Natural disasters in northwestern China, AD 1270-1949

The long-term dynamic of natural disasters drawn from historical records is vital for predicting the future impacts of such disasters and developing proper countermeasures against them. While many studies have examined historical natural disasters in eastern and southern China, few works published in international journals address past disasters in northwestern China. This study seeks to explore the factors underlying various disasters (drought, flood, hail, frost, dust storms, pests and famine) in the Gan-Ning-Qing Region of northwestern China from AD 1270 to 1949 at a multi-decadal scale. Via principal component analysis, we extracted 2 rotated principal components, explaining 53.55% of the temporal variance of the 7 types of disasters. The first principal component had hail, flood, dust storms and frost loading on it, which positively correlated with population pressure. The second principal component had drought and famine loading on it, which were significantly linked to atmospheric circulation. The remaining variance might be attributable to the independent character of pest disasters and low-frequency temperature forcing. Due to global warming and local geographic context, both expanding population and anomalous atmospheric circulation may increase societal vulnerability to natural disasters in northwestern China.