Abstract
Quantifying the impact of climate change on evapotranspiration is necessary for devising accurate water and energy budgets in light of global warming. Nevertheless, in the Middle East and North Africa (MENA), little has been done to bridge this gap. This study, then, implements Penman and Budyko approaches to climatic data retrieved from the sixth phase of the Coupled Model Intercomparison Project (CMIP6) to assess evapotranspiration and water availability evolutions through the twenty-first century. Outcomes reveal that the MENA region is indeed vulnerable to a surge in temperature, which can increase evapotranspiration losses and decrease water availability. Under the shared socioeconomic pathway (SSP2-4.5), the potential evapotranspiration (PET) has been projected to increase throughout the MENA region by up to 0.37 mm per year during the middle of the twenty-first century (2021–2050) and by up to 0.51 mm per year during the end of the twenty-first century (2071–2100). Meanwhile, the actual evapotranspiration (AET) has been projected to increase by up to 0.3 (~0.2) mm per year before 2050 (2100). The trends in both projections (PET and AET) are exaggerated under SSP5-8.5. The analysis predicted a shortage of water availability (precipitation—AET), which is alarming for most MENA regions. Relative to the reference period (1981–2010), the decline in annual water availability would reach 26 (62) mm by 2100 under SSP2-4.5 (SSP5-8.5). The rise in temperatures appears to be the principal reason for MENA and water availability responses. This study’s outcomes can facilitate accurate and realistic predictions related to evapotranspiration and water availability, which are key elements in not only managing water resources but also in devising effective climate change mitigation and adaptation plans.Graphical abstract
Highlights
Evapotranspiration refers to water movement from land to atmosphere through two processes: (1) evaporation from water surfaces and soil and (2) transpiration from plants
The present study investigated the evolutions of evapotranspiration and water availability throughout the twenty-first century across the Middle East and North Africa (MENA) region
The analysis under SSP2-4.5 revealed that potential evapotranspiration (PET) and actual evapotranspiration (AET) would increase by up to 0.37 mm per year during the mid-twentyfirst century (2021–2050)
Summary
Evapotranspiration refers to water movement from land to atmosphere through two processes: (1) evaporation from water surfaces and soil and (2) transpiration from plants. The evapotranspiration phenomenon is of high interest in many disciplines, including hydrology, agriculture, energy budget, and climate studies. It is a required component when identifying irrigation demands and runoff quantities (Li et al 2020), when looking into an energy budget for the earth-atmosphere system (Diak et al 2004), when improving the predictions of atmospheric circulation models (Pielke et al 2003), and when undergoing climatic characterization (Wang et al 2017). Accurate estimations of evapotranspiration enable farmers to apply suitable crop water requirements, which saves water, energy, and chemicals apart from preventing regional environmental contaminations. PET is calculated under standard conditions—in a uniform and completely vegetated area with a permanent water supply and shading
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