A contrasting climate
Algeria's climate varies enormously, from Mediterranean to Saharan. In the north, hot, dry summers dominated by subtropical high pressure are followed by wet, cool winters, more temperate near the sea, harsher at higher altitudes. As a general rule, the eastern zone receives more rain (around 2,000 mm) than its western counterpart, protected from disturbances by the Rif and the Moroccan Middle Atlas mountains. Algiers is known for its sometimes "heavy" and stormy summer atmosphere, which is difficult to bear.
The high peaks in the east remain covered in snow from October to June. Because of its altitude, the Tellian Atlas is a little cooler and wetter, although it experiences more or less the same climatic trends. The high plateaus, dominated by continental aridity (200 to 400 mm rainfall, mainly in spring), experience extreme temperatures. In summer, a hot, dry wind from the Sahara, the maddening sirocco (also known as chehili, khamsin), reduces rainfall on the high plateaus and in the Saharan Atlas. Protected from the marine influence of the Mediterranean by the mountain ranges, the Sahara receives very little water (less than 120 mm on average in the north, less than 30 mm in the south), but certain areas of the desert can be violently sprinkled during a storm, and the wadis, often thought to be lifeless, suddenly fill with water, making them dangerous. Temperatures are high (up to 50°C in In-Salah), although softened by altitude, but can be surprisingly cold in winter (0°C). The aridity of the climate is accentuated by the simoun, a sometimes violent sand wind. The lowest humidity level was recorded in Tamanrasset: 3%.
Desertification
The Earth is currently undergoing a period of global warming as a result of normal natural cycles and human intervention. Desertification is the consequence of both. As the Earth cannot influence natural cycles, which it has adapted to quite well since its birth some 5 billion years ago, we need to consider the influence of mankind. This awareness is recent, since the term desertification dates back to 1949. Desertification in Africa affects several zones. It manifests itself in the rarefaction and disappearance of the trees and shrubs that prevent the desert from advancing. Over-intensive grazing and, above all, excessive consumption of wood for cooking are at the root of the destruction of the vegetation cover.
Paradoxically, poorly controlled irrigation can also contribute to the retreat of fertile land. In fact, if the concentration of salt is too high in the water draining the newly conquered desert land, particularly but not only near the mouth of a river, the high evaporation due to heat will fix the salt in the soil. In the long term, this will lead to poor harvests at best, and even the disappearance of all vegetation that cannot cope with the high salinity.
But the process is not as irreversible as we are seeing at present, and we are quickly learning that desert does not mean barren land. In fact, for some years now, much more frequent rainfall has been keeping pasture alive all year round, and we can now see a few plants "hanging on" in a region we had always imagined... deserted.
Earthquakes
They often have serious repercussions, as we saw with the earthquake of May 21, 2003. With a magnitude of 6.7 on the Richter scale and an epicenter located in Thénia, just sixty kilometers east of Algiers, it could have had even more serious consequences if we compare it with the one that devastated Bam (Iran) on December 26, 2003, of the same force. The north of Algeria, closest to the coast, is located on a highly active fault due to the convergence of the European and African plates, with the latter rising towards the former as it slips beneath it. The country has already experienced numerous earthquakes in the past: Algiers was destroyed in 1716, Oran in 1790, Chlef in September 1954 (Orléansville) then in October 1980 (El-Asnam), etc.
Another major earthquake occurred in May 2016, measuring 5.3 on the Richter scale. It resulted in 65 injuries and extensive material damage. Surprisingly, in forests or wooded areas that had been deserted during the dark years of terrorism, flora and fauna have often regained their rights, and some protected areas are seeing their ecosystems strengthen.
A magnitude 5.1 earthquake struck near Oran on the evening of Sunday June 26, 2022. Damage was minor, with a few cracked houses. On Saturday July 16, 2022, an earthquake originating in the wilaya of Mostaganem was recorded at 4:55 a.m., measuring 4.2 on the Richter scale. In 2023 and 2024, only low-magnitude earthquakes shook the country - less than 4.5 on the Richter scale - causing little or no material damage.
Fires
Algeria has only 4.1 million hectares of forest, with a meagre reforestation rate of 1.76%. Every year, the north of the country is hit by forest fires. In 2020, almost 44,000 ha of coppice went up in smoke. It's hard not to remember the violent fires that ravaged Kabylia in the summer of 2021. These mostly arson fires were difficult to control and led to the deaths of around 90 people, including 33 soldiers. At the end of June 2022, the Sétif region suffered numerous fires, resulting in the death of at least two people. At the end of July 2023, no fewer than 17 regions were affected by forest fires caused by an exceptional heat wave. 140 fires broke out across the country, killing at least 34 people, including 10 military personnel, and injuring dozens more. These fires devastated almost 11,000 hectares, including 4,000 hectares of orchards and farmland.
Every summer, with global warming, temperatures get hotter and hotter. At the end of June 2022, they exceeded 47°C in the following wilayas (regions): Ouargla, El-Menia, Adrar, In-Salah and Bordj Badji Mokhtar. The forest fires of July 2023 were caused by a heat wave during which temperatures reached 48°C in the shade in 13 of the country's wilayas.
