Climate change is NOT the main cause of floods – and those today are ‘nowhere near’ the most extreme that have happened in the past, scientists say

Climate change is usually blamed for today’s wild floods – including the extreme deluge in Spain last year. 

But despite the common narrative, recent flooding events cannot solely be attributed to climate change, scientists say. 

Ancient floods going back 8,000 years dwarf modern flooding events which are mistakenly described by some as ‘unprecedented’, they reveal.  

Study author Professor Stephan Harrison at the University of Exeter said recent floods are not exceptional if we look further into the past. 

‘In recent years, floods around the world – including in Pakistan, Spain and Germany – have killed thousands of people and caused enormous damage,’ he said. 

‘Such floods are seen as “unprecedented” – but if you look back over the last few thousand years, that’s not the case. 

‘In fact, floods we call unprecedented may be nowhere near the most extreme that have happened in the past.’ 

Apart from climate change, floods can be caused by melting winter snow, blocked drainage systems, storm surges, dam failures and more. 

The Pakistan floods in 2022 killed over 1,700 people with an estimated financial cost of around $15 billion (£11.6 billion). Pictured, children use a satellite dish to move  across a flooded area after heavy monsoon rainfalls in Jaffarabad district, Balochistan province, August 26, 2022

Homes are surrounded by floodwaters in Sohbat Pur city, a district of Pakistan’s southwestern Baluchistan province, August 29, 2022

Other flooding events occur due to natural processes, rather than human influence, such as ‘convective storms’ – severe thunderstorms, including heavy rainfall, strong winds, hail and tornadoes. 

It’s well known by scientists that global warming raises air temperatures globally, and warmer air can hold more water, so rainfall is increasing on average. 

Although this new study does not contest the link between global warming and flooding, it shows that big flooding events are not new. 

In fact, they were happening well before greenhouse gas emissions soared around the time of the industrial revolution. 

Professor Harrison and colleagues studied ‘paleo-flood records’ for the Lower Rhine region (Germany and Netherlands), the Upper Severn (UK) and rivers around Valencia (Spain). 

Paleo-flood records use a range of evidence including floodplain sediments, dating sand grains and past movement of boulders to identify past extremes. 

In the Rhine, records for about 8,000 years show at least 12 floods that are likely to have exceeded modern peaks, the team found. 

Meanwhile, the Severn analysis shows that floods in the last 72 years of monitoring are not exceptional in the context of paleo-flood records of the last 4,000 years. 

Floods can be generated by multiple types of weather events – such as snow melt, rain-on-snow, intense convective storms (severe thunderstorms, including heavy rainfall, strong winds, hail and tornadoes)

Spanish authorities issued a red weather alert for extreme rain and flooding in Malaga (pictured) in November 2024 

Pakistani flood victims are evacuated to a safer place following flash flood in Daddu district southern Sindh province, Pakistan, September 7, 2022

An aerial view as traffic passes along a road bridge over the flooded A421 dual carriageway on September 24, 2024 in Marston Moretaine, England 

Recent extreme flood events  

• 2024: Germany (Bavaria, Baden-Württemberg) 
• 2024: Spain (Valencia, Albacete, and Málaga) 
• 2024: UK (English Midlands)
• 2023: New Zealand (Aukland) 
• 2023: Italy (Emilia-Romagna)
• 2022: Pakistan (Balochistan, Sindh, Khyber Pakhtunkhwa, Gilgit-Baltistan, Azad Kashmir and southern parts of Punjab)

The largest flood in the Upper Severn occurred in about 250 BC and is estimated to have had a peak discharge – the highest rate of water flow – 50 per cent larger than the damaging floods in the year 2000. 

The fact many previous floods exceeded recent extremes highlights the need to use palaeo records – not just river gauge data that typically exists for the last century or less. 

Policy makers and politicians have said that the flood magnitude of recent events are unprecedented, or that ‘this is the new normal’ or ‘this is the dramatic reality of climate change’. 

But the study finds a better understanding of past records of flood events ‘over extended timescales questions such assertions’, according to the team. 

However, they warn that the combination of natural extremes and global warming could lead to truly ‘extraordinary’ floods. 

‘It does mean that we should be planning for much bigger floods in the future,’ Professor Harrison told MailOnline. 

‘The floods we have seen are nowhere near the size of the floods that could occur.’ 

Due to the threat of flooding, projects such as housing and infrastructure are built to be resilient to extreme floods, based on assumptions such as a ‘one-in-200 year’ or ‘one-in-400 year’ flood event, but these terms don’t have much real-world meaning.  

Professor Harrison and colleagues studied ‘paleo-flood records’ for the Lower Rhine region (Germany and Netherlands), the Upper Severn (UK) and rivers around Valencia (Spain)

Recent ‘unprecedented’ floods are not exceptional if we look further into the past, new research shows. This photo shows flooding around Pulborough, West Sussex, January 7, 2025

‘If we rely on relatively short-term records, we can’t say what a “one-in-200 year” flood is,’ said study author Professor Mark Macklin at the University of Lincoln. 

‘Therefore our resilient infrastructure may not be so resilient after all. This has profound implications for flood planning and climate adaptation policy.’ 

The study, published in the journal Climatic Change, analyses the ‘true frequency and magnitude’ of past floods, when human-caused greenhouse gas emissions were low.

‘[We] demonstrate past floods were occasionally of much higher magnitudes than those of the present-day,’ the authors say. 

‘Flood magnitude was significantly higher before the 20th century, despite there being a negligible greenhouse gas contribution from humans. 

‘This has profound implications for flood planning and climate adaptation policy, as many recent floods cannot be viewed as unprecedented, even in the historical record.’ 

One in FOUR properties in England will be at risk of flooding by 2050 thanks to climate change – with Londoners most affected, report warns 

One in four properties in England will be at risk of flooding by 2050 due to climate change, a report has warned.

The Environment Agency (EA) found that England’s flood risk is much higher than previously estimated, with 6.3 million properties currently under threat.

The new data shows that 4.6 million homes and businesses are currently at risk of surface water flooding by rainfall.

London is the most affected area, with more than 300,000 properties already at high risk of surface flooding. 

Alison Dilworth, Friends of the Earth campaigner, says: ‘This report is yet another stark warning about the growing threat the climate crisis poses to people, homes and communities across the country.’ 

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