Outils pédagogiques

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Evidence shows a continuing increase in the frequency and severity of global heatwaves1,2, raising concerns about the future impacts of climate change and the associated socioeconomic costs3,4. Here we develop a disaster footprint analytical framework by integrating climate, epidemiological and hybrid input–output and computable general equilibrium global trade models to estimate the midcentury socioeconomic impacts of heat stress. We consider health costs related to heat exposure, the value of heat-induced labour productivity loss and indirect losses due to economic disruptions cascading through supply chains. Here we show that the global annual incremental gross domestic product loss increases exponentially from 0.03 ± 0.01 (SSP 245)–0.05 ± 0.03 (SSP 585) percentage points during 2030–2040 to 0.05 ± 0.01–0.15 ± 0.04 percentage points during 2050–2060. By 2060, the expected global economic losses reach a total of 0.6–4.6% with losses attributed to health loss (37–45%), labour productivity loss (18–37%) and i

Anthropogenic emissions drive global-scale warming yet the temperature increase relative to pre-industrial levels is uncertain. Using 300 years of ocean mixed-layer temperature records preserved in sclerosponge carbonate skeletons, we demonstrate that industrial-era warming began in the mid-1860s, more than 80 years earlier than instrumental sea surface temperature records. The Sr/Ca palaeothermometer was calibrated against ‘modern’ (post-1963) highly correlated (R2 = 0.91) instrumental records of global sea surface temperatures, with the pre-industrial defined by nearly constant (<±0.1 °C) temperatures from 1700 to the early 1860s. Increasing ocean and land-air temperatures overlap until the late twentieth century, when the land began warming at nearly twice the rate of the surface oceans. Hotter land temperatures, together with the earlier onset of industrial-era warming, indicate that global warming was already 1.7 ± 0.1 °C above pre-industrial levels by 2020. Our result is 0.5 °C higher than IPCC estim

L'entropie est une mesure quantitative du désordre ou du chaos d'un système, mais de quoi parle-t-on précisément ?

Permafrost and glaciers in the high Arctic form an impermeable ‘cryospheric cap’ that traps a large reservoir of subsurface methane, preventing it from reaching the atmosphere. Cryospheric vulnerability to climate warming is making releases of this methane possible. On Svalbard, where air temperatures are rising more than two times faster than the average for the Arctic, glaciers are retreating and leaving behind exposed forefields that enable rapid methane escape. Here we document how methane-rich groundwater springs have formed in recently revealed forefields of 78 land-terminating glaciers across central Svalbard, bringing deep-seated methane gas to the surface. Waters collected from these springs during February–May of 2021 and 2022 are supersaturated with methane up to 600,000 times greater than atmospheric equilibration. Spatial sampling reveals a geological dependency on the extent of methane supersaturation, with isotopic evidence of a thermogenic source. We estimate annual methane emissions from prog

Terrestrial ecosystems have taken up about 32% of the total anthropogenic CO2 emissions in the past six decades1. Large uncertainties in terrestrial carbon–climate feedbacks, however, make it difficult to predict how the land carbon sink will respond to future climate change2. Interannual variations in the atmospheric CO2 growth rate (CGR) are dominated by land–atmosphere carbon fluxes in the tropics, providing an opportunity to explore land carbon–climate interactions3–6. It is thought that variations in CGR are largely controlled by temperature7–10 but there is also evidence for a tight coupling between water availability and CGR11. Here, we use a record of global atmospheric CO2, terrestrial water storage and precipitation data to investigate changes in the interannual relationship between tropical land climate conditions and CGR under a changing climate. We find that the interannual relationship between tropical water availability and CGR became increasingly negative during 1989–2018 compared to 1960–1989

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

Global CO2 emissions for 2022 increased by 1.5% relative to 2021 (+7.9% and +2.0% relative to 2020 and 2019, respectively), reaching 36.1 GtCO2. These 2022 emissions consumed 13%–36% of the remaining carbon budget to limit warming to 1.5 °C, suggesting permissible emissions could be depleted within 2–7 years (67% likelihood).

An international team of scientists painstakingly gathered data from more than 50 years of seagoing scientific drilling missions to conduct a first-of-its-kind study of organic carbon that falls to the bottom of the ocean and gets drawn deep inside the planet.

Gestational exposure to ambient fine particles (PM2.5) increases the risk of stillbirth, but the related disease burden is unknown, particularly in low- and middle-income countries (LMICs). We combine state-of-the-art estimates on stillbirths, and multiple exposure–response functions obtained from previous meta-analyses or derived by a self-matched case-control study in 54 LMICs. 13,870 stillbirths and 32,449 livebirths are extracted from 113 geocoded surveys from the Demographic and Health Surveys. Each stillbirth is compared to livebirth(s) of the same mother using a conditional logit regression. We find that 10-µg/m3 increase of PM2.5 is associated with an 11.0% (95% confidence interval [CI] 6.4, 15.7) increase in the risk of stillbirth, and the association is significantly enhanced by maternal age. Based on age-specific nonlinear PM2.5–stillbirth curves, we evaluate the PM2.5-related stillbirths in 137 countries. In 2015, of 2.09 (95% CI: 1.98, 2.20) million stillbirths, 0.83 (0.54, 1.08) million or 39.7%

La preuve scientifique d’un risque sanitaire ou environnemental lié aux microplastiques n’est, aujourd’hui, pas établie. Pourtant, le traitement médiatique de ce sujet suggérerait l’inverse. D’après les chercheurs, l’écho donné à leurs travaux témoigne d’abord d’une montée en puissance de notre conscience environnementale.

Observons finement l’effet des ressources naturelles à l’intérieur d’un pays. Une chronique de Phoebe W. Ishak et Pierre-Guillaume Méon. Elle est postdoctorante CNRS à l'école d’économie d'Aix-Marseille, à la Faculté d’économie et de gestion (FEG) d'Aix-Marseille Université. Il est professeur de science économique au Centre Emile Bernheim de Recherche interdisciplinaire en gestion et Dulbea de l'Université libre de Bruxelles.

L’actualisation de précédents travaux par des chercheurs de l’Université Columbia et de l’Université de Californie (États-Unis) soutient que la sécheresse qui touche le sud-ouest de l’Amérique du Nord depuis une vingtaine d’années est la plus sévère depuis au moins 1200 ans. Les résultats ont été publiés dans la revue Nature Climate Change ce 14 février.

Trois jeunes sur quatre sont éco-anxieux, nous apprenait fin 2021 une étude du Lancet. Demain, fera-t-on face à une génération de dépressifs ? Pas forcément, nous apprennent la sociologue Dominique Méda et le psychologue Pierre-Eric Sutter, qui ont tous deux participé à l’exposition « Renaissances », visible à la Cité des sciences et de l’industrie jusqu’au 6 mars 2022. Il est possible de surmonter l’effondrement et l’éco-anxiété, à l’échelle individuelle comme collective.

Beaucoup de scientifiques considèrent que parler de leurs émotions dans le cadre de leur activité professionnelle pourrait les décrédibiliser . Dans ce recueil, des scientifiques témoignent de leur prise de conscience face aux changements environnementaux d'origine anthropique ; il y a quelque chose qui échappe à la raison, une humanité qui a peur de se perdre en chemin et qui a pris conscience des limites du monde qu'elle habite.

Christophe Bonneuil, directeur de recherche au CNRS, Pierre-Louis Choquet, sociologue à Sciences po, et Benjamin Franta, chercheur en histoire à l'université américaine de Stanford, ont étudié les archives du groupe pétrolier, devenu TotalEnergies, ainsi que des revues internes et des interviews, selon cet article publié dans la revue Global Environmental Change.

Mais pour certains spécialistes, elle illustre également les ratés des mesures mises en place pour lutter contre le réchauffement climatique. France 24 s'est entretenu avec Benjamin Coriat, professeur émérite de sciences économiques à l'université Sorbonne Paris Nord, membre des Économistes atterrés et auteur notamment de l'ouvrage “Le bien commun, le climat et le marché” (Éd. Les Liens qui libèrent).

Comprendre - Transmettre - Agir Un outil simple pour tous les enseignants des cycles 2 et 3

Which effects did the heat wave of summer 2020 have in Siberia? geologists compared the spatial and temporal distribution of methane concentrations in the air of northern Siberia with geological maps. the methane concentrations in the air after last year’s heat wave indicate that increased gas emissions came from limestone formations.

Quel rôle l'école doit-elle jouer dans la transition écologique? Invité mercredi dans La Matinale, le docteur en sciences de l'environnement à l'Université de Lausanne Daniel Curnier estime que la prise de conscience de l'école sur la question est "largement insuffisante".

Les océans couvrent plus de 70 % de la surface de notre Planète. Les scientifiques savent depuis longtemps qu'il est un rouage essentiel de la machine climatique. Ne pourraient-ils pas jouer un rôle dans notre lutte contre le dérèglement climatique ? La question est posée. Mais la réponse n'est pas si simple. Deux chercheurs nous en détaille les tenants et les aboutissants.

"Trajectoires du Système Terre dans l'Anthropocène", une étude récente cosignée par Will Steffen, chimiste réputé, analyste des systèmes climatiques et professeur de la science du Système Terre à l'Université nationale australienne, met en garde contre des changements catastrophiques du climat de la Terre si les tendances actuelles en matière d'émissions ne sont pas immédiatement inversées.

Human activities are threatening to push the Earth system beyond its planetary boundaries, risking catastrophic and irreversible global environmental change. Action is urgently needed, yet well-intentioned policies designed to reduce pressure on a single boundary can lead, through economic linkages, to aggravation of other pressures. In particular, the potential policy spillovers from an increase in the global carbon price onto other critical Earth system processes has received little attention to date. To this end, we explore the global environmental effects of pricing carbon, beyond its effect on carbon emissions. We find that the case for carbon pricing globally becomes even stronger in a multi-boundary world, since it can ameliorate many other planetary pressures. It does however exacerbate certain planetary pressures, largely by stimulating additional biofuel production. When carbon pricing is allied with a biofuel policy, however, it can alleviate all planetary pressures. In the light of nine Earth Syst

Freshwater availability is changing worldwide. Here we quantify 34 trends in terrestrial water storage observed by the Gravity Recovery and Climate Experiment (GRACE) satellites during 2002–2016 and categorize their drivers as natural interannual variability, unsustainable groundwater consumption, climate change or combinations thereof. Several of these trends had been lacking thorough investigation and attribution, including massive changes in northwestern China and the Okavango Delta. Others are consistent with climate model predictions. This observation-based assessment of how the world’s water landscape is responding to human impacts and climate variations provides a blueprint for evaluating and predicting emerging threats to water and food security. Analysis of 2002–2016 GRACE satellite observations of terrestrial water storage reveals substantial changes in freshwater resources globally, which are driven by natural and anthropogenic climate variability and human activities.

Infographie : Les chiffres du climat comme vous les avez jamais vus !