June 26, 2019

expert reaction to European heatwave

Reactions to news that a heatwave will soon hit Europe.

Dr Anastasia Mylona, Head of Research at The Chartered Institution of Building Services Engineers, said: 

“The way we design buildings has to change.  Our building regulations current focus entirely on keeping homes warm in the winter, but there is no requirement to consider how to keep them cool in the summer. 

“In the UK we need to consider a number of issues.  Why do our windows all open outwards which stops us using shutters to keep out the sun?  Why are apartment blocks allowed where windows only face one direction and don’t allow air to move through easily?  Maximum window sizes also need to be considered – apartments with floor-to-ceiling windows facing West are a particular problem);

“Buildings are complex engineering structures and we need to design them both to keep us warm and keep us cool.  This is possible but it needs a comprehensive redesign of our Building Regulations.  This is happening now and the regulations on thermal insulation and ventilation are currently being revised.” 

Prof Dann Mitchell, Associate Professor in Atmosphere Science at the University of Bristol, said:

 “Over the next week temperature records will likely be topped, especially in Central and Northern Europe. The heatwave is being caused by a very persistent large atmospheric wave, which is causing a cut off low to the west of Europe and drawing up hot air from over the Sahara.

“A similar sort of atmospheric pattern was seen in most of the major European heatwaves in the last 20 years, with projected daytime temperatures in France expected to rival, or even exceed, the temperatures of the infamous 2003 heatwave, which saw around 15000 deaths in the region, and around 50,000 deaths across Europe.

“Climate change already had a significant role to play in 2003, with 70% of the French heatwave deaths attributed to human-induced climate change. While the proportion of attributable deaths is likely to be higher for the current heatwave, the death toll may well be lower as different countries, especially France, have significantly improved their emergency heatwave plans. However, this should not be taken as a given, and hospitals in particular should prepare for patients with increased heat stress and associated physiological conditions.”

Dr Friederike Otto, Acting Director of the Environmental Change Institute at the University of Oxford, said:

Q: What does this mean for how Northern Europe needs to change the way it makes it buildings, from a cooling perspective?

A: “All over Europe we need to build much better. We need well insulated buildings that keep cool in summer & warm in winter, without that we will suffer in heat waves but importantly also not reach net zero carbon emissions.”

Q: Are you expecting more wildfires as a result of the heatwave and to what extent can you blame increased fires on a changing climate?

A: “Heat is one component of wildfires and everything else being equal you would expect to see an increase as we do see a strong increase in temperatures. But whether all other components are indeed staying unchanged is questionable and currently a priority for climate research.”

Q: how much more likely in general is climate change making heatwaves?

A: “Almost everywhere in the world the likelihood and intensity of heatwaves has increased, but how much depends strongly on how you define a heat wave, e.g. local maximum temperatures or large-scale continental averages, and also on local factors, how is soil moisture changing, the large scale circulation etc. In Europe we’ve seen from a doubling last year in Dublin to an increase in orders of magnitude in the Mediterranean.”

Q: What is causing this heatwave?  What defines a heatwave?

A: “There are always multiple causes, large scale circulation, soil moisture, land use, but also in Europe climate change is always playing a role nowadays. There is no one definition of a heat wave, if you work outside extreme maximum temperatures are the most relevant indicator, for office workers high night time temperatures might be much more strenuous.”

Professor Hannah Cloke, natural hazards researcher at the University of Reading, said:

“High temperatures are not necessarily dangerous. Heatwaves only become dangerous to people’s health when there is a combination of factors, and particularly when people aren’t used to it, and that’s what we are likely to see in Europe this week.

“Unrelenting daytime heat due to clear skies, combined with hot and humid air being pulled into central Europe from Spain and northern Africa, are a potentially lethal combination. Children, the elderly and people with underlying health conditions are particularly at risk, although everyone will have to modify their behaviour to stay out of trouble.

“There have been several serious heatwaves in Europe in the last few years, including a severe one in 2015 which claimed many lives. This upcoming heatwave is quite similar in nature to 2015 and it is possible that the records set that year will be broken again.

“As heatwaves become more common we will have to get used to forecasting and responding to heat hazards more often. An increase in heatwaves is one of the clearest impacts of climate change. Killer heat events of this kind will become even more widespread by the middle of the century in Europe, but this outlook could get worse unless action is taken to curb future greenhouse gas emissions.”

Professor Len Shaffrey, NCAS Professor of Climate Science at the University of Reading, said:

 “The hot temperatures forecast for central Europe this week could break records for June. The heatwave is due to high pressure, which leads to clear skies over Europe but also drags up hot air from northern Africa. Forecasts suggest the heatwave could last until the weekend.

“Global temperatures are increasing due to climate change. The global rise in temperatures means the probability that an extreme heatwave will occur is also increasing. For example, recent studies have assessed that climate change has at least doubled the probability of extremes such as the 2018 European heatwave.”

Professor Janet Barlow, Professor of Environmental Physics at the University of Reading, said:

“In summer 2003, 600 people died in London alone due to excess heat. An urban heat island is when the centre of a city is much warmer than the rural surroundings. London can be up to 9C warmer than the countryside at times. In the UK a lot of our buildings were built for Victorian climates, and they’re not even withstanding the heatwaves of today let alone the climate change of tomorrow. In terms of how we cope with urban heat islands, we need to think of ways to cool our cities by using green roofs and maybe by using different building materials.”

Video of Professor Barlow explaining this here: https://www.youtube.com/watch?v=0Z4RmHImDFM

Prof Robert Wilby, Professor of Hydroclimatic Modelling at Loughborough University, said:

“If climate models tell us one thing, it is that the threat of deadly heat is set to rise. Major urban areas are literally ‘hot spots’ of risk because of the additional heat trapped in built environments. Those living and working within low income communities of rapidly expanding cities in the tropics are globally the most vulnerable.”

Prof Guillermo Rein, Professor of Fire Science, Imperial College London, said:

“The heatwave is expected to increase the number of wildfires. Heatwaves quickly dry out the vegetation and make it more susceptible to ignition and spread of fire. The longer and the hotter the heatwave, the drier the vegetation gets and the larger the number of wildfires.

“Fire Brigades in the North of Europe will be getting ready for more suppression operations. Quick detection will be vital. There is little time left now for prevention policies (but camp fires and BBQ could be temporarily banned). It is way too late for vegetation management or creation of firebreaks. Let’s hope for the best, no loss of life, little damage and a quick ecosystem recovery after the fires.”

Dr Tom Matthews, Lecturer in Climate Science at Loughborough University, said:

“There is no universally accepted definition of a heatwave, but the temperature/humidity combinations forecast for parts of northwest Europe are cause for real concern. A lot has changed in preparedness since the infamous 2003 heatwave, but nothing should be taken for granted. These conditions are potentially deadly.”

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