were launched by public authorities since the seventies. This includes the realization of a “great green dam”, a forest cover of 1200 km long and 20 km large, on average. This achievement constitutes today one of the great prides of the country and represents a significant carbon sink. Other big projects were also initiated, such the program of pastoral plantation covering thousands of hectares.
With regard to floodings, the country is always facing this phenomenon. Several regions witnessed tragic events resulting in heavy losses human lives and considerable material damages. For example, the 2001 catastrophic floods in Algiers resulted in the death of 715 persons and thousands of disaster victims. The recurrent floods continue to adversely impact public financial resources.
The analysis of climate data from 1931 to 1990 in northern Algeria reveals a rise in temperature of 0.5 °C would reach an increase of 1 °C by 2020. A temperature rise of 2 °C is expected by 2050. The decrease of water resources, declining agricultural yields, encroaching desert, the challenge of planning and the energy consumption for air conditioning are only the initial impacts to which Algeria must find answers supportable economically and socially.
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