Heavy rainfall and flooding during Storm Claudia earlier this month were made twice as likely by climate change, scientists have found.
They also said luck prevented even worse damage as the downpours came during a neap tide when high tides were lower than usual.
Storm Claudia struck on November 14th and 15th, primarily affecting counties Dublin, Wexford and Wicklow, which were under an orange rain warning. But it also hit counties Carlow, Kildare, Laois, Louth, Meath and Kilkenny, whose rivers run into Dublin, Wexford and Wicklow.
Scientists from Met Éireann and the Icarus climate research centre at Maynooth University analysed conditions before and during the storm to try to understand why its impacts were so severe. They found that both the storm rain and the 30 days of heavy rain before it had become twice as likely because of the heating planet.
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As global temperatures continue to rise, they warned, the frequency of similar events would increase.
“We would expect similar two-day rainfall events to happen once every one to two years and 30-day rainfall events to happen once every two years,” they said.
September and October were unusually wet in the region, a pattern that continued into November.
“These conditions left soils saturated, river levels elevated, and catchments highly responsive to additional rainfall,” they said.
That additional rainfall came with Storm Claudia.
At Johnstown Castle weather station in Co Wexford, 58 per cent of the average rainfall for the month of November fell in just one 24-hour period on November 14th.
The research team found the amount of rain that fell over the two days was 12 per cent more than would have fallen before the heating of the planet and oceans created more intense conditions.
With further global warming forecast for the coming decades, they expect rainfall to increase again by 3 to 8 per cent.
They also found that the rainfall in the 30 days before Storm Claudia was made 7 per cent greater by climate change.
They expect that to increase by a further 2 to 4.5 per cent.
“The science confirms that when these rainfall events occur, they will bring more rain than in the past because a warmer atmosphere holds more moisture,” said Paul Moore, climatologist at Met Éireann. “This is one of the consequences of living in a warmer world.”
Lionel Swan, a PhD researcher at Icarus, said timing prevented worse flooding because the neap tide allowed water from the swollen rivers to escape to the ocean.
“The worry is that our luck will run out eventually,” he said.
“We will experience an extreme event that coincides with a spring high tide, and the resulting impacts for flooding are likely to be far worse than we’ve experienced before.”
