Weather extremes ‘wreaking havoc’ on global water systems

Scientists say climate extremes wreaked havoc on the global water cycle last year, leading to flooding and droughts around the world that displaced millions and cost the global economy billions.

Last year, half of the world’s population experienced their warmest year yet. Air temperatures were 1.2ºC warmer than at the start of the century and 2.2ºC above the pre-industrial era.

Water systems have borne the brunt of this change, with rising sea surface temperatures intensifying and causing tropical cyclones and droughts, a report by the Australian National University said.

Water-related disasters killed more than 8,700 people, displaced 40 million people and caused economic losses exceeding $550 billion. The most damaging water-related disasters last year included flash floods, river floods, droughts, tropical cyclones and landslides.

“In 2024, Earth experienced its hottest year on record, for the fourth year in a row. Water systems across the globe bore the brunt,” according to ANU professor Albert van Dijk, who said these extremes were changing how water was moving around the planet.

This year was not an isolated occurrence but part of a worsening trend of more intense floods, prolonged droughts, and record-breaking extremes, he added.

Speaking to The National, Prof van Dijk said devastating flooding and record rainfall recorded in the UAE in April last year were probably related to the same wider water crisis.

“Where attribution studies on these sorts of downpours have been done they typically indicate that they would have been only half as likely without climate change. That's even more the case in coastal areas where warming seas increase the moisture in the air”. He also warned that extreme events would occur increasingly more often in the future, including in the UAE.

The research team used data from thousands of ground stations and satellites orbiting the Earth to deliver near real-time insights into variables such as rainfall, soil moisture, river flows, and flooding.

“We found rainfall records are being broken with increasing regularity. For example, record-high monthly rainfall totals were achieved 27 per cent more frequently in 2024 than at the start of this century, whereas daily rainfall records were achieved 52 per cent more frequently. Record-lows were 38 per cent more frequent, so we are seeing worse extremes on both sides,” he said.

“In Bangladesh, in August, heavy monsoon rains and dam releases caused widespread river flooding. More than 5.8 million people were affected and at least one million tonnes of rice was destroyed. In Spain, more than 500 millimetres of rain fell within eight hours in late October, causing deadly flash floods.”

Flooding in Brazil caused more than 80 deaths, with the region recording more than 300 millimetres of rainfall, he added.

Prof van Dijk also said that while rainfall records were being broken, elsewhere droughts in many regions of the world were affecting farming and helping fuel further climate instability.

In the Amazon Basin, one of the Earth’s most important ecosystems, low river levels cut off transport routes and disrupted hydropower generation. Wildfires destroyed more than 52,000 square kilometres in September alone, releasing vast amounts of greenhouse gases, the report said.

Southern Africa also suffered a severe drought which reduced maize production by more than 50 per cent and left more than 30 million people facing food shortages.

“We need to prepare and adapt to inevitably more severe extreme events. That can mean stronger flood defences, developing more drought-resilient food production and water supplies, and better early warning systems. “Water is our most critical resource, and its extremes – both floods and droughts – are among the greatest threats we face,” Prof van Dijk said.