Vulnerabilities - Cold stress

As regards the consequences in terms of health, the forecast is mixed: the increase in the number of deaths, which will be particularly high on the hottest summer days, will be compensated for by a decline in the number of deaths resulting from severe cold in winter (4).

Vulnerabilities - Heat stress

Heat waves combined with urban heat islands (11) can result in large death tolls with the elderly, the unwell, the socially isolated, and outdoor workers (12) being especially vulnerable. Heat waves thus pose a future challenge for major cities (13).

The 2003 heat wave

In August 2003, France was hit by a severe heat-wave, with catastrophic health consequences. Unusually high temperatures, as well as socioeconomic vulnerability, along with social attenuation of hazards led to an excess of 14,947 deaths in France, between August 4 and 18, 2003. The greatest increase in mortality was due to causes directly attributable to heat: dehydration, hyperthermia, heat stroke. In addition to age and gender, combinatorial factors included pre-existing disease, medication, urban residence, isolation, poverty, and, probably, air pollution (ozone) (1,9). For the whole of summer 2003, the number of heat related deaths in Western Europe is believed to amount to over 44,000 (6,9).

The French experience confirms research establishing that heat waves are a major mortal risk, number one among so-called natural hazards in postindustrial societies.The experience of 2003 shows that those most likely to die of the heat are the old, the chronically ill, and the isolated. Both northern and southern Europe are at risk (9).

The 2003 health crisis was unforeseen, was only detected belatedly and brought to the fore several deficiencies in the French public health system: a limited number of experts working in the sphere; poor exchange of information between several public organizations which were under strength because of the summer holidays and whose responsibilities were not clearly defined in this particular area; health authorities overwhelmed by the influx of patients; crematoria/cemeteries unable to deal with the influx of bodies; nursing homes underequipped with air-conditioning and in manpower crisis; and a large number of elderly people living alone without a support system and without proper guidelines to protect themselves from the heat (2).

The heat wave called for the sudden mobilisation of several processes and mechanisms, i.e. monitoring, communication with the public, general organisation and response capability of hospitals and nursing homes, care to elderly people at home, etc. The difficulty was for the many services unexpectedly and suddenly to change the status of their readiness and level of activity, from normal to emergency mode. However, this emergency mode is foreign to most organisations, outside the ‘‘911’’ services. Many systemic flaws soon became apparent. In August, most people in charge, especially directors, were on a holiday, which impeded a swift modification in the status of mobilization (3).

One of the lessons of recent crises is that very few people are adequately trained to adapt to the loss of traditional frameworks of reference (3).

How rare was the high-mortality event of 2003

How rare was this extreme event, and what is the human influence on this through anthropogenic climate change? These questions were answered by carrying out two model experiments: (1) simulations of the year 2003 whereby all known climate forcings are included in the model, (2) simulations of 2003 whereby only natural internal and external forcings are included (i.e. no anthropogenic climate change). To determine whether any human influences contributed to the mortality associated with the 2003 heat wave, mortality for both scenarios (with and without anthropogenic climate change) were compared. This was done for two major European cities: Paris, which recorded unprecedented levels of mortality during the 2003 heat wave, and London, which experienced increased mortality but to a lesser extent than that of Paris (26).

Over the 3-month period June–August 2003, the seasonal heat-related mortality rate was around 34 per 100,000 for Paris and 4.5 per 100,000 for London. It was estimated that human influence was responsible for ∼24 heat related deaths in Paris, and ∼1 in London (per 100,000 population). Anthropogenic climate change increased the risk of heat-related mortality in Central Paris by ∼70% and by ∼20% in London. Out of the estimated ∼315 and ∼735 summer deaths attributed to the heat wave event in Greater London and Central Paris, respectively, 64 (±3) deaths were attributable to anthropogenic climate change in London, and 506 (±51) in Paris.

Without anthropogenic climate change the 2003-like mortality would have been a 1-in-300-year event (±200) for Paris and a 1-in-7-year event (±0.5) for London. Due to climate change this return level has increased to a 1-in-70-year event (±30) for Paris and a 1-in-2.5-year event (±0.2) for London.

The 2006 heat wave

Between 10 and 28 July 2006, Europe experienced another major heat wave. In France, it ranked second only to the one in 2003 as the most severe heat wave since 1950 (14,15). The 2006 heat wave was longer in duration than that of 2003, but was less intense and covered less geographical area (14). Based on a historical model, the temperatures were expected to cause around 6,452 excess deaths in France alone, yet only around 2,065 excess deaths were recorded (15).

Urban heat island intensities of French cities

Nighttime summer urban heat island intensities have been calculated in a hindcast simulation over the period 2000-2016. For Dijon and Toulouse, the maximum intensity varied between +2 and + 2.5 °C, and between +1 and + 1.5 °C, respectively. For Paris, a maximum heat island intensity was simulated between +3.5 and + 4 °C (28). For the city of Rennes, an urban heat island (UHI) up to 5 °C was measured in 2011 and from 2017-2022. The UHI intensity increased from winter to summer (27,29).

Vulnerabilities - Vector-borne diseases

Birds and mosquitoes that come from Africa, bearing the West Nile virus, already seem to reach the Mediterranean coast at certain times. Other vector-borne infectious diseases, including leishmania, which is currently limited to the Mediterranean zone, could move north. …  It is therefore necessary to reinforce the epidemiological monitoring of these illnesses, while also monitoring their vectors (birds, mosquitoes, ticks, mites, etc.) and the environmental factors (including changes in climate) that are conducive to their propagation (4).

While climatic factors may favor autochthonous transmission, increased vector density, and accelerated parasite development, other factors (socioeconomic, building codes, land use, treatment, etc) limit the likelihood of climate related re-emergence of malaria in Europe (7).

Sand-fly-borne diseases

Leishmaniasis is a protozoan parasitic infection caused by Leishmania infantum that is transmitted to human beings through the bite of an infected female sandfly. Sandfly distribution in Europe is south of latitude 45⁰N and less than 800 m above sea level, although it has recently expanded as high as 49⁰N. Currently, sandfly vectors have a substantially wider range than that of L infantum, and imported cases of infected dogs are common in central and northern Europe. Once conditions make transmission suitable in northern latitudes, these imported cases could act as plentiful source of infections, permitting the development of new endemic foci. Conversely, if climatic conditions become too hot and dry for vector survival, the disease may disappear in southern latitudes. Thus, complex climatic and environmental changes (such as land use) will continue to shift the dispersal of leishmaniasis in Europe (7).

Vulnerabilities - Floods

Floods are the most common natural disaster in Europe. The adverse human health consequences of flooding are complex and far-reaching: these include drowning, injuries, and an increased incidence of common mental disorders. Anxiety and depression may last for months and possibly even years after the flood event and so the true health burden is rarely appreciated (8).

Effects of floods on communicable diseases appear relatively infrequent in Europe. The vulnerability of a person or group is defined in terms of their capacity to anticipate, cope with, resist and recover from the impact of a natural hazard. Determining vulnerability is a major challenge. Vulnerable groups within communities to the health impacts of flooding are the elderly, disabled, children, women, ethnic minorities, and those on low incomes (8).

Adaptation strategies - France

The health crisis during the summer of 2003 without precedent since the Second World War, has had serious repercussions and has led the French government to take various steps to limit the effects on public health of any future heat-waves (2).

In 2003, a Heat Health Watch Warning System was developed in France to anticipate heat waves that may result in a large excess of mortality. The system was developed on the basis of a retrospective analysis of mortality and meteorological data in fourteen pilot cities (5).

A national action plan was activated on 1st June 2004. The system implies a close cooperation between the French Weather Bureau (Météo France), the National Institute of Health Surveillance (InVS) and the Ministry of Health. The system is supported by a panel of preventive actions, to prevent the sanitary impact of heat waves (5).

It has been suggested that Marseille’s experience of a heat wave in 1983 and the existence there of a risk management plan for hospitals and a public communication strategy may have led to a death excess in that city of only 26%, compared with 53% for Nice (9).

In the national strategy of France the following adaptation measures are recommended (10):

Short term:

• heatwave plan (already implemented);
• implement an interministerial structure responsible for coordinating national competences in relation to studying the health consequences of climate changes;
• monitor health and environmental factors that can be modified by climate change, vectorial populations and reservoir hosts, the quality of continental, coastal and estuary air and water and of soils, natural radiation, resistance and adaptation to pathogenic agents, pneumallergens;
• implementing and generalising response plans to extreme meteorological phenomena including the systematic study of health effects (somatic and psychological) of these phenomena;
• organise responsibility for populations that are fragile and at risk of fragility when faced with extreme climatic phenomena;
• integrate health risks of climatic origin in training for healthcare professionals;
• integrate health risks of climatic origin into the information;
• messages and campaigns destined for the public and media, in particular aimed at adolescents.

Medium term:

• monitor the health impact of changes to biological diversity (flora and fauna);
• observe the change events of infectious agents and their hosts, in particular in relation to natural radiation.

Adaptation strategies - General - Heatwaves

The outcomes from the two European heat waves of 2003 and 2006 have been summarized by the IPCC (16) and are summarized below. They include public health approaches to reducing exposure, assessing heat mortality, communication and education, and adapting the urban infrastructure.

1. Public health approaches to reducing exposure

A common public health approach to reducing exposure is the Heat Warning System (HWS) or Heat Action Response System. The four components of the latter include an alert protocol, community response plan, communication plan, and evaluation plan (17). The HWS is represented by the multiple dimensions of the EuroHeat plan, such as a lead agency to coordinate the alert, an alert system, an information outreach plan, long-term infrastructural planning, and preparedness actions for the health care system (18).

The European Network of Meteorological Services has created Meteoalarm as a way to coordinate warnings and to differentiate them across regions (19). There are a range of approaches used to trigger alerts and a range of response measures implemented once an alert has been triggered. In some cases, departments of emergency management lead the endeavor, while in others public health-related agencies are most responsible (20).

2. Assessing heat mortality

Assessing excess mortality is the most widely used means of assessing the health impact of heat-related extreme events.

3. Communication and education

One particularly difficult aspect of heat preparedness is communicating risk. In many locations populations are unaware of their risk and heat wave warning systems go largely unheeded (21). Some evidence has even shown that top-down educational messages do not result in appropriate resultant actions (22).

More generally, research shows that communication about heat preparedness centered on engaging with communities results in increased awareness compared with top-down messages (23).

4. Adapting the urban infrastructure

Several types of infrastructural measures can be taken to prevent negative outcomes of heat-related extreme events. Models suggest that significant reductions in heat-related illness would result from land use modifications that increase albedo, proportion of vegetative cover, thermal conductivity, and emissivity in urban areas (24). Reducing energy consumption in buildings can improve resilience, since localized systems are less dependent on vulnerable energy infrastructure. In addition, by better insulating residential dwellings, people would suffer less effect from heat hazards. Financial incentives have been tested in some countries as a means to increase energy efficiency by supporting those who are insulating their homes. Urban greening can also reduce temperatures, protecting local populations and reducing energy demands (25).

References

The references below are cited in full in a separate map 'References'. Please click here if you are looking for the full references for France.

1. Poumadere et al. (2005)
2. Michelon et al. (2005)
3. Lagadec (2004)
4. République Française (2001)
5. Pascal et al. (2006)
6. Swedish Government Official Reports (2007)
7. Semenza and Menne (2009)
8. Hajat et al. (2003)
9. Kosatsky (2005)
10. ONERC (2007/2009)
11. Basara et al. (2010); Tan et al. (2010), in: IPCC (2012)
12. Maloney and Forbes (2011), in: IPCC (2012)
13. Endlicher et al. (2008); Bacciniet al. (2011), both in: IPCC (2012)
14. Météo France (2006), in: IPCC (2012)
15. Fouillet et al. (2008), in: IPCC (2012)
16. IPCC (2012)
17. Health Canada (2010), in: IPCC (2012)
18. WHO (2007), in: IPCC (2012)
19. Bartzokas et al. (2010), in: IPCC (2012)
20. McCormick (2010b), in: IPCC (2012)
21. Luber and McGeehin (2008), in: IPCC (2012)
22. Semenza et al. (2008)), in: IPCC (2012)
23. Smoyer-Tomic and Rainham (2001), in: IPCC (2012)
24. Yip et al. (2008); Silva et al. (2010), both in: IPCC (2012)
25. Akbari et al. (2001), in: IPCC (2012)
26. Mitchell et al. (2016
27. Foissard et al. (2019)
28. Michau et al. (2023)
29. Amorim et al. (2024)