A recent study led by the University of Oxford reveals that climate change is driving the warmest days in North-West Europe to heat up at twice the pace of standard summer days. The contrasting trends are particularly noticeable in England, Wales, and Northern France. Alarmingly, current climate models, while accurately projecting the warming rate for ordinary days, fall short in estimating the accelerating rate at which the warmest days are heating, as compared to the actual observations.
Dr. Matthew Patterson, the lead researcher from the Department of Physics at the University of Oxford, stated that the findings suggest an increasing frequency of extreme heat events, like the record-setting UK heatwave from the previous summer.
Dr. Patterson said: “These findings underline the fact that the UK and neighboring countries are already experiencing the effects of climate change and that last year’s heatwave was not a fluke. Policymakers urgently need to adapt their infrastructure and health systems to cope with the impacts of higher temperatures.”
For the study, recently published in Geographical Research Letters, Dr. Patterson analyzed data from the past 60 years (1960-2021) recording the maximum daily temperature, provided by the European Centre for Medium-Range Weather Forecasts.
Although the maximum recorded temperature varied between years, the overall trend clearly showed that the hottest days for North-West Europe had warmed at twice the rate of average summer days. For England and Wales, the average summer day increased by approximately 0.26°C per decade, whilst the hottest day increased by around 0.58°C per decade. However, this faster warming of the hottest days was not observed to this extent elsewhere in the Northern Hemisphere.
The reason causing this faster warming of the hottest days relative to average summer days is not yet understood. According to Dr. Patterson, this may be due to the hottest summer days in North-West Europe often being linked to hot air transported north from over Spain. Because Spain is warming faster than North-West Europe, this means that air carried in from this region is ever more extreme relative to the ambient air in North-West Europe. The hottest days of 2022, for instance, were driven by a plume of hot air carried north from Spain and the Sahara. However, further research is needed to verify this.
Dr. Patterson added: “Understanding the warming rate of the hottest days will be important if we are to improve climate model simulation of extreme events and make accurate predictions about the future intensity of such events. If our models underestimate the rise in extreme temperatures over the coming decades, we will underestimate the impacts this will have.”
Extreme heat has significant negative impacts on many different aspects of society, including energy and transport infrastructure, and agriculture. It also exacerbates conditions including respiratory and cardiovascular diseases, putting a strain on health services.
The current UK Government has been criticized by the Climate Change Committee (CCC) for failing to act quickly enough to adapt to the impacts of global heating. These new findings add even more urgency for policymakers to adapt infrastructure and systems vulnerable to extreme heat.
Reference: “North-West Europe Hottest Days Are Warming Twice as Fast as Mean Summer Days” by Matthew Patterson, 17 May 2023, Geophysical Research Letters.