Réseau Transition be

Le riz nourrit plus de la moitié de l’humanité depuis 9 000 ans. Mais selon une étude publiée dans Communications Earth & Environment, le réchauffement climatique progresse désormais 5 000 fois plus vite que la capacité d’adaptation de cette plante. Les régions rizicoles atteignent des températures jamais enregistrées dans toute l’histoire de cette culture — et le milliard de personnes qui en dépendent directement commence à manquer de temps.

Dr. Hansen periodically posts commentary on his recent papers and presentations and on other topics of interest to an e-mail list. To receive announcements of new postings, please click here.

Depuis le début de la guerre avec les Etats-Unis et à Israël, les autorités iraniennes ont coupé l’accès à Internet, menaçant de poursuites toute personne qui contournerait les restrictions.

The Gulf Stream is part of the Atlantic Meridional Overturning Circulation (AMOC). The AMOC is a tipping element and may collapse under changing forcing. However, the role of the Gulf Stream in such a tipping event is unknown. Here, we investigate the link between the AMOC and Gulf Stream using a high-resolution (0. 1°) stand-alone ocean simulation, in which the AMOC collapses under a slowly-increasing freshwater forcing. AMOC weakening gradually shifts the Gulf Stream near Cape Hatteras northward, followed by an abrupt northward displacement of 219 km within 2 years. This rapid shift occurs a few decades before the simulated AMOC collapse. Satellite altimetry shows a significant (1993–2024, p < 0.05) northward Gulf Stream trend near Cape Hatteras, which is also confirmed in subsurface temperature observations (1965–2024, p < 0.01). These findings provide indirect evidence for present-day AMOC weakening and demonstrate that abrupt Gulf Stream shifts can serve as early warning indicator for AMOC tipping.

Climate regime shifts (CRSs), characterized by abrupt and persistent transitions between alternative stable states in the climate system, pose serious threats to ecosystems and human well-being. Understanding the potential drivers of CRSs is crucial, particularly in a warming world where CRSs are becoming more frequent.

En 2023, l’administration Biden avait choisi Calibri comme police de caractères standard, dans un souci d’accessibilité et d’inclusivité pour les personnes malvoyantes et dyslexiques.

We report striking discoveries of numerous seafloor seeps of climate-reactive fluid and gases in the coastal Ross Sea, indicating this process may be a common phenomenon in the region. We establish the recent emergence of many of these seep features, based on their discovery in areas routinely surveyed for decades with no previous seep presence. Additionally, we highlight impacts to the local benthic ecosystem correlated to seep presence and discuss potential broader implications. With these discoveries, our understanding of Antarctic seafloor seeps shifts from them being rare phenomenon to seemingly widespread, and an important question is raised about the driver of seep emergence in the region. While the origin and underlying mechanisms of these emerging seep systems remains unknown, similar processes in the paleo-record and the Arctic have been attributed to climate-driven cryospheric change. Such a mechanism may be widespread around the Antarctic Continent, with concerning positive feedbacks that are curr

Une découverte scientifique majeure vient de rapprocher l’humanité d’une révolution technologique sans précédent. Des chercheurs chinois ont franchi un cap décisif dans la construction du futur Internet quantique, cette technologie mystérieuse qui promet de transformer radicalement nos communications numériques.

Un rapport analysant des images publiques de décorations du 16ᵉ centre du FSB, la branche du renseignement intérieur russe responsable de l’espionnage des communications, révèle de précieuses informations sur son organisation.

Le Japon a franchi un pas colossal vers l’avenir des télécommunications en atteignant une vitesse de transmission de données de 1,02 pétabit par seconde, suffisante pour télécharger l’intégralité du catalogue Netflix en moins d’une seconde. Ce résultat n’est pas qu’un chiffre impressionnant : il redéfinit les limites de ce que nous pensions possible en matière de connectivité.

La déconnexion quasi totale de l’Iran s’explique par une stratégie suivie depuis plusieurs années par les autorités iraniennes, qui contrôlent de près l’unique point de passage des données entrant et sortant d’Iran.

The ocean ecosystem is a vital component of the global carbon cycle, storing enough carbon to keep atmospheric CO2 considerably lower than it would otherwise be. However, this conception is based on simple models, neglecting the coupled land-ocean feedback. Using an interactive Earth system model, we show that the role ocean biology plays in controlling atmospheric CO2 is more complex than previously thought. Atmospheric CO2 in a new equilibrium state after the biological pump is shut down increases by more than 50% (163 ppm), lower than expected as approximately half the carbon lost from the ocean is adsorbed by the land. The abiotic ocean is less capable of taking up anthropogenic carbon due to the warmer climate, an absent biological surface pCO2 deficit and a higher Revelle factor. Prioritizing research on and preserving marine ecosystem functioning would be crucial to mitigate climate change and the risks associated with it.

Pesticides affect a diverse range of non-target species and may be linked to global biodiversity loss. The magnitude of this hazard remains only partially understood. We present a synthesis of pesticide (insecticide, herbicide and fungicide) impacts on multiple non-target organisms across trophic levels based on 20,212 effect sizes from 1,705 studies. For non-target plants, animals (invertebrate and vertebrates) and microorganisms (bacteria and fungi), we show negative responses of the growth, reproduction, behaviour and other physiological biomarkers within terrestrial and aquatic systems. Pesticides formulated for specific taxa negatively affected non-target groups, e.g. insecticidal neonicotinoids affecting amphibians. Negative effects were more pronounced in temperate than tropical regions but were consistent between aquatic and terrestrial environments, even after correcting for field-realistic terrestrial and environmentally relevant exposure scenarios. Our results question the sustainability of current

Cette prouesse dans le domaine quantique ouvre des perspectives fascinantes pour l’avenir des communications.

Depuis le début de la guerre contre le Hamas à Gaza et le Hezbollah dans le Sud-Liban, l’armée israélienne a renforcé ses opérations de brouillage des télécommunications. Et notamment des signaux GPS qui permettent de guider les missiles et drones. Quitte à perturber profondément la vie quotidienne des Libanais et des Israéliens.

Under current emission trajectories, temporarily overshooting the Paris global warming limit of 1.5 °C is a distinct possibility. Permanently exceeding this limit would substantially increase the probability of triggering climate tipping elements. Here, we investigate the tipping risks associated with several policy-relevant future emission scenarios, using a stylised Earth system model of four interconnected climate tipping elements.

Natural ecosystems store large amounts of carbon globally, as organisms absorb carbon from the atmosphere to build large, long-lasting, or slow-decaying structures such as tree bark or root systems. An ecosystem’s carbon sequestration potential is tightly linked to its biological diversity. Yet when considering future projections, many carbon sequestration models fail to account for the role biodiversity plays in carbon storage. Here, we assess the consequences of plant biodiversity loss for carbon storage under multiple climate and land-use change scenarios. We link a macroecological model projecting changes in vascular plant richness under different scenarios with empirical data on relationships between biodiversity and biomass. We find that biodiversity declines from climate and land use change could lead to a global loss of between 7.44-103.14 PgC (global sustainability scenario) and 10.87-145.95 PgC (fossil-fueled development scenario). This indicates a self-reinforcing feedback loop, where higher levels

Land degradation is a complex socio-environmental threat, which generally occurs as multiple concurrent pathways that remain largely unexplored in Europe. Here we present an unprecedented analysis of land multi-degradation in 40 continental countries, using twelve dataset-based processes that were modelled as land degradation convergence and combination pathways in Europe’s agricultural (and arable) environments. Using a Land Multi-degradation Index, we find that up to 27%, 35% and 22% of continental agricultural (~2 million km2) and arable (~1.1 million km2) lands are currently threatened by one, two, and three drivers of degradation, while 10–11% of pan-European agricultural/arable landscapes are cumulatively affected by four and at least five concurrent processes. We also explore the complex pattern of spatially interacting processes, emphasizing the major combinations of land degradation pathways across continental and national boundaries. Our results will enable policymakers to develop knowledge-based st

La plantation d'arbres, outil classique de la lutte contre le réchauffement climatique, peut avoir l'effet inverse si elle transforme des terrains clairs, qui réfléchissent l'énergie du soleil, en une forêt sombre qui l'absorbe, avertit une étude publiée mardi, qui cartographie les lieux propices au reboisement.

Quelques jours après le passage du cyclone Belal, de nombreux foyers sont encore privés d’eau et d’électricité. Certains travaux pour la production électrique prendront « plusieurs mois », selon EDF.