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September 4, 2025

French national debt under presidents Chirac, Sarkozy, Hollande and Macron: a look at the numbers

Source: The Conversation – France (in French) – By François Langot, Professeur d’économie, Directeur adjoint de l’i-MIP (PSE-CEPREMAP), Le Mans Université

French national debt has grown steadily over the last 30 years. It is the sum of all public deficits accumulated since the mid-1970s. To compare the amount of national debt to the government’s financing capacity, it is expressed as a percentage of gross domestic product (GDP) – debt-to-GDP ratio – which indicates how many years of wealth creation (GDP) are needed to repay it.

Under Jacques Chirac, the debt rose from €663.5 billion to €1,211.4 billion, or from 55.5% to 64.1% of GDP. Under Nicolas Sarkozy, it reached €1,833.8 billion, or 90.2% of GDP. Under François Hollande, it hit €2,258.7 billion, or 98.4% of GDP.

At the end of the first quarter of 2025, France’s debt stood at €3,345.4 billion, or 113.9% of GDP. While this debt is the result of political choices that determine the country’s revenue and spending, it also depends on the economic climate, which can make managing the debt easier or more difficult.

Amid developments such as the dot-com bubble, the economic boom of the 2000s, the subprime crisis in 2008, the eurozone recession, and the Covid-19 pandemic, the governments of Chirac, Sarkozy, Hollande and current President Emmanuel Macron have experienced both gloomy and bright economic conditions.

How economic conditions influence the debt

The economic situation may be analysed using two parameters, both of which are rates: the interest rate (r), set by the European Central Bank (ECB), which determines the interest payable on debt; and growth rates (g for growth), which measure the annual increase in wealth created (GDP).

This situation has two effects.

The first effect is unfavourable to public finances. It occurs when economic conditions cause the interest rate (r) to be higher than the growth rate (g), ie r-g > 0. In this context, the surplus wealth created by growth is less than the interest payable on the debt. De facto, the debt increases, even if policy choices lead to government revenue financing government spending (excluding interest payments on the debt), ie if the primary deficit is zero.

Figure 1 shows that this unfavourable economic situation occurred during Chirac’s mandate. During this period, the sum of the primary deficits (government expenditure excluding debt servicing) and revenue remained virtually stable (blue curve). Debt rose due to high interest rates (r between 2.5% and 5%), combined with moderate growth (g around 4%), which caused debt to increase (red curve).

A second effect is favourable to public finances. If the real interest rate is lower than the growth rate (r-g < 0), then debt (debt-to-GDP ratio) can be stabilised, even if spending, excluding interest charges, exceeds revenue – that is, even if policy choices lead to a primary deficit. In this case, the annual increase in wealth created (GDP growth) is greater than the interest burden.

Figure 1 shows that such a situation occurred during Macron’s terms in office. During this period, the sum of primary deficits rose sharply (blue curve): political choices led to government spending (excluding interest payments on debt) exceeding its revenue. However, debt increased at a slower rate (red curve), as interest rates remained lower than growth (less than 2% for interest rates, r, compared to more than 2.5% for growth, g).

Figure 1: The gap between the red line and the blue line measures the contribution of net interest charges from growth (r-g) to the change in the debt-to-GDP ratio. Data from France’s National Institute of Statistics and Economic Studies (INSEE).
Fourni par l’auteur

How economic conditions contribute to the debt

Recent history divides presidential terms into two groups. The first group includes those in which “bad” economic conditions are the main reason for the increase in debt (debt-to-GDP ratio), which is shown by the red curve rising more than the blue curve in Figure 1. The second group includes terms in which primary deficits are the main reason for the increase in debt, which is shown by the blue curve rising more than the red curve.

The first group includes the terms of Chirac and Sarkozy. The second includes those of Hollande and Macron.

The data show that during Chirac’s two terms in office (1995–2007), the debt-to-GDP ratio increased by 8.99 points (0.75 points per year). This increase was due to a “poor” economic climate for public finances (r-g effect > 0), which caused the debt-to-GDP ratio to rise by 10.07 points, while the dynamics of primary deficits helped to reduce it by 1.08 points. During this period, interest rates on public debt were very high, ranging between 4% and 6%.

Under Sarkozy’s term (2007-2012), the debt-to-GDP ratio rose by 22.76 points (4.55 points per year), of which 11.01 points were due to primary deficits, representing 48% of the total increase, and 11.75 points were due to economic conditions (52% of the total). Interest rates remained high, between 3% and 4%. The large primary deficits followed policy choices aimed at cushioning the subprime crisis.

Conversely, during Hollande’s term (2012-2017), rising primary deficits accounted for 71.5% of the total increase in the debt-to-GDP ratio (9.13 points out of a total increase of 12.74 points, or 2.55 points per year). Interest rates continued to fall, from 3% to less than 2%, while primary deficits were not curbed, even though the subprime and sovereign debt crises had passed.

Primary deficits under Macron

Macron’s time in office, until 2024, further accentuates this trend. The debt has only increased by 10.8 points (1.35 points per year), as the economic situation has caused it to fall by 15.31 points, with interest rates becoming very low, falling below 1% in 2020.

The increase in debt can be explained solely by the very sharp rise in primary deficits, which caused it to grow by 26.11 points during a period when the Covid pandemic and the energy crisis led the government to protect citizens from excessive declines in purchasing power.

The period from 2025 to 2029 falls into the second scenario, in which economic conditions will make it increasingly difficult to manage public debt (r-g < 0). Even with a policy objective of controlling debt, primary deficits can only be reduced gradually. With these deficits continuing to weigh on debt, growth will increasingly fail to offset rising interest rates.

The budget that Prime Minister François Bayrou presented on July 25 will increase the debt-to-GDP ratio by 4.6 points (0.92 points per year) in a context in which economic conditions will reduce it by 1.7 points. Primary deficits will increase it by 6.3 points. Bayrou’s budgetary proposal will stabilise the debt-to-GDP ratio at around 117%, which is far from the stabilisation at around 60% achieved during Chirac’s terms in office.

Balance between spending and revenue

The evolution of the primary deficit (the difference between spending, excluding interest charges, and revenue) shows that over the last 29 years, there have been 10 years in which it increased. There have been three major increases: by 1.82 points in 2002, with the stock market crash; by 4.2 points in 2009, with the subprime crisis; and by 6.1 points in 2020, with the Covid pandemic. In 2002, the increase in the deficit consisted of 1.1 points linked to increases in spending and 0.72 points linked to reductions in revenue. The sharp increases in 2008 and 2020 were mainly due to spending increases: 95% of the 4.2 points in 2008 and 97% of the 6.1 points in 2020. To contain debt, revenues eventually increased after crises: between 2004 and 2006, between 2011 and 2013, and between 2021 and 2022. However, there were no reductions in spending after 2011 or after 2023.

It is therefore persistent spending at a high level that explains the increase in the debt-to-GDP ratio. Only a very recent period, in 2023, amid the Ukraine crisis, led the government to reduce revenues in order to preserve purchasing power in a context of high inflation.

Restricting public spending

The Bayrou government’s plan, by placing three-quarters of the adjustment on spending, proposes to regain control of public spending so that it represents 54.4% of GDP in 2029 – the level seen before the 2007 crisis. Beyond stabilising the debt-to-GDP ratio, this policy choice also permits consideration of the possibility of managing a potential future crisis. The question that then arises is: which spending items should be reduced as a priority?

Figure 2: Variation in a type of expenditure per term in office. The variation measures the difference in GDP points between expenditure at the end of a term (or, for Macron, 2023) and expenditure at the beginning. INSEE data.
Fourni par l’auteur

The spending items that have increased since 1995 are those related to the environment (+0.8 percentage points of GDP); health (+3.2 percentage points of GDP); leisure, culture and religion (+0.6 percentage points of GDP); and social protection (+1.3 percentage points of GDP). Those that have fallen are related to general government services (-4.1 points of GDP), defence (-1.1 points of GDP) and education (-1.5 points of GDP). In the future, a budget that reallocates spending in favour of defence and education through better restriction of health and social protection spending should therefore be seen as a simple rebalancing exercise.

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François Langot ne travaille pas, ne conseille pas, ne possède pas de parts, ne reçoit pas de fonds d’une organisation qui pourrait tirer profit de cet article, et n’a déclaré aucune autre affiliation que son organisme de recherche.

– ref. French national debt under presidents Chirac, Sarkozy, Hollande and Macron: a look at the numbers – https://theconversation.com/french-national-debt-under-presidents-chirac-sarkozy-hollande-and-macron-a-look-at-the-numbers-264411

September 4, 2025

Afrique de l’Ouest : une étude met en lumière la dure réalité des enfants migrants travailleurs

Source: The Conversation – in French – By Aly Tandian, enseignant-chercheur, Université Gaston Berger

Une récente enquête menée au Sénégal, en Mauritanie, en Côte d’Ivoire et en Guinée (avril 2023 à avril 2025) décrit la réalité souvent invisible des enfants migrants travailleurs. Ces enfants vulnérables sont confrontés à l’exploitation, à la précarité éducative et à de graves obstacles d’accès aux soins. L’auteur de cette étude, le chercheur Aly Tandian, s’est entretenu avec The Conversation Africa. Il plaide pour des politiques inclusives afin de garantir leurs droits fondamentaux et prévenir l’apatridie.

Qui sont les enfants migrants en Afrique de l’Ouest ?

En Afrique de l’Ouest, les enfants migrants sont des filles et des garçons de moins de 18 ans qui se déplacent à l’intérieur de leur pays ou au-delà des frontières, de manière volontaire ou contrainte, temporaire ou permanente. Certains voyagent seuls, parfois envoyés par leurs parents ou tuteurs pour trouver du travail, apprendre un métier ou fréquenter une école coranique. D’autres se déplacent avec un ou les deux parents, dans le cadre de migrations familiales (exode rural, déplacements transfrontaliers pour le travail saisonnier).

Nombreux sont ceux placés chez des proches, maîtres d’apprentissage ou maîtres coraniques. Ce qui fait d’eux des migrants placés sous la responsabilité d’un adulte autre que leur parent. Leur mobilité est souvent liée à des stratégies familiales, comme le confiage, la recherche d’opportunités économiques ou l’accès à l’éducation. Elle s’explique aussi par des logiques communautaires, telles que le placement chez un maître coranique, l’apprentissage d’un métier ou le travail saisonnier, mais également par la pauvreté, les conflits, les catastrophes, la traite et l’exploitation.

La prévalence des migrations d’enfants est élevée en Afrique de l’Ouest, mais la quantification précise est difficile à établir en raison de l’informalité, de la mobilité non enregistrée et de l’invisibilité statistique.

Comment caractérisez-vous la réalité des enfants migrants travailleurs dans la région ?

En Afrique de l’Ouest, les enfants migrants travailleurs sont visibles dans les différents secteurs économiques comme l’agriculture, à la fois urbaine et rurale (plantations de cacao et de café, marchés et gares routières, quartiers périphériques et chantiers, les environnements religieux et éducatifs détournés ainsi que zones minières et portuaires). Ils peuvent être doublement vulnérables à cause des conditions d’abus, d’exploitation, de soumission à des travaux indignes auxquels ils sont soumis mais également à l’isolement et à d’autres difficultés liées au parcours migratoire.

Dans certaines circonstances, ils peuvent ne pas avoir la capacité juridique de faire valoir leurs droits contre des entreprises commerciales et d’autres parties qui les engagent dans le travail. Ces enfants, vulnérables en raison de leur statut d’étrangers, ont un accès limité à la justice, à l’éducation et sont exposés aux abus et à la discrimination.

L’invisibilité juridique et administrative à laquelle ils sont confrontés renvoie à une absence d’identité juridique et à une privation de divers droits. De même, la protection juridique n’est pas équitable et les enfants migrants travailleurs ont besoin dans certains cas de mécanismes particuliers pouvant éviter l’apatridie (situation d’une personne dont aucun Etat ne reconnait la nationalité).

Quels sont les principaux risques auxquels ces enfants sont exposés ?

Les vulnérabilités sont liées principalement à leur statut irrégulier, au manque de document d’identité, à l’accès limité aux services publics et à l’absence de protection juridique. Elles limitent leur accès à une éducation de qualité et leur développement personnel.

Leur situation scolaire n’est pas favorable car ils vivent dans un déséquilibre scolaire profond avec les nationaux. De fait, leur droit à l’éducation n’est pas respecté. Mais les garçons et les filles de migrants ne sont pas égaux avec les autres ni en termes de droit à l’éducation ni en termes d’opportunités ou d’obligations après un décrochage.

Par ailleurs, ces enfants ont souvent un accès limité aux soins de santé. Les barrières administratives, la non-inscription dans les systèmes de santé nationaux, et la mobilité géographique des familles rendent difficile la continuité des soins, notamment dans les zones urbaines où les migrants sont concentrés.

Les services de santé mentale sont rares, souvent inaccessibles dans les zones rurales ou les camps de réfugiés, et parfois méconnus des familles. Les enfants se heurtent aussi à la stigmatisation, au manque d’information et à l’insuffisance de moyens financiers. Ce qui les empêche de recevoir les soins dont ils ont besoin. En Guinée, par exemple, la vulnérabilité sanitaire des enfants de migrants s’est particulièrement remarquée à la faveur des épisodes d’épidémie d’Ébola et de la pandémie de la Covid-19 en contradiction avec le droit guinéen.

Quelles sont les conséquences de la séparation familiale des enfants de migrants ?

Au cours de nos enquêtes, nous avons pu constater que de nombreux enfants vivant avec un des deux parents ou avec des tuteurs souffrent de vulnérabilités émotionnelles et psychologiques. Ils sont confrontés à un manque de protection et d’encadrement, des difficultés éducatives ainsi que des risques de migration autonome.

A Bouaké (Côte d’Ivoire) et à Nouadhibou (Mauritanie), certains enfants séparés de leurs parents biologiques affirment « souffrir de sentiments d’abandon ». A Dakar et à Conakry, d’autres disent « ne pas être à l’abri des risques d’exploitation ou de maltraitance ».

L’absence des parents influence différemment la scolarisation des enfants. L’absence du père peut entraîner une faible autorité dans le foyer et un sentiment d’abandon. Quand la mère manque, les filles risquent davantage d’interrompre leur scolarité pour assumer des tâches domestiques.

En outre, il y a une perte du lien émotionnel, car la mère joue souvent un rôle affectif et éducatif quotidien. On constate une baisse du suivi scolaire et nutritionnel, surtout pour les jeunes enfants.

La séparation familiale des enfants de migrants constitue un défi majeur qui exige des politiques inclusives et un soutien coordonné pour leur bien-être et la réunification. Les enfants expriment de façon récurrente leur besoin de surmonter cette séparation.

Entre autres conséquences de la séparation familiale sur les enfants, ces derniers citent le sentiment d’abandon, d’anxiété, de troubles du comportement, de perte de repères, un manque de lien parental, une rupture dans la construction identitaire, un isolement, une déscolarisation possible, etc.

Quelles formes de soutien ou de protection pourraient améliorer leur condition ?

Les enfants migrants travailleurs ont besoin d’avoir accès aux documents d’état civil (actes de naissance, certificats de résidence, papiers d’identité, etc.). L’absence de ces documents entraîne une absence d’identité légale. Sans les papiers, il est impossible pour les autorités d’identifier l’enfant, de vérifier son âge, son origine ou son lien avec un éventuel accompagnant.

Une telle situation est à l’origine de l’échec de l’instruction ou de la scolarisation de nombreux enfants migrants. L’inaction des autorités publiques favorise des réseaux illicites d’établissement de documents administratifs qui ne satisferont pas les objectifs du tuteur. Ils ont également besoin d’assistance juridique pour défendre leurs droits.

L’absence de documents administratifs limite l’accès des enfants migrants travailleurs à l’éducation, aux soins et à la justice. Elle restreint aussi leurs droits dans leur pays d’origine et peut entraver leur mobilité et leur travail.

Les besoins en santé et bien-être incluent la vaccination, la prise en charge psychologique des enfants migrants travailleurs, ainsi que la santé, la nutrition et la santé mentale des enfants.

Les enfants de migrants séparés de leurs parents rencontrent des obstacles liés aux préjugés et à la marginalisation, qui limitent leur accès aux soins et affectent leur santé mentale. La sensibilisation des tuteurs aux besoins nutritionnels propres à chaque âge est essentielle pour assurer leur développement normal.

Les enfants migrants travailleurs ont besoin de reconnaissance, de soutien moral et d’espaces d’écoute favorisant le dialogue et la médiation. Ils doivent également voir leurs droits fondamentaux, ainsi que ceux liés à leur statut d’enfant migrant, respectés.

Que recommanderiez-vous aux décideurs pour encadrer cette migration dès l’enfance ?

Pour améliorer la situation des enfants migrants travailleurs en Afrique de l’Ouest, il est impératif que les États de la région mettent en place des politiques migratoires et des systèmes d’enregistrement civil garantissant leurs droits fondamentaux, indépendamment de leur statut. Ils doivent aussi renforcer les mécanismes de protection et de justice en faveur des enfants les plus vulnérables.

L’inclusion des enfants de migrants passe par des efforts coordonnés entre les gouvernements, les ONG, les institutions internationales et les communautés locales.

En termes de recommandation, il faut :

renforcer des politiques de protection sociale en facilitant l’accès aux soins et à l’éducation pour les enfants de migrants ;
créer des mécanismes de régularisation pour assurer un statut légal aux enfants de migrants et leur donner accès aux droits fondamentaux ;
lutter contre les discriminations à l’école en sensibilisant les enseignants et les élèves à l’inclusion ;
encourager l’éducation des filles en réduisant les obstacles socioculturels et en sensibilisant les familles ;
faciliter l’enregistrement des naissances issues de couples de migrants pour garantir un accès aux droits fondamentaux ;
mener des campagnes de sensibilisation auprès des communautés migrantes sur l’importance des documents d’identité.

Les enfants migrants constituent une réalité multiple. Ils sont exposés à des formes d’exploitation et leur situation devrait interroger les politiques publiques car ce sont des enfants le plus souvent dépourvus de documents administratifs. Ils se retrouvent confrontés à une non-admission dans les pays de transit, de destination et parfois d’origine.

L’avenir de ces enfants en Afrique de l’Ouest sera déterminé par la capacité des États, des communautés et des organisations régionales à transformer une mobilité souvent synonyme d’exploitation en une mobilité protégée et valorisée.

Aly Tandian does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.

– ref. Afrique de l’Ouest : une étude met en lumière la dure réalité des enfants migrants travailleurs – https://theconversation.com/afrique-de-louest-une-etude-met-en-lumiere-la-dure-realite-des-enfants-migrants-travailleurs-264289

September 4, 2025

Mars has a solid inner core, resolving a longstanding planetary mystery — new study

Source: The Conversation – UK – By Kevin Olsen, UKSA Mars Science Fellow, Department of Physics, University of Oxford

Scientists have discovered that Mars has an interior structure similar to Earth’s. Results from Nasa’s Insight mission suggest that the red planet has a solid inner core surrounded by a liquid outer core, potentially resolving a longstanding mystery.

The findings, which are published in Nature, have important implications for our understanding of how Mars evolved. Billions of years ago, the planet may have had a thicker atmosphere that allowed liquid water to flow on the surface.

This thicker atmosphere may have been kept in place by a protective magnetic field, like the one Earth has. However, Mars lacks such a field today. Scientists have wondered whether the loss of this magnetic field led to the red planet losing its atmosphere to space over time and becoming the cold, dry desert it is today.

A key property of the Earth is that its core has a solid centre and liquid outer core. Convection within the liquid layer creates a dynamo, producing the magnetic field. The field deflects charged particles ejected by the Sun, preventing them from stripping the Earth’s atmosphere away over time and leading to the habitable conditions we know and enjoy.

From residual magnetisation in the crust, we think that Mars did once have a magnetic field, possibly from a core structure similar to that of Earth. However, scientists think that the core must have cooled and stopped moving at some point in its history.

On the surface of Mars there is a tremendous amount of evidence that liquid water once flowed, suggesting more hospitable conditions in the past. The evidence comes in many forms, including dry lake beds with minerals that formed under water, or the dramatic valley networks carved by rivers and streams. However, the Martian atmosphere is thin today and the necessary amount of water is nowhere to be found.

Teams working with the seismometers on Nasa’s InSight Mars lander first identified the Martian core and determined that it was actually still liquid. Now, the new results from Huixing Bi, at the University of Science and Technology of China in Hefei and colleagues, show that there may also be a solid layer inside the liquid core.

The nature of the interior structure of Mars has been an intriguing mystery. Was it ever like Earth’s, with a dynamic liquid layer around a solid centre? Or did Mars’ smaller size prevent such a formation? How big must a planet be to gain the protection of a magnetic field, like Earth’s, and support a habitable climate?

To understand what happened, how Mars evolved, we need to understand Mars today. These questions about Mars’ atmosphere, water, and core have motivated several high profile Mars missions. While the Nasa Mars rovers, Spirit, Opportunity, Curiosity, and Perseverance have studied the surface mineralogy, the European Space Agency’s ExoMars Trace Gas Orbiter is studying the water cycle, Nasa’s Maven spacecraft is studying atmospheric loss to space, and Nasa’s InSight lander was sent to study seismic activity.

In 2021, Simon Stähler, from ETH Zurich in Switzerland, and colleagues, published a seminal paper from the InSight mission. In it, they presented an analysis of the way that seismic waves pass through Mars from Mars quakes in the vicinity of InSight, through the mantle, through the core, and then reflecting off the other side of the planet and reaching InSight.

They detected evidence of the core for the first time and were able to constrain its size and density. They modelled a core with a single liquid layer that was both larger and less dense than expected and without a solid inner core. The size was huge, about half of Mars’ radius of 1,800 km, and the low density implied that it was full of lighter elements. The light elements, such as carbon, sulphur, and hydrogen, change the core’s melt temperature and affect how it could crystallise over time, making it more likely to remain liquid.

The solid inner core (610 km radius) found by Huxing Bi and colleagues is hugely significant. The very presence of a solid inner core shows that crystallisation and solidification is taking place as the planet cools over time.

The core structure is more like Earth’s and therefore more likely to have produced a dynamo at some point. On Earth, it is the thermal (heat) changes between the solid inner core, the liquid layer, and the mantle that drive convection in the liquid layer and create the dynamo that leads to a magnetic field. This result makes it more likely that a dynamo on Mars was possible in the past.

With Simon Stähler and co-authors reporting a fully liquid core and Huxing Bi and colleagues reporting a solid inner core, it might seem as if there will be some controversy. But that is not the case. This is an excellent example of progress in scientific data collection and analysis.

The findings will help guide scientists towards a better understanding of Mars’ evolution as a planet.
JPL-Caltech

Competing models of Mars

InSight landed in November 2018 and its last contact with Earth occurred in December 2022. With Stähler publishing in 2021, there is some new data from InSight to look at. Stähler’s model was revised in 2023 by Henri Samuel, from the Université Paris Cité, and colleagues. A revised core size and density helped reconcile the InSight results with some other pieces of evidence.

In Stähler’s paper, a solid inner core is specifically not ruled out. The authors state that the signal strength of the analysed data was not strong enough to be used to identify seismic waves crossing an inner core boundary. This was an excellent first measurement of the core of Mars, but it left the question of additional layers and structure open.

For the latest study in Nature, the scientists achieved their result through a careful selection of specific seismic event types, at a certain distance from InSight. They also employ some novel data analysis techniques to get a weak signal out of the instrument noise.

This result is sure to have an impact within the community, and it will be very interesting to see whether additional re-analyses of the InSight data support or reject their model. A thorough discussion of the broader geological context and whether the model fits other available data that constrain the core size and density fit will also follow.

Understanding the interior structure of planets in our Solar System is critical to developing ideas about how they form, grow, and evolve. Prior to InSight, models for Mars that were similar to Earth were investigated, but were certainly not favoured.

The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.

– ref. Mars has a solid inner core, resolving a longstanding planetary mystery — new study – https://theconversation.com/mars-has-a-solid-inner-core-resolving-a-longstanding-planetary-mystery-new-study-264325

September 4, 2025

Tragedy has struck Lisbon’s funicular railway. A transport expert explains how these old-fashioned trains work

Source: The Conversation – Global Perspectives – By Peter Newman, Professor of Sustainability, Curtin University

Some 15 people have died after the Gloria funicular railway car in Lisbon, Portugal, derailed and crashed on Wednesday local time.

Emergency services have also confirmed that more than 18 people were also injured, five of them seriously, in the tragedy, which occurred at the start of the evening rush hour.

It follows another accident on the same line in May 2018, when one of the cars derailed due to flaws in the maintenance of its wheels. No one was killed in that incident.

The exact cause of the most recent accident is not yet known. Witnesses have reported that the yellow-and-white tram appeared out of control as it sped downhill, before derailing as it rounded a bend and crashing into a building. Photos of the aftermath show a crumpled heap of cables and steel.

These cable car–like transport systems are rare relics of the 19th century, found in only a few very hilly places around the world. So how do they work? And why are they still in use?

How do funicular railways work?

Trains and trams typically only work on flat terrain. That’s because their steel wheels can’t get enough traction on steel rails on steep hills. As a workaround, railway engineers often build tunnels through steep mountainsides.

Funicular railways, however, can go up very steep hills.

They usually feature two counterbalanced cars that are attached via a haulage cable.

As one car descends, it helps pull the ascending car up the hillside. The weight of the ascending car also prevents the descending one from careening out of control. Some now have electric motors to help power them and some are able to engage a one-way mechanical drive just for steep hills.

Even though funicular systems are typically quite slow and clunky, they are still popular with both tourists and residents in the places where they’re found.

Where are they found?

The Gloria funicular railway line in Lisbon opened in 1885. One of three funicular lines in Lisbon, it connects the city’s downtown area with the Bairro Alto (Upper Quarter).

But there are other examples of these transport relics around the world.

Switzerland has several funicular railways. The most notable is the Stoosbahn – the steepest funicular in the world. It covers a total ascent of around 744 metres, reaching a gradient of 47 degrees. It is a very popular tourist trip.

In Hong Kong, the Peak Tram is a funicular railway that has operated since 1888 and takes people to near the top of Hong Kong Island.

Last year, there was also some discussion about installing a new funicular railway system in the Blue Mountains in New South Wales, Australia, that would travel 14 metres every second.

A yellow and black railway car travels along a track, with mountains in the background. — The Stoosbahn in Switzerland is the steepest funicular in the world.
Stéphane Gottraux/Wikipedia, CC BY

The rise of trackless trams

Funicular railways still serve a purpose for people living in – or visiting – steep areas where they’re found. However, newer technology means more conventional forms of rail transport are now far less limited in travelling up and down hills.

For example, trackless trams are kind of a combination between a tram and a bus. They use GPS and digital sensors to move precisely along an invisible track and have rubber wheels, enabling them to ascend gradients of up to 15%. However, these have not yet been built for steeper hills.

I have enjoyed riding such funicular trams in a range of hilly cities, but this crash is likely to take the shine off the tourist experience. It’s about time we had a 21st-century option that is clearly safer.

Peter Newman receives funding from the CRC RACE.

– ref. Tragedy has struck Lisbon’s funicular railway. A transport expert explains how these old-fashioned trains work – https://theconversation.com/tragedy-has-struck-lisbons-funicular-railway-a-transport-expert-explains-how-these-old-fashioned-trains-work-264574

September 4, 2025

Google just dodged a major penalty in the courts – here’s what happens next

Source: The Conversation – Global Perspectives – By Rob Nicholls, Senior Research Associate in Media and Communications, University of Sydney

Google will not have to sell its Chrome web browser in order to fix its illegal monopoly in the online search business, a United States federal judge has ruled. It will, however, need to do a few other things, such as sharing data with rival companies, in order to improve competition.

The remedies ruling was handed down by DC District Court Judge Amit Mehta, who last year found Google had violated antitrust laws in relation to its online search business.

This was not the worst-case scenario for Google, and the share price of its parent Alphabet rose 8% after the news. But the ruling could still have a significant impact on the tech giant – and the entire internet.

What was the case actually about?

The US Department of Justice (DOJ) filed its antitrust suit against Google in 2020, arguing the tech giant had used exclusive agreements with device makers such as Apple and Samsung to unfairly box out competitors from the search engine market.

For years, Google accounted for reportedly 90% of all search queries in the US, using what the DOJ called “anticompetitive tactics” to maintain and extend its monopolies in search and search advertising.

In August 2024, Judge Mehta ruled in the DOJ’s favour, finding Google had maintained an illegal monopoly.

The case centred on Google’s practice of entering into exclusionary agreements that collectively locked up the primary avenues through which users access online search, making Google the pre-set default general search engine on billions of mobile devices and computers – and particularly on Apple devices.

The remedies – proposed and actual

The DOJ urged the sell-off of the Chrome browser and possibly its Android operating system, and the sharing of search data. It said these remedies would limit Google’s ability to monopolise the search market and prevent it from gaining an unfair advantage in other markets, notably artificial intelligence (AI).

The DOJ also demanded an end to its multibillion-dollar agreements with Apple and other partners.

Judge Mehta’s remedies ruling fell significantly short of the DOJ’s harshest demands.

Under the remedies ordered, Google will be barred from entering or maintaining exclusive contracts relating to the distribution of Google Search, Chrome, Google Assistant, and the AI-powered Gemini app.

Google cannot enter agreements that condition the licensing of any Google application on the distribution or placement of these products, or condition revenue share payments on maintaining these products on any device for more than one year.

Google must also provide competitors with access to its search results and advertising services at standard rates. This will help them to deliver quality search results to their own users while building their own technology.

However, Google will not be barred from paying device makers to preload its products, including Google Search and generative AI products.

A technical committee will be established to help enforce the final judgment, which will last six years and go into effect 60 days after entry. Judge Mehta ordered the parties to meet by September 10 for the final judgment.

Shortly after the judge’s ruling, Google released a statement reiterating its opposition to the initial ruling in August 2024, which it still plans to appeal.

Today’s decision recognises how much the industry has changed through the advent of AI, which is giving people so many more ways to find information. This underlines what we’ve been saying since this case was filed in 2020: competition is intense and people can easily choose the services they want.

More cases to come

This decision opens up competition in the search market while allowing Google to maintain its core business structure. The data-sharing requirements could particularly benefit AI competitors who need large datasets to train their models.

Google faces additional antitrust pressure beyond this search case. In April 2025, US District Judge Leonie Brinkema found Google illegally monopolised advertising technology markets. The remedies trial for that case is scheduled for later this month.

As William Kovacic, a global competition law professor at George Washington University and former Federal Trade Commission commissioner, told TechCrunch:

We’ve never had a circumstance in which the Department of Justice has had two largely parallel cases involving major elements of alleged misconduct against the same dominant firm with two parallel remedy processes going ahead.

Google’s competitors, however, believe the remedies should have been more severe in this case.

In a statement, Gabriel Weinberg, the chief executive of search engine competitor DuckDuckGo, claimed Google “will still be allowed to continue to use its monopoly to hold back competitors, including in AI search”. He also called on the US congress to step in “to swiftly make Google do the thing it fears the most: compete on a level playing field”.

It seems likely the DOJ will need to demonstrate abuse of dominance in the AI search field in order to get a remedy that will satisfy DuckDuckGo.

The full resolution of these cases likely won’t occur until late 2027 or early 2028, as Google has indicated it will appeal both the liability and remedy decisions.

Rob Nicholls receives funding from the Australian Research Council.

– ref. Google just dodged a major penalty in the courts – here’s what happens next – https://theconversation.com/google-just-dodged-a-major-penalty-in-the-courts-heres-what-happens-next-264473

September 4, 2025

Scrolling on the toilet increases your risk of haemorrhoids, new study shows

Source: The Conversation – Global Perspectives – By Vincent Ho, Associate Professor and Clinical Academic Gastroenterologist, Western Sydney University

Many of us are guilty of scrolling our smartphones on the toilet. But a new study from the United States, published today, has found this habit may increase your risk of developing haemorrhoids by up to 46%.

So, what’s the link? How can time on your phone lead to these painful lumps in and around your anus? Here’s what we know.

What are haemorrhoids?

Every healthy person has haemorrhoids, sometimes called piles. They are columns of cushioned tissue and blood vessels found close to the opening of the anus.

Diagram showing haemorrhoid types: normal, internal and external. — We don’t notice haemorrhoids until they’re symptomatic.
Aleksandr Kharitonov/Getty

Haemorrhoids have a really important role in maintaining bowel continence or, to put it simply, keeping your poo in.

When all is well, we don’t notice them. But haemorrhoids can get swollen and this can lead to symptoms such as pain, bleeding or feeling a lump just inside your anus (internal haemorrhoids) or protruding outside (external haemorrhoids).

So when someone “has haemorrhoids”, it means they have become inflamed or symptomatic.

This is extremely common: more than one in two of us will experience symptomatic haemorrhoids at some point in our lives.

You are more likely to get haemorrhoids if you:

are older (over 45)
are pregnant
are overweight
have persistent constipation or diarrhoea
regularly lift heavy objects
spend a lot of time on the toilet.

The link between toilet time and haemorrhoids

Prolonged sitting in general has not been linked to developing haemorrhoids.

However, a standard toilet seat – unlike a chair or couch – has a large internal opening that provides no support for the pelvic floor (the group of muscles and ligaments that support the bladder, bowel and uterus).

Prolonged sitting on a toilet seat is believed to increase pressure inside the pelvic floor and lead to blood pooling in the vascular cushions of the anus. This makes haemorrhoids more likely to develop.

What the new study looked at

The new US study recruited 125 adults, aged 45 and older, who were undergoing a colonoscopy at Beth Israel Deaconess Medical centre.

Researchers surveyed them about their smartphone habits while using the toilet, including how often they checked their phone and for how long. Participants also reported on other behaviours such as straining, their fibre intake, and how much physical activity they did.

The researchers recorded whether they had haemorrhoids. Since the participants were all having a colonoscopy, the presence of internal haemorrhoids could be directly confirmed visually.

What did the study show?

Two-thirds (66%) of all participants used smartphones while on the toilet. The most common activity was reading news (54.3%), followed by social media (44.4%).

Those who used their smartphones spent longer on the toilet than those who didn’t. More than one in three (37.3%) toilet smartphone users spent over five minutes on the toilet, compared to just over one in 20 (7%) of those who didn’t use their smartphones.

The smartphone users had a 46% higher risk of haemorrhoids, compared to those who didn’t use their smartphone. To calculate this, researchers took into account other known risk factors for haemorrhoids such as gender, age, body mass index, exercise activity, straining and fibre intake.

However, unlike some other research, this study did not find a link between straining and haemorrhoids.

As a result, the researchers concluded that time spent on the toilet poses a more significant risk for haemorrhoids than straining. However, we can’t rule out straining as a risk factor, based on one study.

Some other limitations to consider

The study relied on participants remembering whether or not they strained, and how long they spent on the toilet.

This kind of recall is subjective, and may also be influenced by taking part in the study. For example, if the participants thought they had haemorrhoids, they may be more likely to report straining.

The study’s small sample size and the participants’ age (all over 45) also mean it is unlikely to be representative of the broader population.

Toilet sitting time

The new study is not the first to study the link between time spent on the toilet and developing haemorrhoids. In 2020, a Turkish study found spending more than five minutes on the toilet was associated with haemorrhoids.

Another 2020 study from Italy of 52 people with diagnosed internal or external haemorrhoids noted the longer they spent on the toilet, the more severe their haemorrhoids.

So, what are we doing on the toilet?

Defaecation itself usually doesn’t take long. One study found it took healthy adults an average two minutes when sitting, but only 51 seconds when squatting.

The majority of “toilet sitting time” usually means just that – sitting on the toilet, doing other activities aside from pooing (or weeing).

One 2008 study from Israel surveyed 500 adults and found more than half (52.7%) read books or newspapers while on the toilet. It also found toilet readers spent significantly more time on the toilet.

How to avoid haemorrhoids

The usual advice is to increase the amount of fibre in your diet (eating more fruit, vegetables and wholegrains) and ensure you drink enough water. This makes it easier to pass a stool and reduces straining – which you should also try to avoid.

However, the new research confirms previous evidence that cutting down toilet sitting time may also help. So, avoiding distractions by leaving your smartphone outside the bathroom is a good idea (and as a bonus, will expose your device to fewer germs).

If you have any concerning symptoms, such as blood in your stool, a new lump in the anal region, or pain when passing a bowel motion then you should see your local doctor for further investigations and treatment.

Vincent Ho does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.

– ref. Scrolling on the toilet increases your risk of haemorrhoids, new study shows – https://theconversation.com/scrolling-on-the-toilet-increases-your-risk-of-haemorrhoids-new-study-shows-264107

September 4, 2025

The science behind a freediver’s 29-minute breath hold world record

Source: The Conversation – Global Perspectives – By Theresa Larkin, Associate Professor of Medical Sciences, University of Wollongong

Croatian freediver Vitomir Maričić. Facebook.com @molchanovs, Instagram.com @maverick2go, Facebook.com @Vitomir Maričić, CC BY

Most of us can hold our breath for between 30 and 90 seconds.

A few minutes without oxygen can be fatal, so we have an involuntary reflex to breathe.

But freediver Vitomir Maričić recently held his breath for a new world record of 29 minutes and three seconds, lying on the bottom of a 3-metre-deep pool in Croatia.

Vitomir Maričić set a new Guinness World Record for “the longest breath held voluntarily under water using oxygen”.

This is about five minutes longer than the previous world record set in 2021 by another Croatian freediver, Budimir Šobat.

Interestingly, all world records for breath holds are by freedivers, who are essentially professional breath-holders.
They do extensive physical and mental training to hold their breath under water for long periods of time.

So how do freedivers delay a basic human survival response and how was Maričić able to hold his breath about 60 times longer than most people?

Increased lung volumes and oxygen storage

Freedivers do cardiovascular training – physical activity that increases your heart rate, breathing and overall blood flow for a sustained period – and breathwork to increase how much air (and therefore oxygen) they can store in their lungs.

This includes exercise such as swimming, jogging or cycling, and training their diaphragm, the main muscle of breathing.

Diaphragmatic breathing and cardiovascular exercise train the lungs to expand to a larger volume and hold more air.

This means the lungs can store more oxygen and sustain a longer breath hold.

Freedivers can also control their diaphragm and throat muscles to move the stored oxygen from their lungs to their airways. This maximises oxygen uptake into the blood to travel to other parts of the body.

To increase the oxygen in his lungs even more before his world record breath-hold, Maričić inhaled pure (100%) oxygen for ten minutes.

This gave Maričić a larger store of oxygen than if he breathed normal air, which is only about 21% oxygen.

This is classified as an oxygen-assisted breath-hold in the Guiness Book of World Records.

Even without extra pure oxygen, Maričić can hold his breath for 10 minutes and 8 seconds.

Resisting the reflex to take another breath

Oxygen is essential for all our cells to function and survive. But it is high carbon dioxide, not low oxygen that causes the involuntary reflex to breathe.

When cells use oxygen, they produce carbon dioxide, a damaging waste product.

Carbon dioxide can only be removed from our body by breathing it out.

When we hold our breath, the brain senses the build-up in carbon dioxide and triggers us to breathe again.

Freedivers practice holding their breath to desensitise their brains to high carbon dioxide and eventually low oxygen. This delays the involuntary reflex to breathe again.

When someone holds their breath beyond this, they reach a “physiological break-point”. This is when their diaphragm involuntarily contracts to force a breath.

This is physically challenging and only elite freedivers who have learnt to control their diaphragm can continue to hold their breath past this point.

Indeed, Maričić said that holding his breath longer:

got worse and worse physically, especially for my diaphragm, because of the contractions. But mentally I knew I wasn’t going to give up.

Mental focus and control is essential

Those who freedive believe it is not only physical but also a mental discipline.

Freedivers train to manage fear and anxiety and maintain a calm mental state. They practice relaxation techniques such as meditation, breath awareness and mindfulness.

Interestingly, Maričić said:

after the 20-minute mark, everything became easier, at least mentally.

Reduced mental and physical activity, reflected in a very low heart rate, reduces how much oxygen is needed. This makes the stored oxygen last longer.

That is why Maričić achieved this record lying still on the bottom of a pool.

Don’t try this at home

Beyond competitive breath-hold sports, many other people train to hold their breath for recreational hunting and gathering.

For example, ama divers who collect pearls in Japan, and Haenyeo divers from South Korea who harvest seafood.

But there are risks of breath holding.

Maričić described his world record as:

a very advanced stunt done after years of professional training and should not be attempted without proper guidance and safety.

Indeed, both high carbon dioxide and a lack of oxygen can quickly lead to loss of consciousness.

Breathing in pure oxygen can cause acute oxygen toxicity due to free radicals, which are highly reactive chemicals that can damage cells.

Unless you’re trained in breath holding, it’s best to leave this to the professionals.

– ref. The science behind a freediver’s 29-minute breath hold world record – https://theconversation.com/the-science-behind-a-freedivers-29-minute-breath-hold-world-record-264020

September 4, 2025

How RFK Jr.’s misguided science on mRNA vaccines is shaping policy − a vaccine expert examines the false claims

Source: The Conversation – USA (3) – By Deborah Fuller, Professor of Microbiology, School of Medicine, University of Washington

RFK Jr. canceled $500 million of funding for research on mRNA vaccine technology. Anadolu/Getty Images

On Sept. 4, 2025, Health and Human Services Secretary Robert F. Kennedy Jr. is scheduled to testify before the Senate Finance Committee, where he is expected to face questions about his vaccine policies.

A few days prior, on Sept. 1, 2025, President Donald Trump demanded pharmaceutical companies to prove that COVID-19 mRNA vaccines work, saying that the CDC was “being ripped apart over this question.” It was his first public acknowledgment of the chaos roiling the Centers for Disease Control and Prevention amid the firing of CDC Director Susan Monarez and subsequent resignations of four high-level agency officials.

Meanwhile, public health experts and HHS staffers are calling for Kennedy to be fired.

The turmoil comes about a month after HHS announced US$500 million in funding cuts for 22 research contracts on mRNA vaccine technology. The agency said it will instead pour these funds into research on a traditional approach to designing vaccines that was first used more than 200 years ago. With such vaccines, called whole-virus vaccines, a person’s immune system is presented with the whole virus, often in weakened or inactivated form. This switcheroo has puzzled many scientists.

As a vaccinologist who has studied and developed vaccines for over 35 years, I see that the science behind mRNA vaccine technology is being widely misstated. This incorrect information is shaping long-term health policy in the U.S. – which makes it urgent to correct the record.

Are mRNA vaccines less safe than whole-virus vaccines?

HHS defended its cancellation of mRNA vaccine research based, in part, on a nonpeer-reviewed compilation of selected publications called the COVID-19 mRNA “vaccine” harms research collection. This document lists about 750 articles claimed to describe harms caused by mRNA vaccines against COVID-19. However, the vast majority of these articles aren’t about vaccines but about the harms of getting infected with SARS-CoV-2, the virus that causes COVID-19. And notably absent from it is the huge body of data showing mRNA vaccines actually prevent these harms.

a SARS-CoV-2 particle whole and in cross-section. — Spike proteins on SARS-COV-2 can cause tissue damage – and although mRNA vaccines produce them in small amounts, they prevent the virus from replicating to produce them in large amounts.
https://www.scientificanimations.com/wiki-images/, CC BY-SA

For example, the document being used to justify RFK Jr.’s claims about mRNA vaccines highlights 375 studies reporting that the virus’s spike protein alone, which is produced when the virus replicates, can cause excessive inflammation and tissue damage. This is true. But the document marshals this evidence to support the claim that mRNA vaccines, which are designed to produce spike proteins, cause the same harm – which is not accurate.

While viral replication results in uncontrolled production of a large amounts of the protein, the way it’s produced by the mRNA vaccine is very different. The vaccine produces a small, controlled amount of spike protein inside a few cells – just enough to induce an immune response without causing damage. And by blocking the virus’s replication, it reduces the amount of spike protein in circulation, actually having the opposite effect.

What about side effects like myocarditis?

Early reports flagged a type of heart swelling called myocarditis as a rare side effect of the mRNA vaccine, particularly for young men ages 18 to 25 after a booster dose. A 2024 review identified about 20 cases out of 1 million people who received the vaccine. However, that same study found that unvaccinated people had an elevenfold higher risk of getting myocarditis after a COVID-19 infection than vaccinated people.

What’s more, another 2024 study showed that people who developed myocarditis after vaccination had fewer complications than those who developed the condition after getting infected with COVID-19.

Do mRNA vaccines make the SARS-CoV-2 virus resistant?

Another claim from the compilation of supposed mRNA vaccine harms that was cited as a reason for cutting funding for mRNA technology is that mRNA vaccines cause mutations in the SARS-CoV-2 virus that make them resistant or less susceptible to the vaccine.

When a virus replicates in its host, it produces millions of copies of its genetic material. Mutations are copying errors that occur naturally during the replication process. These acquired mutations produce new variants, which is why both the COVID-19 mRNA and the whole-virus flu vaccine get updated annually – to keep up with natural changes in the virus.

Slowing down viral replication decreases the rate at which a virus can acquire new mutations. Since both mRNA and whole-virus vaccines stop or slow the virus from replicating, both types of vaccines help reduce the emergence of resistant viruses.

Viruses can mutate to escape from antibodies, but the mRNA vaccines are not causing the emergence of more virulent strains, likely for at least two reasons. First, mRNA vaccines induce immune responses that can attack the virus at multiple spots, so it would have to come up with many mutations at once to escape the vaccine’s defenses. Second, even if the virus could acquire all these mutations, they would likely weaken it, making it unable to cause or even transmit disease.

mRNA vaccines versus new SARS-CoV-2 variants

Kennedy, in announcing cuts to mRNA vaccine research on Aug. 5, 2025, claimed that mRNA vaccines don’t work against respiratory viruses and that HHS was moving toward “safer, broader vaccine platforms that remain effective even as viruses mutate.”

Both whole-virus vaccines and mRNA vaccines protected against COVID-19 and prevented hospitalization and death for millions of people worldwide between 2020 and 2024, but there’s clear evidence that the mRNA-based vaccines provided significantly better protection than whole-virus vaccines. And for COVID-19, mRNA vaccines are more effective against new variants, which emerge as viruses mutate, than whole-virus vaccines.

mRNA vaccines’ superpower is that they can be updated and manufactured very quickly, unlike traditional whole-virus vaccines.

The COVID-19 mRNA vaccines started with exceptionally high efficacy, exceeding 94%. When the SARS-CoV-2 delta and omicron variants emerged in the spring and fall of 2021, mRNA vaccines became less effective in preventing infections. However, they remained highly effective in preventing severe illness, whereas in unvaccinated people the rates of severe illness and hospitalization remained high.

This is because mRNA vaccines induce the immune system to make both antibodies and specialized immune cells called T cells. These elements can recognize multiple parts of the virus, including ones that don’t change, enabling significant protection against new variants.

What’s more, the mRNA vaccines have a superpower that no other type of vaccine can currently match: They can be quickly updated and manufactured within two to three months. To develop a whole-virus vaccine, researchers must first spend months isolating and propagating the virus. Conversely, making an mRNA vaccine requires just sequencing the virus’s genetic code – a process that today takes just hours.

If a new pandemic began today, mRNA vaccines are currently the only type of vaccine that could be developed quickly enough to disrupt its spread.

The future of mRNA vaccine technologies

Thirty years ago, when scientists first started developing mRNA vaccine technology, they recognized its potential to overcome major limitations of whole-virus vaccines – namely, slow production time and more limited ability to protect from new viral variants. Today, mRNA vaccines are also being developed to prevent or treat diseases including HIV and cancer, as well as autoimmune and genetic diseases.

Of course, this technology can be further improved. New mRNA vaccine technologies are aimed, among other things, at making mRNA vaccines easier to store to allow for faster distribution and reduce their short-term side effects, eliminate the rare risk of myocarditis and more quickly block a respiratory infection.

The National Institutes of Health is funneling money away from new mRNA technologies toward a single project developing universal vaccines based on traditional whole-virus vaccine technology. Universal vaccines are urgently needed to provide broader protection against ever-changing respiratory viruses, such as influenza, that are major pandemic threats.

A 2022 study in mice and ferrets showed that a universal flu vaccine NIH plans to support has promise. However, multiple studies of potential universal flu vaccines based on mRNA technology show even more potential. Such vaccines could induce broader immunity than whole-virus vaccines by eliciting antibody and T-cell responses that target an even wider range of flu viruses.

It’s hard to square those benefits with the fact that HHS and NIH have named the planned new universal vaccine platform “Generation Gold Standard,” insisting that it represents a new standard in science and transparency. The effort seems more akin to eliminating all e-bike technology and telling everyone who seeks one to get by with a single brand of a 10-speed bike: Getting to the intended destination may still be possible, but it will be slower and harder.

And in the case of abandoning mRNA vaccine research, it may lead to lives needlessly lost, whether due to potential medicines untapped or to pandemic unpreparedness.

Deborah Fuller receives funding from the National Institutes of Health. She is co-founder and a scientific advisor for two biotech companies developing nucleic acid vaccine technologies that are not based on mRNA.

– ref. How RFK Jr.’s misguided science on mRNA vaccines is shaping policy − a vaccine expert examines the false claims – https://theconversation.com/how-rfk-jr-s-misguided-science-on-mrna-vaccines-is-shaping-policy-a-vaccine-expert-examines-the-false-claims-263027

September 3, 2025

Herbívoros y fuego controlado: una alianza necesaria para prevenir grandes incendios forestales

Source: The Conversation – (in Spanish) – By Rosa María Canals, Catedrática en Pascicultura y Restauración de Ecosistemas, Universidad Pública de Navarra

Tras la oleada de incendios que ha sacudido y conmocionado España, se ha generado una conciencia común: es necesario gestionar el paisaje para hacerlo menos vulnerable a los fuegos de alta intensidad.

Sin embargo, junto a esta lección aprendida surgen muchas preguntas que no tienen una respuesta sencilla. ¿Podrán recuperarse los bosques originales en las áreas de mayor valor ecológico si aplicamos una gestión adecuada? ¿Podemos evitar que el fuego vuelva a aparecer en el mismo lugar? ¿Cómo debemos afrontar la gestión de las interfaces urbano-forestales de una manera económica y duradera?

Son cuestiones complejas. Trataré de abordar algunas de ellas a la luz de lo aprendido durante más de tres décadas de trabajo en ecología de comunidades vegetales y en proyectos de restauración ambiental en los que el fuego y los herbívoros han sido herramientas clave.

Alteración de las dinámicas de perturbación natural

Sabemos que las comunidades vegetales que se establecen en un determinado lugar responden a las condiciones de clima y de suelo imperantes, seleccionándose el conjunto de especies vegetales mejor adaptadas a ese ambiente en particular.

Pero eso no lo es todo. Existe un tercer factor decisivo que determina el establecimiento de una comunidad vegetal: el régimen histórico de perturbaciones. Bajo este concepto se engloban procesos naturales que en apariencia podrían parecer destructivos, pero que en realidad han moldeado la vegetación durante millones de años, como las sequías, las plagas, los aludes, la presencia de herbívoros y, por supuesto, el fuego. Cada comunidad vegetal está adaptada a un régimen concreto de perturbación y lo demuestra con las estrategias adaptativas de las especies dominantes: espinas y toxinas frente al herbívoro, cortezas aislantes y piñas serótinas frente al fuego, etc.

Leer más:
De crecer bajo tierra a autopodarse: los secretos de las plantas para sobrevivir a las llamas

Lo cierto es que los seres humanos hemos alterado profundamente estas dinámicas de perturbación natural y de manera más intensa a lo largo del último siglo. Por ejemplo, los ecosistemas abiertos –aquellos en los que domina el componente herbáceo, como pastizales, matorrales poco densos, dehesas y sabanas– han visto muy mermado el consumo de biomasa vegetal por herbívoros y están desapareciendo en favor de comunidades vegetales más lignificadas y con mayor carga combustible.

Aunque la extinción de megafauna es un proceso que arranca a finales del Pleistoceno, en el Holoceno las poblaciones de herbívoros ungulados se han visto seriamente reducidas, contribuyendo los humanos a ello de una manera decisiva.

Leer más:
Mucha fibra para poco ciervo: por qué hay menos herbívoros silvestres de los que pueden albergar los ecosistemas

Además, las domesticaciones en el Neolítico se centraron en un grupo concreto de herbívoros, los pastantes, por ser animales de comportamientos más gregarios, tener movimientos migratorios predecibles y alimentarse en áreas abiertas, de buena visibilidad. Durante los últimos miles de años, los herbívoros domésticos han emulado el régimen de perturbación de los salvajes pastantes, contribuyendo a mantener ecosistemas abiertos. Pero en las últimas décadas, la caída en picado de la ganadería extensiva y el auge de explotaciones intensivas han cambiado radicalmente esta dinámica.

Algo similar ha sucedido con los regímenes naturales del fuego. Muchas comunidades vegetales, en ambientes mediterráneos y también en ambientes templados y tropicales, tienen un régimen natural de incendios asociado, con un profundo rol ecológico ligado al reciclado y la regeneración vegetal. El cambio climático, generando condiciones extremas propicias para el fuego y llevando a las cubiertas vegetales a situaciones de gran estrés térmico e hídrico, la acumulación de combustible por falta de aprovechamientos y la llamada paradoja de la extinción (décadas de supresión de incendios naturales que favorecen la acumulación de combustibles), han trastocado completamente ese equilibrio y alimentan fuegos cada vez más intensos y difíciles de controlar. En este escenario, los incendios serán inevitables y recurrentes, mientras exista vegetación para arder.

Tierra calcinada — Terreno calcinado tras el incendio forestal que tuvo lugar en Llerena (Extremadura) en agosto de 2025 y arrasó 5.900 hectáreas.
Right Perspective Images/Shutterstock

Leer más:
La era de los incendios que ya no podemos apagar

Interconexión entre el fuego y los herbívoros

El herbívoro y el fuego han estado siempre estrechamente interconectados y en latitudes templadas y mediterráneas han sido los dos grandes gestores y recicladores de la materia vegetal. La descomposición, aunque también cumple esa función, tiene un papel más relevante en otros ambientes. El herbívoro consume la vegetación de manera selectiva, lenta y recurrente, transformándola en energía, crecimiento animal y en nutrientes que devuelve parcialmente al suelo a través de sus excrementos. El fuego, en cambio, es un evento poco frecuente que actúa de forma rápida e intensa, reciclando compuestos orgánicos tan resistentes como la lignina. Así, genera una gran mineralización de la materia vegetal –al reducirla a cenizas–, que puede retenerse en el ecosistema o perderse (volatilización, escorrentía, lixiviación) en función de la intensidad del fuego y de las condiciones locales tras el paso de las llamas.

Mientras el herbívoro escoge lo más nutritivo y digestible, el fuego no discrimina. Son procesos distintos, pero complementarios, y cuando se gestionan de forma conjunta y planificada, emulando regímenes naturales de perturbación, permiten mantener, a costes económicos reducidos, paisajes abiertos y en mosaico, donde se combinan distintos tipos de vegetación, con baja carga de combustible y elevada biodiversidad.

Leer más:
Más herbívoros salvajes para prevenir los incendios

Lecciones finales desde la ecología de la perturbación

Las comunidades vegetales que conocemos han evolucionado durante millones de años adaptándose a regímenes de perturbación concretos, definidos por su tipología, su intensidad y su frecuencia. De modo que el tipo de perturbación dominante marca las características de los ecosistemas, tanto como el clima y el suelo. Allí donde prevalecen los herbívoros, las comunidades vegetales tienden a ser nutritivas y atractivas al animal, buscando ser pastadas para asegurar su regeneración. Allí donde domina el fuego, prosperan especies inflamables, de combustión veloz y regeneración rápida, que favorecen la ocurrencia de nuevos incendios. Sin herbívoros y con un cambio climático en progreso, es fácil adivinar qué tipos de comunidades vegetales van a verse favorecidas en el futuro, comunidades adaptadas al fuego y que dependen de él principalmente para regenerarse.

Como apuntan diversos expertos, muchas comunidades vegetales ya no se corresponden con el clima en el que se originaron. Podemos añadir también que están evolucionando y respondiendo al régimen de perturbaciones actual, diferente al histórico, en el que la ausencia casi total de herbívoros deja al fuego como principal reciclador natural de la biomasa vegetal.

Todo apunta a que, azuzados por el cambio climático, los incendios se repetirán con mayor frecuencia y, en muchos casos, resultará imposible recuperar muchos ecosistemas tal como los conocíamos. Ante esta realidad, la gestión debe orientarse a reducir el estrés que están sufriendo nuestros bosques, rebajando su densidad y cobertura para sanear las masas forestales y mitigar la virulencia de los incendios. Pero también es fundamental promover paisajes en mosaico y espacios abiertos, donde la ganadería extensiva y el pastoreo de los herbívoros desempeñen el papel reciclador perdido, tan esencial en estos momentos.

Leer más:
Y tras los incendios, matorrales: cómo recuperar los bosques y hacerlos más resistentes al fuego

Las quemas técnicas pueden ayudar a controlar la vegetación leñosa en fases iniciales. No obstante, sólo la combinación con planes de pastoreo plurianuales evitará la consolidación de comunidades pirófitas y reducirá la peligrosa dependencia del fuego como único mecanismo regulador de la materia vegetal. La combinación de fuego técnico y pastoreo ambiental, llamado herbivorismo pírico, ofrece una vía de gestión sostenible, capaz de mantener ecosistemas más resilientes, menos inflamables y, al mismo tiempo, más biodiversos. En ello estamos trabajando.

Rosa María Canals y su equipo de investigación han recibido y reciben fondos de entidades públicas (Fundación Biodiversidad, Agencia Estatal de Investigación,..) en convocatorias competitivas para financiar sus líneas de investigación.

– ref. Herbívoros y fuego controlado: una alianza necesaria para prevenir grandes incendios forestales – https://theconversation.com/herbivoros-y-fuego-controlado-una-alianza-necesaria-para-prevenir-grandes-incendios-forestales-264085

September 3, 2025

What are the key purposes of human writing? How we name AI-generated text confuses things

Source: The Conversation – Canada – By Taylor Morphett, Assistant Professor, English, University of Northern British Columbia

As another school year returns, large language models (LLMs) present difficult questions around learning, thinking, plagiarism and authorship for educators.

New approaches to assignments and assessment are required. Student papers that use LLM technology require additional labour on many fronts. Professors have expressed frustration, worry and anxiety.

As an assistant professor of English whose research has focused on the histories of writing and how it’s taught, I have been involved in many discussions at institutions of higher learning about this topic.

The immediate issue of LLMs in the classroom points to a larger reality. For too long, instructors and universities have been treating students’ writing difficulties as a deficiency in the mind — instead of confronting the truth that writing, as a technology for thinking, is cognitively demanding.

Writing is a technology that helps us understand our own ideas better. Where people are involved in thinking and invention — including at universities — it needs to be taught in that spirit.

Why consider AI output ‘writing?’

Given what LLM technology actually does and does not do, why do we even consider it writing — as in, “they used an LLM to write their assignment?”

LLM technology creates — at best — a facsimile of a textual object, meaning that based on its training on existing texts, it can create output that resembles a “text.”

When generated for the purpose of a university assignment, it resembles the standard academic English that has ruled the academy (historical and present-day institutions of higher learning including colleges, technical schools and universities) and has been endowed with a special relationship to truth.

I’ve seen anger and frustration expressed towards the student who uses LLM output in their writing process or submitted work. The reason seems to be that it undermines that special relationship to truth that academic writing has long held.

The artificial output reveals that academic writing is not an “absolute.” Rather, the LLM shows us how academic writing is a social construction. But academia at large has long resisted acknowledging this.

Historical and social concerns

Using standard academic writing is a choice. It is a style of writing that has been invisible within academia, thought to be the default and “correct.”

Many of the problems and questions that arise with LLM technology in relation to writing are really historical and social concerns that get to the very heart of what we understand writing to be.

As I continue to discover in my research, writing in the context of the English-speaking academy since the 19th century has been taught within two distinct streams: literary and technical communication. Both of these streams flourished within the larger context of the British Empire because both are adept strategies for maintaining the status quo.

The combination of the veneration of canonical British literature and the instruction of a utilitarian language that acts as a “neutral” communication tool (one that is not at all neutral), and a standard one, serves to create an understanding of writing that over-prioritizes the finished text.

Writing and context

Still today, what is technically “correct” is seen as “good” writing, while “good” writing has come to be represented as the product of a strong mind. This, of course, implies “bad writing” is the product of a mind not as able, or even suited for post-secondary study. Scholars in writing studies have pointed to academia’s focus on correctness and how ways of teaching academic writing can perpetuate inequities, including those related to colonialism and racism.

“Correctness” in writing is, as writing scholars have long discussed, subjective and contextual. For example, “ill c u l8r” would work as a perfectly fine text message in 2008. In another setting — including texting today with QWERTY-keyboard equipped phones — it would seem “off” or even incomprehensible.

When a student’s ability to write academically is taken to represent their intelligence, we should not be surprised when some use LLMs.

Revisiting the final product

Because LLM technology can mimic standard academic writing, it becomes the perfect context through which to address how we think about the final product of writing. The truth is, if university instructors are only interested in a “correct” piece of writing, it sort of makes sense for a computer to do it.

However, if we are interested in a way of teaching that supports students’ inquiry and thought as they interrogate the often oppressive systems they find themselves in, we need to broaden our understanding of writing beyond the confines of a “correct” standard academic English.

It is important that educators begin to see our students’ writing as part of a social situation which requires clarity on their end, yes, but also our listening.

Without reconsidering how western institutions have positioned writing, instructors risk educating a generation of students who are alienated from their own ability to think and create new knowledge, perspectives and understandings because of an over-reliance on LLMs. Western institutions will create students alienated from themselves and the potentialities of their ideas.

Re-think what writing is

Part of re-thinking what writing is means allowing students to submit work in process, providing for feedback from instructors on ungraded drafts of assignments and developing scaffolding assignments that reveal the process behind writing.

It also means teaching students a new approach to writing that draws attention to the power structures implicated in the instruction of writing and embraces invention — a rhetorical concept under-utilized within the western academy. “Invention” implies many considerations, including around audience, relationships and circumstances.

Writing experts need to be brought into AI-policy creation and the implications of this field’s research must be considered by a wider audience. If LLMs are implemented in universities without careful consultation with writing experts, I fear we will soon find that all that can be written is the status quo of received ideas.

It’s time for us to reconsider writing in universities or risk our students losing access to their own writing. The study of writing is uniquely situated to help our institutions navigate these urgent questions.

Taylor Morphett does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.

– ref. What are the key purposes of human writing? How we name AI-generated text confuses things – https://theconversation.com/what-are-the-key-purposes-of-human-writing-how-we-name-ai-generated-text-confuses-things-261899