Spatiotemporal behavior of floods and droughts and their impacts on agriculture in China

Abstract

China is an agricultural country with the largest population in the world. However, intensification of droughts and floods and amplification of precipitation extremes are having critical negative impacts on agriculture. In this study, flood- and drought-affected, flood- and drought-damaged crop areas, and also flood- and drought-induced agricultural loss from 29 provinces across China are analyzed in both space and time. Results indicate the following: (1) Large parts of China are dominated by intensified floods. Comparatively, spatial ranges dominated by intensifying drought hazards are smaller than those by intensifying flood hazards. (2) Drought intensity is increasing in northwest China with moderate changes in the degree of influence. Increasing flood intensity can be observed in northwest, southwest and central China. However, flood risks are higher in arid regions such as northwest China and drought risks are higher in humid regions such as southwest China. (3) Agreements are identified between abrupt behaviors of flood-affected and -destroyed crop areas. The change points of flood-affected and -destroyed crop areas is in the 1980s in northeast, north and central China and in the 1990s in south and southwest China. Nevertheless, spatial patterns of the change points in the drought-affected and -destroyed crop areas are sporadic but not confirmative. (4) Flood- and drought-induced losses of agricultural production have significant increasing trends in most parts of China. The loss rate and loss magnitude of agriculture before change points are significantly higher than those after change points. (5) Generally, amplifications of precipitation extremes, decreasing consecutive wet days and increasing consecutive dry days in both space and time are the major driving factors behind the changes of drought- and flood-affected, and -destroyed crop areas and their impacts on agriculture across China. These results are theoretically and practically relevant for planning and management of agricultural activities and may help provide a theoretical framework for similar studies in other regions of the globe.