Mid-Century Changes in the Mean and Extreme Climate in the Kingdom of Saudi Arabia and Implications for Water Harvesting and Climate Adaptation

Abstract

The Kingdom of Saudi Arabia (KSA) is a water-scarce region with a dry, desert climate, yet flood-producing precipitation events and heat extremes lead to loss of life and damages to local infrastructure, property and economy. Due to its distinctive natural and man-made spatial features (e.g., coastal features, wadis, agricultural areas) studying changes in the mean climate and extreme events requires higher-resolution climate projections than those available from the current generation of Earth System Models. Here, a high-resolution convection-permitting regional climate model is used to downscale the middle of the 21st century (2041–2050) climate projections of the Community Earth System Model (CESM) under representative concentration pathway (RCP) 8.5 and for a historical time period (2008–2017) focusing on two months (August and November) within KSA’s dry-hot and wet seasons, where extreme events have historically been observed more frequently. Downscaling of climate reanalysis is also performed for the historical time period (2008–2017) to evaluate the downscaling methodology. An increase in the intensity and frequency of precipitation events is found in August by mid-century, particularly along the mountainous western coast of KSA, suggesting potential for water harvesting. Conversely, the northern flank of the Empty Quarter experiences a noticeable reduction in mean and extreme precipitation rates during the wet season. Increasing August heat index is found to particularly make regional habitability difficult in Jeddah by mid-century.

Robust increase in population exposure to heat stress with increasing global warming

“…Similar levels of HI have been used in others studies to defined dangerous events (high chance of heat strokes) (e.g. [25][26][27]), although it is sometimes wrongly referred as a NWS warning level [28].…”

TIN‐Copula bias‐correction method for model‐derived maximum temperature in the MENA region

“…This result agrees with Zittis and Hadjinicolaou (2017), who mentioned the challenges in simulating temperature over the savanna regions of Africa, as well as Komurcu et al . (2020), who noted statistically significant biases with the WRF model in the representation of mean August temperatures over the Arabian Peninsula.…”