Impacts of temporal-spatial compound extreme heat and drought on oil crops in China

Dietary diversification increased edible vegetable oil (EVO) demand. Climate change intensifies temporal-spatial compound extreme heat and drought (terms to above extremes co-occurring spatially and temporally), risking nationwide oil crops production and EVO supply, but were rarely quantified. We developed a panel model using heat degree days (HDD), Standardized Precipitation Evapotranspiration Index (SPEI), irrigation conditions, and year (representing agricultural technology) as yield predictors. Year-types were categorized by extreme climate-induced production losses: normal, temporal-spatial extreme heat (HDD change), temporal-spatial drought (SPEI change), and temporal-spatial compound extreme heat and drought (HDD and SPEI change). Historical, extreme heat and drought caused a 6.6% (4.0%), 5.6% (3.6%), and 3.5% (2.1%) yield loss for soybean, peanut, and rapeseed without (with) irrigation, respectively. Future temporal-spatial compound extreme years: crop yields would decrease over 14.0% (12.8%), EVO self-sufficiency rate would decrease to 15.5–16.5% (19.0–21.9%) without (with) area expanding, indicating alarming oil crop yield reduction under extreme climate.