July 12, 2023

expert reaction to current heatwave conditions in mainland Europe

We’ve had a few questions from journalists about the current European heatwave, so here are some comments from scientists in case useful.

Dr Melissa Lazenby, Lecturer in Climate Change, University of Sussex, said:

“The current European Heatwave is being driven by stable atmospheric conditions from a stationary high pressures feature. This heatwave is likely driven by a combination of climate change, El Niño and a stationary high-pressure system also known as an anticyclone. Europe is not particularly affected by El Niño events directly, see diagram below from the NOAA, therefore it is likely the high-pressure system and climate change that are the main contributors to this heatwave event. It is not possible to determine all the drivers and their exact contributions to the current heatwave in Europe, only a full attribution study after the event will illustrate the exact drivers and their proportion of impact on the event. 

“The UK at the moment is not experiencing the same high temperatures as the rest of Europe and that is mainly due to the placement of the current high-pressure system, which does not cover the UK and is situated further south, which provides stable atmospheric conditions for enhanced warming and resulting heatwaves. If you are in the UK today, you will notice the higher winds which are not associated with a high-pressure feature and therefore not allowing conducive heatwave conditions explaining why UK temperatures are not anomalously warm like the rest of Europe.” 

El Niño Global Teleconnections or Impacts Figure (source: https://www.climate.gov/news-features/featured-images/global-impacts-el-ni%C3%B1o-and-la-ni%C3%B1a) 

Current Surface temperatures over Europe and can see the UK is not as warm as the rest of Europe: (source: https://earth.nullschool.net/#current/wind/surface/level/overlay=temp/orthographic=-341.48,38.77,501/loc=-96.994,77.478

Dr Chloe Brimicombe, Climate Scientist and Extreme Heat Researcher, University of Graz, said:

“We know that high pressure patterns such as that currently over mainland Europe is increasing in likelihood with climate change and that heatwaves are more intense when there has been prolonged dry periods which we have seen this year. Certain weather patterns are also more likely with an El Nino and other teleconnections.

“The Saharan dust presents more of a potential health challenge for southern Europe – increasing dust content and pollution. This heatwave presents a challenge to Europe’s health, productivity, infrastructure and agriculture.

“The reason the UK is not experiencing the heatwave is because the current pressure pattern puts the country in a dominant low pressure – the atmosphere is always trying to reach equilibrium and so we have a constant pattern of high and low pressures.”

Prof Julienne Stroeve, Professor of Polar Observation & Modelling, University College London (UCL), said:

“Last week there was extreme heat over NW Africa that has been since moving northwards over Europe. Looking at the 500 hPa Geopotential heights shows a heat dome that stretches from NW Africa through Southern Europe.

“This appears to be stuck in place at the moment and thus the persistence of the heat wave. You can see that all here in the map for today from Climate Reanalyzer which shows the anomalies in the 500 hPa Geopotential heights. 

“This blocking pattern is what is keeping the warm stuck in place for now.”

Dr Leslie Mabon, Lecturer in Environmental Systems, The Open University, said:

“To an extent, the European heatwave we are seeing in summer 2023 reflects what has been observed over the last few years in the science. Namely, that Europe has been warming much faster than other continents in recent decades, and that this trend is especially pronounced in north-west Europe – including the UK. A common theme across much of the research is that it is difficult to pinpoint one single factor that is responsible for making Europe warm so fast. This is because there are so many complex relationships between the different elements in the system, which are still being researched and understood.

“However, we can be in absolutely no doubt that a critical driver behind this warming trend is carbon dioxide emissions from the burning of fossil fuels. Until we rapidly reduce emissions from fossil fuels, extremes like the heatwave we are seeing in Europe at the moment are going to become more and more likely. The differences that we are seeing in the extent of warming both globally and between regions of Europe are also a stark reminder that the earth’s climate is a complex system. As we get to higher degrees of warming, the danger of feedback loops or unexpected events occurring becomes greater. This is why we need to urgently reduce emissions from fossil fuels and limit the extent of global heating at all costs.”

Rebekah Sherwin, Expert Meteorologist from the Met Office’s global forecasting team, said:

“The heatwave conditions which are affecting parts of southwest Europe and northwest Africa are expected to extend eastward eventually reaching the Middle East later in the week.

“Peak temperatures – which are around 10 to 15°C higher than average – could reach the mid-40s degrees Celsius in parts of southern Europe and up to 50°C in parts of North Africa. Higher than average temperatures are also likely at times further north across Europe, but these will be shorter lived and less impactful.

 “The high temperatures are being driven by an established high pressure system that is sat across the region, allowing temperatures to build day by day. Unusually high sea surface temperatures are also occurring across the region, with many parts of the Mediterranean seeing surface temperatures as high as 25 to 28°C. This will exacerbate the effects of the heat over surrounding land areas, as even in coastal regions overnight temperatures are unlikely to drop much below the mid-20s Celsius. 

“The southern shift of the Jet Stream that has pushed the high pressure southwards across this region has also led to low pressure systems being directed into the UK, bringing more unsettled and cooler weather here than we experienced in June when the Jet stream was at a more northerly latitude.” 

Declared interests

Prof Julienne Stroeve: I have no interest

Dr Chloe Brimicombe: I declare no conflict of interest.

Rebekah Sherwin: Rebekah is an Expert Operational Meteorologist at the Met Office working in the Guidance Unit. The Met Office Guidance Unit is funded through the Public Weather Service including provision of international services to the FCDO.  

Dr Leslie Mabon: no conflicts of interest to declare. He is an Ambassador for Scotland’s National Centre of Resilience – a Scottish Government-funded organisation committed to connecting research, government and practice for an evidence-driven approach to resilience in Scotland – however his comments are made purely in a personal capacity.

For all other experts, no reply to our request for DOIs was received.