A research team, led by Prof. Shuo WANG, Associate Professor of LSGI, a core member of the Research Institute for Land and Space, and a member of the State Key Laboratory of Climate Resilience for Coastal Cities, from the Department of Land Surveying and Geo-Informatics (LSGI) at The Hong Kong Polytechnic University (PolyU), has used innovative explainable machine learning to uncover the persistent negative impact of snow droughts on winter wheat yields. As warmer winters become more prevalent, insufficient snowfall leaves wheat vulnerable to frost damage and water stress, posing a major threat to global food security. The findings have been published in Nature Food.
Over the past 60 years, the frequency of snow droughts across the Northern Hemisphere’s winter wheat croplands has risen sharply. The proportion of affected croplands surged from 46–54% in 1960–1970 to 70–99% in 2010–2020, indicating that snow droughts have evolved from a localised risk into a widespread phenomenon.
The research team developed the XGB-SHAP model framework, which combines Extreme Gradient Boosting (XGBoost) with Shapley Additive exPlanations (SHAP) to quantify the direct impact of snow drought on yields while excluding interference from other climate factors. The study found that approximately 45% of croplands in the Northern Hemisphere experienced significant adverse effects, with Europe, Central Asia and the United States being the most severely affected. In East Asia, the yield benefits of longer growing seasons are diminishing, and the hydrothermal balance is becoming increasingly unstable.
Prof. Shuo WANG noted, “As global warming continues, climate risks are no longer limited to ‘acute stressors’ such as heatwaves, but also include gradually accumulating and far-reaching ‘chronic stressors’ such as snow droughts. As winter wheat is a major commodity in global agricultural trade, the effect of its yield variability can ripple through global trade networks, driving up food prices and potentially leading to regional food security crises.”
The research team recommends strengthening climate resilience by enhancing crop varieties, improving agricultural management, and incorporating snow cover monitoring into early warning systems. These steps will help maintain stable food production and steer global agriculture towards a more sustainable future.
Press release:
English - https://polyu.me/4nOZhRH; Chinese - https://polyu.me/4u1BBv3
Online coverage:
The National Tribune - https://polyu.me/4dNTZ4t
Mirage - https://polyu.me/42YLSx2
Ta Kung Pao - https://polyu.me/4e8weVZ
Wen Wei Po - https://polyu.me/3RKk4dd
