Water resources under climate change: Strategies for sustainable agriculture in Colombia

The growing population, food security, and climate change pose future threats to the sustainability of water resources around the globe. Therefore, projecting future water consumption is crucial for decision-making in water governance, policy reforms, and management planning. In this study, we estimated Colombia's current (2005–2016) and future (2031–2090) water demand under climate change Representative Concentration Pathways (RCP2.6 and RCP8.5) using CORDEX data, and evaluated alternative, spatially-explicit water-saving strategies based on a temporal water footprint assessment approach. The results show that the average harvested area is 3.65 million hectares. In this area, coffee takes the largest share, followed by corn, plantain, and rice. Sugarcane showed the highest average yield (19.9 t ha⁻¹), followed by potato (16.0 t ha⁻¹) and yucca (10.5 t ha⁻¹), highlighting substantial differences in crop productivity. Currently, the total water consumption is 27 km³ /year, consisting of 86% green water (precipitation) and 14% blue water (irrigation water from surface and/or groundwater sources). Oil palm, plantain, and coffee are highly water-intensive crops that account for 80% of total blue water use. Future projections under climate change scenarios indicate that green water consumption could rise slightly, while blue water consumption could increase by up to + 26% in RCP2.6 and up to + 124% in RCP8.5. This increase will be gradual in the mid-term (2031–2060) and will become extreme in the late century (2061–2090). However, the future rise in blue water demand could be reduced by up to −78% by replacing water-intensive crops with crops using less blue water per unit area. A further reduction of up to −91% is possible through the combined implementation of improved irrigation technologies and optimized cropping patterns, rather than traditional surface irrigation practices.