Extreme summer heat threat to Ireland: record temperatures ‘now 20 times more likely’, says research

Scientists are warning of a rapid increase in the likelihood of Ireland experiencing extreme summer heat events.

Research shows the chances of temperatures reaching 33C have increased twentyfold in the lifetime of the country’s octogenarians.

In 1942, hitting 33C – the hottest it has ever been in Ireland - was rated a one in 180-year event but by 2020 it was one in nine years.

The odds of reaching 34C, which has never been recorded here, dropped over the same period from one in 1,600 years to one in 28.

Other high temperature events showed not only an increase in frequency but also in the number of counties affected.

A 28C temperature spike is now likely to affect double the geographic area than it did previously.

The findings, from Maynooth University, show extreme temperatures are getting hotter, happening more often and spreading wider.

Professor Andrew Parnell, one of the study leads, said its aim was to more accurately predict the risk of extreme temperatures so that policymakers and the public could prepare for them.

“We talk a lot about changes in average temperatures since pre-industrial times which is around 1850 and the fact that we’re worried about a 1.5C average rise.

“But we’re also seeing a rise in the extremes of much more than that and that’s only since 1942 so that’s why we’re really concerned about it,” he said.

“A&E admissions rise when extreme temperatures get very high because extreme heat causes all kinds of health problems.

“Extreme heat is also linked to low rainfall and that has all kinds of connotations for the important agricultural component of our economy.

“And there are more general economic effects of what happens when, for example, roads start to melt.”

Prof Parnell likened the increasing risk of extreme heat in Ireland to a loaded dice.

“It's like once every year we roll a dice and if you get a six you get a really hot day and if you get a one you get a really cold day and we’re changing the fives to sixes.

“You’re rolling that dice and there are more sixes on it so we’re changing the chances of that hot day.

“And you might get unlucky and get sixes every year.”

The study is by scientists from Maynooth University’s ICARUS climate research centre and mathematicians from its Hamilton Institute.

Their findings will feed into the work of the Climate+ initiative, a cross-border collaboration between all the universities on the island funded by Science Foundation Ireland.

Already, they are updating the predictions to include data up to 2023 which Prof Parnell believes will hasten the likelihood of hitting 34C to within 20 years.

“The next piece of work on this is to use it like an extreme weather forecaster so we can say to policymakers these are the likely extremes that are going to happen over the next year to five years.

“We don’t know exactly what’s going to happen next but if we can work out the risk we can do something about it.”

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