World Water Day

Water shortages around the world can no longer be described as seasonal or exceptional. Around 4 billion people already live with severe water scarcity for at least one month every year . In many regions, water scarcity is increasingly driven by persistent long-term over-extraction and quality degradation rather than only by climatic variability. In many systems, water scarcity is therefore defined not only by how much water is available , but by how much of that water meets basicquality standards for human use, food production, and ecosystem health; polluted water or saline water may still appear in volumetric accounts, yet functionally it behaves as if it were not there.  Over 1.8 billion people—nearly one in four humans—were living under drought conditions in 2022–2023 , with the vast majority of them in low- and middle-income countries. Drought-related damages, intensified by land degradation, groundwater depletion, and climate change rather than by rainfall deficits alone,...

  Cryospheric decline compounds the existing pressures on water resources. The world, in multiple locations, has already lost over 30% of its glacier mass since 1970, and several low-latitude mountain ranges risk losing functional glaciers entirely within decades, eliminating long-standing natural savings accounts that once buffered seasonal water shortages . Snowpack and permafrost degradation add further uncertainty to water availability and storage in highlatitude and high-altitude systems. In glacier-fed basins across Asia, the Andes, and other mountain regions, communities are already experiencing a transition from “peak water” — a period of temporarily increased melt and runoff—to declining flows, with implications for hydropower, irrigation, and ecological integrity. Mountain glaciers and seasonal snowpacks function as the “water towers of the world,” storing cool-season precipitation and releasing it as meltwater during dry and warm periods. The downstream water suppl...

  Globally, built reservoir capacity per person is decreasing, as reservoir expansion has not been able to keep pace with population growth, but also because storage capacity of existing reservoirs is decreasing, chiefly due to sedimentation . The  Average annual storage volume losses equal about 1% of total built reservoir capacity, and the estimated costs for restoring these losses are approximately US$13 billion per year. An assessment of the value of storage capacity for Enhancing water security in the world’s 400 largest river basins identified water shortage risks in many parts of Africa, as well as in Australia, northern China, India, Spain and the western USA. There are widespread declines in total water storage and associated freshwater availability that are primarily attributed to the intensive overextraction of groundwater and an increasing Temperature-induced surface water loss .