Intense droughts and extreme floods increasing around the world are a “foretaste” of things to come as climate change makes the water cycle more erratic, the UN warned on Monday.
“Water is becoming more and more unpredictable” and “the warning signs are impossible to ignore,” Celeste Saulo, secretary general of the World Meteorological Organization (WMO), a UN agency, told a conference press.
In a new report, the WMO warns of a worsening global water shortage. Examining 33 years of data, the organization found that the world’s rivers last year reached a level of drought never seen in this period.
“In the context of climate change, water gives us a foretaste of the developments to come,” warned Mme Saulo, in a press release.
“The warning signs are increasing: we are witnessing an exacerbation of extreme precipitation, floods and droughts, which are taking a heavy toll on lives, ecosystems and economies,” she observes.
With 2023 being the hottest year on record, high temperatures and widespread low precipitation have contributed to prolonged droughts.
However, floods have also increased on the planet: extreme hydrological events have been favored not only by natural climatic factors, notably the transition from La Niña conditions to an El Niño episode in mid-2023, but also by climate change. of human origin, indicates the WMO.
“The rise in temperature has accelerated the hydrological cycle, which has also become more irregular and less predictable,” explains Mme Saulo.
The consequences are multiple: “A warmer atmosphere can contain more humidity, global warming increases the risk of heavy precipitation” while “at the same time, the acceleration of evaporation and the drying of soils aggravate droughts”.
“Atmospheric Rivers”
Water is either too abundant or insufficient, plunging many countries into increasingly difficult situations.
“There is now a lot more water in the form of vapor and in what we call atmospheric rivers” that we “cannot control with dams,” explained M.me Saulo.
It was on the African continent that water-related weather phenomena caused the most human losses last year, according to the WMO.
In Libya, two dams collapsed following a major flood in September 2023, killing thousands. Floods also hit the Horn of Africa region, the Democratic Republic of Congo, Rwanda, Mozambique and Malawi.
Currently, 3.6 billion people have insufficient access to water for at least one month per year and their number is expected to exceed 5 billion by 2050, according to the UN.
The report shows that the flow of about 50% of the world’s rivers was below normal last year. And inflow into reservoirs, such as dams, has been lower than normal in many parts of the world over the past five years.
Glaciers are also on the front line of global warming: according to preliminary data for the period from September 2022 to August 2023, they have lost more than 600 gigatons of water, which represents the worst loss in 50 years of observation.
“Melting ice and glaciers threaten the long-term water security of millions of people. However, we are not taking the urgent measures that are necessary,” said the WMO Secretary General.
The organization calls for early warnings for all to protect water-related lives and livelihoods, and calls for improved knowledge and data sharing on water resources.
Stefan Uhlenbrook, Director of the Hydrology, Water and Cryosphere Department at WMO, stressed the importance of investing in infrastructure to preserve water and protect populations from dangers, but also the need to save water , particularly for agriculture which uses 70% of global fresh water consumption.
As for returning to a more regular natural water cycle, things look difficult. “The only thing we can do is stabilize the climate. It’s a generational challenge,” he said.