The observations collected in this thesis suggest that the risks of future heat waves are connected to the loss of assets and loss of thermal comfort and perhaps, morbidity during the intense and unexpected episodes of heat, but no increase in mortality for the territory of Plaine Commune and even a significant decrease compared to the heat wave of 2003 is expected. We suggest that due to the measures implemented on the national level – introduction of National Heat wave Plan (Plan National Canicule 2014) and early warning system (Laaidi et al., 2012), as well as with higher awareness of risks of heat wave and preventive measures popularized by joined efforts of the Ministry of Health and Social Protection, InVS and Higher Council of Public Health and of course local actors (local Heatwave Plans of Villetaneuse, Épinay-sur-Seine, inscription in the Register of vulnerable population in Saint-Denis, Villetaneuse , Agenda 21 projects for social cohesion and networks building), the future heat waves of the same intensity will not yield the same number of victims as the heat wave of 2003 did. This assumption is in a way confirmed by the statistics of 2006 heat wave, with much lower death toll than during the previous episode of heat wave (1388 victims as opposed to 15 000 – 19 490 victims in 2003 (EM-DAT; Hémon and Jougla, 2003) There’s also scientific evidence that the mortality of 2006 heat wave was lower than predicted by models, it has changed its pattern due to the decrease of vulnerability of the population because of the measures described before.
As for the risks of heat waves in terms of morbidity, they will potentially decrease due to the launch of the program for better supply of the territory of Seine –Saint-Denis with general practitioners and of course due to the better living conditions in newly constructed housing. The better living conditions in new housing, including better thermal quality, more spacious apartments are stipulated in the New Housing Quality Convention (Plaine Commune, 2011). Agenda 21 project “Terre d’avenir” launched by general council of Plaine Commune is also tremendously important for the development of the territory and therefore for adapting to climate change. The project has a manifested social dimension, and aims at common identity construction, decrease of pauperization, development of relations with other territories, better and safer public space, respect to others to fight delinquency, and many more. By creating precondition for social cohesion, the project helps create more and better relations among the inhabitants, which is supposed to translate into mutual help and care, indispensable in everyday life and in case of a disaster, especially for the lonely and isolated, vulnerable groups of the population.
On the other hand, population growth and ageing, possible increased migration to the territory are the factors which are increasing the risk in terms of morbidity and mortality: more inhabitants mean more pressure on public space, transport, and overuse of urban refreshment zones. Moreover, population growth contributes to anthropogenic heat pollution, as well as air and water pollution, which in case of a heat wave adversely affect human health. It also means higher local GHG emissions because of increased air conditioning and personal transport use.
In terms of assets loss, the territory of Plaine Commune is likely to experience higher energy consumption for air conditioning, freezers, etc., as well as impacts on power network and transport. According to Pierre Bornard, director of the department of electrical systems in RTE, “For each degree of temperature above 25˚C, France consumes about 250 to 300 megawatts, which is roughly the consumption of the city of Nantes” (Rapport d’information du Sénat, « La France et les Français face à la canicule : les leçons d’une crise », 2004). In the absence of adaptation measures to improve summer thermal comfort in buildings and in dense urban areas, the increase in average summer temperatures and heat waves should lead to a sharp increase in energy demand in summer for cooling residential and commercial buildings (heating, ventilation, etc.), as well as some transport.
As the experience lived in 2003 suggests, power network of the territory is rather vulnerable: the whole region of Île-de-France is dependent on the extraterritorial energy production (it produces only 10% of the consumed energy), which in case of extreme heat episodes is very sensitive to the cooling water temperature as well as to the increased energy demand. In August 2003, in Paris, the overheated soil resulted in a spate of incidents of the underground distribution network: total of 237,000 customers in the Île-de-France were affected by temporary interruptions. Peak electricity consumption which Plaine Commune experiences during episodes of extreme cold will be more frequent in summer in the future. At the same time, the reduced flow of rivers could have an effect on electricity production: lack of water for cooling thermal and nuclear power plants, as mentioned earlier, may lead to the failure to provide electricity for the territory, which may cause a chain of detrimental effects, from food insecurity to mortality, which will in its turn cause financial and human losses.
Fig.37 Rails deformation near Corbeil in August 2003.Source: SNCF 2012
As for the transport network, both railway and auto transport networks can be damaged during a heat wave, the traffic can be disturbed. High temperatures cause premature aging of materials, deformation of rails, bitumen melting, etc. For air temperature of 30 ˚C, temperature of rails can reach 45˚C. High temperatures lead to the deformation of rails and roads cover. In August 2003 deformation of the rails near Corbeil disturbed the traffic on RER line D for 3 weeks (Fig.36). The increase in frequency and intensity of heat waves in the context of climate change will have consequences on the quality and continuity of transport services and, consequently, cause losses.
Any territory and its socio-environmental system react on the periods of extreme heat differently. According to the performed vulnerability analysis, the discriminative mark of Plaine Commune is its population, most notably, its characteristics: diverse, with high proportion of low-income migrant young population with weak social ties. These characteristics are the framework of many factors of physical vulnerability to heat wave, inherent in the territory; they frame the exposure of the territory to climate change.
There’s a lot of work done in order for Plaine Commune to become, on the one hand, a place where a new common identity for its population is constructed, a community bound by close personal relations, solidarity and social inclusion is created, and, on the other hand, to establish stronger relationship with the capital in order to provide for continuity between Paris and the territories adjacent to it. These measures, which are at first sight not related to climate change, form a basis of adaptation measures. Although today the social projects of Plaine Commune don’t attract as much population as it would be desirable, and sometimes the population seems to be mostly passive consumers of activities proposed by the general council of Plaine Commune, it’s important to remember these kind of projects take time and effort to implement, so the results are going to show themselves in some years.
As underlined before, the social cohesion or inequalities, socio-economic atmosphere in the community in a certain way condition the physical urban environment, that in the case of Plaine Commune increases exposure to heat waves. The major components of the built environment that expose the population to heat are as follows.
First, it’s the method of urban planning, urban form and density, which predispose the cities to urban heat island effect and thus increase the discomfort of the population during a heat wave.
Second, the low thermal quality of residential and commercial buildings also expose the people to uncomfortable and in some cases (old, with no thermal insulation housing, located on the last floors, no sun protection, no access to air conditioned rooms, etc.) even dangerous conditions.
Third, the outdoor conditions are not comfortable for use during the heat waves, parks are either oversaturated with visitors, or difficult to reach; low proportion of shaded streets with trees, small proportion of public transport has air conditioning, oversaturated public transport.
As for the adaptive capacity, Plaine Commune and its member cities are planning or already introduced many actions that may contribute to adaptation to various impacts of climate change.
Although adaptation is rarely explicitly identified as one of the objectives of these actions, the existence of the latter is a solid foundation on which to build the adaptation strategy of Plaine commune. There are four major levers which are at the base of adaptation capacity of Plaine Commune:
- Urban planning and renewal, in order to improve stormwater management, while enhancing the ecological continuity of the territory;
- Improved thermal quality of housing and commercial premises and, thus improved energy efficiency of buildings;
- Improved access to healthcare, especially during heat wave;
- Better awareness of people and businesses on the territory of climate change issues and preventive and adaptation measures.
Future vulnerability will depend on several factors.
First and foremost, the ability to reduce the increasing trend of social inequalities (especially for the low-income, the elderly and socially isolated people) considering that climate change is likely to disproportionately affect the marginalized population, is a significant factor, especially in terms of access to adequate housing and healthcare.
Secondly, the adaptation should benefit from ability to maintain the robustness of the warning and crisis management system in a context of increasing frequency of episodes of heat waves, from the alignment of climate and social policies, cooperation with the private sector. Appropriate financing is indispensable. And of course, the ability to provide adequate public space and housing, the presence of nature in the cities, decrease the regional inequalities of access to refreshment areas, as well as the ability to diversify energy sources (including renewable energy) and produce it on the territory of Plaine Commune.
Life conditions of the population are not constant; they are changing, as well as climate, so one of important factors is to make adaptation measures (especially technical ones) as flexible as possible, in order to be able to easily make the needed modifications without reinstallation or rebuilding.
The results of vulnerability diagnostics lead us to further reflections that however powerful the adaptation measures might be implemented on the territory, due to the uncertain future, depending on the multitude of decisions and actions on the hierarchy of levels from local to global, the measures implemented on the local level will never be enough to fully protect the territory from the impacts of climate change, unless the action is simultaneously taken on other territories. So the effort of Plaine Commune launching the vulnerability study and implementing the adaptation actions should be even more valued, as a reference experience for vulnerability assessment and adaptation measures of other territories.
 Rapport d’information du Sénat, « La France et les Français face à la canicule : les leçons d’une crise », 2004