Rising global temperatures drive water cycle extremes

Record-breaking temperatures in 2024 drove extremes in the global water cycle, contributing to major flooding and droughts, Australian-led international research has found.

The 2024 Global Water Monitor Report, which was published on Monday by a team of international researchers led by Albert van Dijk from Australian National University (ANU), found that rising temperatures as a result of climate change are changing how water moves around the planet.

According to the report, 111 countries accounting for approximately half the world's population experienced their warmest year on record in 2024.

Van Dijk said that air temperatures over land in 2024 were 1.2 degrees Celsius higher than at the start of the 21st century and 2.2 degrees Celsius higher than at the start of the Industrial Revolution (around 1760).

"In 2024, Earth experienced its hottest year on record, for the fourth year in a row. Water systems across the globe bore the brunt," he said in a media release.

He said that global weather extremes in 2024 were part of a worsening trend of more intense floods and droughts.

The report found that rising sea surface temperatures have intensified droughts and tropical cyclones in the Amazon Basin and southern Africa and that global warming has also contributed to heavier downpours and slower-moving storms.

Water-related disasters killed more than 8,700 people globally in 2024, displaced 40 million and caused economic losses exceeding $550 billion, the report said.

It found that record-high monthly rainfall totals were recorded 27 percent more frequently in 2024 than at the start of the century. At the same time, record-lows were 38 percent more frequent.

The research team said the data shows more preparation is needed for extremes on both sides of the global water cycle, including stronger flood defenses and more drought-resilient food production and water supplies.

"Water is our most critical resource, and its extremes – both floods and droughts – are among the greatest threats we face," van Dijk said.

The annual report is based on observations from thousands of ground stations and satellites that deliver near real-time data on rainfall, soil moisture, river flows and flooding.

(Cover: The Sau reservoir in Catalonia, Spain, February 2, 2024. /CFP)