Sparrow Slaughter and Grain Yield Reduction During the Great Famine of China

At least 16.5 million people died of hunger in the Great Famine of China from 1959 to 1961. One direct reason is huge grain yield reduction. Here we show that massive sparrow slaughter which resulted in pest outbreaks is an important cause of grain yield reduction. The data we extracted from historical records shows ~2.1 billion sparrows were killed in 1958 and severe pest outbreaks followed. Further mechanism test shows that the consumption of pesticide during 1958 to 1961 was several times that of other years. While due to capacity restrictions, the supply of pesticide was still in shortage. Furthermore, provinces with a greater shortage of pesticide supplies also had more sparrows slaughtered. The unrecovered grain yield by pesticide is ~10.4% of the total grain output. Regression result shows sparrow slaughter caused annual loss of ~7 million metric tons of grain which could have fed ~28 million people. Our theory can explain approximately 33% reduction in crop yields in those years. This paper reveals a negative ecological case, which again warns human kind about the importance of maintaining ecological balance