Future water availability and crop yields in Kenya’s Sand River Basin enhanced by elevated CO2 under climate change
Year: 2025
Type: article
Abstract: The Sand River Basin, Kenya This study evaluates the combined impacts of future climate change and elevated atmospheric CO 2 on basin water balance and crop responses in the Sand River Basin using the SWAT+ model driven by ten General Circulation Models (GCMs) from ISIMIP3b. Simulations followed the SSP5–8.5 scenario for the near-future (2025–2054) and far-future (2070–2099) periods, comparing climate-only runs with simulations that include dynamically increasing CO 2 concentrations. Two crop cultivars were assessed: “non-adapted” cultivar and a “late-maturing” cultivar representing an adaptation strategy. Water availability is projected to increase toward the end of the century, particularly when CO 2 physiological effects are included, as reduced transpiration enhances soil moisture, runoff and percolation. Under far future CO 2 -enhanced conditions, water availability rises during both rainy seasons (e.g., +222 mm in MAM and +178 mm in ONDJ), and crop water and temperature stress decline. CO 2 -induced simulations also produced higher yields, with stronger gains for late-maturing cultivars. Yield improvements were greatest under combined climate and CO 2 effects in the far future (+7.6 % for maize; +10.4 % for beans), whereas climate-only simulations showed smaller increases. These findings highlight the importance of accounting for CO 2 physiological effects when assessing future hydrology and crop productivity and show that late-maturing cultivars represent a valuable adaptation strategy for strengthening agricultural resilience in the study region. • Water availability is expected to increase as atmospheric CO 2 levels rise. • CO 2 physiological effects on vegetation increased surface runoff and crop productivity. • Reduced growth constraints as projected temperature and rainfall benefit maize and beans. • Increases in CO 2 concentrations lead to higher yields for both maize and beans. • Late-maturing crops are projected to achieved higher yields than non-adapted crops.
Authors: Pablo Sarmiento, Jingshui Huang, Markus Disse
Institution: Technical University of Munich
Language: English
Domain: Life Sciences
Open Access status: gold
Estimated APC paid: $2,600
OpenAlex ID: W4417288113