Projecting rice water footprint for different shared socioeconomic pathways under arid climate conditions

Authors: ELSADEK, ELSAYED AHMED - University Of Arizona; ELSHIKHA, DIAA ELDIN - University Of Arizona; AWAD, AHMED - The Ohio State University; HAMOUD, YOUSEF ALHAJ - Hohai University; ELSHEIKHA, AHMED - Damietta University; Williams, Clinton; ORR, ETHAN - University Of Arizona; SHAGHALEH, HIBA - Hohai University; HAMAD, AMAR ALI ADAM - Hohai University; Thorp, Kelly; ELBELTAGI, AHMED - Mansoura University

Submitted to: Irrigation Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/11/2025
Publication Date: 5/27/2025
Citation: Elsadek, E., Elshikha, D.M., Awad, A., Hamoud, Y., Elsheikha, A., Williams, C.F., Orr, E., Shaghaleh, H., Hamad, A., Thorp, K.R., Elbeltagi, A. 2025. Projecting rice water footprint for different shared socioeconomic pathways under arid climate conditions. Irrigation Science. 43:955-969. https://doi.org/10.1007/s00271-025-01019-8.
DOI: https://doi.org/10.1007/s00271-025-01019-8

Interpretive Summary: Under future climate scenarios, atmospheric carbon dioxide concentrations and air temperature will rise while rainfall distribution will be more variable, especially affecting arid areas. This will directly affect agricultural production and the sustainability of the water resources that irrigated agriculture depends on. Therefore, it is imperative to project changes in agricultural productivity and water use under these potential future climate conditions, as agricultural producers and water managers will require guidance in dealing with those changes. A modeling study was conducted to evaluate rice productivity and the water use footprint in the Nile River Delta of Egypt under projected climate conditions for the period 2021–2099. The study coupled the Aquacrop-GIS model, which models crop responses to water inputs, with different sets of predicted climatic variables generated by global climate models. In addition, the study considered two emission scenarios of SSP as climate projections, the moderate and highest-forcing CO2 emission scenarios (SSP2-4.5 and SSP5-8.5, respectively). The global change models used in the study were selected based on their ability to predict temperatures and rainfall in the study area for a baseline period. Climate change impacts were evaluated, considering and without considering changes in atmospheric carbon dioxide concentrations. Results suggest that the projected temperature increase alone will eventually undermine productivity and increase the water use footprint. In contrast, increasing CO2 could attenuate the effect of rising temperatures on yield and decrease the water footprint due to increased photosynthetic efficiency.

Technical Abstract: Climate change is expected to intensify water scarcity and food shortage challenges, especially in arid and semi-arid regions. In this context, the present study was conducted to project the effect of climate change on rice yield (Y), evapotranspiration (ET), and total water footprint (WFT) in Damietta. Two emission scenarios of Shared Socioeconomic Pathways (SSP) were applied as climate projections: SSP2-4.5 and SSP5-8.5. First, four statistical evaluation metrics, namely, Pearson’s correlation coefficient (R), the index of agreement (Dindex), the mean absolute error (MAE), and the bias of temperature (BIAST) and precipitation (BIASPr), were used to evaluate five global climate models (GCMs) with respect to the baseline temperatures (T) and precipitation (Pr) over the study area under the two SSP scenarios. Then, AquaCrop-GIS, integrated with the ensemble downscaled GCMs data, was used to project the future climate change impacts on rice Y, ET, and WF under the 3-day irrigation frequency regime (3IF) and the two SSP and CO2 emission scenarios during 2021–2099. Our results demonstrated a moderate-to-strong correlation between all GCMs and historical average annual Pr and T (0.52 > R > 0.99) over the study area. Moreover, MAE less than 7.04 mm and 5.19 °C, with a Dindex between 0.57 and 0.99, were recorded for Pr and T variables, respectively, indicating an acceptable degree of agreement between predicted and observed climate variables during the baseline period. Without CO2 effects, rice yields would slightly increase (1.07%–3.03%) during the 2030s and 2050s. In contrast, it would significantly decline (4.55%–18.94%) during the 2070s and 2090s under the two SSP scenarios. On the other hand, with CO2 effects, rice yields would significantly increase (14.19%–28.31%) under the two SSP scenarios over time. Projected ET, by AquaCrop-GIS, would decline (1.42%–18.98%) under the two SSP and CO2 scenarios over time. Meanwhile, without CO2 effects, the WFT would increase by 5.55% to 17.13% during the 2090s. However, with CO2 effects, the WFT would decrease significantly (15.45%–34.50%) under the two SSP scenarios over time. Our findings are helpful for growers and policymakers to formulating customized water conservation management strategies and achieve agricultural sustainability, especially in arid regions.