Ireland and other parts of Europe are experiencing record-breaking high temperatures because of an “extreme” meteorological event that has caused high pressure to build.
“We’re seeing a very substantial blocking event in the atmosphere,” Peter Thorne, director of the Icarus Climate Research Centre at Maynooth University, said.
“A block is an area of high pressure that gets stuck in place, and this has been stuck in place for several days and it’s enabled heat to build.
“It’s an extreme event, and then you’ve just got climate change on top, which means when this does happen, it happens with more ferocity.”
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Paul Moore, a climatologist with Met Éireann, said the hot weather is being caused by “an intense area” of high pressure over northwest Europe, including Ireland.
High pressure is being “stacked up through the atmosphere”, leading to “sinking air”.
“The pressure is higher, pushing the air down, and that suppresses cloud formation, because cloud forms with rising air,” Moore said.
He said the air is compressing and causing the heat to rise.
“Just think of pumping a tyre on a bicycle – it heats up because you’re causing the pressure to go up, and so the same thing happens in the atmosphere when you get high pressure over the same area, stacked through the atmosphere for a number of days over and over again.
[ Met Éireann issues status yellow high temperature warning for eight countiesOpens in new window ]
“It keeps the pressure, the air keeps sinking down, and the temperature underneath keeps rising.”
A temperature of 28.6 degrees was recorded at Shannon Airport on Monday, provisionally breaking the record for the highest temperature documented in the month of May by Met Éireann.
Moore said there was “a good likelihood” that the May record will be broken again on Tuesday.
Met Éireann has issued a status yellow high temperature warning for eight counties: Clare, Kerry, Limerick, Tipperary, Galway, Kilkenny, Laois and Offaly. The warning will be in place from midday on Tuesday until 6pm on Wednesday.
The national forecaster has warned of water safety issues due to the increased use of lakes and beaches, potential forest fires, heat stress and uncomfortable sleeping conditions.
Warnings have been issued in a number of European countries with record-breaking temperatures also recorded in the UK and France.
Extreme heat has huge issues for morbidity, mortality, huge challenges for our farmers, potentially
— Peter Thorne
Despite the hot weather in recent days, it is not technically a heatwave in the Republic – Met Éireann classes a heatwave as five consecutive days with a maximum temperature in excess of 25 degrees at the same weather station. Low pressure is expected to move in over Ireland on Thursday, meaning it’s unlikely the current hot spell will reach that criteria.
Moore said Ireland was under “Arctic air masses” for much of May, leading to “cooler than average” temperatures, but a “warm air mass” has come up from the south in recent days.
Thorne described moving from one extreme to another as “weather whiplash”, a phenomenon becoming more common due to climate change.
He also warned the current hot spell could result in deaths in Ireland.
“Extreme heat has huge issues for morbidity, mortality, huge challenges for our farmers, potentially,” Thorne said.
“Undoubtedly this extreme heat, particularly in houses that are poorly ventilated and are sun traps, will have an impact upon the most vulnerable in society. So, I would be surprised if, in the next week, we didn’t see a spike in death notices.”
Thorne said people whose houses get very hot should make efforts to increase ventilation this week.
“Under the long-term, maybe we will start looking at artificial cooling of houses. From a Government perspective, it’s about opening up libraries, leisure centres, other things as community ‘cool spaces’, so people can actually go and cool down.”
