Grass roofs and siestas: How Paris is preparing for the day temperatures hit 50C
As the French capital suffers regular heatwaves of increasing intensity, local officials are now preparing for the day when temperatures hit 50C - something that could result in power grid failure, transport shutdowns and deaths if nothing is done, a new report predicts.
The record for Paris - 42.6C in the shade - was set in 2019, but as the climate crisis brings rising global temperatures, experts predict that within 30 years Paris will see temperatures top 50C (122F).
Temperatures are rising across Europe, but the French capital suffers from the further problem that it is simply not designed for hot weather and its most distinctive architecture - the wide, open Haussmannian boulevards and the zinc-topped roofs - are the precise things that make the city so unsuited to heat.
The 'heat sink effect' of this type of architecture, combined with a lack of green space and high population density, means that Paris is regularly 10C hotter than the greater Paris area.
And things are only going to get worse.
A wide-ranging report lays out what could happen, and the changes that need to be made to avoid the worst-case scenario. The report was produced by a cross-party group of Paris elected representatives who spent six months working on it, in consultation with engineer Franck Lirzin, author of Paris face au changement climatique (Paris facing climate change).
A la une de @Libe ce week-end :
🥵 𝗣𝗮𝗿𝗶𝘀 𝘀𝗼𝘂𝘀 𝟱𝟬°𝗖
Lire : https://t.co/nj2k4mQWWP pic.twitter.com/ROZXtuRg1T
— Libération (@libe) April 21, 2023
Predictions
Experts say that a 50C day in Paris can no longer be discounted, with some predicting it will happen as soon as 2050.
"It is difficult to say when, but [...] this possibility can no longer be excluded,' climatologist Robert Vautard told French daily Libération.
France's current record is 46C, set in the summer of 2019 in Hérault, south east France, while neighbouring Italy recorded 48.8C in the summer of 2022. Paris hit 42.9C in 2019.
In addition to the very high temperatures, it is also predicted that heatwaves will last for longer - it's predicted that Paris will see an average of 34 heatwave days per year in 2030, compared to 14 in 2008.
The number of 'tropical nights' - where the temperature never falls below 20C - is likely to increase from 5 to 35. These nights are particularly bad for human health, and as they cause severe heat stress by giving the body no opportunity to cool.
Effects
The number 1 danger envisaged by the reports authors are power cuts, since the electricity grid is simply not designed to function in prolonged periods of extremely high temperatures.
Not only would this knock out lights and air conditioning, it's also likely to bring about shutdowns on public transport, while a prolonged power outage could even affect the drinking water supplies. Roads may have to be closed as asphalt melts, and this could also affect airports and see flights cancelled, as happened in London in 2022.
Traditional zinc-roofed Paris apartments could become uninhabitable.
Even without power cuts, its highly likely that summer events would have to be curtailed or cancelled in these temperatures, including the famous Tour de France cycle race.
And there would be deaths. The 2003 heatwave in Paris saw 15,000 deaths - since then the city has got much better at managing heatwaves, but with extreme temperatures it is not beyond the realms of possibility to see such numbers again. In 2022 - the overall hottest year since records began but not a year when temperature records were broken, France recorded 10,000 excess deaths over the summer.
Actions
All of which is to say that the risk is serious.
The report's authors have laid out a series of recommendations to change the city infrastructure to make it more able to withstand extreme heat - essentially trying to make it more like France's southern Mediterranean cities, which for centuries have been designed to keep inhabitants as cool as possible during the summer months.
Green - Paris has a notorious lack of green space and the general rule is that the more asphalt a city has, the hotter it is. The report proposes expanding on something that city hall is doing - trying to 'green up' any and every available space.
Buildings would have greenery on vertical spaces and rooftops, trees planted wherever possible, tram tracks and school playgrounds planted with grass while asphalt car and bike parking spaces would replaced with a grass and paving slab mix.
Shade - umbrellas and awnings would be extended to cover as much public space as possible - as for example happens along the quais of the Seine in summer.
Cool rooms - the 'cool room' scheme, already in place to point people towards their nearest public cool space in summer, would be massively expanded, along with other heatwave measures like drinking fountains and cool mist sprays in public spaces.
Glazed buildings - the report suggests banning any future developments built in the 'greenhouse' style with huge areas of glass, since these buildings cannot be naturally cooled during the summer.
Working day - there are also proposals to adapt the working day to produce a daily rhythm similar to that already in place in hot countries; an early start, a long break in the middle of day when temperatures are are their hottest, restarting work in the late afternoon and working longer in the evening. Evening events would start later when temperatures begin to cool.
Roofs - but perhaps the biggest battle is likely to be waged over rooftops. They distinctive grey zinc rooftops of the traditional Haussmannian buildings are an emblem of Paris, instantly recognisable the world over. Unfortunately, however, they are designed to keep heat in, and even in current summer temperatures are unbearably stuffy.
At temperatures of 50C it is likely that huge swathes of the city's real estate could become uninhabitable. More practical designs for hot weather would be getting rid of the zinc and using more heat-efficient materials, with rooftops painted white as they are in southern Spain, Greece and Portugal. The other option is to green rooftop spaces with plants - something that is already required for many buildings.
The plan, however, is likely to raise the ire of traditionalists.
What about air-con?
One of the first things that many visitors to Paris in the summer notice is that AC is not common in domestic buildings, or in many hotels, shops and offices.
The report's authors describe their 'nightmare scenario' of Paris becoming like certain Gulf cities - where many buildings are entirely un-adapted to the climate and where daily life cannot function without air-conditioning.
Instead, they propose low-tech solutions - "natural ventilation, blackout blinds, bio-based insulation" in order to avoid a dependence on air-conditioning which both renders the city intensely vulnerable to any power outages and also contributes to making the climate crisis worse through intensive energy usage.
"There are no technical surprises," said the group's spokesman Alexandre Florentin. "What is new is the political consensus we have obtained around this catalogue of measures, with a particular insistence that renovation policies should target the most vulnerable groups and low-income neighbourhoods as a priority.
"Heatwaves aggravate social inequalities. The richest people will be able to adapt, carry out work and move to the countryside, while the disadvantaged groups, who are affected by the situation, are more vulnerable."
What next?
The report has been presented to Paris city hall and work is underway to implement some of its recommendations. Although some of the proposed solutions are already in place, the report's authors say that a dramatic acceleration is needed in the months and years to come.
In October Paris will run an emergency planning exercise to prepare for a 50C day.
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See Also
The record for Paris - 42.6C in the shade - was set in 2019, but as the climate crisis brings rising global temperatures, experts predict that within 30 years Paris will see temperatures top 50C (122F).
Temperatures are rising across Europe, but the French capital suffers from the further problem that it is simply not designed for hot weather and its most distinctive architecture - the wide, open Haussmannian boulevards and the zinc-topped roofs - are the precise things that make the city so unsuited to heat.
The 'heat sink effect' of this type of architecture, combined with a lack of green space and high population density, means that Paris is regularly 10C hotter than the greater Paris area.
And things are only going to get worse.
A wide-ranging report lays out what could happen, and the changes that need to be made to avoid the worst-case scenario. The report was produced by a cross-party group of Paris elected representatives who spent six months working on it, in consultation with engineer Franck Lirzin, author of Paris face au changement climatique (Paris facing climate change).
A la une de @Libe ce week-end :
— Libération (@libe) April 21, 2023
🥵 𝗣𝗮𝗿𝗶𝘀 𝘀𝗼𝘂𝘀 𝟱𝟬°𝗖
Lire : https://t.co/nj2k4mQWWP pic.twitter.com/ROZXtuRg1T
Predictions
Experts say that a 50C day in Paris can no longer be discounted, with some predicting it will happen as soon as 2050.
"It is difficult to say when, but [...] this possibility can no longer be excluded,' climatologist Robert Vautard told French daily Libération.
France's current record is 46C, set in the summer of 2019 in Hérault, south east France, while neighbouring Italy recorded 48.8C in the summer of 2022. Paris hit 42.9C in 2019.
In addition to the very high temperatures, it is also predicted that heatwaves will last for longer - it's predicted that Paris will see an average of 34 heatwave days per year in 2030, compared to 14 in 2008.
The number of 'tropical nights' - where the temperature never falls below 20C - is likely to increase from 5 to 35. These nights are particularly bad for human health, and as they cause severe heat stress by giving the body no opportunity to cool.
Effects
The number 1 danger envisaged by the reports authors are power cuts, since the electricity grid is simply not designed to function in prolonged periods of extremely high temperatures.
Not only would this knock out lights and air conditioning, it's also likely to bring about shutdowns on public transport, while a prolonged power outage could even affect the drinking water supplies. Roads may have to be closed as asphalt melts, and this could also affect airports and see flights cancelled, as happened in London in 2022.
Traditional zinc-roofed Paris apartments could become uninhabitable.
Even without power cuts, its highly likely that summer events would have to be curtailed or cancelled in these temperatures, including the famous Tour de France cycle race.
And there would be deaths. The 2003 heatwave in Paris saw 15,000 deaths - since then the city has got much better at managing heatwaves, but with extreme temperatures it is not beyond the realms of possibility to see such numbers again. In 2022 - the overall hottest year since records began but not a year when temperature records were broken, France recorded 10,000 excess deaths over the summer.
Actions
All of which is to say that the risk is serious.
The report's authors have laid out a series of recommendations to change the city infrastructure to make it more able to withstand extreme heat - essentially trying to make it more like France's southern Mediterranean cities, which for centuries have been designed to keep inhabitants as cool as possible during the summer months.
Green - Paris has a notorious lack of green space and the general rule is that the more asphalt a city has, the hotter it is. The report proposes expanding on something that city hall is doing - trying to 'green up' any and every available space.
Buildings would have greenery on vertical spaces and rooftops, trees planted wherever possible, tram tracks and school playgrounds planted with grass while asphalt car and bike parking spaces would replaced with a grass and paving slab mix.
Shade - umbrellas and awnings would be extended to cover as much public space as possible - as for example happens along the quais of the Seine in summer.
Cool rooms - the 'cool room' scheme, already in place to point people towards their nearest public cool space in summer, would be massively expanded, along with other heatwave measures like drinking fountains and cool mist sprays in public spaces.
Glazed buildings - the report suggests banning any future developments built in the 'greenhouse' style with huge areas of glass, since these buildings cannot be naturally cooled during the summer.
Working day - there are also proposals to adapt the working day to produce a daily rhythm similar to that already in place in hot countries; an early start, a long break in the middle of day when temperatures are are their hottest, restarting work in the late afternoon and working longer in the evening. Evening events would start later when temperatures begin to cool.
Roofs - but perhaps the biggest battle is likely to be waged over rooftops. They distinctive grey zinc rooftops of the traditional Haussmannian buildings are an emblem of Paris, instantly recognisable the world over. Unfortunately, however, they are designed to keep heat in, and even in current summer temperatures are unbearably stuffy.
At temperatures of 50C it is likely that huge swathes of the city's real estate could become uninhabitable. More practical designs for hot weather would be getting rid of the zinc and using more heat-efficient materials, with rooftops painted white as they are in southern Spain, Greece and Portugal. The other option is to green rooftop spaces with plants - something that is already required for many buildings.
The plan, however, is likely to raise the ire of traditionalists.
What about air-con?
One of the first things that many visitors to Paris in the summer notice is that AC is not common in domestic buildings, or in many hotels, shops and offices.
The report's authors describe their 'nightmare scenario' of Paris becoming like certain Gulf cities - where many buildings are entirely un-adapted to the climate and where daily life cannot function without air-conditioning.
Instead, they propose low-tech solutions - "natural ventilation, blackout blinds, bio-based insulation" in order to avoid a dependence on air-conditioning which both renders the city intensely vulnerable to any power outages and also contributes to making the climate crisis worse through intensive energy usage.
"There are no technical surprises," said the group's spokesman Alexandre Florentin. "What is new is the political consensus we have obtained around this catalogue of measures, with a particular insistence that renovation policies should target the most vulnerable groups and low-income neighbourhoods as a priority.
"Heatwaves aggravate social inequalities. The richest people will be able to adapt, carry out work and move to the countryside, while the disadvantaged groups, who are affected by the situation, are more vulnerable."
What next?
The report has been presented to Paris city hall and work is underway to implement some of its recommendations. Although some of the proposed solutions are already in place, the report's authors say that a dramatic acceleration is needed in the months and years to come.
In October Paris will run an emergency planning exercise to prepare for a 50C day.
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