Increasing Intensity of Spring Frost Threatens Global Food Security Despite Climate Warming

Spring frost, an extreme weather event, can significantly impact food security. However, the intensity of these events and their effects on crops at a global scale in the context of global warming are not well-documented. In this study, we analyzed temperature data, global production data of three major crops (corn, soybeans, and winter wheat) from 1981 to 2016, and global temperature anomaly data to assess the impact of spring frost on crop yield. We also developed intensity factor indices, including temperature difference, temperature fluctuation, and the duration of spring frost events, to measure the intensity of these events. Our results showed that the number of spring frost events has decreased due to global warming, but the yield loss of crops impacted by spring frosts has increased from 1981-2001 to 1986-2016. Corn's yield loss increased by 5.63 percentage points, soybean's yield loss rose from 12.32% to 15.01%, and winter wheat's yield loss increased from 16.42% to 18.99%. Our study also found that the intensity factor indices increased with temperature anomaly, and these intensity factors were positively correlated with the crops' yield loss. Furthermore, our multiple linear regression and principal component analysis suggested that the temperature anomaly not only increased the intensity of spring frost but, together with intensity factors such as temperature fluctuation and duration of spring frost events, exacerbated the yield loss. However, the temperature difference decreased the yield loss. These findings are crucial for evaluating the impact of climate change on food security.