The chances of seeing Ireland experiencing temperatures in excess of 33 degrees Celsius, Ireland's hottest ever recorded temperature, has gone from being a 1 in 180-year event in 1942 to a 1 in 9-year event in 2020, according to a new study involving a Lancaster University statistician.
The study, which developed a new model to predict the frequency, magnitude and spatial extent of extreme summer temperature events across Ireland, also estimates that a temperature of more than 34 degrees Celsius occurring somewhere in Ireland changed from a 1 in 1,600-year event to a 1 in 28-year event between 1942 and 2020.
The study, which involved Lancaster University's Distinguished Professor Jonathan Tawn, was carried out by a team of researchers led by Professor Andrew Parnell and Dr Dáire Healy of Maynooth University, as well as Professor Peter Thorne, also of Maynooth University.
Distinguished Professor Tawn, of Lancaster University's School of Mathematical Sciences, said: "it was very exciting to be part of this multi-disciplinary research team, which addressed the impact of climate change on the characteristics of widespread extreme events.
"Traditionally the statistics of such extreme events have been studied at single locations. Our use of novel spatial extreme value statistical methods has opened the possibility to study how widespread this behaviour is for the first time. It has enabled us to provide considerable new insights into the impact of climate change for Ireland."
"We found that spatial heatwave events over thresholds that are critical for society have become much larger, having at least doubled in extent for 28 degree Celsius, with this change increasing at more extreme temperatures," Dr Healy said.
The findings were detailed in a recent paper "Inference for Extreme Spatial Temperature Events in a Changing Climate with Application to Ireland" and were read to The Royal Statistical Society at a meeting on 'Statistical Aspects of Climate Change' held online on June 3.
According to Prof Parnell: "We are often focussed on average changes, and particularly focus on the Paris Climate Agreement of 1.5 degrees Celsius. What we have shown here is that the changes in extremes are much larger than the changes in the average, and are something we should be seriously concerned about."
He said the findings underscored the urgency for societal adaptation to increasing extreme temperature events, which have profound implications for public health, agriculture, economic stability, and infrastructure resilience. The research team believe that the model's ability to predict spatial patterns of extreme events offers a powerful tool for policymakers and stakeholders to mitigate risks and plan for future climate scenarios.
The model captures both location and temporal variations in extreme daily maximum temperatures using new mathematical techniques. Analysis by the research team identifies a significant change in the behaviour of extreme temperature events over time, which exceeds the observed changes in mean temperature levels over the same period.
The full study can be found here.
Graphic showing how temperature has changed in Ireland over 80 years.
Credit: Professor Andrew Parnell and Dr Daire Healy of the Hamilton Institute at Maynooth University
