Freshwater availability status across countries for human and ecosystem needs

Abstract

Water demand is expected to continue rising to support growing population, particularly in water-stressed countries and regions. Amid competitive water needs for agricultural, domestic, and industrial sectors, water allocations for environmental requirements are critical to ensure the sustainability of the ecosystems. This study takes stock of water availability trends per capita across countries and proposes a water scarcity indicator to quantify the amount of water available for agricultural, domestic, and industrial activities after the needs of freshwater ecosystems (environmental flow requirements, EFR) are ideally fulfilled. The study reveals that by 2050, 87 out of 180 countries will have annual renewable water resources (ARWR) per capita below 1700 m3/year. The number of countries with absolute water scarcity – ARWR per capita below 500 m3/year is projected to increase from 25 in 2015 to 45 by 2050. Population growth is projected to cause a sharp decline in water availability in many low-income and lower-middle-income countries, while economic development will push water use upwards, making the water supply gap more complicated and challenging to address. After the Middle East and North Africa region, Sub-Saharan Africa is expected to become the next hotspot of water scarcity along with several countries from Asia. In response, water-scarce countries need to promote water conservation, water recycling, and reuse; ensure sustainable water resources augmentation via harnessing the potential of unconventional water resources; support productivity enhancement of underperforming land and water resources; and address challenges beyond technical solutions. Pertinent political agenda and associated public policies, supportive institutions, institutional collaborations, and skilled professionals would be the key to ensure sufficient water supply for human use and ecosystems.