2023 was the warmest year on record, driven by climate change and the transition between weather phenomena such as La Niña and El Niño, according to the World Meteorological Organization (WMO) in a new report.
This led to extreme weather – which varied. The weather has become more unpredictable.
We can call it an irregular hydrological cycle, leading to sudden floods and severe drought, says WMO Secretary-General Celeste Saulo at a press conference.
Less water in rivers
A warmer atmosphere absorbs more moisture. This leads to some areas drying out, while others are hit by heavier rainfall.
In the majority of the planet's rivers surveyed in the report, water levels deviate from the norm. In 45 percent of the rivers, less or much less water flowed than normal. Examples include the severe drought that has hit South, North, and Central America, where the Amazon and Mississippi basins were record-low.
2023 was the warmest year, resulting in dry rivers, says Stefan Uhlenbrook, head of hydrology, water, and cryosphere (frozen water) at WMO.
In South America, where they rely on hydropower, the low flows have affected the power supply.
In Ecuador's capital Quito, they have regular power outages, because there is simply no water in the reservoirs, he says.
Dams burst
In other parts of the world, river water levels were unusually high. In Libya, heavy rainfall led to dams bursting, resulting in catastrophic consequences with at least 4,700 deaths and 8,000 missing. From a Nordic perspective, Storm Hans is mentioned, which in August 2023 caused over 700 landslides.
The rising temperatures are also taking a toll on the world's glaciers, which lost more than 600 gigatons of water last year. They haven't lost that much in 50 years. In some parts of Asia, the so-called water peak has been passed, where the glaciers have simply become so small that the amount of meltwater from them is now decreasing.
It will be very dramatic when the summer high water from the melting glaciers disappears, as there will be no more ice layers, says Uhlenbrook.
The changes are here to stay, according to Saulo.
We will clearly not be able to return to normal, but what we can do is stop the acceleration we see, she says.
