Met Office 11th March Record-breaking rainfall like that seen on 3 October 2020 could be 10 times more likely by 2100.
A new study by scientists in the Met Office Hadley Centre has found that days with extreme rainfall accumulations will become more frequent through the century. The research used the record rainfall observed on 3 October 2020 as an example and found that while in a natural environment, with no influence from human induced climate change, an event similar or more extreme would be a 1 in 300 year event, it is now a 1 in 100 year event in the current climate. By 2100 under a medium emissions scenario (SSP2 4.5) that level of extreme daily rainfall could be seen every 30 years, making it 10 times more likely than in a natural environment.
In addition to increased frequency of these extreme events, the research found that 3 October 2020 was provisionally the UK’s wettest day in a daily series stretching back to 1891. The rainfall was very widespread resulting in provisional average rainfall across the entire UK of 31.7mm, or to put it another way, if expressed as the volume of rain that is more than the capacity of Loch Ness – the largest lake in the UK by volume at 7.4 cubic kilometres of water.
The rainfall on 3 October followed on from Storm Alex, which caused disruption across Europe, especially south-east France and north-west Italy.
Head of the Met Office’s National Climate Information Centre, Mark McCarthy, said: “The record daily UK rainfall recorded on 3 October 2020 in the wake of Storm Alex was really quite extreme. The preceding drier conditions through September helped prevent significant widespread impacts but an event like this has the potential to cause damaging effects to infrastructure and services.”
Lead author of the paper Dr Nikos Christidis, Senior Climate Scientist in the Met Office Hadley Centre, said: “Our study shows that in a medium emissions scenario these sorts of rainfall extremes could become much more frequent, reinforcing the need to plan for the consequences of a warming global climate. We are also now starting to see how more frequent extreme rainfall events are already impacting the UK, showing that human induced climate change is already having an impact on the weather we experience in the UK.”