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Which species will survive the Earth’s sixth mass extinction?

Mass extinctions are more complicated than ‘strength in numbers’. Corinata/wikimedia, CC BY-SA
Matthew Wills, University of Bath

Scientists recently suggested that the Earth’s sixth mass extinction has begun. As terrifying as that sounds, surely humans are too smart and too important to get wiped out? Palaeontologists have long tried to shed light on this question by looking for general rules that might predict the survival of a species.

While this is not exactly a straightforward exercise, research so far indicates that the odds are not in our favour.

Limitations of diversity

Life on Earth can be traced back to a single unicellular species, perhaps some 3.5 billion years ago. Since then, diversity and maximum complexity has increased and millions of species have evolved.

But how did we go from one species to millions of species? Let’s do a simple thought experiment. Lineages can split in two so that one species yields two, two yield four, four yield eight, and so forth. If plotting this process as a curve, the number of species would grow exponentially over time. Of course, species will also go extinct, but provided this happens less often than new ones arise, you will still end up with an exponentially increasing curve.

But can diversity go on increasing forever? Charles Darwin certainly thought not, and believed that the Earth probably had a carrying capacity. He likened species to wedges driven into a log, each occupying their own niche or patch of ecospace. As the number of wedges approaches the carrying capacity, it becomes more difficult to insert new ones, until adding new wedges forces older ones out.

Sigmoidal curve, same shape as a diversity curve. wikimedia, CC BY-SA

The idea that the Earth can only accommodate a finite number of species modifies our simple model somewhat. Early on in the process, numbers are far from carrying capacity, and growth is exponential. Later on, progressively harder brakes are put on, and the rate of growth slows down, so that diversity reaches a plateau. Together, these forces yield an S-shaped or sigmoidal curve.

So what do we see when we look at the real history of life in the fossil record? Fortunately, palaeontologists have systematically compiled catalogues of fossil genera, making it possible to compare. What they show, however, is a much more complex picture.

Mass extinctions as game changers

Some of the earliest diversity curves were produced for marine organisms. These revealed five mass extinction events over the last half billion years, in which diversity markedly and rapidly reduced. The first two of these – the end of the Ordovician, about 444m years ago, and and the end of the Devonian, about 359m years ago, occurred at a time when diversity appeared to have reached a plateau. Diversity simply bounced back to previous levels after they struck.

The third mass extinction, dubbed the “Great Dying”, some 252m years ago at the boundary between the Permian and Triassic periods, was much bigger. It eclipsed both of its predecessors, as well as that which later killed off the dinosaurs – wiping out perhaps 96% of all marine species.

Its after-effects were also much more radical: far from just recovering to former levels, numbers of genera and families eventually grew through the apparent ceiling of the Ordovician to Permian, and continued to do so until the present biodiversity crisis.

How was such a gear change possible? Mass extinctions almost certainly result from catastrophic physical changes to the environment, with a speed that makes it difficult or impossible for animals to adapt and evolve to accommodate. Some groups are depleted much more than others, and in ways that are difficult to predict.

Bivalve. shellnut/wikimedia, CC BY-SA

The idea is best illustrated by two groups of clam-like, filter-feeding marine organisms with similar ecologies and life habits: the brachiopods (Phylum Brachiopoda) and the bivalves (Phylum Mollusca). Prior to the end of the Permian, 252m years ago, brachiopods were much more diverse than bivalves. However, the Great Dying hit the brachiopods much harder than the bivalves, and bivalves also recovered much faster. Not only did the bivalves rise to dominance in the wake of the mass extinction – they went on to become much more diverse than the brachiopods had ever been.

Brachiopod from the Upper Ordovician. wikimedia

Such a turning of the tables may be possible when one group has already filled an ecospace, making it difficult for other groups to get a foothold. Only rapid change in the physical environment can dislodge them, offering ecological competitors the opportunity they previously lacked. These ascendant groups may also subdivide ecospace more finely (smaller wedges in Darwin’s analogy), allowing a stalled diversity curve to take off again. New species may also change the environment in ways that provide niches for others, thereby creating new ecospace (or enlarging Darwin’s log).

Something of this sort happened on land with the extinction of the dinosaurs at the Cretaceous–Paleogene extinction event some 66m years ago, which saw mammals comparatively mildly affected. Ironically, the Great Dying event had previously knocked the then hugely successful ancestors of the modern mammals – the therapsids – into the background some 186m years earlier, allowing the archosaurs and ultimately the dinosaurs to flourish in the first place. What goes around comes around.

Predicting winners

With such major shifts in the Earth’s biodiversity seemingly hostage to the whims of fortune, palaeontologists have looked for any general rules that might predict survival. On land, large size seems to be disadvantageous.

Being big seems to increase the risk of being wiped out when mass extinctions hit. Mohan Raj/wikimedia, CC BY-SA

Alarmingly, few animals larger than a dog survived the Cretaceous–Paleogene event. Other disadvantages include ecological specialisation and having a restricted geographical distribution.

In between extinction events, a wide geographic distribution appears to offer considerable insurance. However we have recently shown that geographical range had no effect on the number of surviving terrestrial vertebrate species at the end of the Triassic mass extinction some 201m years ago. The physical events causing mass extinctions, whether asteroids, mass volcanism or other physical factors, are so disruptive and have such global consequences that even the most widespread and numerous species can be wiped out.

It is, therefore, very difficult to make generalisations and predictions. But we do know that nothing is ever really safe. As we face the prospect of the sixth mass extinction, albeit caused by human activity this time, it is well to remember that extinctions can quickly escalate in unpredictable ways.

The loss of one species can have unforeseen consequences for many others, since ecosystems are connected by a complex web of interactions that we do not always fully understand. We must hope that such an ecosystem collapse is far enough down the road for us to forestall it. Unfortunately, early signs – such as habitat fragmentation and species loss in rainforests and reefs – are not good.The Conversation

Matthew Wills, Professor of Evolutionary Palaeobiology at the Milner Centre for Evolution, University of Bath

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UNIFIED DIFFERENCES


HOW TO BUILD HUMAN SOCIETIES

The main picture is made of differences


  • For five years, Mi Casa has received countless guests from different countries (over 72 nationalities). Everyone wanted to discover Indonesia and its plurality, its people, its cultures, the power of its nature. In each of them reside the old human instinct to go and see beyond the horizon, if life is more beautiful there, the grass is greener. We have contributed as much as we could to fill their memories with imperishable images, to make them want to come back. We hope that once the pandemic is over, more than ever women and men from elsewhere will forget their fears and will once again travel the world, with an Indonesian stopover, country of smiles and friendship, example of diversity in unity.


  • For five years, Mi Casa has received countless guests from different countries (over 72 nationalities). Everyone wanted to discover Indonesia and its plurality, its people, its cultures, the power of its nature. In each of them reside the old human instinct to go and see beyond the horizon, if life is more beautiful there, the grass is greener. We have contributed as much as we could to fill their memories with imperishable images, to make them want to come back. We hope that once the pandemic is over, more than ever women and men from elsewhere will forget their fears and will once again travel the world, with an Indonesian stopover, country of smiles and friendship, example of diversity in unity.


  • For five years, Mi Casa has received countless guests from different countries (over 72 nationalities). Everyone wanted to discover Indonesia and its plurality, its people, its cultures, the power of its nature. In each of them reside the old human instinct to go and see beyond the horizon, if life is more beautiful there, the grass is greener. We have contributed as much as we could to fill their memories with imperishable images, to make them want to come back. We hope that once the pandemic is over, more than ever women and men from elsewhere will forget their fears and will once again travel the world, with an Indonesian stopover, country of smiles and friendship, example of diversity in unity.


  • For five years, Mi Casa has received countless guests from different countries (over 72 nationalities). Everyone wanted to discover Indonesia and its plurality, its people, its cultures, the power of its nature. In each of them reside the old human instinct to go and see beyond the horizon, if life is more beautiful there, the grass is greener. We have contributed as much as we could to fill their memories with imperishable images, to make them want to come back. We hope that once the pandemic is over, more than ever women and men from elsewhere will forget their fears and will once again travel the world, with an Indonesian stopover, country of smiles and friendship, example of diversity in unity.


  • For five years, Mi Casa has received countless guests from different countries (over 72 nationalities). Everyone wanted to discover Indonesia and its plurality, its people, its cultures, the power of its nature. In each of them reside the old human instinct to go and see beyond the horizon, if life is more beautiful there, the grass is greener. We have contributed as much as we could to fill their memories with imperishable images, to make them want to come back. We hope that once the pandemic is over, more than ever women and men from elsewhere will forget their fears and will once again travel the world, with an Indonesian stopover, country of smiles and friendship, example of diversity in unity.


  • For five years, Mi Casa has received countless guests from different countries (over 72 nationalities). Everyone wanted to discover Indonesia and its plurality, its people, its cultures, the power of its nature. In each of them reside the old human instinct to go and see beyond the horizon, if life is more beautiful there, the grass is greener. We have contributed as much as we could to fill their memories with imperishable images, to make them want to come back. We hope that once the pandemic is over, more than ever women and men from elsewhere will forget their fears and will once again travel the world, with an Indonesian stopover, country of smiles and friendship, example of diversity in unity.


  • For five years, Mi Casa has received countless guests from different countries (over 72 nationalities). Everyone wanted to discover Indonesia and its plurality, its people, its cultures, the power of its nature. In each of them reside the old human instinct to go and see beyond the horizon, if life is more beautiful there, the grass is greener. We have contributed as much as we could to fill their memories with imperishable images, to make them want to come back. We hope that once the pandemic is over, more than ever women and men from elsewhere will forget their fears and will once again travel the world, with an Indonesian stopover, country of smiles and friendship, example of diversity in unity.


  • For five years, Mi Casa has received countless guests from different countries (over 72 nationalities). Everyone wanted to discover Indonesia and its plurality, its people, its cultures, the power of its nature. In each of them reside the old human instinct to go and see beyond the horizon, if life is more beautiful there, the grass is greener. We have contributed as much as we could to fill their memories with imperishable images, to make them want to come back. We hope that once the pandemic is over, more than ever women and men from elsewhere will forget their fears and will once again travel the world, with an Indonesian stopover, country of smiles and friendship, example of diversity in unity.


  • For five years, Mi Casa has received countless guests from different countries (over 72 nationalities). Everyone wanted to discover Indonesia and its plurality, its people, its cultures, the power of its nature. In each of them reside the old human instinct to go and see beyond the horizon, if life is more beautiful there, the grass is greener. We have contributed as much as we could to fill their memories with imperishable images, to make them want to come back. We hope that once the pandemic is over, more than ever women and men from elsewhere will forget their fears and will once again travel the world, with an Indonesian stopover, country of smiles and friendship, example of diversity in unity.


  • For five years, Mi Casa has received countless guests from different countries (over 72 nationalities). Everyone wanted to discover Indonesia and its plurality, its people, its cultures, the power of its nature. In each of them reside the old human instinct to go and see beyond the horizon, if life is more beautiful there, the grass is greener. We have contributed as much as we could to fill their memories with imperishable images, to make them want to come back. We hope that once the pandemic is over, more than ever women and men from elsewhere will forget their fears and will once again travel the world, with an Indonesian stopover, country of smiles and friendship, example of diversity in unity.


  • For five years, Mi Casa has received countless guests from different countries (over 72 nationalities). Everyone wanted to discover Indonesia and its plurality, its people, its cultures, the power of its nature. In each of them reside the old human instinct to go and see beyond the horizon, if life is more beautiful there, the grass is greener. We have contributed as much as we could to fill their memories with imperishable images, to make them want to come back. We hope that once the pandemic is over, more than ever women and men from elsewhere will forget their fears and will once again travel the world, with an Indonesian stopover, country of smiles and friendship, example of diversity in unity.


  • For five years, Mi Casa has received countless guests from different countries (over 72 nationalities). Everyone wanted to discover Indonesia and its plurality, its people, its cultures, the power of its nature. In each of them reside the old human instinct to go and see beyond the horizon, if life is more beautiful there, the grass is greener. We have contributed as much as we could to fill their memories with imperishable images, to make them want to come back. We hope that once the pandemic is over, more than ever women and men from elsewhere will forget their fears and will once again travel the world, with an Indonesian stopover, country of smiles and friendship, example of diversity in unity.


  • For five years, Mi Casa has received countless guests from different countries (over 72 nationalities). Everyone wanted to discover Indonesia and its plurality, its people, its cultures, the power of its nature. In each of them reside the old human instinct to go and see beyond the horizon, if life is more beautiful there, the grass is greener. We have contributed as much as we could to fill their memories with imperishable images, to make them want to come back. We hope that once the pandemic is over, more than ever women and men from elsewhere will forget their fears and will once again travel the world, with an Indonesian stopover, country of smiles and friendship, example of diversity in unity.


  • For five years, Mi Casa has received countless guests from different countries (over 72 nationalities). Everyone wanted to discover Indonesia and its plurality, its people, its cultures, the power of its nature. In each of them reside the old human instinct to go and see beyond the horizon, if life is more beautiful there, the grass is greener. We have contributed as much as we could to fill their memories with imperishable images, to make them want to come back. We hope that once the pandemic is over, more than ever women and men from elsewhere will forget their fears and will once again travel the world, with an Indonesian stopover, country of smiles and friendship, example of diversity in unity.


  • For five years, Mi Casa has received countless guests from different countries (over 72 nationalities). Everyone wanted to discover Indonesia and its plurality, its people, its cultures, the power of its nature. In each of them reside the old human instinct to go and see beyond the horizon, if life is more beautiful there, the grass is greener. We have contributed as much as we could to fill their memories with imperishable images, to make them want to come back. We hope that once the pandemic is over, more than ever women and men from elsewhere will forget their fears and will once again travel the world, with an Indonesian stopover, country of smiles and friendship, example of diversity in unity.


  • For five years, Mi Casa has received countless guests from different countries (over 72 nationalities). Everyone wanted to discover Indonesia and its plurality, its people, its cultures, the power of its nature. In each of them reside the old human instinct to go and see beyond the horizon, if life is more beautiful there, the grass is greener. We have contributed as much as we could to fill their memories with imperishable images, to make them want to come back. We hope that once the pandemic is over, more than ever women and men from elsewhere will forget their fears and will once again travel the world, with an Indonesian stopover, country of smiles and friendship, example of diversity in unity.


  • For five years, Mi Casa has received countless guests from different countries (over 72 nationalities). Everyone wanted to discover Indonesia and its plurality, its people, its cultures, the power of its nature. In each of them reside the old human instinct to go and see beyond the horizon, if life is more beautiful there, the grass is greener. We have contributed as much as we could to fill their memories with imperishable images, to make them want to come back. We hope that once the pandemic is over, more than ever women and men from elsewhere will forget their fears and will once again travel the world, with an Indonesian stopover, country of smiles and friendship, example of diversity in unity.


  • For five years, Mi Casa has received countless guests from different countries (over 72 nationalities). Everyone wanted to discover Indonesia and its plurality, its people, its cultures, the power of its nature. In each of them reside the old human instinct to go and see beyond the horizon, if life is more beautiful there, the grass is greener. We have contributed as much as we could to fill their memories with imperishable images, to make them want to come back. We hope that once the pandemic is over, more than ever women and men from elsewhere will forget their fears and will once again travel the world, with an Indonesian stopover, country of smiles and friendship, example of diversity in unity.


  • For five years, Mi Casa has received countless guests from different countries (over 72 nationalities). Everyone wanted to discover Indonesia and its plurality, its people, its cultures, the power of its nature. In each of them reside the old human instinct to go and see beyond the horizon, if life is more beautiful there, the grass is greener. We have contributed as much as we could to fill their memories with imperishable images, to make them want to come back. We hope that once the pandemic is over, more than ever women and men from elsewhere will forget their fears and will once again travel the world, with an Indonesian stopover, country of smiles and friendship, example of diversity in unity.


  • For five years, Mi Casa has received countless guests from different countries (over 72 nationalities). Everyone wanted to discover Indonesia and its plurality, its people, its cultures, the power of its nature. In each of them reside the old human instinct to go and see beyond the horizon, if life is more beautiful there, the grass is greener. We have contributed as much as we could to fill their memories with imperishable images, to make them want to come back. We hope that once the pandemic is over, more than ever women and men from elsewhere will forget their fears and will once again travel the world, with an Indonesian stopover, country of smiles and friendship, example of diversity in unity.


  • For five years, Mi Casa has received countless guests from different countries (over 72 nationalities). Everyone wanted to discover Indonesia and its plurality, its people, its cultures, the power of its nature. In each of them reside the old human instinct to go and see beyond the horizon, if life is more beautiful there, the grass is greener. We have contributed as much as we could to fill their memories with imperishable images, to make them want to come back. We hope that once the pandemic is over, more than ever women and men from elsewhere will forget their fears and will once again travel the world, with an Indonesian stopover, country of smiles and friendship, example of diversity in unity.


  • For five years, Mi Casa has received countless guests from different countries (over 72 nationalities). Everyone wanted to discover Indonesia and its plurality, its people, its cultures, the power of its nature. In each of them reside the old human instinct to go and see beyond the horizon, if life is more beautiful there, the grass is greener. We have contributed as much as we could to fill their memories with imperishable images, to make them want to come back. We hope that once the pandemic is over, more than ever women and men from elsewhere will forget their fears and will once again travel the world, with an Indonesian stopover, country of smiles and friendship, example of diversity in unity.


  • For five years, Mi Casa has received countless guests from different countries (over 72 nationalities). Everyone wanted to discover Indonesia and its plurality, its people, its cultures, the power of its nature. In each of them reside the old human instinct to go and see beyond the horizon, if life is more beautiful there, the grass is greener. We have contributed as much as we could to fill their memories with imperishable images, to make them want to come back. We hope that once the pandemic is over, more than ever women and men from elsewhere will forget their fears and will once again travel the world, with an Indonesian stopover, country of smiles and friendship, example of diversity in unity.


  • For five years, Mi Casa has received countless guests from different countries (over 72 nationalities). Everyone wanted to discover Indonesia and its plurality, its people, its cultures, the power of its nature. In each of them reside the old human instinct to go and see beyond the horizon, if life is more beautiful there, the grass is greener. We have contributed as much as we could to fill their memories with imperishable images, to make them want to come back. We hope that once the pandemic is over, more than ever women and men from elsewhere will forget their fears and will once again travel the world, with an Indonesian stopover, country of smiles and friendship, example of diversity in unity.


  • For five years, Mi Casa has received countless guests from different countries (over 72 nationalities). Everyone wanted to discover Indonesia and its plurality, its people, its cultures, the power of its nature. In each of them reside the old human instinct to go and see beyond the horizon, if life is more beautiful there, the grass is greener. We have contributed as much as we could to fill their memories with imperishable images, to make them want to come back. We hope that once the pandemic is over, more than ever women and men from elsewhere will forget their fears and will once again travel the world, with an Indonesian stopover, country of smiles and friendship, example of diversity in unity.


  • For five years, Mi Casa has received countless guests from different countries (over 72 nationalities). Everyone wanted to discover Indonesia and its plurality, its people, its cultures, the power of its nature. In each of them reside the old human instinct to go and see beyond the horizon, if life is more beautiful there, the grass is greener. We have contributed as much as we could to fill their memories with imperishable images, to make them want to come back. We hope that once the pandemic is over, more than ever women and men from elsewhere will forget their fears and will once again travel the world, with an Indonesian stopover, country of smiles and friendship, example of diversity in unity.

REMINDER


REPORT COVID-19 2020

La mortalité des moins de 65 ans a-t-elle vraiment diminué en 2020, comme l’affirme le professeur Didier Raoult ?

Ce constat est fait par l’Insee. Il s’explique notamment par une baisse vertigineuse du nombre d’accidents de la circulation en France.

Ce constat chiffre en France peut etre applicable dans la majorite des pays.

“Les chiffres, pour moi, n’ont pas un sens symbolique particulier.” Alors que la France a franchi, jeudi 15 avril, le seuil des 100 000 victimes du Covid-19, Didier Raoult a refusé d’y voir un symbole. Invité de BFMTV, le directeur de l’Institut hospitalo-universitaire (IHU) de Marseille a cependant commenté le passage de ce cap vertigineux. 

>> Suivez les dernières informations sur l’épidémie de Covid-19 dans notre direct

“Si vous prenez les gens de moins de 65 ans, il est mort moins de gens en 2020 qu’en 2019 et en 2018. Moins. Tandis que si vous prenez les gens de plus de 75 ans ou les gens de plus de 85 ans, il en est mort beaucoup plus”, a relevé le microbiologiste, révélé au grand public par ses prises de position iconoclastes sur la lutte contre la pandémie. Didier Raoult dit-il vrai ou fake ?

Une baisse avérée de la mortalité des moins de 65 ans l’année dernière

Toutes causes confondues, 667 400 décès ont été enregistrés en France en 2020, “soit 9% de plus qu’en 2018 ou 2019”, dénombre l’Institut national de la statistique et des études économiques (Insee) dans une estimation provisoire. Une plongée dans ces chiffres de l’Insee permet d’identifier un double phénomène. D’un côté, une hausse de la mortalité de plus de 10% a touché les plus de 65 ans entre 2020 et 2019. De l’autre, les moins de 65 ans ont été moins nombreux à perdre la vie en 2020.

Dans le détail, la mortalité a baissé de 6% pour les moins de 25 ans et de 1% pour les 25-49 ans. Mais pour les personnes âgées de 50 à 64 ans, elle s’est accrue de 2%. L’Insee considère donc que la hausse de la mortalité a été “négligeable” chez les moins de 65 ans. Ce qui donne raison au professeur Raoult.

L’effet protecteur des restrictions sanitaires

Comment expliquer une telle baisse de la mortalité chez les plus jeunes ? Pour le démographe et épidémiologiste Jean-Marie Robine, joint par franceinfo, l’explication tient aux mesures sanitaires, qui ont eu des effets bénéfiques collatéraux. “Le confinement, en forçant les gens à rester chez eux, a diminué une grande partie de la mortalité des plus jeunes.” Premier phénomène identifié par le conseiller scientifique de l’Institut national d’études démographiques (Ined) : la diminution des accidents de la route. “Ce sont très souvent des jeunes qui en sont victimes”, relève Jean-Marie Robine.

Ce que confirment les données de l’année 2020. Le nombre d’automobilistes tués dans un accident de la route a diminué de 28% entre 2019 et 2020, s’établissant à 1 172 morts, rapporte l’Observatoire national interministériel de la sécurité routière. Chez les 18-24 ans, pour qui la mort sur la route représente “la première cause de décès” selon le gouvernement, cette diminution atteint 22%. Pour l’organisme public, la limitation des “déplacements pendant les confinements et périodes de couvre-feu” et des départs en vacances moins nombreux expliquent cette baisse drastique du nombre de morts sur la route.

Les gestes barrières ont eux aussi joué dans la baisse de la mortalité des moins de 65 ans, estime Jean-Marie Robine. “Porter le masque les a protégés de tout ce qu’ils auraient pu attraper par ailleurs, que ce soit des gastro-entérites, des grippes ou les maladies infectieuses en général”, liste l’épidémiologiste. Des pathologies effectivement en net recul en 2020. Selon Santé publique France (document PDF), l’épidémie de grippe de 2019-2020 aurait fait 3 680 morts, contre 9 000 décès en temps normal.

Une mortalité faible face au Covid-19

Cette baisse de la mortalité chez les moins de 65 ans s’explique aussi par une plus faible létalité du virus chez les plus jeunes, fait remarquer Jean-Marie Robine. “C’est une population très très peu à risque de décéder du Covid, à moins d’avoir des comorbidités”, relève l’épidémiologiste et démographe. Les données extraites de la plateforme publique Géodes sur 44 000 décès l’attestent : 87% des morts du Covid-19 étaient âgés de plus de 70 ans, dont trois quarts de personnes au moins octogénaires.

Autre phénomène mis en avant par Jean-Marie Robine : contrairement aux craintes dues au contexte sanitaire et aux restrictions, “il n’y a pas eu d’augmentation du nombre de suicides en 2020”, affirme le démographe. Chaque année, près de 10 000 personnes mettent fin à leurs jours en France. Une situation qui touche principalement les adultes de 25 à 59 ans, révèle Santé publique France. Si l’Observatoire national du suicide n’a, pour l’heure, pas publié de bilan pour l’année écoulée, les indicateurs pointent en effet plutôt vers une absence de hausse du nombre de passages à l’acte en 2020, révélait Le Monde en novembre.

Cette baisse peut sembler paradoxale et provisoire, alors que les conséquences psychologiques des restrictions sanitaires et de la pandémie se font jour. Ainsi, 9% des personnes interrogées par Santé publique France confiaient avoir des pensées suicidaires à la mi-mars 2021. Et 20,7% des répondants présentaient un état dépressif. Santé publique France constate que la santé mentale est particulièrement dégradée chez les étudiants et les moins de 49 ans.

Has under-65 mortality really decreased in 2020, as Professor Didier Raoult asserts?

This observation is made by INSEE. It can be explained in particular by a dizzying drop in the number of traffic accidents in France.

This figure in France may be applicable in the majority of countries.

“The numbers, for me, don’t have a particular symbolic meaning.” While France crossed the threshold of 100,000 Covid-19 victims on Thursday April 15, Didier Raoult refused to see it as a symbol. Guest of BFMTV, the director of the University Hospital Institute (IHU) of Marseille, however, commented on the passage of this vertiginous cape.

Follow the latest information on the Covid-19 epidemic in our direct

“If you take people under 65, fewer people died in 2020 than in 2019 and 2018. Less. While if you take people over 75 or people over 85 , he died a lot more “, noted the microbiologist, revealed to the general public by his iconoclastic positions on the fight against the pandemic. Is Didier Raoult telling the truth or fake?


A proven drop in under-65 mortality last year

All causes combined, 667,400 deaths were recorded in France in 2020, “or 9% more than in 2018 or 2019”, counts the National Institute of Statistics and Economic Studies (Insee) in a provisional estimate. A dive into these INSEE figures makes it possible to identify a double phenomenon. On the one hand, an increase in mortality of more than 10% affected those over 65 between 2020 and 2019. On the other hand, those under 65 were less likely to lose their lives in 2020.

In detail, mortality has fallen by 6% for those under 25 and by 1% for those aged 25-49. But for people aged 50 to 64, it increased by 2%. INSEE therefore considers that the increase in mortality was “negligible” among those under 65. Which gives reason to Professor Raoult.

The protective effect of sanitary restrictions

How to explain such a drop in mortality among the youngest? For the demographer and epidemiologist Jean-Marie Robine, joined by franceinfo, the explanation lies in the health measures, which have had beneficial collateral effects. “The lockdown, by forcing people to stay at home, has reduced much of the mortality among the youngest.” First phenomenon identified by the scientific adviser of the National Institute of Demographic Studies (INED): the reduction in road accidents. “It is very often young people who are victims”, notes Jean-Marie Robine.

This is confirmed by the data for the year 2020. The number of motorists killed in a road accident decreased by 28% between 2019 and 2020, settling at 1,172 deaths, reports the National Interministerial Safety Observatory road. Among 18-24 year olds, for whom death on the road represents “the leading cause of death” according to the government, this decrease reaches 22%. For the public body, the limitation of “travel during confinements and periods of curfew” and fewer departures on vacation explain this drastic drop in the number of road deaths.

Barrier gestures have also played a role in lowering mortality among those under 65, believes Jean-Marie Robine. “Wearing the mask protected them from anything they could have caught elsewhere, whether it be gastroenteritis, flu or infectious diseases in general”, lists the epidemiologist. Pathologies effectively in decline in 2020. According to Public Health France (PDF document), the 2019-2020 flu epidemic would have caused 3,680 deaths, against 9,000 deaths in normal times.


Low mortality in the face of Covid-19

This drop in mortality among those under 65 is also explained by a lower lethality of the virus among the youngest, notes Jean-Marie Robine. “It is a population very, very little at risk of dying from Covid, unless they have comorbidities”, notes the epidemiologist and demographer. Data extracted from the public platform Géodes on 44,000 deaths attest to this: 87% of Covid-19 deaths were over 70 years old, of which three quarters were at least in their eighties.

Another phenomenon highlighted by Jean-Marie Robine: contrary to fears due to the health context and restrictions, “there was no increase in the number of suicides in 2020”, says the demographer. Each year, nearly 10,000 people end their life in France. A situation that mainly affects adults aged 25 to 59, reveals Public Health France. If the National Suicide Observatory has, for the time being, not published a report for the past year, the indicators indeed point to an absence of an increase in the number of acts in 2020, revealed the news paper Le Monde in November.

This decline may seem paradoxical and temporary, as the psychological consequences of health restrictions and the pandemic emerge. Thus, 9% of the people questioned by Public Health France confided to having suicidal thoughts in mid-March 2021. And 20.7% of the respondents presented a depressive state.

Public Health France notes that mental health is particularly degraded among students and those under 49 years old.

Julien Nguyen Dang – franceinfo France Télévisions