/news

  • Les scientifiques préviennent de nombreuses boucles de rétroactions climatiques dangereuses | Terra Projects
    https://www.laterredufutur.com/accueil/les-scientifiques-previennent-de-nombreuses-boucles-de-retroactions-

    Un nouveau rapport rédigé par une équipe internationale de chercheurs, dont des scientifiques de l’Université de l’État de l’Oregon (OSU), met en garde contre de nombreuses boucles de rétroaction climatique à risque et la nécessité d’agir tant au niveau de la recherche que des politiques. Publié dans la revue One Earth le 17 février 2023, le rapport indique qu’en raison notamment de l’amplification des rétroactions climatiques, « une réduction très rapide des émissions sera nécessaire pour limiter le réchauffement futur. »

    Des chercheurs des États-Unis et d’Europe ont répertorié et décrit 41 boucles de rétroaction climatique qui ont des implications majeures sur les perspectives du changement climatique. Les boucles de rétroaction climatique sont des processus qui peuvent soit amplifier soit diminuer les effets de nos émissions de gaz à effet de serre, initiant une réaction en chaîne cyclique qui se répète sans cesse. Il existe de nombreuses rétroactions amplificatrices importantes qui accentuent le réchauffement. Au total, les chercheurs ont identifié 27 rétroactions amplificatrices, 7 rétroactions amortissantes et 7 rétroactions incertaines.

    Source : https://phys.org/news/2023-02-scientists-dangerous-feedback-loops-climate.html

    D’autres articles en rapport avec les boucles de rétroaction climatiques (les liens figurent sur la page précédente) :

    https://scientistswarning.forestry.oregonstate.edu/climate_feedbacks

    https://scientistswarning.forestry.oregonstate.edu/climate_feedbacks_references

    https://bigthink.com/the-present/the-environmental-costs-of-war

    #boucles_de_rétroaction #feedback_loops #climat

  • ’Worthless’ forest carbon offsets risk exacerbating climate change
    https://phys.org/news/2023-08-worthless-forest-carbon-offsets-exacerbating.html

    In early 2023, the Guardian published an article suggesting that more than 90% of rainforest carbon offsets are worthless. […]. Verra, the largest certifier of these offset credits, said the claims were “absolutely incorrect” […].

    The claims in the Guardian article rested heavily on analysis which had been published as a preprint (before peer review). Now the research has been fully peer-reviewed and is published in the journal Science. It shows unequivocally that many projects which have sold what are known as REDD+ (reducing emissions from #deforestation and degradation) credits have failed to reduce deforestation.

    Source :
    Action needed to make carbon offsets from forest conservation work for climate change mitigation | Science
    https://www.science.org/doi/10.1126/science.ade3535

    #carbone

  • Archaeologists refute claims that a comet destroyed Hopewell culture
    https://phys.org/news/2023-08-archaeologists-refute-comet-destroyed-hopewell.html

    In February 2022, the journal Scientific Reports published a paper with the claim that a comet exploded over what is now Cincinnati around 1,500 years ago, raining fire over the area and destroying villages and farm fields, supposedly resulting in the rapid decline of the ancient Indigenous Hopewell culture.

    Research led by University of Cincinnati archaeologist Dr. Kenneth Tankersley claimed “evidence of a cosmic airburst at 11 Hopewell archaeological sites in three states stretching across the Ohio River Valley.” His evidence included the presence of meteorites, iron and silica-rich microspherules claimed to be from meteorites, and spikes in iridium and platinum—all supposedly associated with burned charcoal-rich Hopewell habitations.

    Dr. Kevin C. Nolan, director and senior archaeologist of the Applied Anthropology Laboratories at Ball State University, along with eleven other scholars with varied expertise—including several specialists in the Hopewell culture and the Smithsonian Institution’s Curator of Meteorites—have reviewed that evidence and found it to be wholly inadequate to support such an extraordinary claim.

    The results of their review are published as a response in issue 13 of Scientific Reports, published August 9. Dr. Nolan had worked with very few of the other researchers prior, but they all came together through this effort to set the record straight on Dr. Tankersley’s questionable research.

    “There is no evidence for catastrophically burned habitations at any of the 11 Hopewell sites studied by Tankersley’s team,” Dr. Nolan said. "The burned surfaces identified by the University of Cincinnati researchers are either localized episodes of burning for ceremonial purposes, such as cremating the honored dead, or are not even burned surfaces at all.

    “Whatever meteorites are present at these sites were collected by ancient Indigenous peoples—probably from various locations—and brought to these Hopewell sites to be crafted into ceremonial regalia,” he continued. “The iron and silica-rich microspherules do not have the chemical composition typical of meteorites, and so are natural products of local soil chemistry.”

    Further evidence discovered by Dr. Nolan and his team indicates that the available radiocarbon dates for all the Hopewell sites claimed to have been destroyed by the effects of a comet airburst do not come close to being the same age.

    “There is no evidence of any catastrophic comet airburst,” Dr. Nolan concluded. "And there is no evidence of any supposed decline in the Hopewell culture that supposedly followed in the wake of the devastation caused by the alleged airburst.

    “Many features of the Hopewell culture, including the construction of monumental earthworks and the accumulation of unusual raw materials obtained from places as distant as the Gulf Coast and the Rocky Mountains, did cease by around 400 CE. But there was no decline in local populations, so these cultural shifts simply reflect changes in the social and religious fabric of these Indigenous societies that, for a time, had knitted them together.”

    Dr. Nolan said the numerous instances of possibly intentional data manipulations to support the comet impact are even more troubling than the myriad errors in interpreting the evidence, and the research response clearly details those.

  • De multiples effondrements d’écosystèmes pourraient se produire avant 2050...
    https://ricochets.cc/De-multiples-effondrements-d-ecosystemes-pourraient-se-produire-avant-2050

    Le réchauffement climatique et les destructions écologiques produits par la civilisation industrielle (Etats, capitalisme, techno-industrie, extractivisme...) semblent s’accélérer. Des scientifiques voient par exemple l’accélération des la fonte des glaces et davantage d’événements « météo » extrêmes. Une étude scientifique affirme que les « stress » cumulés pourraient produire des effondrements en cascade d’écosystèmes bien avant 2050, bien plus tôt que l’horizon 2100 souvent mis en avant dans les discours (...) #Les_Articles

    / #La_civilisation,_la_civilisation_industrielle, Catastrophes climatiques et destructions (...)

    #Catastrophes_climatiques_et_destructions_écologiques
    https://phys.org/news/2023-06-ecological-doom-loops-ecosystem-collapses-sooner.html
    https://www.terrestres.org/2023/07/17/la-niche-climatique-humaine

  • New research shows climate change will increase impacts of volcanic eruptions
    https://phys.org/news/2023-06-climate-impacts-volcanic-eruptions.html

    “Sea level rise, glacial melting, aquifer depletion, and mountain erosion can all affect the likelihood and frequency of volcanic eruptions,” he said. “With the increasing seriousness of climate impacts on society, the search for ’geoengineering’ solutions will make it more likely that countries will consider volcano-mimicking interventions—like an injection of aerosols into the stratosphere to cool the Earth’s surface. Volcano scientists will need to advise policymakers on the details of how such events would likely evolve.”

  • Opinion : The US will send depleted uranium munitions to Ukraine—despite military, health and environmental effects
    https://phys.org/news/2023-06-opinion-depleted-uranium-munitions-ukrainedespite.html

    The Biden administration has agreed to provide Ukraine with depleted uranium shells to equip M1A1 Abrams tanks that the U.S. is sending there. Britain has already delivered tanks to Ukraine equipped with depleted-uranium shells.

    DU munitions, developed in the 1970s, are not nuclear weapons and do not produce a nuclear explosion. But soldiers or civilians can be exposed to the uranium, either in combat or afterward. Health physicist Kathryn Higley explains what depleted uranium is and what’s known about potential health and environmental risks.

    Une bonne façon d’empêcher les Russes d’exploiter les terres Ukrainiennes ça. Très malin. De grands stratèges les occidentaux.

    • La rupture du barrage a pollué la zone inondée avec un cocktail d’hydrocarbure digne de l’atmosphère d’une exoplanète.
      Des 2 cotés de la ligne de fronts des milliers de mines ont été disséminées. Mais il ne faudrait surtout pas s’illusionner : on peut encore faire pire !
      Si il reste des stocks d’obus à uranium appauvri non utilisés en Irak (ou plus probablement re-cantinés depuis...) dans les entrepôts de l’US Army, l’occasion est trop belle de s’en débarrasser avant la date de péremption afin de pouvoir procéder au renouvellement sans avoir à se farcir le recyclage.

      Anne Morelli « Principes élémentaires de propagande de guerre » Editions Labor, 2001 :

      L’OTAN confirmera également, en mars 2000, avoir utilisé 31 000 obus à uranium appauvri lors de la guerre contre la Yougoslavie mais rappellera que cette arme, soupçonnée de provoquer des malformations chez les enfants à naître, des décès et des problèmes de stérilité n’étaient prohibée au moment de son utilisation par aucune convention internationale

      Manifestement ça a vachement évolué depuis...

  • War tourists fighting on a virtual front, since Ukraine-Russia war
    https://phys.org/news/2023-02-war-tourists-virtual-front-ukraine-russia.html

    Since the start of the war in Ukraine, a new group of “war tourists” has emerged—those who are fighting on a virtual front.

    A new study from the University of Portsmouth has found that war tourism, which typically used to be people traveling to past or present war zones, is now also an online phenomenon.

    #jeu #guerre

  • Pénis et léopards : découverte de la plus ancienne sculpture narrative du monde | Slate.fr
    https://www.slate.fr/story/237581/penis-leopards-decouverte-ancienne-sculpture-narrative-monde-histoire-turquie-

    Ce serait la première histoire sculptée. En tout cas, la plus ancienne que l’on ait à ce jour trouvé. Voici la superbe découverte que viennent tout juste de faire des archéologues travaillant sur les fouilles de Sayburç, dans le sud-est de la Turquie.

    Le site en question était habité au néolithique, il y a environ 11.000 ans, aux prémices de la sédentarisation de l’homme, rapporte le média scientifique Phys.org. Les fouilles sont encore loin d’être terminées, mais elles ont déjà révélé plusieurs sculptures remarquables, racontant une histoire vieille de plusieurs millénaires.

    Dans ce qui aurait été une grande salle communale jonchée de bancs, les archéologues ont mis à jour deux grands panneaux représentant des personnages divers, interagissant avec des animaux dangereux. On y voit notamment un homme, phallus en main, face à des léopards qui tenteraient, semble-t-il, de l’entourer. Sur le second panneau, un autre homme muni cette fois-ci d’un hochet, affronte un serpent et un taureau.
    Première scène narrative

    Des œuvres d’art similaires, et parfois bien plus anciennes, on en a déjà trouvées tout un tas me direz-vous. Sauf que cette fois-ci, c’est légèrement différent. Ici, les figures communiquent entre elles et forment une scène narrative, un véritable récit ancien.

    Les deux panneaux sont en effet juxtaposés horizontalement, de sorte qu’ils puissent être vus de manière progressive, à l’image d’une histoire que l’on raconte. « Ces figures gravées ensemble pour dépeindre un récit sont les premiers exemples connus d’une telle scène holistique », explique dans la revue Antiquity l’archéologue Dr. Eylem Özdoğan, de l’Université d’Istanbul.

    Avec ses bancs et ses espaces, la pièce commune actuellement fouillée sur le site pourrait avoir été comme une sorte de salle de cinéma, un théâtre où l’on peut voir et découvrir les personnages mythiques de cette communauté néolithique alors en pleine mutation.

    11,000-year-old carving may be earliest narrative scene
    https://phys.org/news/2022-12-year-old-earliest-narrative-scene.html

    The discovery, reported by Dr. Özdoğan in the journal Antiquity, was made during excavations at Sayburç which began in 2021. The site is located beneath a modern village in the Şanlıurfa Province of Turkey.

    The excavations revealed the site was inhabited during the Neolithic, in the 9th millennium BC. This period saw an important transition, with people shifting from a mobile hunter-gatherer lifestyle to farming and living in long-term settlements like Sayburç.

    Archaeologists uncovered several residential buildings as well as a large communal structure. This may have served as a place for special gatherings, with benches lining the walls. The narrative images were found carved into the back rests of some of these benches.

  • The fountain of life: Water droplets hold the secret ingredient for building life
    https://phys.org/news/2022-10-fountain-life-droplets-secret-ingredient.html

    Purdue University chemists have uncovered a mechanism for peptide-forming reactions to occur in water—something that has puzzled scientists for decades.

    “This is essentially the chemistry behind the origin of life,” said Graham Cooks, the Henry Bohn Hass Distinguished Professor of Analytical Chemistry in Purdue’s College of Science."This is the first demonstration that primordial molecules, simple amino acids, spontaneously form peptides, the building blocks of life, in droplets of pure water. This is a dramatic discovery."

  • The world’s most unwanted plants help trees make more fruit
    https://phys.org/news/2022-02-world-unwanted-trees-fruit.html

    Under the guidance of FIU professors Suzanne Koptur and Krishnaswamy Jayachandran, Kleiman compared mango trees at a local farm in Homestead, Florida. One plot of trees had weeds growing around them. The other plot was maintained and weed-free.

    The pollinators preferred the trees with the weeds. In turn, the trees benefitted and produced more mangos. In fact, there were between 100 to 236 mangos on the trees with weeds, compared to between 38 to 48 on the trees without weeds.

    Kleiman points out findings apply to mango trees, but also to all of the roughly 80 percent of flowering plants of Earth, including fruit trees and all flowering vegetable plants like tomatoes, beans, eggplants and squash. She also hopes this information can help farmers save time and money, as well as reduce the use of chemical pesticides.

    #agriculture #mauvaises_herbes #permaculture #fruitiers #pollinisateurs

  • Study challenges evolutionary theory that DNA mutations are random
    https://phys.org/news/2022-01-evolutionary-theory-dna-mutations-random.html

    The findings add a surprising twist to Charles Darwin’s theory of evolution by natural selection because it reveals that the plant has evolved to protect its genes from mutation to ensure survival.

    “The plant has evolved a way to protect its most important places from mutation,” Weigel said. “This is exciting because we could even use these discoveries to think about how to protect human genes from mutation.”

    #evolution #darwin #aléa #gènes

  • COVID gets airborne: Team models delta virus inside an aerosol for the first time
    https://phys.org/news/2021-11-covid-airborne-team-delta-virus.html

    Visualization of delta #SARS-CoV-2 in a respiratory #aerosol, where the virus is depicted in purple with the studded spike proteins in cyan. Mucins are red, albumin proteins green, and the deep lung fluid lipids in ocher. Credit: UC San Diego’s Abigail Dommer, the Amaro Lab, and the research team

  • French scientist recognized for rapid DNA sequencing technique key in COVID fight
    https://phys.org/news/2021-09-french-scientist-rapid-dna-sequencing.html

    After studying at the University of Strasbourg and completing postdoctoral fellowships in Canada and in France, Mayer tested his idea for the first time in Geneva, in the research center of a pharmaceutical company where he then worked.

    Two key patents were filed in April 1997.

    The technology was later acquired by a start-up founded by Balasubramanian and Klenerman, two British scientists working on the same problem.

    Their company was eventually bought by the US genetic research company Illumina, the global leader in genetic sequencing, […]

    Mayer does not own the property rights to the sequencing method, so he doesn’t share in the profits.

  • Largest-ever study of artificial insemination in sharks—and the occasional ’virgin birth’
    https://phys.org/news/2021-05-largest-ever-artificial-insemination-sharksand-occasional.html

    In the genetic analysis of the offspring, the team also found two instances of parthenogenesis, where the mother reproduced on her own without using the sperm she’d been inseminated with. “These cases of parthenogenesis were unexpected and help illustrate how little we know about the basic mechanisms of sexual reproduction and embryo development among sharks,” says Wyffels

    #parthénogénèse

  • When Chauvet Cave artists created their artwork, the Pont d’Arc was already there
    https://phys.org/news/2021-04-chauvet-cave-artists-artwork-pont.html

    Scientists from the CNRS, Université Savoie Mont Blanc, and the Muséum National d’Histoire Naturelle now know the answer. By studying the landform of the area and making novel use of applied mathematics to date sand transported by the Ardèche River, they determined that the Pont d’Arc was formed about 124,000 years ago.

    This study, published in Scientific Reports, reports that these past communities were therefore familiar with the same landmarks we know today: the gorge entrance, a natural archway, and a ledge leading directly to the cave entrance, which was then wide open.

  • (Google trad)
    « Ce travail, publié dans la revue Science le 8 avril, signifie également que ce type de connexion œil-cerveau est antérieur aux animaux vivant sur terre. La théorie existante était que cette connexion a d’abord évolué chez les créatures terrestres et, à partir de là, s’est poursuivie chez les humains où les scientifiques pensent qu’elle aide à notre perception de la profondeur et à notre vision 3D.

    Et ces travaux, menés par des chercheurs de l’organisme public de recherche Inserm en France, font plus que remodeler notre compréhension du passé. Elle a également des implications pour les futures recherches en santé.

    L’étude de modèles animaux est un moyen inestimable pour les chercheurs de se renseigner sur la santé et les maladies, mais établir des liens avec les conditions humaines à partir de ces modèles peut être difficile.

    Le poisson zèbre est un animal modèle populaire, par exemple, mais son câblage œil-cerveau est très différent de celui d’un humain. En fait, cela aide à expliquer pourquoi les scientifiques pensaient que la connexion humaine avait d’abord évolué chez des créatures terrestres à quatre membres, ou tétrapodes. »

    A discovery that ’literally changes the textbook’
    https://phys.org/news/2021-04-discovery-literally-textbook.html

    The network of nerves connecting our eyes to our brains is sophisticated and researchers have now shown that it evolved much earlier than previously thought, thanks to an unexpected source: the gar fish.

    Michigan State University’s Ingo Braasch has helped an international research team show that this connection scheme was already present in ancient fish at least 450 million years ago. That makes it about 100 million years older than previously believed.

    “It’s the first time for me that one of our publications literally changes the textbook that I am teaching with,” said Braasch, as assistant professor in the Department of Integrative Biology in the College of Natural Science.

    This work, published in the journal Science on April 8, also means that this type of eye-brain connection predates animals living on land. The existing theory had been that this connection first evolved in terrestrial creatures and, from there, carried on into humans where scientists believe it helps with our depth perception and 3D vision.

    And this work, which was led by researchers at France’s Inserm public research organization, does more than reshape our understanding of the past. It also has implications for future health research.

    Studying animal models is an invaluable way for researchers to learn about health and disease, but drawing connections to human conditions from these models can be challenging.

    Zebrafish are a popular model animal, for example, but their eye-brain wiring is very distinct from a human’s. In fact, that helps explain why scientists thought the human connection first evolved in four-limbed terrestrial creatures, or tetrapods.

    “Modern fish, they don’t have this type of eye-brain connection,” Braasch said. “That’s one of the reasons that people thought it was a new thing in tetrapods.”

    Braasch is one of the world’s leading experts in a different type of fish known as gar. Gar have evolved more slowly than zebrafish, meaning gar are more similar to the last common ancestor shared by fish and humans. These similarities could make gar a powerful animal model for health studies, which is why Braasch and his team are working to better understand gar biology and genetics.

    That, in turn, is why Inserm’s researchers sought out Braasch for this study.

    “Without his help, this project wouldn’t have been possible,” said Alain Chédotal, director of research at Inserm and a group leader of the Vision Institute in Paris. “We did not have access to spotted gar, a fish that does not exist in Europe and occupies a key position in the tree of life.”

    To do the study, Chédotal and his colleague, Filippo Del Bene, used a groundbreaking technique to see the nerves connecting eyes to brains in several different fish species. This included the well-studied zebrafish, but also rarer specimens such as Braasch’s gar and Australian lungfish provided by a collaborator at the University of Queensland.

    In a zebrafish, each eye has one nerve connecting it to the opposite side of the fish’s brain. That is, one nerve connects the left eye to the brain’s right hemisphere and another nerve connects its right eye to the left side of its brain.

    The other, more “ancient” fish do things differently. They have what’s called ipsilateral or bilateral visual projections. Here, each eye has two nerve connections, one going to either side of the brain, which is also what humans have.

    Armed with an understanding of genetics and evolution, the team could look back in time to estimate when these bilateral projections first appeared. Looking forward, the team is excited to build on this work to better understand and explore the biology of visual systems.

    “What we found in this study was just the tip of the iceberg,” Chédotal said. “It was highly motivating to see Ingo’s enthusiastic reaction and warm support when we presented him the first results. We can’t wait to continue the project with him.”

    Both Braasch and Chédotal noted how powerful this study was thanks to a robust collaboration that allowed the team to examine so many different animals, which Braasch said is a growing trend in the field.

    The study also reminded Braasch of another trend.

    “We’re finding more and more that many things that we thought evolved relatively late are actually very old,” Braasch said, which actually makes him feel a little more connected to nature. “I learn something about myself when looking at these weird fish and understanding how old parts of our own bodies are. I’m excited to tell the story of eye evolution with a new twist this semester in our Comparative Anatomy class.”

  • New study suggests humans evolved to run on less water than our closest primate relatives
    https://phys.org/news/2021-03-humans-evolved-closest-primate-relatives.html

    Our bodies are constantly losing water: when we sweat, go to the bathroom, even when we breathe. That water needs to be replenished to keep blood volume and other body fluids within normal ranges.

    And yet, research published March 5 in the journal Current Biology shows that the human body uses 30% to 50% less water per day than our closest animal cousins. In other words, among primates, humans evolved to be the low-flow model.

  • Organic materials essential for life on Earth are found for the first time on the surface of an asteroid
    https://phys.org/news/2021-03-materials-essential-life-earth-surface.html

    Dr. Queenie Chan from the Department of Earth Sciences at Royal Holloway, said: "The Hayabusa mission was a robotic spacecraft developed by the Japan Aerospace Exploration Agency to return samples from a small near-Earth asteroid named Itokawa, for detailed analysis in laboratories on Earth.

    "After being studied in great detail by an international team of researchers, our analysis of a single grain, nicknamed ’Amazon,’ has preserved both primitive (unheated) and processed (heated) organic matter within ten microns (a thousandth of a centimeter) of distance.

    “The organic matter that has been heated indicates that the asteroid had been heated to over 600°C in the past. The presence of unheated organic matter very close to it, means that the in fall of primitive organics arrived on the surface of Itokawa after the asteroid had cooled down.”

    Dr. Chan, continues: "Studying Amazon has allowed us to better understand how the asteroid constantly evolved by incorporating newly-arrived exogenous water and organic compounds.

    "These findings are really exciting as they reveal complex details of an asteroid’s history and how its evolution pathway is so similar to that of the prebiotic Earth.

    “The success of this mission and the analysis of the sample that returned to Earth has since paved the way for a more detailed analysis of carbonaceous material returned by missions such as JAXA’s Hayabusa2 and NASA’s OSIRIS-Rex missions. Both of these missions have identified exogeneous materials on the target asteroids Ryugu and Bennu, respectively. Our findings suggest that mixing of materials is a common process in our solar system.”

  • Common weed killers favor antibiotic resistant bacteria, new study shows
    https://phys.org/news/2021-02-common-weed-killers-favor-antibiotic.html

    Scientists from China and the UK studied the effect of three widely used herbicides called glyphosate, glufosinate and dicamba on soil bacterial communities.

    Using soil microcosms, researchers discovered that herbicides increased the relative abundance of bacterial species that carried antibiotic resistance genes. This was because mutations that improved growth in the presence of herbicides also increased bacterial tolerance to antibiotics. Herbicide exposure also led to more frequent movement of antibiotic resistance genes between bacteria.