The region of Xinjiang in China, renowned for producing a quarter of the world’s cotton, stands at a critical crossroads in the face of intensifying climate change. According to the latest Sixth Assessment Report by the Intergovernmental Panel on Climate Change (IPCC), human-induced global warming has not only elevated average temperatures worldwide but also increased the frequency, intensity, and duration of extreme weather events. These climatic shifts threaten agricultural productivity globally, but the impact on Xinjiang—a region already grappling with severe aridity—is particularly acute. With annual precipitation below 270 millimeters and evaporation rates exceeding 1000 millimeters, Xinjiang’s cotton cultivation heavily depends on irrigation. This dependency makes it increasingly vulnerable to shifts in water availability brought on by climate change. Recent research undertaken by Dr. La Zhuo and colleagues at Northwest A&F University provides a nuanced and forward-looking analysis of how the water use dynamics in cotton production might evolve under different climate scenarios, offering indispensable insights for sustainable agricultural management.
The study meticulously quantifies the “water footprint” of cotton in Xinjiang, a measure defining the volume of freshwater expended to produce a ton of cotton fiber. This water footprint is categorized into two components: the blue water footprint, which encompasses water drawn from surface or groundwater sources, and the green water footprint, which relies on precipitation stored in the soil. Diverging sharply from previous research, which predominantly centered on staple food crops or singular irrigation methods, this investigation leverages cutting-edge simulation technologies to evaluate three predominant irrigation methods—furrow irrigation, micro-irrigation (or drip irrigation), and sprinkler irrigation. Modeling these methods at a granular spatial resolution of approximately 9 km by 9 km allows for precise spatiotemporal analyses to capture variations throughout the Xinjiang agricultural landscape.
Timeframes for the study span two critical future periods—the 2050s and the 2090s—under two greenhouse gas concentration trajectories: the moderate SSP2-4.5 emissions scenario and the more severe SSP5-8.5 high emissions scenario. These scenarios reflect different global policy and emissions pathways, enabling researchers to explore a broad spectrum of potential climatic futures and their implications for water use efficiency in cotton farming. The study employs reference crop evapotranspiration (ET₀) as a pivotal indicator of atmospheric water demand, noting a stark increase, particularly under the SSP5-8.5 scenario, where ET₀ rises by 14.3% by the 2090s compared to the baseline years 2000–2018.
Intriguingly, despite the anticipated rise in evaporation and declining precipitation—expected to drop by approximately 15.1% annually—the overall water footprint of cotton production in Xinjiang is projected to decrease substantially in the coming decades. Specifically, the study forecasts reductions of 19.3% and 35.7% under the SSP2-4.5 and SSP5-8.5 scenarios, respectively, by the end of the century. This counterintuitive trend owes much to the physiological effects of rising atmospheric CO₂ concentrations. Elevated CO₂ enhances photosynthetic efficiency in cotton plants while curbing transpiration losses, effectively improving water use efficiency. This dual effect plays a crucial role in the projected contraction of water consumption despite harsher climatic conditions.
However, the composition of water usage tells an evolving story. While the absolute volumes of blue water consumed decline by 16.5% under the SSP2-4.5 pathway and by an even more pronounced 33.4% under SSP5-8.5, the relative proportion of blue water within the total water footprint is expected to increase slightly. This shift arises because the green water footprint—the proportion dependent on rainfall—is predicted to experience greater reductions due to widespread precipitation decreases. These changes manifest regionally, with some areas experiencing minor precipitation upticks between July and September, but overall, the decline in green water sources underscores an intensification of irrigation demands.
A comparative evaluation of irrigation technologies reveals marked disparities in their potential to conserve water within this evolving climate paradigm. Sprinkler irrigation emerges as the most water-efficient technique, reducing the water footprint of cotton by 24.8% and an impressive 40.1% respectively under moderate and high emission scenarios. These water savings are attributed to the precise application patterns inherent to sprinkler systems, which minimize evaporation losses and improve uniform soil moisture distribution. Conversely, furrow irrigation and micro-irrigation, while still offering reductions, demonstrate less pronounced water savings. The findings thus underscore the critical importance of adopting advanced irrigation technologies to mitigate water scarcity risks in an increasingly arid Xinjiang.
Beyond irrigation, the research emphasizes the urgency of integrating water-saving agricultural innovations more broadly. Coupling efficient irrigation with cultivar improvements and modern agronomic practices could compound water use efficiencies and safeguard cotton yields. Such multipronged strategies will be indispensable as changing climatic conditions exert mounting pressure on already scarce water resources. The high economic dependence on cotton in Xinjiang—accounting for over a third of farmers’ income nationwide—heightens the stakes for sustainable water management and technological adoption.
Moreover, the study’s spatially explicit modeling provides policymakers and stakeholders with a powerful predictive tool to allocate water more judiciously across Xinjiang’s diverse agricultural zones. By anticipating which regions may confront heightened irrigation pressures, interventions can be targeted to optimize resource distribution. This proactive approach contrasts with reactive water allocation tactics that risk inefficient water use and crop failures under extreme weather variability.
Importantly, adopting sprinkler irrigation and other water-efficient technologies aligns well with the broader climate resilience goals articulated by global agricultural frameworks. As the IPCC and international agencies emphasize sustainable intensification of agriculture to meet food and fiber demands under climate stressors, region-specific analyses such as this are crucial for tailoring solutions to localized environmental and socioeconomic contexts. Xinjiang’s experience offers valuable lessons for other drylands facing comparable challenges globally.
In conclusion, while climate change undeniably exacerbates water scarcity and agricultural vulnerabilities in Xinjiang, the region’s cotton industry possesses adaptive potential grounded in technological innovation and scientific understanding. The anticipated declines in total water consumption, propelled by elevated CO₂ fertilization effects and improved irrigation methods, offer a cautiously optimistic outlook for cotton production sustainability. Nevertheless, continuous investment in research, infrastructure upgrades, and policy incentives remains vital to ensure these benefits are realized. The study by Dr. La Zhuo’s team exemplifies the caliber of interdisciplinary research essential to navigating the complex nexus of climate change, water use, and agricultural viability in the 21st century.
By demystifying the nuanced interplay between climate dynamics, plant physiology, and irrigation technologies, this research equips stakeholders with actionable knowledge to mitigate risks and harness emerging opportunities. As Xinjiang braces for a hotter, drier future, such integrated water management strategies will define the difference between vulnerability and resilience—not just for cotton farmers in this region but for dryland agriculture worldwide.
Subject of Research: Not applicable
Article Title: Water footprint of irrigated cotton production in Xinjiang under predicted climate change scenarios
News Publication Date: 6-May-2025
Web References: http://dx.doi.org/10.15302/J-FASE-2024585
Keywords: Agriculture, Water footprint, Irrigation technology, Climate change, Cotton production, Water use efficiency, Xinjiang, Dryland agriculture
