This article examines the dynamics of the Water-Energy-Food nexus in two transboundary basins between Ecuador and Colombia, from a political ecology perspective that prioritizes experiences and perspectives of local communities. Through in-depth interviews, emerging categories are identified: territory, community, extractivism and conflict. Communities experience extractive activities as a threat to their territory, culture and ways of life. Water pollution, decreased availability and climate changes negatively impact agriculture and food security. The proposed approach reveals the struggles for environmental justice and power inequalities in the region. The most affected communities are indigenous, Afro-descendant and peasant communities. The recovery of traditional culture and food sovereignty are presented as key strategies to resist and adapt to the negative effects of extractivism and the climate crisis. | El presente artículo examina las dinámicas del nexo agua-energía-alimentos en dos cuencas transfronterizas entre Ecuador y Colombia, desde una perspectiva de ecología política, la cual prioriza las experiencias y perspectivas de las comunidades locales. A través de entrevistas a profundidad, se identifican las categorías emergentes de análisis: territorio, comunidad, extractivismo y conflicto. Los resultados muestran que las comunidades experimentan las actividades extractivas como una amenaza a su territorio, cultura y formas de vida. La contaminación del agua, la disminución de su disponibilidad y los cambios climáticos impactan negativamente en la agricultura y la seguridad alimentaria. El enfoque propuesto revela las luchas por la justicia ambiental y las desigualdades de poder en la región. Las comunidades más afectadas son las indígenas, afrodescendientes y campesinas. La recuperación de la cultura tradicional y la soberanía alimentaria se presentan como estrategias clave para resistir y adaptarse a los efectos negativos del extractivismo y la crisis climática.

Reliable food production relies on consistent water availability. The last two decades have provided a deeper understanding of the role of trees and forests in ensuring this water supply. In this chapter, I highlight the links between trees and water security, an indispensable element of food security. We now know that, in many contexts, trees can improve water access and reliability. Achieving the right densities of the right trees in the right places can increase soil water recharge and maintain dependable baseflow. On a larger scale, atmospheric processes are key, and expanding tree cover can render regions wetter and more productive, yielding more predictable rainfall through enhanced atmospheric moisture import and recycling. Opportunities and implications vary with local circumstances. While new insights raise new questions and research remains essential, existing knowledge can guide land-use policy, planning and practices. The large-scale relationships between tree cover and water cause significant threats if tree cover declines but offer substantial opportunities when forests are preserved and extended. Although forests and trees provide many valuable goods and services to local communities, economies and the planet, any alterations in tree cover can effect water availability, directly impacting food production. Can we boost water security and maximise the wider benefits of tree cover while increasing food production? This chapter emphasises that trees are neither a luxury consideration nor a minor footnote when we consider food security but rather a foundation for achieving it.

The interrelationship among water, energy, food, and carbon emissions has emerged as a critical factor influencing agricultural sustainability. However, existing studies on food crop planting structure (FCPS) optimization primarily focus on the water–food relationship, overlooking the complex and dynamic interactions within the water–energy–food–carbon emissions nexus (WEFCN). Additionally, the concept of harmony provides a quantitative framework for assessing system stability and coordination. Previous research has largely overlooked the influence of the WEFCN harmony degree on optimizing food crop planting structure. In response, this study proposes a novel FCPS optimization method that integrates the WEFCN and incorporates harmony degree constraints, aiming to address two key scientific challenges: (1) integrating the WEFCN into FCPS optimization research, and (2) quantitatively evaluating and constraining system harmony degree to enhance overall system stability and coordination. The results indicate that, compared to approaches focusing solely on single or localized relationships, the proposed method effectively reduces water and energy consumption, mitigates water pollution, and significantly decreases agricultural carbon emissions. Relative to methods without harmony degree constraints, it achieves reductions of 4.591 × 10⁸ m³ in blue water, 3.325 × 10⁸ m³ in grey water, 8.527 × 10⁸ m³ in total water footprint, 6.04 × 107 kgce in energy consumption, and 1.09 × 106 tCO₂eq in carbon emissions, while improving the system harmony degree from 3.411 to 3.434. This study addresses the limitations of conventional research that focuses primarily on the water–food relationship, which often results in suboptimal outcomes insufficient for advancing green agricultural development. It enhances the stability, balance, and coordination of the WEFCN, offers a reference for addressing its internal imbalances, and contributes to the promotion of sustainable agricultural development.

The interrelationship among water, energy, food, and carbon emissions has emerged as a critical factor influencing agricultural sustainability. However, existing studies on food crop planting structure (FCPS) optimization primarily focus on the water–food relationship, overlooking the complex and dynamic interactions within the water–energy–food–carbon emissions nexus (WEFCN). Additionally, the concept of harmony provides a quantitative framework for assessing system stability and coordination. Previous research has largely overlooked the influence of the WEFCN harmony degree on optimizing food crop planting structure. In response, this study proposes a novel FCPS optimization method that integrates the WEFCN and incorporates harmony degree constraints, aiming to address two key scientific challenges: (1) integrating the WEFCN into FCPS optimization research, and (2) quantitatively evaluating and constraining system harmony degree to enhance overall system stability and coordination. The results indicate that, compared to approaches focusing solely on single or localized relationships, the proposed method effectively reduces water and energy consumption, mitigates water pollution, and significantly decreases agricultural carbon emissions. Relative to methods without harmony degree constraints, it achieves reductions of 4.591 × 10⁸ m³ in blue water, 3.325 × 10⁸ m³ in grey water, 8.527 × 10⁸ m³ in total water footprint, 6.04 × 107 kgce in energy consumption, and 1.09 × 106 tCO₂eq in carbon emissions, while improving the system harmony degree from 3.411 to 3.434. This study addresses the limitations of conventional research that focuses primarily on the water–food relationship, which often results in suboptimal outcomes insufficient for advancing green agricultural development. It enhances the stability, balance, and coordination of the WEFCN, offers a reference for addressing its internal imbalances, and contributes to the promotion of sustainable agricultural development.

Studying the water-emissions-food nexus (WEF Nexus) is crucial for the sustainability of agricultural economic systems. The multi-regional input–output (MRIO) model provides insights for water-emissions-food integrated collaborative management. This study develops a detailed agriculture-oriented MRIO model based on the RAS method, which disaggregates the agricultural sector into 12 sub-sectors. The water consumption and greenhouse gas (GHG) emissions are allocated to the entire supply chain to identify the key regions and routes of the WEF Nexus in China for 2017. Then the environmental output level of the agricultural sector and its sub-sectors is analyzed using productivity indicators. Results demonstrate that the agricultural sector exhibits a strongly connected WEF Nexus (coefficient of 0.87), particularly in Coastal and Southwest regions. The synergistic relationship between water and emissions suggests significant opportunities for implementing integrated management strategies. 73.3% of virtual water and 71.7% of embodied emissions are concentrated in downstream non-agricultural sectors of supply chains, highlighting the substantial impact of trade transmission on the environment. The water and emissions productivity in the agricultural sector are spatially aligned except in the Central and Southwest regions. As significant agricultural output regions, Northeast and Central regions have lower water or emissions productivity, making sustainable agricultural development more challenging. Therefore, practical measures should focus on promoting technological innovation and its adoption to enhance water use efficiency and reduce GHG emissions in agricultural production.