Century-Scale Climate Evolution in Semiarid High Plateaus, Algeria

Abstract The study presents a comprehensive analysis of long-term climate trends in Sétif, Algeria, a representative semiarid highland station, using a 125-yr dataset (1900–2024) of monthly and annual precipitation and maximum and minimum temperature. Given the discontinuities in the historical dataset, two neighboring reference stations (Batna and Constantine) and three imputation methods were used: multiple linear regression (MLR), seasonal imputation, and multiple imputation by chained equations (MICE). MICE demonstrated superior performance for all variables. The imputed dataset revealed statistically significant climate changes consistent with Mediterranean aridification patterns. Trend analysis showed precipitation declining at −6.5 mm decade −1 , while maximum temperature and minimum temperature increased at 0.02° and 0.29°C decade −1 , respectively. The asymmetric warming pattern, with minimum temperature rising faster than maximum temperature, is confirmed. However, Pettitt’s changepoint test identifies several breakpoints in the time series 1900–2024; the precipitation pattern breakpoint was in 1975 with a decrease of −77.5 mm. The minimum temperature breakpoint was in 1973 (+2.1°C), and maximum temperature breakpoint was in 1987 (+1.44°C). Recent decades (1980–2024) show accelerated trends, with precipitation decreasing by −13 mm decade −1 and a maximum temperature warming of +0.5°C decade −1 . These findings confirm North Africa as a climate change hotspot, with Sétif experiencing rates of change exceeding global averages. The successful reconstruction of this century-scale dataset provides crucial baseline information for climate adaptation strategies in semiarid regions facing increasing water stress and agricultural challenges.