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.
Chinese Research Academy of Environmental Sciences, Beijing 100012, China.
Sci Total Environ. 2022 Aug 20;835:155343. doi: 10.1016/j.scitotenv.2022.155343. Epub 2022 Apr 27.
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 × 10 tons and Africa imported 41,359.07 Bm 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 Bm·yr. 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.
非洲正面临着日益严峻的水资源短缺(WS)挑战,这是由气候变化、人口增长、社会经济增长以及水资源管理不善共同驱动的。特别是,虚拟水(VW)贸易引起了人们的极大关注,因为它在水资源管理和粮食安全可持续性方面发挥着关键作用。本研究使用双边贸易数据,从 2000 年到 2020 年,持续评估了主要粮食作物的变化和均衡贸易、VW 流动、WS 状况、水依赖度(WD)、水自给率(WSS)以及 5 个非洲次区域及其合作伙伴的水资源节约/损失情况。用水与可用水量的比率用于估计 WS。WD 通过净 VW 进口与区域水资源分配的比率来量化,区域水资源节约/损失也通过跨区域贸易与进口/出口粮食的虚拟水含量的乘积来量化。研究发现,非洲区域的总体贸易逆差增加到-1364.22×10^9 吨,非洲从粮食产品进口了 41359.07 亿立方米的 VW。绿水贡献了总 VW 的 79.33%。东非国家的 WS 值大于 100,表明过度开采。此外,在研究期间,非洲的总体 WD 为 465.5%。非洲与其他地区之间主要粮食作物的贸易导致全球水资源损失 2820.7 亿立方米。然而,未来洲际谷物 VW 贸易模式和高趋势将继续。鉴于 WS 紧张局势的加剧,一些非洲国家需要修订国际作物贸易和水资源保护政策,以促进更平衡的生态系统。本研究表明,决策者将考虑 VW 流量和水资源节约/损失,以提高用水效率和公平贸易,从而增加非洲的粮食产量。