Global River Flows Fell to Record Lows in 2023, WMO Report Says

Last year was the driest for rivers globally in 33 years, according to the State of Global Water Resources 2023 report coordinated by the United Nations’ World Meteorological Organization (WMO).

The world’s river flows fell to record lows in 2023, as extreme heat endangered crucial water supplies in a time of increasing demand, a WMO press release said.

“Water is becoming the most telling indicator of our time of climate‘s distress and yet, as a global society, we are not taking action to protect these reserves,” Celeste Saulo, WMO secretary-general, told reporters at a press briefing in Geneva, as Reuters reported.

For the past five years in a row, river flows all over the globe have recorded below-normal conditions, the press release said. A similar pattern has been observed with reservoir inflows, which means reduced water supplies for communities, ecosystems and agriculture.

The report said glaciers have suffered the greatest mass ice loss ever recorded over the past 50 years. All of the regions on Earth with glaciers reported loss of ice in 2023.

“This severe loss is mainly due to extreme melting in western North America and the European Alps, where Switzerland’s glaciers have lost about 10% of their remaining volume over the past two years,” WMO said.

Overall, the world’s glaciers experienced 600 gigatons of water loss from an extreme melt year, reported Reuters. This was the worst in five decades of observations, according to preliminary data from September 2022 to August 2023, the press release said.

“When the glacier is gone in a few more decades. It will be very dramatic,” said Stefan Uhlenbrook, WMO director of hydrology, as Reuters reported.

Last year was the hottest since records began. Higher temperatures led to widespread dry conditions and prolonged droughts.

There were also a notable number of floods around the world. These extreme hydrological occurrences were influenced by the planet transitioning from La Niña to El Niño mid-year, as well as by human-caused climate change.

“Water is the canary in the coalmine of climate change. We receive distress signals in the form of increasingly extreme rainfall, floods and droughts which wreak a heavy toll on lives, ecosystems and economies. Melting ice and glaciers threaten long-term water security for many millions of people. And yet we are not taking the necessary urgent action,” Saulo said in the press release.

Currently, 3.6 billion people are facing inadequate water access for a minimum of one month each year, with the number projected to increase to over five billion by mid-century, UN Water said. The planet is not on track to meet its Sustainable Development Goal on water and sanitation.

“As a result of rising temperatures, the hydrological cycle has accelerated. It has also become more erratic and unpredictable, and we are facing growing problems of either too much or too little water. A warmer atmosphere holds more moisture which is conducive to heavy rainfall. More rapid evaporation and drying of soils worsen drought conditions,” Saulo said.

The number of stations measuring river discharge used in the report went up from 273 in 14 different countries to 713 in 33 countries, compared with the previous year. Groundwater data collection also expanded to 35,459 wells in 40 nations, in comparison with 8,246 in 10 countries a year earlier. Despite these increases in observational data sharing, South America, Africa and Asia remained underrepresented, underscoring the necessity of better monitoring and data sharing, especially in the Global South.

“And yet, far too little is known about the true state of the world’s freshwater resources. We cannot manage what we do not measure. This report seeks to contribute to improved monitoring, data-sharing, cross-border collaboration and assessments,” Saulo said in the press release. “This is urgently needed.”