Forecasting climate risk and heat stress hazards in arid ecosystems: Machine learning and ensemble models for specific humidity prediction in Dammam, Saudi Arabia

Climate change is intensifying weather-related hazards in arid regions, making precise predictive models crucial for effective adaptation strategies. This study employs machine learning (ML) and ensemble learning (EL) models to predict specific humidity (SH) levels in Dammam, Saudi Arabia, as a foundation for forecasting climate risk and heat stress hazards in arid ecosystems. Using daily climate data from 1982 to 2023, we applied three ML models (Support Vector Machine, M5-Pruned Tree, Reduced Error Pruning Tree) and six EL models (Random Forest, Additive Regression, Random Subspace, Light Gradient Boosting Machine, Adaptive Boosting Regression, eXtreme Gradient Boosting) to predict SH levels. Descriptive statistics showed significant seasonal variations, with the highest SH levels in August (15.87 g/kg) and the lowest in January (7.16 g/kg). The region's minimal annual precipitation (average 60.57 mm) and extreme summer temperatures (average July maximum of 44.06 °C) further underline Dammam’s vulnerability to climate-induced stress. A significant increasing trend in annual SH levels was confirmed through the Mann–Kendall Test and Innovative Trend Analysis, highlighting a rising trend with a Sen's Slope of 0.025 g/kg/year. The most substantial increases occurred in July and August, reaching 0.059 and 0.054 g/kg/year, respectively, indicating escalating heat stress risks during summer season. Among the tested models, LightGBM and XGBoost stood out for accuracy (R2 = 0.99897 and 0.99883 respectively), while Additive Regression achieved the best balance across all performance metrics (R2 = 0.9987). The performance of these models demonstrates strong potential for early warning systems, enabling proactive responses to heat-related hazards. By integrating ML and EL models, this study provides a robust framework for forecasting humidity trends, contributing to improved risk assessment, disaster preparedness, and climate adaptation strategies for arid regions like Dammam.