To what extent should a medico-humanitarian organization become concerned with the field of environmental health? Written in 2025, Fabrice Weissman has conducted a brief literature review on the links between health and the environment to help MSF address this question. Identifying around a dozen paradigms, he encourages the organization to pay particular attention to extreme climatic events, health crises linked to various forms of contamination, and the implications of “environmental justice.”

Like many humanitarian organizations, MSF France wishes to address "environmental health issues" in its operations and public communications. This is a relatively new approach.  

In 2011, Crash piloted a study entitled Taking environmental issues into account at MSF France.TERTRAIS (Julien). - "La prise en compte de l'environnement dans l'action humanitaire médicale", CRASH, May 12, 2011.It showed that, beyond waste management, environmental issues were not considered a priority by the heads of the medical, operations, and logistics departments. The author of the study concluded that environmental issues were "a personal concern expressed by some, which does not directly call into question MSF-F's practices in the field". Believing that environmental protection and humanitarian action do not operate within the same timeframes or fields of expertise, the people interviewed feared "that ongoing programs would become so cumbersome and slow that they would become be unfeasible if environmental considerations were to be integrated into operations."  

Eight years later, OCP's 2019-2024 strategic plan affirmed the association's "duty" to "reduce [its] carbon emissions and [its] environmental impact". As for the operations department, it announced its intention to "pay particular attention to the environmental factors of health crises" and to respond to the "specific needs" of populations affected by climate change and other environmental crises ("contaminant poisoning, water shortages, etc."). Since then, the entire MSF movement has committed to reducing its greenhouse gas emissions by 50% (compared to 2019) by 2030. Several MSF sections have also created positions such as "climate adaptation support officer" (MSF East Africa), "environmental health manager" (MSF Belgium) or "planetary health coordinator" (MSF Swiss). 

How can we explain this shift? The increasing number of climatic disasters in the past 15 years (heatwaves, droughts, uncontrolled fires, storms, floods) has certainly played a role. Although they are not always linked to global warming,https://www.worldweatherattribution.org/ . these disasters are seen as tangible manifestations of climate change - which has gone from being a mathematical model foretelling a bleak future for the next generations, is now perceived as an ongoing catastrophe.According to a linguistic comparison of a corpus of articles published in the French media between 2013 and 2023, the tone of journalistic discourse on the climate has shifted from worrying doubt ("should we worry about global warming?") to alarming certainty ("collapse, crisis, climate emergency"). The same shift characterizes the discourse of many governments and intergovernmental organizations. The OECD, for example, which until the early 2010s was concerned about the long-term consequences that global warming "could" have on the "well-being and economic activities", now considers that the "planet is experiencing catastrophic [and] unprecedented impacts of climate change", "increasingly frequent and extreme".  For many of our colleagues, global warming is already the cause of health crises of an unprecedented nature or scale, justifying an "adaptation" of our operational responses.  

More generally, MSF members are not immune to the "eco-anxiety" that is spreading in their home countries through their home societies. In addition to climate change, the pollution of air, water and soil, the erosion of biodiversity, the modification of water, nitrogen and phosphate cycles, the depletion of resources and other attacks on the "planetary limits" of the Holocene,ROCKSTROM (Johan) et al - "A safe operating space for humanity". - in Nature, Vol. 461, 24 September 2009. In this article, the authors consider the end of the Holocene, a relatively stable period from a biochemical point of view, which created conditions favorable to the development of the human species. This period is threatened by anthropogenic environmental transformations. They define thresholds for 9 biochemical and physical systems and sub-systems, the crossing of which could lead to "unacceptable environmental changes": 1. Climate change; 2. Rate of erosion of terrestrial and marine biodiversity; 3. Alteration of phosphate and nitrogen cycles; 4. Thinning of the ozone layer; 5. Ocean acidification; 6. Increase in freshwater consumption; 7. Change in land use; 8. Atmospheric particle saturation; 9. Chemical pollution.   are perceived as existential threats to humanity. Many colleagues believe that a humanitarian organization cannot ignore the disappearance of ecosystems that have enabled humankind to flourish since the end of the last Ice Age. As a result, they argue that MSF should not only reduce its contribution to environmental degradation but also invest in the field of "environmental health". This is all the more important, as some of the association's managers point out, because the association risks alienating part of its social support base and isolating itself within the aid and global health community by keeping its distance from such a highly contentious social issue.Cf. JOCHUM (Bruno) et. al. - "La question des choix à l'heure de l'urgence climatique". - in Alternatives Humanitaires, n°11, Changement climatique : comprendre, anticiper, s'adapter, 2019.   

My intention is not to discuss these reasons for acting, but to ask how MSF might approach environmental health issues in practice. What could it mean in practice to respond to the specific needs of victims of the climate and environmental crisis - and to pay particular attention to the environmental drivers of health disasters?  

Initial discussions at our Paris headquarters and with our colleagues at MSF Switzerlandm are overwhelming.This is a summary of the opinions expressed by the MSF France "Environmental Health" working group set up by Operations management, and by our colleagues in other MSF sections, during informal exchanges or discussions on the Souk.  While all agree on the necessity to invest in the field of “environmental health”, opinions differ as to its scope. Some limit environmental factors to the climate, its transformations, or its most extreme manifestations (floods, heat waves, droughts). Others include soil, water, air pollution, and exposure to toxic substances in the workplace and/or in daily life. Some insist on the transformations in microbial fauna and its vectors (antibiotic resistance, emergence and spread of new pathogens of animal origin) in connection with climate change, deforestation, industrial livestock farming, international transport, etc. Still others argue that urbanization, changes in lifestyle (diet, mobility, work) and, a fortiori, conflicts cannot be excluded from the environmental factors affecting health. Some point out that environmental protection policies (such as the creation of biodiversity reserves) can also have detrimental effects on the well-being and health of people displaced from protected zonesSee for instance, advocacy campaigns supported by Survival International.   - much like agro-industrial development programs that result in the disappearance of subsistence farming. 

In short, the scope of environmental health issues seems infinite. In fact, if we define health as a "state of complete physical, mental and social well-being"Preamble of the Constitution of the World Health Organization (WHO), 1946. and the environment as anything external to the human body... then environmental health concerns everything in the world that contributes to thumanity’s happiness or misery. 

We could stop here and conclude that the call to integrate environmental health issues into humanitarian relief operations is merely a symptom of our eco-anxiety, one that is unlikely to lead to any meaningful and consistent changes in operational policy. That may well be the case, but before we get there, let's try to unfold and map environmental health problems more precisely. To help us do this, I set out to find out how the relationship between health and the environment has been (re)problematized in the field of medicine and public health in recent years.  

I haven't found any comprehensive work that answers this question. I have therefore carried out a brief review of the literature in public health and the social science, of which I offer an extremely reductive and by no means exhaustive summary. I have identified no less than ten paradigms or ways of problematizing the relationship between health and the environment, each highlighting a particular aspect of the environment and its impact on health. They can be grouped into two main categories.

1. Paradigms calling for the protection of human health by acting on the environment, highlighting: 

• The role of geography (Hippocratic paradigm) 

• The role of living conditions (social paradigm) 

• The role of microscopic flora and fauna (Pasteurian paradigm) 

• The role of poisons and pollutants (toxicological paradigm) 

• The role of social inequalities (environmental justice paradigm) 

• The role of multiple exposures (exposome paradigm) 

• The role of environmental hypersensitivity (idiopathic paradigm) 

2. Paradigms calling for the protection of the environment in the name of human health, highlighting: 

• The role of climate change (climate paradigm) 

• The role of animal health and ecosystems (One Health, Eco-Health: socio-ecological paradigm) 

• The role of the earth system (Planetary Health) (planetary paradigm) 

Part I: Protecting health by acting on the environment 

1. The role of geography (Hippocratic paradigm) 

All the authors I have consulted consider Hippocrates and his treatise On Airs, Waters and Places to be the father of environmental health. For Hippocrates, diseases have a dual origin: individual behavior and the environment: air, water, wind, sunshine, food, etc. For example, he emphasized the association between swampy areas and fever, and recommended several measures to protect populations in cities from diseases.  But for the most part, Hippocratic medicine focuses on dietary and behavioral recommendations (breathing healthy air, eating healthy food, etc.).This approach was nevertheless used by urban planners in ancient Rome, then rediscovered in Western Europe in the 18th century, where it justified the first public health measures (draining marshes, ventilation of homes, etc.) and informed numerous studies of "medical topography", seeking to highlight the role of environmental factors in the origin of diseases: geographical location, nature of soils, temperatures, hygrometry, prevailing winds, but also living conditions (diet, housing, lifestyle) and work conditions. See BOURDELAIS (Patrice). – « Histoire de la santé publique ». – in FASSIN, HAURAY (dir.). – Santé publique : l’état de savoirs. - Paris, La Découverte, 2010, pp. 13-22.This paradigm is still used today to describe the exceptional longevity of certain populations living in "healthy" regions and lifestyles (the Ikaria population in the Dodecanese, or the "Cretan diet", for example).Cf. for example POULAIN (Michel), HERM (Anne) and PES (Gianni). - "The Blue Zones: areas of exceptional longevity around the world". – in Vienna Yearbook of Population Research, Vol. 11, Special issue on Determinants of unusual and differential longevity (2013), pp. 87-108 (22 pages). 

2. The role of living conditions (social paradigm) 

According to medical historians,GAUDILLIERE (Jean-Paul). – Médecine et science. XIXe - XXe siècles. – Paris : La Découverte, "Repères", 2008.  the environment was a central concern of modern medicine, which by the mid-19th century was organized around three poles: clinical, experimental and social. In towns and cities, where the population was growing exponentially with the industrial revolution, doctors documented the harmful impact of living and working conditions on mortality and epidemics. Following the example of Rudolph Virchow in Germany, who believed "that politics is nothing other than medicine on a grand scale", they became involved in promoting public policies to regulate child labor, and to improve housing, sanitation, waste collection and hygiene education.As Foucault describes it, "Urban medicine is not really a medicine of man, of the body and the organism, but a medicine of things: of air, of water, of decomposition, of fermentations; it is a medicine of the living conditions of the environment of existence" (quoted p. 66 in in SENN (Nicolas), GAILLE (Marie), DEL RIO CARRAL (Maria) et al.. - Santé et environnement. Vers une nouvelle approche globale. - Médecine & Hygiène, « Hors collection », 2022, https://www.cairn.info/sante-et-environnement--9782880495008.htm).  These policies were promoted on the basis of observations, sometimes statistical, but without any understanding of the causal mechanisms linking the (urban) environment to disease. The improved living conditions, hygiene and diet promoted by social medicine are thought to be primarily responsible for the fall in the incidence of infectious diseases between 1850 and 1970 in Europe – an incidence which, in the case of tuberculosis, collapsed before the discovery of antibiotics and vaccination policies.CICOLLELA (André). - "Santé et Environnement: la 2e révolution de Santé Publique". – in Santé Publique 2010/3 (Vol. 22), pages 343 to 351 Éditions S.F.S.P. ”The trend for measles is even more spectacular, as cases plummeted suddenly from the First World War onwards, even though vaccination only became widespread in the 1970s’” recalls historian Patrice Bourdelais.BOURDELAIS, ibid

The social framing of the relationship between health and the environment is thus associated with a form of politicization that highlights issues of urban planning, sanitation, architecture and health education, as well as the reduction of socio-economic inequalities, access to food and the protection of the vulnerable (children, factory workers, inner-city residents, etc.). This health/environment paradigm is based on what Fassin calls a "sanitisation of the social", i.e. the "reframing of a social problem in health terms" based on a "double operation of medicalization and politicization of social facts", in which statistics and epidemiology play a key role - and medicine a secondary one.FASSIN (Didier). - Faire de la santé publique. – Rennes : Presses de l'EHESP, "Hors collection", 2008.  

 

This paradigm is at the heart of the primary health care strategy promoted by the World Health Organization (WHO) in the 1970s-1980s, which emphasizes education, access to water, food, etc. and “demedicalization”. As Rony Brauman and Jean-Hervé Bradol explain, at the beginning of the 1980s, "providing medical care was very poorly regarded" among organizations involved in the field of international public health.BRADOL (Jean-Hervé), BRAUMAN (Rony). - « Soigner la santé, une histoire de MSF comme acteur de la santé publique mondiale ». - Podcast La Zone Critique – C’est quoi le problème ?, 2 avril 2025, https://msf-crash.org/fr/podcasts/soigner-la-sante-une-histoire-de-msf-comme-acteur-de-la-sante-publique-mondiale. In the political context of the time, MSF's commitment to providing medical care, rather than health care, seemed like heresy. Nonetheless, MSF rapidly get involved in environmental health as it took on public health responsibilities in refugee camps in the 1980s and 1990s, which led to its involvement in water supply, latrine construction, waste management and vector control.It should be noted that the provision of medical care in refugee camps was not questioned by major international public health agencies such as the WHO.She also runs a number of water and sanitation programs in informal settlements, notably in Guatemala. This awareness of the socio-economic context of health has also contributed to the (nascent) development of social support initiatives in certain MSF projects.Cf. BURNS (Jacob). - Too much Never Enough : Social Support at MSF. – Paris : Crash, 24 june 2024, https://msf-crash.org/en/humanitarian-actors-and-practices/too-much-never-enough-social-support-msf. But for the most part, the environmental paradigm to which MSF refers to is Pasteurian, not social.   

3. The role of microscopic flora and fauna (Pasteurian paradigm) 

At the end of the 19ème century, Pasteur and Koch highlighted the role of micro-organisms in the etiology of infectious diseases. By establishing a univocal causal relationship between a micro-organism and a pathology, the Pasteurian paradigm led to a "narrowing of the concept of infection, its causes and its prevention."Hill-Cawthorne (Grant A.). - « One Health/EcoHealth/Planetary Health and their evolution”; - in WALTON Merrilyn (dir.). – One Planet, One Health – Sidney University Press, 2019.  The role of the environment was reduced to that of germs, viruses, parasites, their hosts and vectors. In the second half of the 20th century, advances in biomedicine effectively sidelined the socio-economic determinants of health in favor of the fight against specific pathogens. Therapeutic innovation (vaccines, antibiotics) and, in France, health insurance, which democratized access to care, overshadowed social medicine and its concern regarding the reduction of inequalities in access to education, employment, housing, food, etc. CICOLELLA, 2010, art. cit.

The Pasteurian framing of health/environment relations justifies policies focused on access to healthcare, vaccination, vector control targeting specific pathogens, behavioral changes (individual lifestyle habits, smoking, alcoholism, etc.) and the identification of genetic predispositions. For Fassin, this paradigm is characteristic of French public health.FASSIN, op. cit.  "In France, social inequalities in the face of illness or death have had difficulty in being identified as a priority commitment of health policies, both in terms of statistical production and public action. When they have been, it's mainly from the point of view of social protection and access to care, whereas it's well established that it's social determinants such as disparities in education, employment and housing that have a decisive influence on health inequalities". For Chabrol and Gaudillière, this is also characteristic of global health since the turn of the 2000s, in particular its preference for vertical health programs based on the alignment between a pathology, a technology and a mass treatment procedure (such as the malaria eradication programs of the 1950s-60s, the Expanded Programme on Immunization (EPI), or the programs to combat AIDS).CHABROL (Fanny), GAUDILLIERE (Jean-Paul). - Introduction à la santé globale. – Paris : La Découverte, « Repères », 2023.  This framework for analyzing the relationship between health and the environment is the one that predominates at MSF.  

4. The role of poisons and pollutants (the toxicological paradigm) 

The Industrial Revolution and the first half of the 20thème century also saw an increase in knowledge about the "poisons" to which certain craftsmen and workers were exposed. The existence of occupational diseases had already been highlighted by Hippocrates, who described the colic suffered by workers handling lead, and later by the father of toxicology, Paracelsus, who during the Renaissance documented the "mountain sickness" afflicting miners working in the extraction of ores and metals (now known to be caused by exposure to radon). He is the author of the maxim of toxicology: "only the dose makes the poison."The exact quote is "Everything is poison, and nothing is without poison; the dose alone makes a thing not a poison."  

On the eve of the Industrial Revolution, Ramazzini and later Pott laid the foundations of occupational medicine. They investigqated the high incidence of scrotal cancer among young chimney sweeps, which Pott finally attributed in 1775 to exposure to chimney soot. Although identified by physicians as early as the end of the 19th century, silicosis was not recognized as an occupational disease in France until after the Second World War. This was because of reasons that stemmed both from social and political resistance on the part of the authorities and industrial circles, and from the epistemological problems raised by establishing a causal link between miners' working conditions and pulmonary fibrosis: difficulties in diagnosing the disease, identifying the pathogenic agent, characterizing exposure and demonstrating a causal relationship.DEVINCK (Jean-Claude), ROSENTAL (Paul-André). - « ‘Une maladie sociale avec des aspects médicaux’ : la difficile reconnaissance de la silicose comme maladie professionnelle dans la France du premier XXe siècle ». - in Revue d’histoire moderne & contemporaine, 2009/1 (n° 56-1), p. 99-126. The biological mechanism behind silicosis (the phenomenon of pulmonary overload linked to the accumulation of carbon and silica particles in the lungs) was not understood until the 1980s."A very important concept emerged in the 1980s, that of pulmonary overload, i.e. the fact that low-toxicity dusts inhaled over long periods and in varying quantities could, depending on the individual, be the cause of chronic lung pathologies through accumulation and persistence of these dusts in the tissues. Molecular mechanisms then affect the lung when elimination processes (clearance) are overwhelmed or insufficiently efficient. Particle accumulation does not immediately lead to pathology, so the question of their bio-persistence is central. They are at the origin of a biological response that can become chronic, the inflammatory response". MARANO (Francely). - « Des risques avérés aux risques suspectés : particules atmosphériques et Nanoparticules manufacturées » - in Responsabilité & Environnement, Octobre 2021, n°104, Annales des mines.

The same political and epistemological difficulties characterize the controversies over the carcinogenic effects of tobacco and the regulation of its use. These difficulties have led to a rethinking of the notion of causality, notably driven by Hill.HILL, A. B. - “The environment and disease: association or causation?.” – in Proceedings of the Royal Society of Medicine vol. 58,5 (1965): 295-300. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1898525/.  Faced with the impossibility of demonstrating a Pasteurian-type causal link between tobacco and cancer, he proposed relying on the observation of events "which suggest an association between an environment and an effect on human health, which is more or less strong, continuous, specific, plausible, consistent, analogous to others better known, etc.".GAILLE (Marie). - Vers une médecine fondée sur l'idée de santé planétaire", Annales des mines, 2021/3 (N°104), p. 10-13.This type of demonstration lends itself particularly well to the strategies of agnotology (production of ignorance) used by industrial lobbies to contest the health impact of pollutants and thus delay the adoption of preventive measures contrary to their interests.  

Demonstrating the harmful effects of air pollution in the general population (put on the political agenda in the 1950s following the London smog phenomenon that claimed 12,000 lives in December 1952Attributed to the "black fumes" enveloping the city: "These were made up of particles mainly from the combustion of coal for heating and vehicle exhausts, an aggregation of fine (< 1 μm) and ultrafine (≤ 0.1 μm) particles. Combined with the polluting gases sulfur dioxide and nitrogen dioxide emitted by transport and factories, they formed a deleterious mix for the most fragile populations: children, the elderly or those suffering from respiratory and cardiovascular diseases." (MARANO 2021, art. cit.).) was even more difficult to establish, due to the heterogeneity of exposed populations, challenges in characterizing types and levels of exposure, and low levels of individual risk (but which affect an entire population with very significant overall health impacts). The first epidemiological evidence was provided in the 1990s and confirmed by subsequent surveys. The Santé Publique France survey published in 2021 estimates that PM2.5 fine particles are responsible for 40,000 deaths a year in France, mainly due to background pollution rather than pollution peaks. Combined with animal experiments that help us to understand the biological mechanisms of action of particles in the atmosphere, these investigations justified the adoption of prevention policies in Europe based on air quality measurement, the regulation of industrial smoke emissions (factory and vehicle emissions), and motor vehicle traffic restrictions (low-emission zones). These policies do not exist everywhere in the world. As a result, the specialists state: 

"Air pollution is currently the biggest environmental cause of illness and premature death in the world. Diseases caused by pollution were responsible for around 9 million premature deaths in 2015 (16% of all deaths worldwide) - three times more deaths than those caused by AIDS, tuberculosis and malaria combined (Landrigan et al., 2018). Air pollution increases the incidence of a wide range of diseases, including respiratory and heart disease, stroke and lung cancer (Brunekreef et al., 2002; Beelen et al., 2014; Raaschou-Nielsen et al., 2013; Cohen et al., 2017)." BOCZKOWSKI (Jorge). - « Pollution atmosphérique et infections virales ». - in Responsabilité & Environnement, Octobre 2021, n°104, Annales des mines. 

This health/environment paradigm, centred on the role of "poisons", shares the Pasteurian paradigm’s mono-causal approach: each pathology corresponds to a specific pathogenic agent, causing effects that occur with varying frequency and over varying timeframes. It differs from the Pasteurian paradigm in its approach to causality (a cause that is not always necessary or sufficient) and the significant role played by epidemiological evidence.  

This paradigm applies to many other pollutants besides atmospheric particles (water pollution, food contamination, radiation, etc.), whether emitted continuously or as a result of industrial disasters. It leads to prevention policies based on health risk assessment.DAB (William). - Santé et environnement. – Paris : Presses Universitaires de France, « Que sais-je ? », 2020.This involves estimating the toxic potential of physico-chemical substances and regulating their use through a process based on a rationale combining hazard analysis, characterization of dose-effect relationships, measurement of exposure levels, risk assessment, and so on. This regulatory work (involving doctors, biologists, chemists, epidemiologists, engineers, lawyers, economists, etc.) is at the root of numerous scientific and political controversies concerning the way in which laboratory results and epidemiological surveys are analyzed, how actual exposure is taken into account, how toxicity thresholds set, and how the "precautionary principle" is applied. Today, these controversies are particularly heated, for example concerning the carcinogenic effects of pesticides,HUC (Laurence), JOUZEL (Jean-Noël). - "Pesticide risk assessment: between regulatory knowledge and academic science". - Responsabilité & Environnement. - October 2021, n°104, Annales des mines. the risks associated with the use of new materials such as nanoparticles,MARANO 2021, art. cit.  acceptable radiation exposure limits for residents of areas contaminated by radioactive particles following the nuclear accident (Fukushima)HASEGAWA (Reiko). – “Returning home after Fukushima”. - Médialab Sciences Po, 1 septembre 2015, https://medialab.sciencespo.fr/en/productions/2015-09-returning-home-after-fukushima-dispalcement-from-a-nuclear-disaster-and-international-guidelines-for/. and the toxicity of green algae and the role of agricultural effluents in their proliferation in Brittany.BOURBLANC (Magalie). - « Définir des indicateurs en milieu controversé : retour sur l’expertise scientifique. ‘Algues vertes’ en France ». – in VertigO - la revue électronique en sciences de l'environnement [En ligne], Volume 16 Numéro 2 | septembre 2016, mis en ligne le 30 septembre 2016, consulté le 25 août 2024. URL : http://journals.openedition.org/vertigo/17601 ; DOI : https://doi.org/10.4000/vertigo.17601; LÉRAUD (Inès) et VAN HOVE (Pierre). - Algues vertes, l'histoire interdite. – Paris : coédition la Revue dessinée/ Delcourt, 159 pages, 2019.   These controversies sometimes take the form of legal and political battles, dron medical and epidemiological expertise in the service of "environmental justice".   

5. The role of environmental inequalities (the environmental justice paradigm) 

The framing of health/environment relations in terms of "environmental justice" combines the two previous paradigms (social and toxicological). It stems from the observation that marginalized populations are more exposed than others to environmental pollution and degradation: the siting of toxic dumps near their residential areas, housing built on polluted soil, exposure to floods and earthquakes, etc.LARRERE (Catherine). - « Une seule santé : la question des inégalités environnementales ». – in Environnement, risque et santé, 2002/3 (vol. 21), p. 205-211. These inequalities have been documented in the USA by sociologists studying social mobilizations, particularly legal ones, demanding recognition, reparation and prevention of environmental harm suffered by racialized minorities. “Environmental justice" mobilizations are organized around the denunciation of three types of inequality: 

• Inequality in exposure to sudden risks (such as Hurricane Katrina in 2005, or the 1984 explosion of the Union Carbide pesticide factory in Bhopal) or long-term risks (soil pollution by chlordecone in the French West Indies for instance). 

• Unequal access to natural resources (water, energy, etc.) 

• Unequal access to decision-making on environmental policies and unequal exposure to their effects. 

According to some sociologists, “there is no doubt, indeed, that whichever way one looks at environmental inequalities, health impacts are among the most important:”idem.As a matter of fact, epidemiological quantification of damage and health inequalities plays a central role in environmental justice mobilizations.  

The problematization of health/environment relations in terms of "environmental justice" (or even "environmental racism" for some authors) leads to policies of recognition, to reparations (medical, financial)  and prevention, in which medicine and epidemiology are drawn upon as evidence.  

MSF's involvement in the "construction" of the lead poisoning epidemic in France falls within this category.FASSIN, op. cit.  This involved diagnosing and counting the cases of lead poisoning, redefining the scope of the disease (from acute intoxication to cognitive impairment) and promoting curative and preventive measures (policy of renovation of substandard housing). The Silicosis multidisciplinary research program, which brought together doctors, chemists, sociologists and historians to study the role of silica dust in a number of occupational pathologies, can also be seen as part of this "environmental justice" approach.Based on the observation that health risks linked to exposure to silica dust have historically been neglected for social, political and scientific reasons, the Silicosis collective combines epidemiological, biochemical and sociological investigative methods to assess the potential role of silica particles and other inorganic particles in systemic inflammatory diseases (sarcoidosis, systemic lupus erythematosus, progressive systemic scleroderma, rheumatoid arthritis, etc.) and other pathologies (chronic obstructive pulmonary disease, renal failure, etc.) and other pathologies (chronic obstructive pulmonary disease, renal failure, etc.). No conclusive results have been published to date. https://www.sciencespo.fr/silicosis/fr.html cf. also cf. aussi FROUARD (Hélène). - « Soigner grâce à l’histoire ». – in CNRS, Le Journal, 4 janvier 2016,é : https://lejournal.cnrs.fr/articles/soigner-grace-a-lhistoire. 

6. The role of multiple exposures (the exposome paradigm) 

The epidemiological transition in wealthy countries is linked to a new conceptualization of the relationship between health and the environment: the exposome. This is based on the observation that the rise in the incidence of non-communicable diseases, such as cancer, cannot be solely explained by an ageing population, changes in behavior or improvements in screening.CICOLELLA (André). - Toxique planète. Le scandale invisible des maladies chroniques. – Paris : Le Seuil, « Anthropocène », 2013. Cohort studies of twins living in different countries, or of migrants who have recently settled in wealthy countries, show that there is a strong environmental component, but that this is not mono-causal as in Pasteurian and toxicological paradigms.  

Indeed, conventional attribution studies fail to identify a single cause, as in the case of cancers, where the doubling of incidence between 1980 and 2000 cannot be linked (with a few exceptions such as cervical or lung cancer) to a precise environmental risk factor. It is the "environment as a whole”CICOLELLA, 2010, art. cit. that is at issue, and in particular exposure, from the intra-uterine stage through to death, to multiple physico-chemical substances. These exposures are characterized by stochastic effects (i.e., unpredictable at the individual level), by their ability to potentiate - or, conversely, neutralize - one another ("cocktail effects"), by the possibility of non-monotonic dose-response relationships (where toxicity may occur at low doses, diminish as doses increase, and intensify again at higher doses - as observed with endocrine disruptors), and by effects that vary according to the life stage at which exposure occurs and its duration 

The exposome concept derives from these observations.On epistemological issues, see SLAMA (Rémy). - Le mal du dehors : l’influence de l’environnement sur la santé. – Paris : Éditions Quae, 2017. Coined in 2005 by Christopher P. Wild, Director of the International Agency for Research on Cancer (IARC), this concept refers to "all environmental exposures throughout life, including lifestyle factors, from the prenatal period onwards." Based on epigenetics (analysis of the role of the cellular environment in the differentiated expression of genes), this concept highlights the interactions between genes and the living environment in the origins of chronic diseases. It calls for genome research to be complemented with multidisciplinary research on the exposome, taking into account all exposures linked to food, water, air, radiation and noise, as well as to the psycho-affective or socio-economic environment, from the embryonic stage onwards.  

This framing is associated with two types of overlapping approaches:  

• approaches initiated by academic researchers trying to investigate the role of exposome through multidisciplinary methodologies and models. For the time being, they are primarily focused on studying the role of certain substances at specific stages of life (notably in utero exposure); 

• and more militant approaches, initiated by groups of patients or their families (such as the "Stop les cancers de nos enfants"https://stopauxcancersdenosenfants.fr/effets-cocktails/ .group in France), funding "citizen research institutes" to investigate the "cocktail effects" of certain exposures, deemed responsible for clusters of pediatric cancers for example, whose environmental origin is denied by conventional epidemiology (such as Santé Publique France - an official public health institutions); or initiatives led by associations campaigning more broadly for research and prevention policies focusing on environmental health and exposome considerations - such as the Réseau Environnement Santé,https://www.reseau-environnement-sante.fr/category/plaidoyer/ .chaired by the chemist and toxicologist André Cicolella.CICOLELLA 2013, cf. aussi ZEITOUN (Jean-David). - Le Suicide de l'espèce. Comment les activités humaines produisent de plus en plus de maladies ». – Paris : Pocket Denoël, 2023.This civil society movement also involved scientists and activists denouncing the responsibilities of the agri-food industry for health crises linked to exposure to phytosanitary products and the consumption of ultra-processed foods.Cf. par exemple Jean-David Zeitoun. - Le suicide de l’espèce : Comment les activités humaines produisent de plus en plus de maladies. – Paris : Pocket, 2023 ; Courtney Marie Dowdall, Ryan J Klotz, Pesticides and Global Health: Understanding Agrochemical Dependence and Investing in Sustainable Solutions (Anthropology and Global Public Health),1st Edition, Routledge 2013. 

7. The role of environmental hypersensitivity (the idiopathic paradigm) 

A final paradigm is that of idiopathic hypersensitivity. This term refers to situations where the environment is deemed responsible for a degraded state of health that medicine is unable to explain. A case in point is "Gulf War Syndrome", evoked by American veterans of the first Gulf War (1990-1991) who reported functional disorders, immune system problems, malformations among their offspring, etc., which they attributed to various environmental factors: use of depleted uranium ammunition, inhalation of smoke from burning oil wells, exposure to nerve gases and/or organophosphate insecticides, administration of neuro-active substances without their knowledge by the military health services... There is also an "unhealthy building syndrome", which refers to a set of medically unexplained symptoms or illnesses that patients associate with a built environment (usually new buildings). We could also mention electromagnetic hypersensitivity,https://www.anses.fr/fr/system/files/AP2011SA0150Ra.pdf . which refers to symptoms (sleep disorders, headaches, skin rashes, etc.) that patients associate with their exposure to various electromagnetic fields (mobile phone masts, wifi terminals, etc.).  

This health/environment paradigm gives rise to numerous controversies about the reality of symptoms, their biomedical explanation, and the role of the environment. It should be noted that many occupational diseases (such as silicosis) were first described through this idiopathic prism. 

Protecting the environment in the name of human health 

8. The role of climate change (climate paradigm) 

With the climate paradigm, we are entering a different framework for defining the issue, one whose starting point is not damage to health but damage to the ‘natural’ environment. This paradigm was introduced by the Intergovernmental Panel on Climate Change (IPCC) in the second part of their reports devoted to the consequences of global warming and ‘adaptation’ measures. It was subsequently adopted by the WHO and numerous medical institutions, such as the Lancet.https://www.thelancet.com/series/climate-and-health-2009 .  

According to this paradigm, climate change represents "the greatest public health threat facing humanity", but also the "greatest opportunity" to achieve health gains thanks to the health "co-benefits" that could result from implementing certain measures to combat global warming (impacting air quality, diet, urban planning or modes of transport).Lancet Series on Climate and Health, 2009.   

The harmful consequences of climate change are described in various ways by different authors, who distinguish between two main categories of effects: the direct and immediate consequences caused by the increase in the intensity and frequency of extreme weather events (heat waves, storms and floods); and the indirect consequences, in the short to long term, linked to the effects of climate on the spread of water-borne and vector-borne diseases, on mental health, on agricultural productivity, as well as on population displacements and conflicts.  

This framing gives rise to different recommendations depending on the authors' political preferences. All agree on the need to "adapt" healthcare policies by strengthening the "resilience" of health systems and equipping them to tackle the "new needs" associated with climate change, particularly heatwaves and infectious diseases whose distribution could evolve. Some, such as the Lancet, advocate establishing joint epidemiological and meteorological surveillance systems to anticipate the evolution of epidemics.  

On the other hand, differences of opinion are emerging regarding how to combat global warming ("mitigation measures" in IPCC parlance). Whilst all proponents of the climate paradigm call for the practice of low-carbon medicine, some recommend that healthcare providers encourage their patients to change their behavior in ways that benefit both their health and climate preservation - an approach contested by others who stress that doctors are ill-placed to advocate eco-responsible behavioral changes, especially to populations in poor countries. But it is above all on the question of the causes of cli;ate change that opinions are most divided: for some, the central problem is the use of fossil fuels ("global health lies at the mercy of fossil fuel,” as the Lancet Commission summarisesLancet Countdown, 2023.). The priority from a public health perspective is therefore to decarbonize energy sources (while ensuring a form of energy justice between poor and rich countries).Lancet Countdown, 2023.For others, the problem lies in the quantity of energy available per capita and its continuous growth. The priority is therefore "the only way to act on the main determinants of health".https://www.cairn.info/environnement-et-sante-publique--9782810910076-page-113.htm .  

Whatever the recommended approaches, the climate-based framework for understanding the relationship between health and the environment has three distinctive features: 

• The first is to primarily focus on the future consequences of environmental changes on health;  

• The second is that it is based on an extremely long chain of causality, far more complex and speculative than that of the exposome. The impact of climate on health is indeed mediated by meteorological conditions (extremely difficult to predict locally, particularly in terms of precipitation), their impact on ecosystems (governed by a multitude of factors that cannot be reduced to heat and humidity), and the way in which human societies adapt to them (highly diverseOn the differentiated morbid effects of heat waves according to social classes and urban policies, see KLINENBERG (Eric). - Heat Wave. A Social Autopsy of Disaster in Chicago. - The University of Chicago Press, 2nd edition, 2002. and unpredictable).  

• Finally, the third characteristic is its instrumental nature: as François Gemenne points out in his preface to the collective work Health and Environment. Towards a new global approach,SENN (Nicolas), GAILLE (Marie), DEL RIO CARRAL (Maria) et al.. - Santé et environnement. Vers une nouvelle approche globale. - Médecine & Hygiène, « Hors collection », 2022, https://www.cairn.info/sante-et-environnement--9782880495008.htm.the climatic framing of environmental health issues serves primarily a marketing objective: convincing people that it is in their interest (in the long-term, and perhaps even today) to take action for the environment. As François Gemenne explains: 

"There is no direct link between the greenhouse gas emissions of a country or generation, and the impacts of climate change that will be suffered by that country or generation. (...) So, if we don't want to rely solely on altruism to trigger climate action, we need to mobilize our interests. And at the forefront of these is health: it is in our interest to mobilize for the climate, because it is also our health that is at stake (...) If we really want to take action to protect the environment, it must become more than a cause: it must become a matter of interests. Starting with health." 

9. The role of animal health and ecosystems - One Health, Eco-Health (socio-ecological paradigm) 

The climate paradigm has given rise to many reservations and even controversy among meteorologists, ecologists, epidemiologists, sociologists and anthropologists interested in environmental health. Many criticize its reductionist approach and the lightness with which it often addresses questions of causality.  

This is the case for researchers adopting the framework of "health ecology" and its most recent incarnation, "One Health." The concept of "One Health" was popularized in the early 2000s by the Wildlife Conservation Society in a global health context preoccupied by the emergence of new infectious diseases of animal origin (AIDS, Ebola, H1N1, etc.). This paradigm is based on the idea that human health, animal health and biodiversity are interdependent. Endorsed by the WHO in 2008 and by numerous public health institutions, the "One Health, One World" approach calls for the launch of multi-disciplinary research and action programs involving doctors, veterinarians, biologists, naturalists, agronomists, epidemiologists, etc., on topics "at the interface between human health, animal health and the environment." In practice, the prevention and detection of zoonoses is at the heart of this approach, which by extension also covers vector-borne diseases, antibiotic resistance, animal nutrition, etc.  

Boosted by the Covid-19 epidemic, the One Health approach is the heir to an older stream of research known as "health ecology" (EcoHealth) or "health socio-ecology", initiated in France in the 1960s by Jean-Antoine Rioux, a parasitologist and botanist who combined ecological and epidemiological approaches to understand the mechanisms of parasitic transmission, notably of leishmaniasis. Proponents of the socio-ecology of health criticize the climate paradigm for failing to consider the multiplicity of environmental determinants of health. For toxicologist and ecologist Jean-François Guégan, for example:GUEGAN (Jean-François). - « Changement climatique ou changement global, il faut choisir pour la santé ». – in Responsabilité & Environnement, Octobre 2021, n°104, Annales des mines. 

Microorganisms, their hosts and their transmission vectors form an important part of biodiversity (Guégan et al., 2021), and as such are subject to the effects of climate change. Temperature, the abundance and seasonal distribution of precipitation, the concentration of certain atmospheric components, variations in the intensity and frequency of extreme events, or changes in ocean circulation, independently or in association with some of these parameters, can have an impact on biodiversity (Lavorel et al., 2017) and a fortiori on host-micro-organism interactions. On the other hand, climate change over the last 150 years or so has not been the major cause of the recent evolution of infectious or parasitic agents and their associated species (reservoir hosts, vectors, relay hosts, accidental hosts). Several studies focusing on both endemic infectious and parasitic diseases, and on others of recent origin, known as emerging diseases, show, that the overwhelmingly dominant causes of their current spread are changes to the land resulting from deforestation and urbanization, the expansion of agriculture and livestock farming, human demographics and societal changes, as well as inadequate health and healthcare systems in certain regions of the world (Woolhouse and Gowtage-Sequeria, 2005; Thoisy et al, 2021).  

Guégan takes as an example the expansion of tiger mosquitoes which, unlike other insects (butterflies in particular), are not colonizing European northern latitudes in a uniform fashion, but are dispersing in a "diffuse and scattered manner all along the French road and motorway networks, which therefore does not correspond to a continuous front of progression as might be expected under the hypothesis of global warming." This mode of dispersal is in fact explained by the role of road traffic, with tiger mosquitoes embarking in the cabs of trucks and containers from southern Spain before dispersing within a radius of a few dozen to hundreds of meters along the route to northern Europe.  

Guégan also reviews studies on dengue fever and malaria, which establish a positive link global warming and an increase in the incidence of these diseases, pointing out that, according to meta-analyses, around 50% of these studies fail to record a positive association, and the remainder do not take into account the possible existence of confounding factors. In the case of dengue fever, his colleagues point out, ecological niche models show that its spread is mainly due to high population densities, unsanitary conditions and human transport networks - and only to a very limited extent to global warming.PLANTARD (Olivier), HUBER (Laurent), GUEGAN (Jean-François). - "Towards an ecology of health". - in Pour la science, 2015.  

Rather than limiting our focus to climate change, these authors urge us to consider "global changes" and "syndemic health crises", i.e. health crises linked to the complex interweaving of biological, environmental, human and societal dynamics, in which climate change obviously plays a role, but not in isolation. They advocate that the "socio-ecology of health" should be at the heart of research and public action programs. Such an approach would respond to...:PLANTARD (Olivier), et al, op. cit.  

... the need to reinforce joint action in the fields of human health, animal and plant health, and environmental management. This integrative approach avoids the mistake of artificially isolating the effect of climate change from other human-induced modifications, which are also implicated in the development of epidemics (e.g. changes in land use, introduction of invasive species linked to human movements or the transport of goods). Long-term monitoring systems such as the Long-Term Ecological Research Network are particularly valuable. They should soon incorporate epidemiological research into the effects of climate change on human, animal and plant diseases, thereby improving the accuracy of numerical models. Finally, it is important to emphasise that identifying and quantifying the effects of global changes on health is a challenge that can only be met if climatologists, epidemiologists, modelers, ecologists, entomologists, microbiologists, parasitologists, immunologists, socio-economists and others work together on an integrated project. 

The superficial enthusiasm for the One Health approach masks the under-investment in multidisciplinary ecological health research programs, lament these researchers, who denounce the "One Health Washing"Cf. GIRAUDOUX (Patrick) et al - "One Health or 'One Health washing'? An alternative to overcome now more than ever". - in CABI One Health (2022). "For example, investment in Ebola and Marburg virus research between 1997 and 2015 is estimated at US$1035 million, of which 61.3% was allocated to research on vaccines, 29.2% to research on new therapeutics and 9.5% to research on diagnostic kits (Fitchett et al., 2016). We were unable to find figures estimating the investment in ecological and anthropological research on socio-ecosystems and animal population dynamics in the areas affected by these viruses, and we are aware of only a few ongoing ecological studies (e.g. the EBO-SURSY programme; https://rr-africa.oie.int/fr/projets/ebo-sursy-fr)."  and "climate opportunism" within the public health research community.  

Similar critiques warn against the misleading generalisations of the climate paradigm in other areas, such as the links between climate and natural disasters,CABANE (Lydie), REVET (Sandrine). - « La cause des catastrophes. Concurrences scientifiques et actions politiques dans un monde transnational ». - in Politix, 2015/3 (n° 111), p. 47-67. climate and population displacement,Cf. BALDWIN (Andrew), MULA (Vanessa) (trad.). - « Pourquoi nous devrions abandonner le concept de « réfugié climatique ». – in The conversation, 31 octobre 2022, https://www.ritimo.org/Pourquoi-nous-devrions-abandonner-le-concept-de-refugie-climatique. climate and conflict.For example, on the Sahel, see FOUCHER (Vincent). - « Boko Haram et le mythe du ‘lac qui disparaissait’ ». - in Afrique XXI, 15 mars 2023. https://www.afriquexxi.info/Boko-Haram-et-le-mythe-du-lac-qui-disparaissait.  

10. The role of the earth system - Planetary Health (planetary paradigm) 

The last paradigm may appear as a response to the criticisms levelled by the socio-ecology of health, in the sense that it places global warming within a broader framework, that of the transgression of planetary boundaries. Introduced by the Rockefeller Foundation in 2015,The Rockefeller Foundation-Lancet Commission. - "Safeguarding human health in the Anthropocene epoch: report of The Rockefeller Foundation-Lancet Commission on planetary health." - in The Lancet Commissions, 2015. https://www.thelancet.com/article/S0140-6736(15)60901-1/fulltext.  the planetary health framework is based on the following assumption: the major progress made in the field of health over the past decades has been at the expense of future generations, to whom we are bequeathing a dysfunctional earth system. The cause: "highly inequitable, inefficient and unsustainable patterns of resource consumption and technological development, together with population growth." "In essence, humanity has traded off many of the Earths supportive and regulating processes to feed and fuel human population growth and development," summarizes the Rockefeller Foundation.  

The planetary health approach proposes integrating the preservation of the earth system into health policies. As Jakob Zinnstag, Professor of Epidemiology at the University of Basel, explains, this means moving from a patient-centered approach to a planet-centered one:  

It's becoming increasingly clear that we need to adapt to our planet's limited resources in order to preserve human health and life in the long-term. Human health can no longer be considered without taking into account the environment, the air, water, plants, and animals that surround us. Today's medicine, with a strong focus on individual patient care, puts too much pressure on the environment. Medicine must now take into account social, cultural, spiritual and ecological factors in diagnosis and therapy, and reduce its ecological footprint. Future doctors, nurses and other healthcare professionals will have to shift from a patient-centered approach to a more systemic way of thinking, to ensure the health of people, animals and the environment as a whole.ZINSSTAG (Jakob). – « Santé et environnement : vers des approches intégrées ». - in SENN et al. (dir.), op. cit., p. 77.  

The field covered by planetary health is therefore extremely broad, as it evidently includes the fight against global warming, but also against ocean acidification, aquifer depletion, changes in water cycles, the disappearance of wetlands, deforestation, artificialization and soil degradation, changes in the nitrogen and phosphorus cycles, chemical pollution from agriculture (pesticides), cement manufacturing (heavy metals), mining (dust, heavy metals), electronic waste recycling (dioxins), ship dismantling (asbestos), pharmaceutical production, and textile and electronics production. Finally, it must also combat the erosion of biodiversity. How can we do this? By acting on food production and consumption patterns, by investing in "sustainable cities", by practicing a "sound management of chemicals", by reviewing land-use plans, by "integrating environmental care into the healthcare system"... and, last but not least, by improving access to family planning. It is worth noting that actions relating to the provision of medical care occupy only half a page out of 56 pages (0.9%) in the Rockefeller report.   

There is a slightly less technocratic version of planetary health, championed by philosophers such as Marie Gaille.GAILLE (Marie). - Health and the environment. - PUF, Philosophies, 2018. Cf. summary here.  Like the proponents of the socio-ecological paradigm, she proposes taking into account the diversity of environmental factors that affect health, but adopting a less anthropocentric approach - that is, not making the preservation of human health the ultimate goal and replacing the concept of interdependence of different forms of life with the notion of solidarity, which defends the environment as an end in itself - a stance that is not without raising a number of philosophical questions...  

So what does this mean for a medical humanitarian organization like MSF? 

This brief journey into the field of environmental health shows just how abundant and heterogeneous it is. As epidemiologist William Dab, former Director General of Health in France, points out, environmental health does not constitute a coherent, unified set of issues, practices, methods or standards. This is why its translation into policy is so difficult, chaotic, and even impossible. Regarding France, which since 2004 has had a National Environmental Health Plan, whose 4th version, adopted in 2021, aims to "act for an environment favorable to all healths", William Dab points out that:DAB (William). - "Health risk management in France: the challenge of uncertainty". - in Responsabilité & Environnement, n°104, Annales des mines, October 2021.  

“environmental health is at the crossroads of a whole range of policies: health, social security, environment, labor, energy, housing, transport, industrial and agricultural development, consumer affairs and fraud control, etc. These policies are based on different legal regimes, values, standards and mechanisms. They give rise to fierce power rivalries and battles over the perimeters of responsibilities, which absorb considerable energy. (...)  

Thus, from a public policy perspective, environmental health remains largely a fictional object. The 4th National Environmental Health Plan shows that it is simply a collection of concerns expressed by various ministerial departments, with no hierarchy of risks and no real priorities. Let's judge: thirty-seven existing sectoral plans, twenty non-hierarchical and non-budgeted actions, performance indicators that reflect means more than results, and a regional roll-out that remains mere rhetoric due to a lack of budgetary allocation. Moreover, there is no initial assessment and no defined objectives. The impact of this latest plan cannot be assessed any more than that of previous plans.  

There is a great risk that humanitarian organizations seeking to incorporate environmental health into their policies will achieve the same result. Unless they make the deliberate and reasoned choice to restrict the scope. How? I would propose starting from the following premises:  

1. As a humanitarian organization, we assume a form of anthropocentrism. We place the preservation of human health in the here and the now, above the conservation of nature and ecosystems for future generations.  

2. Yet, we recognize the legitimacy of the environmental struggle and the plurality of values that drive it (recognition of the intrinsic value of non-humans and nature, preservation of the ecological niche of humankind, aesthetic and cognitive interests, concern for future generations, etc.). We claim an "enlarged anthropocentrism such that valuing humans does not necessarily imply devaluing nature.”Cf. LARRERE Catherine, "Les éthiques environnementales", Natures Sciences Sociétés, 2010/4 (Vol. 18), pp. 405-413. URL: https://www.cairn.info/revue-natures-sciences-societes-2010-4-page-405.htm.  As such, we recognize the need to find a compromise between "humanitarian ethics" and the various "environmental ethics".  

3. This compromise takes into account the fact that we are a medical organization, not a public health organization. Our means of action on the environment and the socio-ecological determinants of health are extremely limited. Our first responsibility is to limit our own contribution to environmental degradation.  

On this basis, we propose three orientations at institutional, operational, and political levels.  

At the institutional level, we should continue our efforts to reduce our environmental footprint, in particular by developing (when appropriate) “low carbon and low consumption” operational methods. But we must guard against the techno-solutionist illusion promising to reconcile infinite growth in our operations with the reduction of our pollution and greenhouse gas emissions in the proportions required by the Paris Agreement. Reducing our environmental footprint comes at a cost, estimated by MSF France in 2024 at 1% to 3% of its budget – or, at most, 12 million euros in 2024, which corresponds to the combined budgets of the Afghanistan and Iraq missions. In 2024, MSF France allocated “only” 0.25% of its budget to the environmental transition. Should we do more? Have fewer operations, but of better environmental (but also social, medical, human, etc.) quality? Or assume that we could emit more carbon than required of the rest of society in the name of a certain conception of environmental and climate justice that takes into account the specificity of our social mission and the fact that we operates in countries that have emitted the least CO2 and are bearing the brunt of the consequences of global warming and environmental degradation? These are the questions currently being debated within the association. On the state of thinking in the French humanitarian aid community, see cf. HUBERT (Aline). - Objectif de décarbonation juste et équitable pour une ONG internationale, 2024. – URD, 10 janvier 2025, https://www.urd.org/fr/publication/104772/. 

At the operational level, we should resist climate-centrism and one of its most problematic offshoots: futurology. Most climate health initiatives in the aid world (and at MSF) deal with adaptation to the future health consequences of global warming. However, these consequences are at the same time certain and unpredictable, due to possible “non-linear” tipping effects (release of pathogens contained in permafrost, collapse of AMOC ocean currents, etc.) and the complexity of the causal chains linking the composition of the atmosphere to the health of human beings living in society. This is why one of the main challenges for humanitarian organizations is not to anticipate the medium-term consequences of climate change but to detect and respond to the unforeseen crises whose occurrence it already favors – without ignoring the other dimensions of the environmental crisis (pollution, erosion of biodiversity, etc.). In this regard, MSF could strengthen its operational response in two types of situations: 

1. Health crises associated with extreme climate events, particularly floods and heat waves, fields of intervention in which MSF must improve its risk analysis, as well as its infrastructure and medical-operational practices. 

2. Health crises caused by the contamination of air, water, food, or soil by toxic physicochemical substances. Our limited experience in this area highlights the rarity of situations in which we can offer effective curative and preventive solutions, as well as the political difficulties in negotiating a space for intervention. We could prioritize projects supported by existing social and political mobilizations, seeking independent medical and epidemiological expertise. 

Finally, on a political level, it is worth recalling that it took decades to recognize, for the aid sector to recognise that so-called “natural disasters” stem from the convergence of a geophysical hazard and a "social and political vulnerability."Cf. REVET (Sandrine). - Les coulisses du monde des catastrophes « naturelles ». – Paris : Editions de la MSH, Collection le (bien) commun, 2018.Let us not lose sight of this intertwining, which incites us to take into account issues of "environmental justice" - and in particular, with regard to climate change, questions relating to the distribution of the decarbonization effort, the financing of adaptation and compensation for victims.