Urban expansion brought stress to food security in China: Evidence from decreased cropland net primary productivity.
Cropland net primary productivity (CNPP) is a crucial indicator of grain productivity and food security. However, assessments of the impact of urban expansion on the CNPP in China have been inadequate owing to data limitations. In this paper, our objective was to assess the impact of urban expansion on the CNPP in China from 1992 to 2015 in a spatially explicit manner. We first obtained the CNPP before urban expansion between 1992 and 2015 in China using the Carnegie-Ames-Stanford Approach (CASA) model. We then assessed the impact of urban expansion on the CNPP from 1992 to 2015 at multiple scales (the whole country, agricultural zones, and urban expansion hotspots) by combining the CNPP before urban expansion with the urban land coverage time series extracted from multi-source remotely sensed data. We found that the total loss of the CNPP due to urban expansion from 1992 to 2015 was 13.77TgC, which accounts for 1.88% of the CNPP before urban expansion in China. This CNPP loss resulted in a 12.45-million-ton decrease in grain production in China, corresponding to a reduction in the mean annual grain self-sufficiency rate of 2%. Therefore, we concluded that rapid urban expansion from 1992 to 2015 caused stress to China's food security. We suggest that it is still vital for China to effectively protect cropland to improve the urbanization level to 60% by 2020.
Center for Human-Environment System Sustainability (CHESS), State Key Laboratory of Earth Surface Processes and Resource Ecology (ESPRE), Beijing Normal University, Beijing 100875, China; Academy of Disaster Reduction and Emergency Management, Beijing Normal University, Beijing 100875, China. Electronic address: hcy@bnu.edu.cn.
Chunyang
C
He
Center for Human-Environment System Sustainability (CHESS), State Key Laboratory of Earth Surface Processes and Resource Ecology (ESPRE), Beijing Normal University, Beijing 100875, China; Academy of Disaster Reduction and Emergency Management, Beijing Normal University, Beijing 100875, China. Electronic address: Zhifeng.liu@bnu.edu.cn.
Zhifeng
Z
Liu
Center for Human-Environment System Sustainability (CHESS), State Key Laboratory of Earth Surface Processes and Resource Ecology (ESPRE), Beijing Normal University, Beijing 100875, China; Academy of Disaster Reduction and Emergency Management, Beijing Normal University, Beijing 100875, China. Electronic address: enxumin@163.com.
Min
M
Xu
Center for Human-Environment System Sustainability (CHESS), State Key Laboratory of Earth Surface Processes and Resource Ecology (ESPRE), Beijing Normal University, Beijing 100875, China; Academy of Disaster Reduction and Emergency Management, Beijing Normal University, Beijing 100875, China. Electronic address: maqun0127@bnu.edu.cn.
Qun
Q
Ma
Center for Human-Environment System Sustainability (CHESS), State Key Laboratory of Earth Surface Processes and Resource Ecology (ESPRE), Beijing Normal University, Beijing 100875, China; Academy of Disaster Reduction and Emergency Management, Beijing Normal University, Beijing 100875, China. Electronic address: douyinyin1986@163.com.
Yinyin
Y
Dou
D002681:China; D003247:Conservation of Natural Resources; D018556:Crops, Agricultural / Q000254:growth & development*; D005523:Food Supply; D014507:Urbanization
China; Cropland net primary productivity; Food security; Nighttime light data; Urban expansion