Day Zero Water

https://www.ecoticias.com/en/goodbye-to-drinking-water-day-zero-will-arrive-sooner-than-you-thought-and-science-already-knows-when-and-where-it-will-happen/25735/

“Day Zero” Water Shortages Could Arrive Sooner Than Expected

A recent scientific study warns that extreme water scarcity events, known as “Day Zero Droughts” (DZD), could occur much earlier than previously projected, potentially in the 2020s and 2030s rather than later in the century. These events occur when prolonged drought conditions combine with rising temperatures and growing water demand, driving reservoirs and river systems to critically low levels where municipal water systems can no longer supply continuous potable water and taps effectively “stop running”.

The research identifies four conditions that typically converge to trigger a Day Zero event: prolonged rainfall deficits, increased evaporation due to higher temperatures, declining reservoir and river storage, and demand that exceeds the reduced available supply.

Under high-emissions climate scenarios, the study projects that by 2100 nearly three quarters of drought-prone land areas could experience unprecedented levels of water scarcity. Regions identified as particularly vulnerable include the Mediterranean basin, southern Africa, parts of North America, India, northern China, and southern Australia. In some of these areas, the first Day Zero conditions are projected to emerge between 2020 and 2030.

The human impact is expected to be substantial. The study estimates that more than 753 million people could be exposed to Day Zero conditions at the time their region first crosses this threshold, with urban populations facing disproportionately higher risk due to concentrated demand and dependence on centralized water infrastructure.

In several hotspot regions, Day Zero droughts may not be isolated incidents but could recur repeatedly, with limited recovery time between events. This pattern would leave communities in a state of chronic water stress rather than temporary disruption.

The findings also highlight a strong link between warming levels and water security. At approximately 1.5 °C of global warming, hundreds of millions of people could already be exposed to Day Zero drought conditions, underscoring the urgency of both climate mitigation and the need for proactive, forward-looking water management strategies that extend beyond historical climate assumptions.