Climate change increased winter storm rainfall by 20% in UK and Ireland
A warmer climate will increase seasonal rainfall by a further 1.6 times, a new report predicts
Human-induced climate change increased the severity of autumn and winter storm rainfall in UK and Ireland by about 20%, according to a report by scientists at World Weather Attribution (WWA), causing floods, transport disruptions and power outages as well as loss of life.
The UK recorded one of the wettest seasons on record between October 2023 and March 2024, while Ireland recorded its third-wettest winter and western Europe recorded a series of damaging storms and elevated flood risk.
The WWA calls for comprehensive flood risk management in the UK and Ireland, which it says should encompass legislative frameworks, strategic planning and “substantial” funding.
The report, which draws on research from scientists in the UK, Ireland, the Netherlands, Sweden and Germany as well as from each of the National Meteorological Services, uses a storm severity index to compare the number of stormy days between seasons.
The report says winter storms are common in western Europe, but the storminess of the 2023/4 season, which included Babet and Ciaran, was caused by the position and strength of the jet stream – stronger than usual – directing low-pressure systems towards the UK and Ireland.
WWA says in today’s climate, with 1.2C warming, storm days with winds at the strengths recorded in the 2023/4 season occur about every four years, while levels of precipitation recorded in the season were more extreme, at a one-in-20-year event.
“The average precipitation on stormy days is observed to have become approximately 35% more intense, compared to a 1.2C cooler pre-industrial climate,” the report says, with human-induced climate change responsible for an increase of 20%. “Or equivalently, the 2023/4 level has become about a factor of ten more likely.”
In a climate 0.8C warmer than today, the report predicts average precipitation on stormy days will multiple by another 1.6 times and become 4% more intense, while seasonal precipitation in the winter season will become 2% more intense.
However, the report says its analysis of the storm severity index indicates a decreasing trend, with a stormy season on the scale of 2023/4 less likely by a factor of 1.4 due to human-induced climate change.
The report presses for “ongoing research into how climate change may influence the severity and frequency of wind storms in northern Europe”.
