Virtual water transfers in Africa: Assessing topical condition of water scarcity, water savings, and policy implications

Hubert Hirwa; Yu Peng; Qiuying Zhang; Yunfeng Qiao; Peifang Leng; Chao Tian; Guang Yang; Fabien Muhirwa; Salif Diop; Alphonse Kayiranga; Fadong Li; Gang Chen

doi:10.1016/j.scitotenv.2022.155343

Virtual water transfers in Africa: Assessing topical condition of water scarcity, water savings, and policy implications

Sci Total Environ. 2022 Aug 20:835:155343. doi: 10.1016/j.scitotenv.2022.155343. Epub 2022 Apr 27.

Authors

Hubert Hirwa¹, Yu Peng¹, Qiuying Zhang², Yunfeng Qiao¹, Peifang Leng¹, Chao Tian³, Guang Yang⁴, Fabien Muhirwa⁵, Salif Diop⁶, Alphonse Kayiranga⁷, Fadong Li⁸, Gang Chen⁹

Affiliations

¹ Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China.
² Chinese Research Academy of Environmental Sciences, Beijing 100012, China.
³ Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China.
⁴ College of Water and Architectural Engineering, Shihezi University, Shihezi 832003, China.
⁵ University of Chinese Academy of Sciences, Beijing 100049, China; Key Laboratory for Resources Use and Environmental Remediation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China.
⁶ National Academy of Sciences of Senegal, P.O. Box 4344, Dakar, Senegal.
⁷ State Key Laboratory of Resource and Environmental Information, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China.
⁸ Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China; College of Water and Architectural Engineering, Shihezi University, Shihezi 832003, China. Electronic address: lifadong@igsnrr.ac.cn.
⁹ Department of Civil and Environmental Engineering, FAMU-FSU College of Engineering, 2525 Pottsdamer Street, Tallahassee, FL 32310, USA.

PMID: 35489483
DOI: 10.1016/j.scitotenv.2022.155343

Abstract

Africa is facing an increasing challenge with respect to water scarcity (WS), which is driven by climate change, population growth, and socioeconomic growth combined with inadequate water resources management. In particular, there is significant concern of virtual water (VW) trade, which plays the key role in water resource management and food security sustainability. Using bilateral trade data, this study consistently evaluated the change and balanced trade of major grains, the VW flows, WS status, water dependency (WD), water self-sufficiency (WSS), and water savings/losses within5 African sub-regions and their partners from 2000 to 2020. The ratio of water use to water availability was used to estimate the WS. The WD was quantified by the ratio of the net VW import to the regional water appropriation and the regional water savings/losses were also quantified by multiplying the inter-regional trade by the virtual water content of the imported/exported grains. The overall average trade deficit of African regions was found to increase to -1364.22 × 10⁶ tons and Africa imported 41,359.07 Bm³ of VW from grain products. Green water contributed 79.33% of the total VWI. The WS values for East African countries were >100, indicating overexploitation. Besides, the overall WD in Africa was 465.5% for the studied period. The trade of main grains between Africa and the rest of the planet corresponded to a global water loss of 2820.7 Bm³·yr^-1. However, the inter-continental cereal VW trade pattern and high trend will continue in the future. In view of the rising tension of WS, some African countries need to revise international crop trade and water resources conservation policies to promote a more balanced ecosystem. This study exemplifies that decision makers would consider VW flows and water savings/losses for enhancing water use efficiency and fair trading, thus increasing food production in Africa.

Keywords: Africa; Virtual water flows; Water dependency; Water resource management; Water saving; Water scarcity.

MeSH terms

Agriculture / methods
Ecosystem
Edible Grain
Policy
Water Insecurity*
Water Supply
Water*

Substances

Water