Coupling coordination analysis of the water-food-energy-carbon nexus for crop production in Central Asia

The growing resource constraints around land, water, and energy while tackling climate change in Central Asia threaten the agricultural sustainability that underpins food security and people livelihoods. However, there is a lack of comprehensive long-term evaluations of the intricate water -food -energy -carbon nexus on a wider scale, hindering sustainable agriculture across this region. This study developed an integrated top -down and bottom -up approach to quantify the water consumption, energy use, and carbon emissions from crop production in Central Asia and established the coupling coordination model to evaluate the nexus (1995 -2020). The results show that the total water consumption in Central Asia increased from 161.55 x 10 9 to 170.93 x 10 9 m 3 at a rate of 1.39 x 10 9 m 3 / a in which blue water accounted for 59%. However, the energy use and carbon emissions decreased at a rate of - 1.57 PJ/a and - 0.06 Mt CO 2 eq /a, respectively, in which the indirect energy and indirect carbon emissions varied greatly. Furthermore, the coupling coordination level of water -food -energy -carbon nexus oscillated between uncoordinated and transitional development stages before 2000 and then entered coordinated development in 2003 after a short transitional development. The findings revealed that this oscillation may have been abnormal owing to issues such as yield loss and soil degradation. These results highlight the complex interplay between water, food, energy, and carbon of crop production across Central Asia and emphasise the need for a more integrated policymaking with increased regional cooperation, improvement in resource utilization efficiency, agricultural structure optimization, and protection of farmers rights towards agricultural sustainability.