Impact of international trade on water scarcity: An assessment by improving the Falkenmark indicator

Water scarcity, a threat to the sustainable development of human society, is determined mainly by water resource endowment and human water withdrawals. International trade may affect national water withdrawal, indirectly influencing nationwide water scarcity. However, most previous studies could not disentangle the indirect water consumption for local consumption and international trade purposes, failing to assess the sole impact of trade on water scarcity. Here, we developed an improved Falkenmark indicator to separate the effect of trade-related water withdrawal on water scarcity. Results show that international trade alleviates water scarcity for 2.2 billion people in high and upper-middle income countries. However, it aggravates water scarcity for 2.1 billion people in low and lower-middle income countries, of which almost all countries are already facing water scarcity and some even are of severe scarcity. Furthermore, our analysis shows that the primary product and food sectors contribute most significantly to intensifying and alleviating water scarcity, respectively. Hence, much greater attention needs to be paid to low and lower-middle income water-scarce countries since international trade could make these countries drier, which is becoming more important to improve the sustainability of global water resources management with a changing climate.