Context:
Recently, the World Meteorological Organization (WMO) released its 3rd edition of the State of Global Water Resources Report, revealing that 2023 was the driest year for global rivers in the past 33 years.
Understanding the Global Water Crisis
- The WMO’s State of Global Water Resources report highlights severe stress on global water supplies, with five consecutive years of below-normal river flows and reservoir inflows.
- In addition, glaciers experienced their largest mass loss in the last 50 years, with 2023 marking the second year of widespread ice loss globally.
- Approximately 3.6 billion people lack adequate access to water for at least one month each year, a figure projected to rise to 5 billion by 2050.
- The report emphasizes the urgent need for improved monitoring and management of water resources to meet Sustainable Development Goal 6 on water and sanitation.
Factors Contributed to the Driest Year for Global Rivers
- Prolonged Droughts Affected Major River Basins: Prolonged droughts significantly reduced river flows in North, Central, and South America, with the Mississippi and Amazon River basins reporting unprecedented low levels.
In Asia, the Ganges, Brahmaputra and Mekong River basins also faced similarly dire conditions,reflecting a global trend of declining water availability.
- Record Heat Intensified Water Scarcity: 2023 marked the hottest year on record at 1.45 °C above pre-industrial levels, with elevated temperatures contributing to widespread dry conditions.
The transition from La Niña to El Niño conditions, as well as the positive phase of the Indian Ocean Dipole (IOD) contributed to this extreme heat and diverse weather impacts ranging from heavy rains and floods to droughts.
This extreme heat has led to increased evaporation rates, further diminishing river flows and exacerbating existing water shortages.
- Reservoir Inflows and Storage: The inflows into reservoirs showed a pattern similar to that of global river discharge, with India, North, Central and South America, and parts of Australia experiencing below-normal inflow conditions.
Specifically, reservoirs in India, especially along the west coast, experienced below- and much-below-average inflows.
- Dip in Groundwater Levels: The report also highlights a concerning decline in groundwater levels across various regions.
In 2023, 19% of monitored wells showed much below-average levels, while 11% recorded below-average levels. Additionally, 40% were average, and 20% were much above average.
- Low Soil Moisture: The year 2023 ranks just behind 2022 in the recent historical record for dry soils. Soil moisture in 2023 was below or very low over large areas globally throughout the year.
How Has Climate Change Impacted Global Water Resources and Glacier Conditions?
- The WMO report reveals that climate change has accelerated glacier melt, resulting in the largest mass loss recorded in 50 years—totalling 600 gigatonnes of water.
- While rivers fed by glaciers have experienced temporary increases in flow, experts warn that these levels will plummet as glaciers continue to disappear.
- The ongoing changes pose significant risks to future water availability for millions globally.