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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

In 2023, the CO2 growth rate was 3.37 ± 0.11 ppm at Mauna Loa, 86% above the previous year, and hitting a record high since observations began in 1958[1], while global fossil fuel CO2 emissions only increased by 0.6 ± 0.5%[2,3]....

Une expérience de 4 mois pour repenser notre rapport au vivant grâce aux low-tech

Simultaneous harvest failures across major crop-producing regions are a threat to global food security. Concurrent weather extremes driven by a strongly meandering jet stream could trigger such events, but so far this has not been quantified. Specifically, the ability of state-of-the art crop and climate models to adequately reproduce such high impact events is a crucial component for estimating risks to global food security. Here we find an increased likelihood of concurrent low yields during summers featuring meandering jets in observations and models. While climate models accurately simulate atmospheric patterns, associated surface weather anomalies and negative effects on crop responses are mostly underestimated in bias-adjusted simulations. Given the identified model biases, future assessments of regional and concurrent crop losses from meandering jet states remain highly uncertain. Our results suggest that model-blind spots for such high-impact but deeply-uncertain hazards have to be anticipated and acc

The sixth assessment report of the IPCC assessed that the Arctic is projected to be on average practically ice-free in September near mid-century under intermediate and high greenhouse gas emissions scenarios, though not under low emissions scenarios, based on simulations from the latest generation Coupled Model Intercomparison Project Phase 6 (CMIP6) models. Here we show, using an attribution analysis approach, that a dominant influence of greenhouse gas increases on Arctic sea ice area is detectable in three observational datasets in all months of the year, but is on average underestimated by CMIP6 models. By scaling models’ sea ice response to greenhouse gases to best match the observed trend in an approach validated in an imperfect model test, we project an ice-free Arctic in September under all scenarios considered. These results emphasize the profound impacts of greenhouse gas emissions on the Arctic, and demonstrate the importance of planning for and adapting to a seasonally ice-free Arctic in the near

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Flash drought, characterized by unusually rapid drying, can have substantial impact on many socioeconomic sectors, particularly agriculture. However, potential changes to flash drought risk in a warming climate remain unknown. In this study, projected changes in flash drought frequency and cropland risk from flash drought are quantified using global climate model simulations. We find that flash drought occurrence is expected to increase globally among all scenarios, with the sharpest increases seen in scenarios with higher radiative forcing and greater fossil fuel usage. Flash drought risk over cropland is expected to increase globally, with the largest increases projected across North America (change in annual risk from 32% in 2015 to 49% in 2100) and Europe (32% to 53%) in the most extreme emissions scenario. Following low-end and medium scenarios compared to high-end scenarios indicates a notable reduction in annual flash drought risk over cropland. Flash droughts are projected to become more frequent unde

Potential external cost savings associated with the reduction of animal-sourced foods remain poorly understood. Here we combine life cycle assessment principles and monetarization factors to estimate the monetary worth of damage to human health and ecosystems caused by the environmental impacts of food production. We find that, globally, approximately US$2 of production-related external costs were embedded in every dollar of food expenditure in 2018—corresponding to US$14.0 trillion of externalities. A dietary shift away from animal-sourced foods could greatly reduce these ‘hidden’ costs, saving up to US$7.3 trillion worth of production-related health burden and ecosystem degradation while curbing carbon emissions. By comparing the health effects of dietary change from the consumption versus the production of food, we also show that omitting the latter means underestimating the benefits of more plant-based diets. Our analysis reveals the substantial potential of dietary change, particularly in high and upper-

Cela fait des décennies que l’on s’inquiète de la déplétion des ressources notamment minérales, depuis le rapport Meadows. Plus récemment les travaux d’Ugo Bardi avec sa courbe de Sénèque ont attiré l’attention sur la contradiction entre les besoins en métaux de la transition énergétique et l’état des ressources naturelles exploitables....

Climate change affects the Arctic and sub-Arctic regions by exposing previously frozen permafrost to thaw, unlocking soil nutrients, changing hydrological processes, and boosting plant growth. As a result, sub-Arctic tundra is subject to a shrub expansion, called “shrubification”, at the expense of sedge species. Depending on the intrinsic foliar properties of these plant species, changes in foliar mineral element fluxes with shrubification in the context of permafrost degradation may influence topsoil mineral element composition. Despite the potential implications of changes in topsoil mineral element concentrations for the fate of organic carbon, this remains poorly quantified. Here, we investigate vegetation foliar and topsoil mineral element composition (Si, K, Ca, P, Mn, Zn, Cu, Mo, V) across a natural gradient of permafrost degradation at a typical sub-Arctic tundra at Eight Mile Lake (Alaska, USA). Results show that foliar mineral element concentrations are higher (up to 9 times; Si, K, Mo for all spec

Ember modelling of least-cost power system pathways reveals that a clean power system (70-80% wind and solar) by 2035 should be at the core of energy planning for a net-zero continent by mid-century.

Une innovation low-tech ? Quel est cet étrange oxymore ? Faut-il retourner à la bougie ou à l’âge des cavernes au lieu de miser sur le progrès technologique ? Certes, le low-tech ne fait pas rêver comme le high-tech et ses applications futuristes. Et pourtant, si c’était là que se situait la vraie modernité et le courage d’innover ?

La ou les low-tech, mot à mot basses technologies, ou technologies « appropriées » sont un ensemble de technologies et de logiques visant la durabilité forte, la résilience collective et la transformation culturelle1.

Meeting human needs at sustainable levels of energy use is fundamental for avoiding catastrophic climate change and securing the well-being of all people. In the current political-economic regime, no country does so. Here, we assess which socio-economic conditions might enable societies to satisfy human needs at low energy use, to reconcile human well-being with climate mitigation.

Déployer la sobriété numérique - résumé aux décideurs […] Contexte : le numérique, une transition à repenser

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Une innovation low-tech ? Quel est cet étrange oxymore ? Faut-il retourner à la bougie ou à l’âge des cavernes au lieu de miser sur le progrès technologique ? Certes, le low-tech ne fait pas rêver comme le high-tech et ses applications futuristes. Et pourtant, si c’était là que se situait la vraie modernité et le courage d’innover ?

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La consommation d’énergie du numérique est aujourd’hui en hausse de 9 % par an. Il est possible de la ramener à 1,5 % par an en adoptant la « Sobriété numérique » comme principe d’action. La transition numérique telle qu’elle est actuellement mise en œuvre participe au dérèglement climatique plus qu’elle n’aide à le prévenir. Il est urgent d’agir.

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