Climate change is making the UK wetter with the last few months of the year set to see more torrential downpours, the Met Office has said.
Many parts of the UK are bracing for the second storm in as many weeks with warnings issued for flooding, heavy rain and high winds.
As the atmosphere warms it holds more moisture – around 7% for each degree – and results in heavier downpours when clouds finally burst.
Many regions of the world, including the UK, are expected to become warmer and wetter as long as people continue emitting greenhouse gases and heating the average temperature of the Earth.
For October, November and December around the UK but particularly in the west, there would be more days with rainfall above 50mm – the upper end of what London typically receives in a month.
Met Office provisional figures show October to have been the wettest on record for eastern Scotland, in large part because of Storm Babet.
Other parts of the country had higher than average rainfall and were slightly warmer than the previous 30-year average, with southern England seeing an extra 1.5C to 2C.
Storm Ciaran is expected to add to the rainfall this month, dumping large amounts of water over the coming days.
Dr Friederike Otto, of the Grantham Institute at Imperial College London, said: “There are a lot of attribution studies and other lines of evidence showing that autumn/winter storms like this are more damaging because of climate change.
“That’s because the rainfall associated with these types of storms is more severe due to climate change, and the storm surges are higher and thus more damaging due to the higher sea levels.”
The Met Office said Storm Ciaran was likely to make the autumn rainfall figures “increase substantially” and that some parts of the country had already seen 150% of their average rainfall despite being only two-thirds of the way through the meteorological season.
The link between added rainfall and climate change is better understood among scientists than wind speeds in the UK, although it is widely understood that warmer oceans can create more powerful hurricanes in the North Atlantic.
Dr Melissa Lazenby, of the University of Sussex, said the UK would be likely to see more winter storms as the climate warmed, which would increase the risk of flooding and storm surges.
She said: “The Met Office states that increased winter storms, including disproportionately more severe storms, are projected to cross the UK in the future, with fewer to the north, over Iceland, and fewer to the south, over central and southern Europe.
“Therefore, research indicates that the UK should expect to see storms more frequently than it is seeing today and such additional adaptation and mitigation measures will be necessary to mitigate their impacts such as flooding and storm surges.”