Warmer winters in normally snowy places can interfere with the important activities of microbes in the soil.Seogi/500px via Getty Images
When you look out across a snowy winter landscape, it might seem like nature is fast asleep. Yet, under the surface, tiny organisms are hard at work, consuming the previous year’s dead plant material and other organic matter.
These soil microorganisms – Earth’s recyclers – liberate nutrients that will act as fertilizer once grasses and other plants wake up with the spring snowmelt.
Key among them are arbuscular mycorrhizal fungi, found in over 75% of plant species around the planet. These threadlike fungi grow like webs inside plant roots, where they provide up to 50% of the plant’s nutrient and water supply in exchange for plant carbon, which the fungi use to grow and reproduce.
A magnified view shows filaments and vesicles of arbuscular mycorrhizal fungi weaving through the outer cells of a plant root. Outside the root, the filaments of hyphae gather nutrients from the soil. Edouard Evangelisti, et al., New Phytologist, 2021, CC BY
In winter, the snowpack insulates mycorrhizal fungi and other microorganisms like a blanket, allowing them to continue to decompose soil organic matter, even when air temperatures above the snow are well below freezing. However, when rain washes out the snowpack or a healthy snowpack doesn’t form, water in the soil can later freeze – as can mycorrhizal fungi.
In a new study in the Rocky Mountain grasslands, we dug into plots of land that for three decades scientists led by ecologist John Harte had warmed by 2 degrees Celsius (3.6 Fahrenheit) using suspended heaters that mimicked the air temperature the area is likely to see by the end of this century.
Above ground, the plots shifted over that time from predominantly grassland to more desertlike shrublands. Under the surface, we found something else: There were noticeably fewer beneficial mycorrhizal fungi, which left plants less able to acquire nutrients or buffer themselves from environmental stressors like freezing temperatures and drought.
These changes represent a major shift in the ecosystem, one that, on a wide scale, could reverberate through the food web as the grasses and forbs, such as wildflowers, that cattle and wildlife rely on decline and are replaced by a more desertlike environment.
When plants and fungi get out of sync
Warmer winters and a changing snowpack can affect the growth of plants and fungi in a few important ways.
One of the first signs of changing winters is when the timing of plant, fungal and animal activities that rely on one another get out of sync. For example, a mountain of evidence from around the world has documented how early snowmelt can lead to flowers blooming before pollinators arrive.
Timing also matters for plants that rely on mycorrhizal fungi – their growth must overlap.
Since plants are cued to light in addition to temperature, whereas underground microorganisms are cued to temperature and nutrient availability, warmer winters may cause microorganisms to be active well before their plant counterparts.
A view across the subalpine grasslands outside the experimental plots. Stephanie Kivlin
At our research site, in a subalpine meadow in Colorado, we also initiated an early snowmelt experiment in April 2023 that advanced snowmelt in five large plots by about two weeks.
We found that the early snowmelt advanced mycorrhizal fungal growth by one week, but we didn’t find a corresponding change in the growth of plant roots. When mycorrhizal fungi are active before plants, the plants don’t benefit from the nutrients that mycorrhizal fungi are taking up from the soil.
Disappearing nutrients
Early snowmelt can also lead to a loss of nutrients from the soil.
When microorganisms decompose organic matter in warmer soils, nutrients accumulate in the air and water pockets between soil particles. These nutrients are then available for mycorrhizal fungi to transfer to plants. While mycorrhizal fungi transfer nutrients to the plant, other fungi are primarily decomposers that keep the nutrients for themselves.
However, if rain falls on the snow or the snow melts early, before plants are active, the nutrients can leach from the soil into lakes and streams. The effect is similar to fertilizer runoff from farm fields – the nutrients fuel algae growth, which can create low-oxygen dead zones. At the same time, plants in the field have fewer nutrients available.
Without a thick snowpack, soils can also freeze for longer periods in the winter, leading to lower microbial activity and scarce resources at the onset of spring.
The future of changing winters
Under all of these scenarios – a timing mismatch, more rain causing nutrients to leach out or frozen soil – warmer winters are leading to less spring growth.
Ecosystems are often resilient, however. Organisms could acclimate to lower nutrient concentrations or shift their ranges to more favorable conditions. How plants and mycorrhizal fungi both adapt will determine how this hidden world adjusts to changing winters.
So, the next time rain on snow or a snow drought delays your outdoor winter plans, remember that it’s more than a hassle for humans – it’s affecting that hidden world below, with potentially long-term effects.
Stephanie Kivlin received funding from NSF Award #2338421, #1936195 and DOE Award #DE-FOA-0002392. She is an associate professor in the Ecology and Evolutionary Biology department at the University of Tennessee, Knoxville and the Rocky Mountain Biological Laboratory.
Aimee Classen receives funding from the US Department of Energy and the US National Science Foundation. She is a professor in Ecology and Evolutionary Biology at the University of Michigan and the director of the University of Michigan Biological Station.
Lara A. Souza received funding from National Science Foundation and The United States Department of Agriculture. She is affiliated with The University of Oklahoma, Norman and the Rocky Mountain Biological Laboratory.
Au-delà de la performance sportive, les Jeux olympiques d’hiver de Milano-Cortina se déroulent dans un contexte marqué par l’urgence climatique et des attentes croissantes envers la responsabilité environnementale des méga-évènements sportifs. Conscient de l’empreinte carbone liée à la présence des spectateurs, le Comité organisateur a mis en place des mesures pour les inciter à adopter des comportements plus écoresponsables durant ces JO, qui se terminent le 22 février avant de reprendre en mars pour les Jeux paralympiques.
Quelles sont ces mesures et que valent-elles réellement ?
Doctorante en science politique à l’Université de Montréal, mes travaux portent à la fois sur la communication climatique et l’élaboration de politiques environnementales, y compris dans le secteur du sport.
Après avoir assisté aux Jeux olympiques de Paris 2024, souvent présentés comme plus verts, j’ai eu l’occasion d’être présente à ceux de Milano-Cortina, lors du weekend d’ouverture, sur les sites de Bormio et Livigno. Le texte qui suit s’appuie sur mon expertise et les observations que j’ai pu faire sur place, en tant que spectatrice.
Les déplacements des spectateurs pour assister aux Jeux constituent généralement la principale source d’émissions de gaz à effet de serre associée à l’événement. À titre d’exemple, lors des Jeux de Paris 2024, ils représentaient à eux seuls près de la moitié de l’empreinte carbone totale, soit 49 %.
Par ailleurs, l’affluence attendue soulève d’autres défis, notamment en matière de gestion des déchets. Les services de restauration offerts aux spectateurs sur les sites de Milano-Cortina, de même que le traitement des déchets, devraient ainsi représenter plus de 15 000 tonnes de CO₂ équivalent.
De ce fait, plusieurs initiatives sont mises en place pour limiter l’impact des spectateurs.
Mieux se déplacer pour moins polluer
Les organisateurs disposent de peu de leviers pour influencer les voyages aériens des spectateurs se rendant en Italie, mais ils peuvent agir sur les modes de transport utilisés une fois sur le territoire nord-italien.
Ils ont notamment restreint la circulation routière à proximité des sites olympiques, pour des raisons à la fois sécuritaires et environnementales. Les résidents et spectateurs souhaitant s’y rendre en voiture doivent ainsi se munir d’un laissez-passer, à demander plusieurs semaines à l’avance et à apposer sur le pare-brise, contrôlé aux principaux points d’accès. Sans interdire explicitement la voiture, ce dispositif en réduit fortement l’attractivité.
Pour encourager des alternatives, des stationnements relais gratuits ont été aménagés en périphérie, avec des navettes payantes vers les sites. En dehors de Milan, la plupart des sites ne sont pas directement accessibles par métro ou train, de sorte que des navettes gratuites ont été déployées depuis certaines gares.
Enfin, pour les spectateurs logeant plus en altitude dans les vallées, comme ce fut mon cas, les transports en commun locaux constituent une autre option. Ces bus publics, bien que payants et ponctués de nombreux arrêts, permettent ici aussi de rejoindre les sites sans recourir à un véhicule individuel, au prix d’un temps de trajet plus long.
L’or, l’argent… et le plastique
Vous souvenez-vous des Phryges, les mascottes de Paris 2024 devenues virales sur les réseaux sociaux ? À Milano-Cortina, vous avez probablement entendu parler de leurs héritiers, Tina et Milo, dont les noms font écho aux villes de CorTINA et MILanO.
Mais connaissez-vous les Flo ? Contrairement aux mascottes officielles chargées d’animer les foules, ces six petites fleurs perce-neige remplissent une mission bien particulière : promouvoir le recyclage.
Leur nom fait écho à la campagne anti-gaspillage « Follow the Flo », construite sur un jeu de mots avec l’expression anglophone « follow the flow », qui signifie « suivre le mouvement ».
Panneau expliquant le tri sélectif sur le site olympique de Livigno. (Alizée Pillod)
Elles figurent sur les panneaux expliquant le tri sélectif installés à proximité des points de collecte sur les sites olympiques, contribuant à sensibiliser les spectateurs à leurs actions de manière ludique. Plus encore, des peluches à leur effigie sont proposées à la vente, prolongeant cette initiative au-delà des espaces de tri eux-mêmes.
Une performance en demi-teinte
Aucune donnée définitive n’est encore disponible sur le recyclage ou la fréquentation des navettes et transports en commun, mais il est déjà possible de partager quelques constats.
D’abord, les modes de transport mis à disposition semblent victimes de leur succès. Du côté des bus locaux, les organisateurs ont même sous-estimé l’engouement des spectateurs pour ce service.
À Livigno, site olympique situé en haute altitude, un seul bus circule par heure. À la sortie des compétitions, ce qui devait arriver arriva : files d’attente interminables, spectateurs contraints de patienter dans le froid et sentiment général d’improvisation.
Il faut toutefois reconnaître que l’accès au site constitue en soi un défi logistique. Une fois à Bormio, autre site olympique déjà situé en altitude, l’accès à Livigno nécessite d’emprunter une route sinueuse pendant encore près d’une heure et de franchir un col à plus de 2 000 mètres. Cela limite de facto le flux de véhicules et la fréquence des navettes.
Les autres sites n’échappent pas non plus à ce casse-tête logistique. Ici, la géographie impose ses contraintes, et la patience devient une condition implicite de l’expérience olympique.
La stratégie des stationnements relais soulève également des questionnements. Leur nombre reste limité, et certains sont eux-mêmes situés en altitude, comme celui d’Aquilone. Un tel choix interroge : en positionnant ces stationnements plus bas dans la vallée, les organisateurs auraient-ils davantage dissuadé l’usage de la voiture et favorisé celui des transports collectifs ?
Risque d’éco-blanchiment
En outre, si les Flo encouragent le tri sélectif, celui-ci ne peut constituer la seule solution pour diminuer le nombre de déchets.
À ce sujet, il est surprenant qu’aucune vaisselle réutilisable ne soit proposée aux spectateurs et que les services de restauration privilégient des emballages en carton recyclé ou en plastique pour la vente de leurs produits. L’absence de fontaines permettant de remplir des gourdes entraîne également un recours systématique aux bouteilles d’eau en plastique.
De plus, si les Flo partent d’une bonne intention, la vente de peluches contribue malgré elles à la consommation de masse, laquelle va à l’encontre des principes de l’économie durable.
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L’argent récolté par ces ventes de peluches ne semble pas être réinvesti dans des actions vertes. Cela constitue une occasion manquée de prolonger l’impact des gestes individuels et expose l’initiative à un risque significatif d’éco-blanchiment.
Si ces initiatives en 2026 représentent un premier pas encourageant comparé aux éditions précédentes des Jeux d’hiver, elles restent encore insuffisantes en termes de nombre et d’ambition.
Il faut dire que le point de comparaison n’était guère exigeant : les Jeux olympiques d’hiver de Pékin 2022, à l’instar de plusieurs éditions récentes, ont largement été décriés comme une aberration écologique.
Finalement, cela nous invite aussi à réfléchir à la taille de ces méga-évènements sportifs, lesquels ont considérablement grandi au fil du temps. Si le nombre de spectateurs n’est pas davantage limité, l’empreinte carbone restera nécessairement élevée.
Alizée Pillod est affiliée au Centre d’Études et de Recherches Internationales de l’UdeM (CERIUM), au Centre de recherche sur les Politiques et le Développement Social (CPDS) et au Centre pour l’Étude de la Citoyenneté Démocratique (CECD). Ses recherches sont subventionnées par les Fonds de Recherche du Québec (FRQ). Alizée a aussi obtenu la Bourse départementale de recrutement en politiques publiques (2021), la Bourse d’excellence en études environnementales Rosdev (2023), ainsi que la Bourse d’excellence en politiques publiques de la Maison des Affaires Publiques et Internationales (2025). Elle a collaboré par le passé avec le consortium Ouranos, le ministère de l’Environnement du Québec et l’INSPQ. Elle est actuellement chercheuse invitée au Center for Interdisciplinary Research on Sport de l’Université de Lausanne.
En 2026, el planeta ya supera los 8 300 millones de habitantes, según datos de la ONU. La cifra es elevada, pero muy alejada de aquel “crecimiento infinito” que se temía en los años sesenta, reflejado en artículos como Doomsday: Friday, 13 November, AD 2026. El viejo miedo a una superpoblación descontrolada ya no encaja con los datos. Pero ¿por qué?
Hoy sabemos que, si bien la población mundial continúa aumentando, cada vez lo hace a un ritmo más moderado. Si observamos la evolución desde 1960, comprobamos que el número de habitantes se ha duplicado en poco más de medio siglo. El crecimiento ha sido siempre positivo, aunque no constante: tras alcanzar su punto álgido, el ritmo comenzó a descender alrededor de los años setenta, con una desaceleración más marcada en las últimas décadas. En otras palabras, seguimos creciendo, pero cada vez más despacio.
Las transiciones demográficas: clave para entender el cambio
Para entender estos cambios necesitamos introducir el término de transición demográfica, es decir, el proceso histórico por el cual las poblaciones pasan de tener altas tasas de natalidad y mortalidad –típicas de sociedades preindustriales– a bajas tasas de ambos conceptos.
La primera fase es una caída de la mortalidad, impulsada por los avances médicos y sanitarios. En una segunda fase se produce un descenso de la fecundidad por debajo del umbral de reemplazo (2,1 hijos por mujer), acompañado de profundos cambios sociales que retrasan la fecundacion: retraso del matrimonio, aumento de los divorcios, mayor cohabitación y más nacimientos fuera del matrimonio. En muchos casos, los nacimientos son insuficientes para compensar las defunciones, y tiene lugar un crecimiento natural negativo.
La catástrofe maltusiana
El artículo alarmista de 1960, Doomsday: Friday, 13 November, AD 2026, se escribió en pleno auge de la primera transición demográfica, cuando las muertes descendían pero no la natalidad. A este hecho se sumaba un temor social a la superpoblación, alimentado también por las ideas de Thomas Malthus, quien aseguraba que la población humana crece en progresión geométrica (exponencialmente), mientras que los alimentos solo aumentan en progresión aritmética (linealmente).
Eso, anunciaba Malthus, conduce a que la población supere los recursos, causando miseria, hambrunas, guerras y epidemias para regularla, un fenómeno conocido como catástrofe maltusiana.
Nacimientos, defunciones y migraciones
La evolución de la población depende de los nacimientos, las defunciones y las migraciones. La combinación de estos tres fenómenos determina el crecimiento –o decrecimiento– de la población.
En lo que se refiere a las defunciones, la esperanza de vida no ha dejado de aumentar en las últimas décadas. A nivel mundial, ha pasado de 47,8 años en 1960 a 73,8 años en 2026, lo que supone un incremento de casi 26 años, equivalente a unos 0,4 años adicionales por año. Las mujeres presentan sistemáticamente una mayor expectativa que los hombres, una brecha que ha crecido de unos 3 años a alrededor de 5 en la actualidad.
Por el lado de los nacimientos, la baja fecundidad es ya una realidad consolidada, especialmente en los países occidentales. El índice sintético de fecundidad –que estima el número medio de hijos por mujer– ha caído de 4,7 en 1960 a 2,2 en 2026. De nuevo, las diferencias regionales son enormes: mientras países como China, Ucrania o Puerto Rico rondan el hijo por mujer, otros como Somalia, Malí o Chad superan los cinco .
El tercer elemento son las migraciones, cuyo impacto se ha intensificado en un mundo cada vez más global y conectado. A escala mundial, el saldo migratorio es un juego de suma cero –lo que pierde un territorio lo gana otro–. Pero a nivel regional las diferencias son claras: hay zonas netamente receptoras y otras expulsoras o emisoras de población. Estas dinámicas vienen muy condicionadas por las políticas migratorias de cada país.
¿Por qué sigue creciendo la población?
Surgen entonces dos preguntas clave. En primer lugar, ¿cómo puede aumentar la población mundial si la fecundidad no deja de caer? La respuesta está en el aumento de la esperanza de vida. Vivimos más tiempo, lo que hace que cada persona “cuente” durante más años en el total poblacional. Así, el descenso de la fecundidad no tiene un impacto inmediato tan fuerte como cabría esperar.
La segunda pregunta es si seguimos temiendo a la superpoblación. Aunque la población continúa creciendo, el ritmo se está estabilizando y la caída de la fecundidad ha reducido ese temor. De hecho, en muchos países el miedo ha cambiado de signo y en muchos territorios se ha transformado en preocupación por el declive demográfico y el envejecimiento.
Mirando al futuro
Según las proyecciones de Naciones Unidas, en 2100 la población mundial alcanzará los 10 180 millones de personas. La esperanza de vida seguirá aumentando hasta los 81,7 años, con una brecha de género inferior a los cuatro años. La fecundidad, por su parte, continuará descendiendo hasta situarse en torno a 1,84 hijos por mujer.
Ante este escenario, la cuestión no es solo si debemos preocuparnos por la superpoblación o por la desaparición de la población, sino si somos capaces de entender que, en una sociedad global como la actual, la reducción de la mortalidad y el aumento de la longevidad disminuyen la necesidad de un crecimiento basado exclusivamente en los nacimientos. Como ya ocurrió durante la primera transición demográfica, el equilibrio entre fecundidad, mortalidad y migraciones puede dar lugar a un crecimiento poblacional estable.
Eso sí, este equilibrio dependerá de factores clave que habrá que seguir muy de cerca, como el cambio climático, capaz de afectar tanto a la mortalidad como a los movimientos migratorios en las próximas décadas.
Antía Domínguez no recibe salario, ni ejerce labores de consultoría, ni posee acciones, ni recibe financiación de ninguna compañía u organización que pueda obtener beneficio de este artículo, y ha declarado carecer de vínculos relevantes más allá del cargo académico citado.
Source: The Conversation – UK – By Natasha Lindstaedt, Professor in the Department of Government, University of Essex
When the US secretary of state, Marco Rubio, delivered a speech at Europe’s biggest security conference in the German city of Munich on February 14, leaders from across the continent were relieved by its content. In contrast to the previous year, when US vice-president J.D. Vance had launched a scathing attack on European-style democracy, Rubio’s tone was far more friendly and conciliatory.
He described the US as a “child of Europe”, assuring European leaders that his country was intent on building a new world order together with what he called “our cherished allies and our oldest friends”. The president of the European Commission, Ursula von der Leyen, said she was “very much reassured” by these remarks.
However, Rubio also repeated several of the Trump administration’s familiar criticisms of Europe’s approach to immigration and climate action, cautioning that the US is prepared to chart its new path alone. And while he claimed his country wants to reinvigorate the transtlantic alliance, Rubio questioned Europe’s will and capacity to do so.
The speech underscored the balance Rubio must strike between aligning himself with the political priorities of Donald Trump and reassuring European partners. Unlike much of the Trump administration, the secretary of state understands that the US needs to be more diplomatic with Europe to achieve its foreign policy objectives.
This isn’t the case with Vance. One year ago, he chastised Europe for its migration policies and accused its governments of suppressing free speech and populist parties. He claimed that the greatest threat to Europe’s security came “from within”, rather than Russia. According to Vance, Europe had become too politically correct, abandoning fundamental values in the process.
Vance’s speech came as a shock to European leaders in the audience. They were not completely prepared for such a blistering attack, having thought he would focus his address largely on the war in Ukraine. The speech drew praise from Moscow, including from former Russian president and prime minister Dmitry Medvedev, and triggered a year of turmoil in transatlantic relations.
In his speech, Vance echoed Trump’s view of Europe – but it’s a view that matches his own. The vice-president has never really respected Europe. This was made clear in a series of leaked messages between Vance and other US national security officials in March 2025.
When Vance discussed plans for a military strike against Houthi forces in Yemen, which he noted posed a larger threat to European shipping than American trade, he lamented: “I hate bailing out Europe again.” Though he wrote in his 2016 memoir that visiting the UK was a childhood dream, Vance had become a Euro sceptic.
This contrasts with Rubio, who has traditionally been a strong supporter of Europe and the transatlantic alliance. Although ideologically hawkish in foreign policy, he has never been an isolationist – and has consistently backed traditional collective security institutions such as Nato.
In 2015, Rubio declared that the US must make a tough response to any Russian aggression against its Nato ally Turkey. And in 2019, he was part of a bi-partisan effort to prevent any US president from leaving the Nato alliance. He said: “It is critical to our national security and the security of our allies in Europe that the United States remain engaged and play an active role in Nato.”
This stance initially put Rubio at odds with Trump. But after Trump’s election defeat in 2020, Rubio recalibrated and slowly gained his trust. And since entering Trump’s inner circle, he has thrived. Rubio now serves as the president’s national security advisor as well as secretary of state, and has gained tremendous influence in foreign affairs.
Rubio’s delicate balance
To gain so much power, Rubio has had to be ideologically flexible. In Latin America, where his hardline stance against socialist regimes strongly aligns with Trump’s foreign policy goals, Rubio is in the driver’s seat and has largely determined what the US’s interests are. This has included pressing for the ouster of Venezuelan leader Nicolás Maduro, taking a tough stance on Cuba, and pressuring Panama to push out Chinese influence.
But outside of Latin America, Rubio has adopted a more measured communication style. He has engaged in damage control while ultimately clarifying and reinforcing Trump’s positions.
Trump prefers a world where the US acts unilaterally and ignores the rules-based international order. This has been illustrated by the US attacks on Iranian nuclear sites in 2025, as well as the more recent capture of Maduro and threats to take control of Greenland from Denmark.
Rubio tried to defuse tensions with Denmark in January, claiming the US merely wanted to purchase Greenland rather than intervene militarily. He has also toned down his hawkishness on Russia, a country Trump has sought to forge closer relations with. In 2016, Rubio had stated that the Russian president, Vladimir Putin, posed the biggest threat to global security.
As recently as 2024, Rubio praised the bravery of Ukrainians in their fight against Russia. But in his Munich address, he barely mentioned Ukraine, on which Trump has been applying pressure to end the war. Rubio also did not appear at a gathering with European allies immediately before the conference to discuss the conflict in Ukraine, claiming there was a scheduling issue.
Later, he reportedly offered Ukraine’s president Volodymyr Zelensky some assurances of US commitment. Despite also warning that Ukraine would need to accept hard concessions to end the war, this was an improvement from Vance’s past questioning of why the US was spending millions of dollars defending a “few miles of territory”.
Ultimately, while Rubio’s speech in Munich was less divisive and shocking than Vance’s a year earlier, it does not resemble any significant change in US foreign policy under Trump. The US has some shared interests with Europe, but not shared values.
Natasha Lindstaedt 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.
Weight-loss injections have rapidly moved from specialist clinics to social media feeds and high-street pharmacies. Known as GLP-1 medications, they were originally developed to support those with type 2 diabetes but are now widely used to support weight loss.
These medicines mimic a hormone called glucagon-like peptide-1, which helps regulate appetite and blood sugar. By slowing digestion and increasing feelings of fullness, they often lead people to eat less and lose weight.
Evidence suggests they can support weight loss, at least in the short term. But as use has grown, so have questions about possible unintended effects on nutrition and overall health.
A recent review of evidence suggests that some people taking GLP-1 medications may not be getting enough key nutrients. These include vitamins A, C, D, E and K, dietary fibre and minerals such as iron, calcium, magnesium, zinc and copper.
Nutritional deficiencies occur when the body does not receive enough of a nutrient to function properly. Estimates of how common these deficiencies are in those using GLP-1 medications vary widely. Some research suggests that more than 20% of people may be at risk within the first year of starting GLP-1 medications, while other studies indicate the impact may be much smaller, affecting less than 1% of users.
As concern about potential deficiencies has grown, so has a new market. Supplement companies are launching “GLP-1 support” products that claim to offset side-effects such as muscle loss and vitamin deficiencies by providing the “right” nutrients for people using these medications.
But do people taking GLP-1 medications actually need these supplements?
The use of vitamin and mineral supplements has long been debated in nutrition science. Evidence supporting their benefits in generally healthy people who already eat a balanced diet is limited. Supplements can be helpful for people who are deficient in a specific nutrient.
For example, many people in the UK are at risk of vitamin D deficiency during the winter months because there is less sunlight, which the body needs to produce vitamin D. However, if someone already gets enough of a nutrient from their diet, taking extra supplements usually has little or no additional benefit.
Due to reduced sunlight, it is difficult for the body to produce sufficient vitamin D between October and March in the UK, making supplementation a recommended way to maintain bone, muscle and immune health. Fida Olga/Shutterstock
Much of the research linking GLP-1 medications to nutrient deficiencies is observational. These studies studies look for patterns and associations in data but cannot prove cause and effect. In other words, they can show that two things occur together but cannot confirm that one causes the other. This means we cannot yet say for certain that GLP-1 medications directly cause nutrient deficiencies.
Even so, the concern is reasonable. GLP-1 medications often lead to reduced food intake. Eating less food can also mean consuming fewer essential nutrients, which increases the risk of deficiencies over time.
So can these potential deficiencies be addressed without expensive specialist supplements? Often, yes. Small dietary changes may be enough. Eating a range of nutrient-dense whole foods, including fruit and vegetables, whole grains, nuts and seeds, dairy or fortified alternatives, and lean or plant-based proteins, can help maintain adequate nutrient intake.
If supplements are needed, standard vitamin and mineral products available on the high street are often sufficient. There is rarely any need to pay premium prices for products marketed specifically for GLP-1 users. The evidence used in marketing for these products is often weak.
Selective science
While there is some evidence to support the use of certain supplements in specific situations or for certain groups, many GLP-1 support supplements contain ingredients that are not clearly linked to the needs of people taking these medications. These products are often described as “science-backed” or “evidence-based,” but the research behind these claims is frequently selective. Much of it has not been carried out in people using GLP-1 medications at all.
For instance, many GLP-1 support supplements include biotin, a vitamin often promoted for improving hair and skin health. However, the evidence supporting this claim is weak. There is also no strong research showing that biotin offers specific benefits for people taking GLP-1 medications. Most people already get enough biotin from their everyday diet. This means there is no clear evidence that adding more through supplements will help.
While biotin (vitamin B7) is heavily marketed for improving hair, skin and nail health, scientific evidence supporting its efficacy in healthy people is limited and inconclusive. Gabriele Paoletti/Shutterstock
Nutritional and lifestyle support for people using GLP-1 medications should be tailored to personal needs and goals. This approach is often described as personalised care. It recognises that people differ in their diets, health status and risk of deficiency. Guidance suggests that support should be personalised to meet individual needs to meet specific needs, ideally with advice from a qualified healthcare professional such as a registered dietitian or nutritionist. This is particularly important for anyone at higher risk of nutrient deficiency.
Where deficiencies are identified or likely, support may include small dietary changes or the use of standard supplements. However, this does not justify the routine use of expensive GLP-1 support supplements. These products are unlikely to offer benefits beyond those provided by basic, affordable supplements. A higher price does not guarantee higher quality or effectiveness.
The key message is simple. Supplements are most useful when someone has a confirmed deficiency or cannot meet their nutritional needs through diet alone. Taking supplements without a clear need is unlikely to provide any benefit and may simply be a waste of money.
Jordan Beaumont receives funding from the National Institute for Health and Care Research (NIHR). He is affiliated with the Association for the Study of Obesity and the Faculty of Public Health.
Source: The Conversation – UK – By Byron Hyde, Philosopher of Science and Public Policy, University of Bristol, Honorary Research Associate, Bangor University
The Enhanced Games, slated to commence in May 2026, has sparked outrage across the sporting world. This new competition is the first in history to openly permit performance-enhancing drugs, and sporting bodies aren’t happy about it.
World Athletics president Sebastian Coe called the concept “bollocks”, while World Anti-Doping Agency president Witold Bańka has dismissed it as “dangerous” and “ridiculous”.
Such criticisms might be justified, but they overlook the fact that the Enhanced Games is making obvious what society has always quietly accepted – that most people are willing to watch athletes risk harm when the entertainment is good enough. And that’s something that all sporting bodies should spend more time considering.
This bargain between spectacle and safety isn’t new to sport. Ancient Romans packed the Colosseum to watch gladiators fight to the death. It’s certainly been toned down over the last 2,000 years. But the gladiatorial spirit remains alive in modern arenas. How it’s packaged has merely become more sophisticated.
Consider boxing. Society has allowed professional boxing for more than 100 years despite the dangers to fighters. In one group of amateur and professional boxers, 62% were found to have dementia or amnesia.
Yet arenas still sell out. Fans celebrate knockout victories even though they know they may shorten a boxer’s life. Sporting bodies and fans have decided this trade-off is acceptable. Every time a ticket is bought, a statement is made about acceptable risk.
The multi-sport Enhanced Games simply extends this logic. Held in Las Vegas, athletes will be able to use performance-enhancing substances (approved by the drugs regulator for medical uses) “off-label” under medical supervision. These include testosterone, growth hormone and anabolic steroids.
Long-term use of substances like these can damage the heart and blood vessels, harm the liver, disrupt the body’s natural hormone production (potentially causing infertility) and affect a person’s mood and mental health.
The organisers aim to usher in a “new era of elite competition” and with it “the future of human performance”. Founder Aron D’Souza, an Australian businessman, thinks athletes should be free to do whatever they want to their own bodies. The International Federation of Sports Medicine has challenged the Enhanced Games for putting athletes at risk.
But isn’t the Enhanced Games simply a more dangerous version of traditional athletics? If brain trauma is the potential price of boxing entertainment, why the outrage about pharmaceutical enhancement risks? The moral panic about chemical enhancement seems inconsistent with society’s silence about the proven harms in so many of the sports people already love.
The Olympics already celebrates athletes who push their bodies to extremes through punishing training regimens, strict diets and recovery methods that test the limits of human physiology. Research has documented serious physical and psychological harms in many sports, including some like gymnastics and figure skating where even child athletes have faced high risks of injury and mental illness, including eating disorders, anxiety and depression.
The Enhanced Games just moves the risk threshold further along a spectrum society has already accepted.
Every time a new enhanced athlete is announced, their national sporting bodies issue condemnations. Sport Ireland stated that they were “deeply disappointed” about swimmer Shane Ryan’s decision to join the Enhanced Games. When fellow swimmer Ben Proud announced his intention to participate, governing body UK Sport said it “condemns everything the Enhanced Games stands for” and that they were “incredibly disappointed” with his decision.
But these same bodies preside over sports where athletes routinely suffer serious injuries. When will they acknowledge the risks they’re already asking athletes to accept?
The question isn’t whether the Enhanced Games introduces something morally unprecedented. It doesn’t. What it does is forces sports fans to confront the bargain they’ve always accepted but rarely discuss. Fans want extraordinary athletic performances, and they’re willing to let athletes pay extraordinary prices to deliver them.
The Enhanced Games describes itself as a ‘sports spectacle for the 21st century’.
Being honest about risk
If sporting bodies are serious about athlete welfare rather than just moral posturing, they need to be honest about risk across all of sport. In research ethics, institutional review boards conduct formal risk-benefit analyses before approving human studies. They document potential harms and assess whether benefits justify risks.
Sporting bodies should do the same. This includes the Enhanced Games. So far, they’re failing just as badly as traditional sports, hiding behind claims of medical supervision rather than stating the trade-offs.
Informed consent is central to medical ethics and some ethicists argue it isn’t talked about enough in sport. Athletes should understand the specific risks of their sport based on robust data, not vague warnings.
For example, all boxers should be aware of the dangers they face each time they take a punch to the head. Similarly, all enhanced athletes should understand what prolonged testosterone and growth hormone do to the body. Informed consent requires real information, not liability waivers.
As a philosopher of science, I suggest we need to be consistent about our judgments across different sports. The sporting establishment denouncing the Enhanced Games should look in the mirror. Boxing, rugby and motorsports organisations as well as bodies representing a host of other sports preside over activities with documented long-term harms.
The selective outrage is telling. It suggests this is more about maintaining comfortable fictions than protecting athletes. We prefer our sports wrapped in the language of safety and personal freedom. The Enhanced Games threatens to make that fiction harder to maintain.
Byron Hyde is a member of the Health Research Authority London Chelsea Research Ethics Committee and the Open University Human Research Ethics Committee. This essay does not reflect the opinions of the Health Research Authority or the Open University.
Source: The Conversation – UK – By Arshad Majid, Professor of Cerebrovascular Neurology, School of Medicine and Population Health, University of Sheffield
An explosion does not need to strike the head to injure the brain. When a blast occurs, it generates a sudden pressure wave that can pass through the body and skull in milliseconds, potentially deforming brain tissue and blood vessels along the way.
For soldiers exposed to improvised explosive devices or other blasts, and civilians caught in industrial accidents or explosions in conflict zones, the neurological effects can be long-lasting – even when brain scans appear normal.
Blast injuries can trigger changes in the brain and its blood vessels that standard medical scans do not always detect. When these injuries go unrecognised, people may receive the wrong care or be left without an explanation for symptoms that persist for years.
Most people are familiar with traumatic brain injuries caused by impacts such as falls, road traffic collisions or sports injuries. In these situations, the brain moves suddenly within the skull, leading to bruising or localised damage that can often be seen on scans.
Blast injury works differently. The rapid rise and fall in pressure created by an explosion can travel through the skull and the fluid that surrounds and cushions the brain. This generates complex mechanical forces that stretch and strain brain tissue. As a result, someone can sustain a brain injury even without any direct blow to the head.
Rather than producing one clearly visible injury, blast exposure tends to cause widespread microscopic damage. These tiny injuries can disrupt how brain cells communicate with each other, and can also damage the blood vessels that keep brain tissue healthy.
Although blast injury is often associated with military settings, it is not confined to war zones. Civilians may be exposed through industrial explosions, terrorist attacks or demolition work. In all these situations, the underlying mechanisms of brain injury are similar.
Despite these differences, blast injuries are often managed in the same way as concussions or other head injuries. When damage to blood vessels is overlooked, the severity of the injury and its long-term impact can be underestimated.
More sensitive diagnostic tools, including advanced imaging and specialised blood tests, could improve detection of subtle blood vessel damage. This would allow for more targeted treatment aimed at reducing inflammation, protecting the brain’s circulation, and ensuring patients receive appropriate long-term care.
Blast-related brain injury can also disrupt the brain’s waste-clearance system. This system normally removes harmful proteins and metabolic waste. When it is impaired, vulnerability to long-term post-concussion symptoms and neurodegenerative diseases may increase.
Brain blood vessels are especially vulnerable
One of the most important, and often overlooked, consequences of blast injury is damage to the brain’s blood vessels.
Blood vessels are thin-walled and flexible, allowing them to cope with normal changes in blood flow and pressure. During a blast, however, the rapid pressure shifts can stretch these vessels beyond their limits. This can cause tiny tears and weaken the protective barrier that normally prevents harmful substances in the bloodstream from entering brain tissue.
This protective layer, often called the blood–brain barrier, plays a crucial role in controlling what passes from the blood into the brain. When it is damaged, inflammatory cells and proteins can leak into brain tissue.
The resulting inflammation may persist long after the initial injury, interfering with normal brain function. Over time, this can contribute to symptoms such as headaches, memory problems, difficulty concentrating, slowed thinking, mood changes and fatigue.
Damage to the blood–brain barrier may help explain why some people experience ongoing symptoms months or even years after blast exposure.
Why scans can appear normal
One of the most frustrating experiences for people with blast-related brain injury is being told that their CT or MRI scan is normal, despite persistent symptoms.
Standard imaging techniques are very good at detecting fractures, bleeding or large areas of tissue damage. Blast injuries, however, often involve microscopic changes such as small vessel damage, disruption to communication between brain cells, and ongoing inflammation. These changes are usually too subtle to be seen on routine scans.
This mismatch between symptoms and imaging can delay diagnosis, complicate rehabilitation and, in some cases, affect access to appropriate support or compensation.
Progress will require close collaboration between neuroscientists, clinicians, emergency services and policymakers. Blast injury is not only a military concern. It offers broader insights into how pressure-related forces damage the brain, and how these injuries might be prevented or treated.
Recognising blast injury as a distinct form of brain trauma, particularly one that affects the brain’s blood vessels, is a crucial step towards improving care for those affected.
Arshad Majid is a NIHR Senior Investigator and his research is funded by the NIHR EME programme and the NIHR Sheffield BRC. His research is also funded by the Stroke Association UK.
Favour Felix-Ilemhenbhio receives funding from the British Heart Foundation (BHF).
Klaudia Kocsy receives funding from Alzheimer’s Research UK.
Source: The Conversation – UK – By Quynh Hoang, Lecturer in Marketing and Consumption, Department of Marketing and Strategy, University of Leicester
For years, big tech companies have placed the burden of managing screen time squarely on individuals and parents, operating on the assumption that capturing human attention is fair game.
But the social media sands may slowly be shifting. A test-case jury trial in Los Angeles is accusing big tech companies of creating “addiction machines”. While TikTok and Snapchat have already settled with the 20-year-old plaintiff, Meta’s CEO, Mark Zuckerberg, is due to give evidence in the courtroom this week.
The European Commission recently issued a preliminary ruling against TikTok, stating that the app’s design – with features such as infinite scroll and autoplay – breaches the EU Digital Services Act. One industry expert told the BBC that the problem is “no longer just about toxic content, it’s about toxic design”.
Meta and other defendants have historically argued that their platforms are communication tools, not traps, and that “addiction” is a mischaracterisation of high engagement.
“I think it’s important to differentiate between clinical addiction and problematic use,” Instagram chief Adam Mosseri testified in the LA court. He noted that the field of psychology does not classify social media addiction as an official diagnosis.
Tech giants maintain that users and parents have the agency and tools to manage screen time. However, a growing body of academic research suggests features like infinite scrolling, autoplay and push notifications are engineered to override human self-control.
Video: CBS News.
A state of ‘automated attachment’
My research with colleagues on digital consumption behaviour also challenges the idea that excessive social media use is a failure of personal willpower. Through interviews with 32 self-identified excessive users and an analysis of online discussions dedicated to heavy digital use, we found that consumers frequently enter a state of “automated attachment”.
This is when connection to the device becomes purely reflexive, as conscious decision-making is effectively suspended by the platform’s design.
We found that the impulse to use these platforms sometimes occurs before the user is even fully conscious. One participant admitted: “I’m waking up, I’m not even totally conscious, and I’m already doing things on the device.”
Another described this loss of agency vividly: “I found myself mindlessly opening the [TikTok] app every time I felt even the tiniest bit bored … My thumb was reaching to its old spot on reflex, without a conscious thought.”
Social media proponents argue that “screen addiction” isn’t the same as substance abuse. However, new neurophysiological evidence suggests that frequent engagement with these algorithms alters dopamine pathways, fostering a dependency that is “analogous to substance addiction”.
Strategies that keep users engaged
The argument that users should simply exercise willpower also needs to be understood in the context of the sophisticated strategies platforms employ to keep users engaged. These include:
1. Removing stopping cues
Features like infinite scroll, autoplay and push notifications create a continuous flow of content. By eliminating natural end-points, the design effectively shifts users into autopilot mode, making stopping a viewing session more difficult.
The issue of social media addiction is of particular concern when it comes to children, whose impulse control mechanisms are still developing. The US trial’s plaintiff says she began using social media at the age of six, and that her early exposure to these platforms led to a spiral into addiction.
Lawyers in the US trial have pointed to internal documents, known as “Project Myst”, which allegedly show that Meta knew parental controls were ineffective against these engagement loops. Meta’s attorney, Paul Schmidt, countered that the plaintiff’s struggles stemmed from pre-existing childhood trauma rather than platform design.
Our study heard from many adults (mainly in their 20s) who described the near-impossibility of controlling levels of use, despite their best efforts. If these adults cannot stop opening apps on reflex, expecting a child to exercise restraint with apps that affect human neurophysiology seems even more unrealistic.
Potential harms of overuse
The consequences of social media overuse can be significant. Our research and recent studies have identified a wide range of potential harms.
Excessive exposure to rapidly changing, highly stimulating content can fracture the user’s attention span, making it harder to focus on complex real-world tasks.
And many users describe feeling “defeated” by the technology. Social media’s erosion of autonomy can leave people unable to align their online actions – such as overlong sessions – with their intentions.
A ruling against social media companies in the LA court case, or enforced redesign of their apps in the EU, could have profound implications for the way these platforms are operated in future.
But while big tech companies have grown at dizzying rates over the past two decades, attempts to rein in their products on both sides of the Atlantic remain slow and painstaking. In this era of “use first, legislate later”, people all over the world, of all ages, are the laboratory mice.
Quynh Hoang 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.
Reports of widespread “dating burnout” and a cultural shift towards heteropessimism – a feeling of disappointment or despair at the state of relations between men and women – have caused panic in the media and dating apps.
Cultural debates have emerged around an alleged “rise of lonely single men” and what it means for society and future generations. Some have suggested that male singleness is a social problem partly caused by women’s supposed reluctance to “settle” in heterosexual partnerships.
For women, singlehood has largely been rebranded as a time for self-love and personal growth. The “single positivity” movement has removed much of the stigma around being a single woman (at least in one’s 20s). Women are allowed to embrace freedom and reclaim singlehood as a chosen identity.
My research on singlehood in Manchester found that single men had equally chosen to be single and were happily so. But they did not feel they could embrace this positivity. Instead, they remain polarised by harmful masculine ideals that misrepresent single men as either carefree bachelors or socially dysfunctional incels (involuntary celibates).
I interviewed ten men, aged 21-55, about their experiences of being single. Lamenting the lack of nuanced or positive portrayals, Simon, in his 40s, commented that single men are typically seen to be “having sex with half the town, or one rejection away from blowing up a school”.
From the playboy trope, characterised by Barney Stinson in How I Met Your Mother, to Theodore in the 2013 film Her, a divorcee who turns to AI for companionship, single men are represented in superficial terms. This can leave men feeling as though they must prove they are neither bachelor nor incel.
Bachelors and incels
Research on men and masculinity has long shown that young men are assumed to experience a period of sexual freedom before eventually “settling down”. Masculine ideals presume men commit to a monogamous relationship only once they have “sown their wild oats”.
On this basis, we might assume that young single men rarely face judgement for being single, and are instead celebrated for pursuing a liberated and carefree lifestyle.
However, in my research, men in their 20s spoke of the challenges they faced being single. Their singlehood was often assumed to be a result of “commitment-phobia” and a reluctance to settle down, rather than their lack of desire for an intimate relationship. In comparison, single women in their 20s did not face the same assumptions, with their singlehood rather understood as “a time to put themselves first” and enjoy freedom from being “tied down”.
Distancing himself from stereotypical representations of single men as “bachelors”, Harvey, in his mid-20s, explained:
You feel like you have to justify being single at times, and it’s because you have to differentiate that you’re not one of those stereotypes, you’re not one of “those guys” who mess girls around.
Several participants noted that masculinity and sexuality felt inescapably linked. Being in a sexual couple was understood as a key marker of masculinity. As a result, some young men worried that, if they were not visibly pursuing a relationship and not regarded as a “bachelor”, they would instead be questioned about their sexuality or desirability.
Stuart, in his early 50s, described how these pressures shaped his experiences in his 30s. He was content being single as it afforded him time to focus on his career and the ability to prioritise his friendships and hobbies. But Stuart’s friends questioned his sexuality and suggested he must be gay or asexual. This experience compelled him to participate in speed dating, not out of personal desire, but to demonstrate that he was “normal”.
Others preferred to remain single as a time to “find themselves” after experiencing difficult relationships, to accommodate caring responsibilities, or simply because they enjoyed their solitude. However, their reasoning was rarely accepted by peers, who failed to accept that their singlehood was by choice.
Pressures on women to couple up are often linked to the biological clock. But accounts in my research suggest that men, too, face age-related expectations.
The expectation for men to settle down in their 30s appears less tied to biology, and more to cultural norms that view coupledom and family life as markers of successful, responsible adulthood. According to my participants, settling down with a partner is seen as conducive to “growing up”.
While men were expected to display sexual interest, being perceived as too sexually active beyond a certain age was also stigmatised. Evan described how he enjoyed the experimentation of singlehood in his early 20s, but by his late 20s felt that remaining single was no longer acceptable. He felt he was increasingly viewed by peers as “sad” or “desperate”, revealing the narrow norms governing masculinity.
When mainstream culture offers few credible or positive narratives about single men’s lives, the search for recognition and belonging can be redirected elsewhere – sometimes with harmful consequences.
Simon, 41, described joining the online group “Men Going Their Own Way” (MGTOW) in search of community with other men who were single by choice. He quickly became concerned by the group’s misogynistic orientation and its links to the broader manosphere, where MGTOW can act as a gateway to incel communities. However, while Simon recognised the risks and disengaged, he worried that younger men seeking belonging might not.
It’s time we challenged reductive stereotype of singlehood and asked: why is being single treated as a social problem? We must create space for nuanced portrayals of single men beyond the bachelor or incel.
Alicia Denby 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.
Source: The Conversation – UK – By Aimee Ambrose, Professor of Energy Policy, Member of Fuel Poverty Evidence and Trustee of the Fuel Poverty Research Network, Sheffield Hallam University
Swedish homes are among the warmest in Europe, reflecting high levels of insulation and longstanding strategies that have kept heating costs low for most households.Antony McAulay/Shutterstock
The new year in Sweden began with some record-breaking cold temperatures. Temperatures in the village of Kvikkjokk in the northern Swedish part of Lapland dropped to -43.6°C, the lowest recorded since records began in 1887.
Yet for the majority of Swedish households, heating is not an issue. Those living in the multi-household apartment blocks that characterise Sweden’s towns and cities enjoy average temperatures of 22°C inside their homes, thanks to communal heating systems that keep room temperatures high and costs low. For many households, heating is charged at a flat rate and included in the rent they pay.
*Some interviewees in this article are anonymised according to the terms of the research.
In the UK, meanwhile, home temperatures average just 16.6 degrees, the lowest in all of Europe. At least 6 million UK households fear the onset of cold weather because they are living in fuel poverty – unable to afford to heat their home to a safe and comfortable level.
The problem is exacerbated by the UK’s reliance on natural gas to heat its homes – a fuel which suffers from escalating price volatility. They are also the most poorly insulated in Europe, making them difficult to keep warm.
In Britain, home heating isn’t just a political hot potato; it has been shown to cost lives. In the winter of 2022-23, 4,950 people were estimated to have died earlier than expected (known as “excess winter deaths”) because of the health effects of living in cold homes – including lung and heart problems as well as damage to mental health. In contrast, despite having a much colder winter climate, Sweden’s excess winter deaths index was around 12%, one of the lowest rates in Europe and considerably below the UK’s 18% figure.
The Insights section is committed to high-quality longform journalism. Our editors work with academics from many different backgrounds who are tackling a wide range of societal and scientific challenges.
So how did two countries that are geographically quite close end up so far apart when it comes to home heating outcomes? As two professors of energy studies – one British, the other Swedish – we have long puzzled over the stark contrast in how winter is experienced inside our homes in the north of England (Sheffield) and southern Sweden (Lund).
For the last three years, we have been researching the modern histories of home heating in both countries (plus Finland and Romania), gathering nearly 300 oral accounts of people’s memories of the daily struggle to keep warm at home for long periods each year.
By charting these experiences of home heating in both countries since the end of the second world war, we show how Britain now finds itself struggling to keep its citizens warm in winter while also facing an uphill battle to meet its environmental targets. The stories from Sweden, on the whole, suggest how different things could have been.
Post-war memories
The second world war changed many things but not, immediately, the way homes were heated. In the UK coal remained the primary domestic fuel, while Sweden stuck mainly with wood, although coal was becoming more common in cities. Cold homes were still considered normal in both countries, as Majvor* (who is now in her 80s and lives in the Swedish city of Malmö) recalled of her post-war childhood living in a one-room flat:
There was a stove in the room and that was the only source of heat – I have a memory of it being so cold in the winter that my mother had to put all three children in the same bed to keep warm. In the winter, all the water froze to ice, so you had to … heat it on the stove to get hot water.
Despite the cold, many of our interviewees remembered the burning of wood and coal to heat their homes with great affection – although less so the drudgery and dirt that went with it.
“There’s just something about a fire, isn’t there,” Sue (now in her 60s and living in Rotherham, England) told us. “The warmth, the smell, the laughter. It’s that family memory and it was just wonderful. Anyone ’round here will tell you the same: life was hard but it was wonderful. We felt loved.”
Mary (now in her 70s and also living in Rotherham) is among a very small minority who still heat their home using a coal fire. Her reflections were less positive:
I remember going to fetch coal when I was pregnant. I gave birth two days later … It’s the dirt that gets you down, the dirt from the fire. It’s disheartening when your walls are always dirty. That’s why I had them tiled because I was painting them every six months before that.
Carolina* (now in her mid-30s and living in Malmö) also had a negative recollection of her wood-burning childhood – but for a very different reason. She described how her mother had once “got the axe in her foot … She continued to chop wood anyway – but I kind of got PTSD [post-traumatic stress disorder] from her doing that. So I can’t do it, I’m really scared of it.”
In Sweden, home heating was seen as key to improving social conditions after the war. The emphasis was on good-quality homes for everyone as the social welfare concept of folkhem (“the people’s home”) finally gained traction. The idea had first been articulated by future prime minister Per Albin Hansson in a speech to the Swedish parliament back in 1928, as a way of expressing his vision for a fair and equal society.
From 1946, housing construction was regarded as a key political issue for improving public health and achieving Sweden’s other social welfare goals. In several cities, municipally owned public housing companies played an important role in the initial phase of new district heating systems, in part by guaranteeing a secure market. The introduction of the varmhyra (“warm rent”) policy meant heating and sometimes other utilities were included in the rent – an arrangement that continues to this day in many Swedish apartment blocks.
The UK, like Sweden, suffered the blight of cold homes during the 1940s, exacerbated by fuel rationing that extended long beyond the war. So it is difficult to explain why Britain’s new post-war welfare state did not explicitly address home heating.
Instead, the focus was on public health, with the birth of the National Health Service and recognition that the mass burning of coal was leading to fatal air pollution and unhealthy homes. Heavy city smogs, triggered by widespread coal burning in homes and factories, became increasingly common. The problem reached a climax when the “great smog of 1952” killed approximately 12,000 people, primarily in London, over just five days.
The justification for rapidly phasing out coal as the UK’s primary fuel for homes and industry was centred around ending the public health crisis of these killer smogs, rather than on changing the way homes were heated – leading to the introduction of the Clean Air Act (1956). And as the UK scrabbled for a cleaner form of heating, a game-changing discovery was made. Huge reserves of “natural gas” (methane) were found off the Yorkshire coast in 1965, offering the huge advantage of reducing visible air pollutants compared with coal.
One man in particular, Kenneth Hutchison, saw and seized the opportunity to present natural gas as the panacea the UK had been waiting for. As incoming president of the National Society for Clean Air, Hutchison hailed the gas industry as the driving force in Britain’s “smokeless revolution”. From the late 1960s, he drove the rollout of networks piping natural gas into UK households at an incredible rate, demanding: “We must convince the public that central heating by gas is best” over the grime and drudgery of coal fires.
A 1965 advert for ‘high-speed’ British gas. Video: Anachronistic Anarchist.
The chairman of British Gas, Denis Rooke – not an objective witness, admittedly – described the rollout as “perhaps the greatest peacetime operation in the nation’s history”. Between 1968 and 1976, around 13 million UK homes (of a total of about 15 million) were made ready for connection to the gas network. The cost of converting domestic heating and cooking systems from coal to gas was largely borne by the national gas supplier, making it effectively free to most households.
Our research suggests this transition was presented to UK households as a fait accompli. But most of our UK-based interviewees remembered the advent of natural gas as a major step forward in cleanliness, comfort and convenience. As 75-year-old Rita from Rotherham recalled of moving into a new council estate with gas heating in 1967:
It was like another universe! It was comfortable, everything became less intense – you didn’t need so much clothing … The days of cooking on the fire were gone. Fabulous! The boiler didn’t have to go all the time – the gas fire could take the chill off.
Britain’s gas rollout not only brought gas central heating but other appliances such as gas fridges and fires that further lightened the domestic load. For Rita’s and many other families, it felt like a cascade of liberations which made homes brighter and more enjoyable to live in.
Yet half a century later, Hutchison’s faith in gas appears less justified. While it certainly cleaned up the UK’s visible air pollution, natural gas is methane by another name – a powerful greenhouse gas.
How Sweden ‘futureproofed’
With a much smaller population and less crowded cities, air quality in Sweden had been less of a concern than in the UK in the immediate post-war period. But in the 1960s, proposals for a mass home-building programme raised fears this could worsen air pollution.
Without the option of “clean” natural gas, Sweden turned to district heating – an idea which had originated in New York in the 19th century. But Sweden committed to it in a big way during the 1960s and ‘70s, deciding it was the best way to meet the heating needs of the 1 million homes now being built. This decision shaped the way homes in Sweden are heated: today, some 90% of its multi-family apartment blocks are connected to district heating systems – with heat distributed from power plants (usually on the edge of cities) as hot water via a network of pipes.
Upon its introduction, district heating was celebrated for its efficiency, affordability for households (especially when combined with the warm rent policy), and flexibility – it is easy to change the fuel source. For some municipalities, district heating plants opened up opportunities to produce cheap electricity. Whereas UK households were (and remain) largely individually responsible for paying for their heating, in Sweden it was seen as a collective good.
Even the 1973 oil crisis – when geopolitical tensions in the Middle East quadrupled the price of oil – failed to dent public trust in the Swedish approach to home heating. In response to the oil crisis, Sweden moved quickly to change the fuels used to power district heating, introducing more domestic waste and biomass into the mix – a move that, from a climate perspective, now appears a highly prescient shift.
According to Kjell* (now in his 60s, living in a small town in south-west Sweden), 1973 was “when the whole concept changed because suddenly fossil fuels became expensive”. He explained:
The expansion of nuclear power [meant] electricity became very cheap … The government promoted the idea that ‘now we should use electricity, we should use direct electric heating’ … All you had to do was turn a thermostat, press a button, and it was warm.
As well as nuclear power expansion, Sweden doubled down on hydropower production and was among the earliest European countries to invest in other renewable energy sources. Its government was also an early proponent of the now-familiar concept of energy efficiency – encouraging both households and industry to conserve energy and invest in insulation. By the mid-1990s, every Swedish home was rated by the EU as having comprehensive insulation and double glazing as a minimum. The equivalent figure in the UK in 2025 was only around 50%.
The flagship initiative “Seal up Sweden” encouraged households to insulate homes and restrict room temperature to 20 degrees (still almost four degrees warmer than the average UK home today). And the warm rent system gave landlords a vested interest in improving the energy performance of their properties.
Whether it was realised at the time or not, in the defining moment of the oil crisis, Sweden was futureproofing its urban heating systems – and laying the foundations for its enduring reputation as a leader in clean energy and climate policy. Sweden eschewed energy imports in favour of harnessing its own energy assets through expansion in hydropower, waste and nuclear energy – although this latter commitment would soon be tested by the major 1979 accident at Pennsylvania’s Three Mile Island nuclear power plant in the US.
The era of power cuts
In stark contrast, the UK’s rapid natural gas rollout couldn’t move fast enough to protect households from the twin effects of the oil crisis and miners’ strikes in the 1970s. Electricity – mostly still generated by coal and oil – was rationed via rolling blackouts. Many workplaces were required to restrict their operations to a three-day week.
With the average British home heated to 13.7 °C at this time (compared with 20-21 °C in Sweden), there was little scope to ask households to cut back further, so nationwide power cuts were imposed instead. Homes were regularly plunged into darkness. Tony (now in his early 70s, from the English town of Whiston on Merseyside) worked as a social worker during this period. He recalled seeing many interiors without doors or bannisters – they had been burnt to keep the family warm.
Extra candles were imported into Britain in 1972 to cope with power cuts. Video: AP Archive.
Nonetheless, “clean” gas pioneer Hutchison was feeling vindicated as the UK enjoyed an era of falling gas prices throughout the 1980s. Climate change was still, at most, a nascent agenda, so it didn’t seem to matter that British households were living in some of the least energy-efficient (and worst insulated) homes in Europe.
Gas remained affordable through the miners’ strike of 1984-85 and privatisation of the gas industry in 1986, with the average household gas bill six times cheaper in real terms than today. Yet British households continued to modestly heat their homes, with average internal home temperatures slowly rising from 16.1 °C in 1990 to 17.8 °C by 1999.
Over the same period, Sweden went through several momentous changes as concern for the environment grew – amid recognition of the greenhouse effect (the build-up of gases trapping heat in the Earth’s atmosphere) and acid rain (rainfall made acidic by air pollution). This resulted in another pioneering move: the world’s first carbon tax on fossil fuels in 1991, which further galvanised its move away from oil.
Amid Sweden’s dash for energy independence, electric-powered home heat pumps increasingly came to be viewed as something of a status symbol. Even households living in multi-family urban apartments were growing increasingly concerned about the monopolistic nature of district heating. They started opting out in favour of individual heat pumps, undermining these collective systems that rely on everyone contributing.
Short-lived progress in the UK
Britain was much slower to embrace the need to address the world’s climate crisis. One promising intervention finally came in 2006, when Tony Blair’s New Labour government required all newly built homes to meet stringent environmental design standards (although this did little to lessen the environmental burden of existing homes).
In turn, higher standards of environmental design in new homes helped establish a market for more environmentally friendly, electric-powered heat pumps in Britain. Installations accelerated from 2004, mainly in social housing. The following year, gas connections peaked at 95% of UK households – then slowly started to fall, down to the current level of 74% across England and Wales.
With this reduction of reliance on gas, the level of emissions associated with heating UK homes also began to decline. Those urging Britain to do something about its position as one of Europe’s least environmentally conscious nations celebrated, if cautiously. But this progress, such as it was, proved short-lived.
From 2010, the new Conservative-Lib Dem coalition government began dismantling key initiatives aimed at domestic energy efficiency, including New Labour’s Code for Sustainable Homes as well as financial incentives to install heat pumps and renewables such as solar panels. Sales of these technologies started to fall away.
Since then, initiatives to promote adoption of renewable forms of home heating in the UK have been dogged by controversies – such as the renewable heat incentive in Northern Ireland, which resulted in the suspension of senior government officials.
Heat pump technology explained. Video: Nesta.
Ambitious plans (driven by the UK’s legally binding emissions reduction targets) to install 600,000 heat pumps a year have been met with public suspicion. Uptake is currently at around 50,000 per year – far below the government target.
Since coming to power, the current Labour government has rolled back its manifesto pledge to ban the sale of gas boilers in homes by 2035 – to the consternation of many environmental pressure groups and climate scientists. And while its recent announcement of more comprehensive investment in domestic energy efficiency (as part of the Warm Homes Plan) is a step in the right direction, many experts still consider the level of investment inadequate to secure the scale of change required to meet the UK’s net zero climate targets.
A sizable majority (74%) of UK homes are still heated by gas boilers – which emit around twice as much CO₂ each year as some electric-powered heat pumps.
The clean heating conundrum
The volatile political scene in the UK is hampering its transition to clean energy. Reform UK, which has adopted a strident anti-net zero position, has made strong gains with disenfranchised voters, according to numerous polls. Should it gain power at the next general election in 2028 (even if as part of a coalition), Reform is likely to double-down on fossil fuel extraction and use, dealing a severe blow to efforts to wean the UK off its enduring gas dependency.
However, a shift to electric heating would not be an overnight panacea to the UK’s energy bill woes. Depending on the energy efficiency of the homes in which they are installed, heat pumps could push bills up in the short-to-medium term, because electricity remains up to five times more expensive than gas.
But as more and more of the UK’s electricity is generated from renewable sources, these costs will fall, with some commentators forecasting that from 2028, the UK will start to see positive price impacts of more electricity being generated from renewables. Most UK households will not be able to take advantage of the cheaper clean electricity coming on stream for their heating, though, because they remain locked into their gas boilers.
In contrast, outside Sweden’s cities and towns, heat pumps have seen exponential growth since the 1990s, such that it now has one of the world’s highest penetration rates, with over a third of homes equipped with them. And the heat generated from these sources is effectively conserved within the country’s well-insulated housing stock.
But Sweden is not immune to political controversies around heating. Electricity price spikes in southern Sweden in recent winters have exposed households reliant on direct electric heating (mainly heat pumps) to affordability concerns. These price spikes were driven by a combination of high wholesale electricity prices, the country’s limited transmission capacity between price zones, and periods of low wind generation.
At the same time, energy-efficient district heating networks continue to be challenged by the rapid adoption of heat pumps.
The public debate about the future of nuclear power in Sweden also continues to rage. In recent years, political signals have shifted towards maintaining and potentially expanding nuclear capacity, which has increased uncertainty about whether a full phase-out remains a credible policy objective.
The Swedish city of Lund boasts the world’s largest low-temperature district heating network. Video: Alfa Laval.
Thermal comfort vs thermal restraint
The UK’s gas habit has not served it well in terms of securing thermal comfort for its households, with average indoor temperatures of 16.6°C lagging far behind the European average of 19°C. In contrast, Swedish homes are among the warmest in Europe, reflecting both affordability for many and a cultural expectation of thermal comfort.
But these contrasting expectations could yet play an intriguing role in the two countries’ home heating strategies. Both countries are entering a new phase where electrification via heat pumps may test the resilience of national grids and the fairness of pricing structures.
Despite greater precarity in the UK, an established tolerance of lower indoor temperatures may mean that, as electricity prices are lowered by increased renewable energy production, UK households can achieve warmer homes using heat pumps than they have been able using gas. Heat pumps have been found to produce up to four times more heat than a gas boiler, using the same energy input.
Conversely, Sweden’s cultural expectation of uniformly high indoor temperatures may challenge its future energy sufficiency targets and climate goals, particularly if electrification accelerates as more people – including those living in cities and large towns – seek the independence of heat pumps.
Sweden’s traditional system of cost-sharing through varmhyra (warm rent) and district heating has historically promoted equity, but growing societal disconnections and price variations risk eroding that solidarity.
In contrast, Britain has tended to rely on individual responsibility and market-led solutions when it comes to home heating. The UK Warm Homes Plan, launched in January 2026, makes clear that heat pumps are the government’s (and many scientists’) favoured route to decarbonising domestic heating, with the exception of district heating schemes in a relatively small number of areas. But this requires incentivising households to move to heat pumps while removing short-term financial pain from this move.
Ultimately, our research suggests that many UK households now understand that change needs to come. As Trevor from Whiston told us firmly:
We just can’t be doing that now [burning fossil fuels for heating] … Greenhouse gases – it’s not on … We’ve got to find another way, haven’t we?
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Aimee Ambrose receives funding from the Arts and Humanities Research Council and Horizon Europe.
Jenny Palm receives funding from Forte under CHANSE ERA-NET which has received funding from the European Union’s Horizon 2020 Research and Innovation Programme.
