Projection of future temperature variations in river basins under climate change scenarios using general circulation models

BACKGROUND AND OBJECTIVES: Jordan faces water resource challenges due to its arid climate and high population density. This study selects general circulation models for the Zarqa River Basin to project future temperature variations under the Shared Socioeconomic Pathways 2-4.5 and 5-8.5 scenarios across four periods: 2015-2040, 2041-2060, 2061-2080, and 2081-2100, assessing climate change impacts on water resources.METHODS: The statistical downscaling model was used to project temperature variations for the two Shared Socioeconomic Pathways over the four periods. The model’s predictors were derived from general circulation models and reanalysis datasets. Results showed a strong correlation between temperatures in the Zarqa River Basin and the selected general circulation models. The model successfully replicated temperature characteristics during both the calibration (1983-2000) and validation (2001-2014) periods. Projections were made for six stations within the Zarqa River Basin.FINDINGS: Among the selected general circulation models, United Kingdm Earth System Modelling project and Hadley Centre Global Environmental Model 3—Global Coupled configuration 3.1 predicted the most rapid temperature increases. High-emission scenarios (Shared Socioeconomic Pathway 5-8.5) forecast larger temperature rises than low-emission scenarios (Shared socioeconomic pathway 2-4.5). The northern Zarqa River Basin is projected to warm more than the southern region, with significant increases expected by the 2090s compared to the 2050s. Minimum temperatures are increasing at twice the rate of maximum temperatures. By 2100, maximum temperatures in the Shared Socioeconomic Pathway 2-4.5 scenario are expected to rise by 3.44-4.91 degrees Celsius, while in the Shared Socioeconomic Pathway 5-8.5 scenario, increases will range from 5.5-6.2 degrees Celsius.CONCLUSION: The study successfully developed a Statistical Downscaling Model for future temperature projections in the Zarqa River Basin under the Shared Socioeconomic Pathway scenarios. The results suggest that the Zarqa River Basin will experience a hotter and drier climate, with more significant temperature increases expected by the late twenty-first century. These findings can inform regional hydrological and environmental modeling and help assess ecosystem sustainability.