WEIYI GU

Crop Migration and Environmental Sustainability

Wed, 12 Jun 2024 00:00:00 +0000

Climate adaptation through crop migration requires a nexus perspective for environmental sustainability in the North China Plain

Agricultural production is progressively shifting toward regions with more favorable climatic conditions to stabilize and enhance yields under climate change. However, the cascading environmental consequences of such migration remain insufficiently examined. During agricultural production, agricultural inputs (e.g., fertilizers and pesticides), land, water, energy, and food systems are closely interconnected. As crop cultivation shifts geographically, patterns of agricultural inputs, irrigation, energy use, and production structures are correspondingly altered. Consequently, climate-induced crop migration may generate multiple climatic and environmental feedbacks. By incorporating a resource nexus perspective into simulations of adaptive behavior, our modelling framework captures how adaptation decisions propagate across resource systems, amplify through interlinkages, and ultimately feed back into the climate-environment system (Fig. 1).

Fig. 1. A conceptual integrated assessment framework linking climate change, adaptive behaviors, and resource-environmental impacts to support the optimization of sustainable climate adaptation strategies.

By integrating CMIP6 climate projections, machine learning and econometric models, and life cycle assessment models, the study quantifies future migration trajectories of wheat and maize cultivation in the North China Plain under different climate scenarios, along with associated changes in land, water, energy use, and carbon emissions. Results indicate that by the 2050s, a northward shift in the center of wheat cultivation (15-17 km) could increase total wheat production by approximately 18.5% (Fig. 2a). However, because areas with higher environmental impact intensities account for a larger share of cultivated land after migration, the ~18.5% gain in wheat production comes at the cost of increased land use (~19.2%), water consumption (~20.2%), energy use (~19.5%), and carbon emissions (~19.9%) (Fig. 2b).

The study further evaluates optimized adaptation strategies to enhance environmental sustainability alongside northward wheat migration, including drip fertigation and improved nitrogen management practices (e.g., controlled-release fertilizers, nitrification inhibitors, and urease inhibitors). Overall, drip fertigation demonstrates more substantial environmental benefits, reducing additional land use (~4.2%), water consumption (~34.0%), and energy use (~16.9%) associated with crop migration. By alleviating groundwater extraction pressures in the North China Plain and lowering nitrogen application intensity, it could also reduce greenhouse gas emissions by approximately 19.7% (Fig. 2c-f). At the global scale, optimized local adaptation strategies in the North China Plain have the potential to enhance regional self-sufficiency and reduce reliance on wheat imports, thereby avoiding approximately 0.20 Mt CO2e of carbon leakage embodied in international wheat trade.

Fig. 2. Impacts of wheat crop migration, including (a) yield gains, (b) multiple environmental impacts, and (c-f) mitigation effects achieved through complementary water and fertilizer optimization strategies.

Agricultural production in the North China Plain represents a microcosm of the multiple challenges confronting global agriculture, including freshwater scarcity, intensifying climate change, and environmental degradation. The integrated framework developed in this study, combined with multi-regional, multi-scale, and high-resolution datasets, provides a scalable approach for simulating agricultural adaptation and optimizing irrigation and fertilization management across broader regions, thereby promoting synergies between climate adaptation and environmental impact mitigation.

Cite this article:

Gu, W., Ma, G., Wang, R. et al. Climate adaptation through crop migration requires a nexus perspective for environmental sustainability in the North China Plain. Nat Food 5, 569–580 (2024). https://doi.org/10.1038/s43016-024-01008-8

Water Inequity in Global Agricultural Trade

Mon, 10 Jun 2024 00:00:00 +0000

The asymmetric impacts of international agricultural trade on water use scarcity, inequality and inequity

Water resources are closely linked to multiple United Nations Sustainable Development Goals (SDGs). Globally, more than 2 billion people live in countries experiencing severe water stress, and approximately 1.2 billion people still lack access to basic safely managed drinking water services. Virtual water transfers associated with agricultural trade may help alleviate water scarcity (SDG 6), reshape the global distribution of water use, and generate heterogeneous impacts across income groups. However, previous research on water risk has primarily focused on perturbations in the hydroclimatic cycle. In contrast, limited attention has been given to how human activities redistribute water-related risks and induce heterogeneous socioeconomic responses. This gap constrains the development of targeted adaptation strategies for different regions and populations and ultimately hinders progress toward global sustainable water management.

Fig. 1. An integrated assessment framework coupling global water use assessment model, physical trade flow model, and water equity assessment model.

To address this issue, building upon prior work on tele-coupled water risk mechanisms and impact assessment, we develop an integrated assessment framework (Fig. 1). By coupling a crop water requirement model, a physical trade flow model, and an equity assessment model, the study constructs a comprehensive framework to quantify water risk redistribution mechanisms and their equity implications. Using historical datasets, the study systematically evaluates how international agricultural trade reshapes the global allocation of scarce water resources and assesses the resulting differentiated impacts across income groups.

Fig. 2. Grid-level water scarcity changes embedded in international agricultural trade.

The results show that although agricultural trade generally alleviates global water scarcity, substantial regional heterogeneity exists and benefits are disproportionately accrued by wealthier populations (Fig. 2). In developing countries, agricultural trade reduces water use equity by approximately 30%; that is, the concentration of water use toward the poorest populations declines by about 30% on average. In contrast, in developed countries, agricultural trade improves water use equity by roughly 65%, increasing the concentration of water use toward relatively poorer populations (Fig. 3). Similarly, in developing countries, 35% of the population simultaneously faces intensified water scarcity and increased inequity in water use, with average incomes only 84% of the national per capita income. Conversely, in developed countries, relatively lower-income groups (13% of the population) tend to benefit from concurrent reductions in both water scarcity and water-use inequity.

Fig. 3. The concentration curve illustrating water use inequality and inequity for developing countries (a), developed countries (b), the low GDP per capita group in developing countries (c), and the low GDP per capita group in developed countries (d).

The study further identifies the relative contributions of different crop types, particularly staple crop trade such as rice and cash crop trade such as cotton, as well as different trade patterns, especially extensive South-South trade cooperation, to the transmission of water-related risks. By elucidating the mechanisms through which water risks are redistributed toward lower-income populations, this work provides a methodological and data foundation for future research on cross-population transmission of water risks under climate change.

In the context of climate change and globalization, this study underscores that while international trade plays a crucial role in safeguarding global food security, it also reshapes water allocation patterns with disproportionate consequences for populations with limited adaptive capacity. The findings highlight the need for targeted regulatory strategies tailored to heterogeneous population groups. Such strategies may help overcome the current methodological limitation of end-user homogeneity in water risk assessments, mitigate the relative disadvantage of low-income populations in international agricultural trade, and promote equitable, inclusive, and sustainable global water resource governance.

Cite this article:

Gu, W., Wang, F., Siebert, S. et al. The asymmetric impacts of international agricultural trade on water use scarcity, inequality and inequity. Nat Water 2, 324–336 (2024). https://doi.org/10.1038/s44221-024-00224-7

Gu, W., Qin, Y. Targeted opportunities to mitigate water scarcity, inequality, and inequity embedded in international food trade for vulnerable countries. Water Research 267, 122568 (2024). https://doi.org/10.1016/j.watres.2024.122568

Potato-as-Staple-Food Policy in China

Sat, 08 Jun 2024 00:00:00 +0000

Promoting potato as staple food can reduce the carbon–land–water impacts of crops in China

Balancing food security with environmental impact mitigation represents a central challenge for sustainable agricultural development. Owing to its agronomic and nutritional advantages, China launched the Potato-as-Staple-Food Policy in 2015, aiming to cultivate improved varieties and expand planting areas to enhance national food security. A systematic assessment of the environmental implications of this strategy helps elucidate China’s potential contribution to synergizing global agricultural development and environmental sustainability.

Fig. 1. Cropland use, GHG emissions and water use under various scenarios.

We develop a regionally differentiated life cycle assessment (LCA) framework for staple crops and find substantial spatial heterogeneity in environmental impacts across crop types and production regions. Under equivalent caloric supply, potatoes generate lower carbon emissions, water stress, and land-use pressure compared with other staple crops. Scenario analyses incorporating “policy implementation” and “production optimization” pathways suggest that by 2030, the Potato-as-Staple-Food Policy could reduce the environmental impacts of domestic staple crop production by 17-25% while meeting projected growth in food demand (Fig. 1).

Fig. 2. Potential global carbon leakage.

The study further highlights that realizing these environmental benefits critically depends on dietary shifts toward increased consumption of potato-based foods. Such transitions are non-trivial, particularly given the central role of rice in Chinese dietary culture. If domestic rice supply becomes relatively constrained, China may increase rice imports. Because the life-cycle carbon intensity of rice production in China is lower than in many other countries, expanded rice imports could induce carbon leakage through international trade. The associated emissions may potentially offset—or even exceed—the domestic mitigation gains achieved through the Potato-as-Staple-Food Policy (Fig. 2). Therefore, alongside adjustments in cropping structure, strengthening the potato food supply chain and facilitating dietary transitions are essential to ensure that structural agricultural transformation delivers net environmental benefits.

Cite this article:

Liu, B., Gu, W., Yang, Y. et al. Promoting potato as staple food can reduce the carbon–land–water impacts of crops in China. Nat Food 2, 570–577 (2021). https://doi.org/10.1038/s43016-021-00337-2

Climate Vulnerability of Hydropower Sector

Wed, 05 Jun 2024 00:00:00 +0000

Prioritizing climate change adaptation needs for hydropower sector in China

Potential impacts of climate change on hydropower have been widely recognized. Given that China consistently ranks among the world’s leading countries in installed hydropower capacity, there is an urgent need for long-term, high–spatial-resolution assessments of hydropower-climate risk to identify the spatiotemporal priorities of adaptation policies and to enable the efficient allocation of limited adaptation resources. This study evaluates changes in economic returns and electricity generation in China’s hydropower sector under climate change throughout the twenty-first century, providing quantitative support for national energy security management. It further simulates the cascading effects of hydropower losses, emphasizing the multiple feedbacks between the climate system and socio-economic systems (Fig. 1).

Fig. 1. Graphic Abstract.

To capture distinct risk characteristics—high-probability, low-impact changes and low-probability, high-impact events—the study constructs a set of climate indicators reflecting shifts in average climate conditions as well as changes in the frequency of extreme weather events. Using micro-level panel data for 5,082 hydropower plants across China from 1998 to 2013, we apply econometric models to uncover the coupled relationship between hydropower performance and climate variability, as well as regional heterogeneity across different climate zones.

Fig. 2. Projected economic revenue losses of hydropower plants in the 2050s and 2090s under the RCP 8.5 scenario driven by 21 global climate models (GCMs), and percentage changes in hydropower revenue losses in major hydropower-producing provinces in the 2090s.

Based on 21 global climate models (GCMs) from the CMIP5 ensemble under two climate scenarios (RCP 8.5 and RCP 4.5), and incorporating historically estimated climate–hydropower relationships, we project annual, plant-level economic impacts on hydropower throughout the twenty-first century and estimate damage functions for precipitation and temperature. The results indicate that under the RCP 8.5 scenario, average economic losses in China’s hydropower sector could reach 9.34%±1.21% by the end of the century—approximately four times higher than under RCP 4.5. Hydropower-intensive regions, including Yunnan and Sichuan provinces in Southwest China and Hubei province in Central China, are projected to face particularly substantial losses, with some provinces experiencing reductions exceeding 20% by the century’s end (Fig. 2).

Fig. 3. Annual carbon leakage resulting from thermal power substitution for hydropower losses under the RCP 8.5 and RCP 4.5 scenarios, based on projections from 21 global climate models (GCMs).

By integrating plant-level revenue panel data with generation statistics from the China Hydropower Yearbook and applying a random forest model, the study establishes a nonlinear relationship between hydropower revenue and electricity generation, enabling further quantification of projected generation losses over the century. Given that renewable technologies such as wind and solar power are also subject to climate constraints, the analysis assumes that part of the lost hydropower generation would be replaced by thermal power. Combining projected energy mix data under different climate scenarios, the results suggest that carbon leakage associated with hydropower losses could reach 467.56±202.63 Mt (Fig. 3).

Cite this article:

Gu, W., He, W., Su, H., Liu, B*. Prioritizing climate change adaptation needs for hydropower sector in China. Environmental Research Letters 17, 034040 (2022). https://iopscience.iop.org/article/10.1088/1748-9326/ac4c1b

Mon, 01 Jan 0001 00:00:00 +0000