The world’s hydrological cycle is increasingly disrupted due to the impacts of climate change and human activities, according to a comprehensive report from the World Meteorological Organization (WMO). The report highlights the urgent need for a stocktake of global water resources as droughts and extreme rainfall events take a toll on lives and economies.
Melting snow, ice, and glaciers are contributing to heightened flood risks and long-term water security threats for millions of people worldwide. The WMO’s “State of Global Water Resources 2022” report underscores the necessity for a fundamental policy shift to address this crisis.
MEASUREMENT AND UNDERSTANDING
The report emphasizes that effective management of water resources begins with measurement and understanding. It calls for improved monitoring, data sharing, cross-border collaboration, and comprehensive assessments of water resources. Increased investments are deemed vital to equip society to cope with the growing challenges of both water scarcity and excess.
The “State of Global Water Resources Report 2022” builds upon a pilot report issued the previous year. It offers a more extensive analysis of critical hydrological variables such as groundwater, evaporation, streamflow, terrestrial water storage, soil moisture, the cryosphere (frozen water), inflows to reservoirs, and hydrological disasters. The report combines field observations, satellite-based remote sensing data, and numerical modeling simulations to provide a global-scale assessment of water resources.
GLACIERS AND ICE COVER
WMO Secretary-General Prof. Petteri Taalas stated, “Glaciers and ice cover are retreating before our eyes. Rising temperatures have accelerated and disrupted the water cycle, leading to more intense precipitation episodes, flooding, and severe droughts.” Prof. Taalas further highlighted the critical role of water management and monitoring in global initiatives like “Early Warnings For All.”
The report reveals a significant lack of timely and accurate hydrological data for decision-making and early action during water-related disasters. It serves as a call to action for more extensive data sharing and integrated water management policies as part of climate action.
GLOBAL-SCALE ASSESSMENT
Currently, over 3.6 billion people experience inadequate access to water for at least one month annually, a figure expected to increase to over 5 billion by 2050, as per UN Water.
The report provides an independent and consistent global-scale assessment of water resources in major river basins, comparing various variables like river discharge, groundwater, evaporation, soil moisture, and inflow to reservoirs to long-term averages.
In 2022, more than 50% of global catchment areas witnessed deviations from normal river discharge conditions, with most areas being drier than usual. Over 60% of major water reservoirs experienced below or normal inflow, posing a challenge in supplying water to users in a changing climate.
SOIL MOISTURE AND EVAPORATION
The report also highlights anomalies in soil moisture and evaporation, particularly in Europe, where extreme heat waves and droughts had a significant impact on agriculture and energy production.
The cryosphere, including regions like the Tibetan Plateau and the Andes, saw notable decreases in glacier mass and snow cover, affecting water supplies for billions.
The report further details water-related disasters, including severe droughts, low river levels, and significant humanitarian crises in various regions. The transition from La Niña to El Niño conditions in 2023 is expected to have a substantial impact on the hydrological cycle, to be analyzed in the next year’s report.