Drought and aridity trends on the Algerian steppe.

Arid regions are characterized by the fragility of their ecosystems, which are very vulnerable to climate change. The increase in aridity in these regions makes them more exposed to drought with serious consequences. This contribution analyzes the trend of aridity and drought in the Algerian steppes, during the period 1951–2022. Robust statistical tests (Mann–Kendall and Sen) and the Reconnaissance Drought Index (RDI) are used. Monthly rainfall data and monthly average temperature as well as potential evapotranspiration (PET) data from the Climatic Research Unit (CRU), characterized by a spatial resolution of 0.5°, were used. The results showed an increase in annual aridity, which led to an expansion of drylands. The change was characterized by the transition of 9.20% of the steppe surface from the semi-arid class to the arid class. At the same time, the entire subhumid class (1.67%) made the transition to the semi-arid class. On the other hand, a significant tendency towards drought over most of the steppe territory (81%) was recorded. The analysis of the results revealed the influence of precipitations and air temperatures in this enlargement. These changes have contributed to the degradation of the environment and natural resources and to an ecological and socio-economic imbalance. [ABSTRACT FROM AUTHOR]