Réseau Transition be

Comment visualiser concrètement l’évolution des températures depuis 1880 ? Comment rendre accessibles les données scientifiques de la NASA ? C’est ce qui m’a motivé à créer NASA GISTEMP Viewer, une application web qui permet de voir les données sur une sphère en 3D.

Between 80% and 89% of the world’s people want their governments to do more about climate change. This fact is the central tenet of the 89% Project for climate journalism. Timed to coincide with Earth Day and Earth Week, the project launched in April, 2025, and will culminate in another week of focused stories in October, just before the next COP meeting in Brazil.

The climate crisis has entered a decisive phase. Delaying climate measures increases the likelihood of crossing tipping points. Political shifts are weakening international cooperation when unity is vital. Yet, the Planetary Boundaries offer a path to a stable and sustainable future.

Identifying the socio-economic drivers behind greenhouse gas emissions is crucial to design mitigation policies. Existing studies predominantly analyze short-term CO2 emissions from fossil fuels, neglecting long-term trends and other GHGs. We examine the drivers of all greenhouse gas emissions between 1820–2050 globally and regionally. The Industrial Revolution triggered sustained emission growth worldwide—initially through fossil fuel use in industrialized economies but also as a result of agricultural expansion and deforestation. Globally, technological innovation and energy mix changes prevented 31 (17–42) Gt CO2e emissions over two centuries. Yet these gains were dwarfed by 81 (64–97) Gt CO2e resulting from economic expansion, with regional drivers diverging sharply: population growth dominated in Latin America and Sub-Saharan Africa, while rising affluence was the main driver of emissions elsewhere. Meeting climate targets now requires the carbon intensity of GDP to decline 3 times faster than the global

In a rapidly changing climate, evidence-based decision-making benefits from up-to-date and timely information. Here we compile monitoring datasets (published at https://doi.org/10.5281/zenodo.15639576; Smith et al., 2025a) to produce updated estimates for key indicators of the state of the climate system: net emissions of greenhouse gases and short-lived climate forcers, greenhouse gas concentrations, radiative forcing, the Earth's energy imbalance, surface temperature changes, warming attributed to human activities, the remaining carbon budget, and estimates of global temperature extremes. This year, we additionally include indicators for sea-level rise and land precipitation change. We follow methods as closely as possible to those used in the IPCC Sixth Assessment Report (AR6) Working Group One report.

An international group of researchers has produced a third update to key indicators of the state of the climate system set out in the IPCC AR6 assessment, building on previous editions in 2023 and 2024. Forster et al. (2025) assess emissions, concentrations, temperatures, energy transfers, radiation balances, and the role of human activity and conclude that, while natural climate variability also played a role, the record observed temperatures in 2024 were dominated by human activity and the remaining carbon budget for 1.5° C is smaller than ever.

The human fingerprint on global warming was likely evident in Earth’s atmosphere far earlier than previously thought—even before the invention of modern cars, a new study says. Using a combination of scientific theory, modern observations and multiple, sophisticated computer models, researchers found a clear signal of human-caused climate change was likely discernible with high confidence as early as 1885, just before the advent of gas-powered cars but after the dawn of the industrial revolution.

Recent simulations using the Community Earth System Model (CESM) indicate that a tipping event of the Atlantic Meridional Overturning Circulation (AMOC) would cause Europe to cool by several degrees. This AMOC tipping event was found under constant pre-industrial greenhouse gas forcing, while global warming likely limits this AMOC-induced cooling response. Here, we quantify the European temperature responses under different AMOC regimes and climate change scenarios. A strongly reduced AMOC state and intermediate global warming (C, Representative Concentration Pathway 4.5) has a profound cooling effect on Northwestern Europe with more intense cold extremes. The largest temperature responses are found during the winter months and these responses are strongly influenced by the North Atlantic sea-ice extent. Enhanced North Atlantic storm track activity under an AMOC collapse results in substantially larger day-to-day temperature fluctuations. We conclude that the (far) future European temperatures are dependent o

the rapid rises in global military spending threaten climate action, undermining our collective security. In a new joint paper we explore how everything from direct emissions to diverted climate finance are threatening SDG 13 on Climate action.

Militaries are huge energy users whose greenhouse gas emissions (GHG) make a significant contribution to the climate crisis. However, countries do not systematically record and report their military emissions so the real share of this source of emissions remains unclear. The Conflict and Environment Observatory (CEOBS) and Scientists for Global Responsibility estimate that everyday military activity could be responsible for around 5.5% of global emissions, meaning that if the world’s militaries were a country, they would be the fourth largest emitter in the world.6 Furthermore, as military spending increases and the rest of society decarbonises, that proportion is set to rise.

L’Organisation Météorologique Mondiale (OMM) publie ses prévisions climatiques pour les cinq prochaines années, 2025-2029. Selon l’OMM, les températures de la terre oscilleront entre +1.2°C et + 1.9°C, ce qui nous amène très près de 2°C de réchauffement en 2030 (OMM). Nous serons alors proches du climat annoncé pour la France à 4°C.

Nouveau "TALK" sur LIMIT avec Matthieu Auzanneau,, auteur et directeur du think tank de la transition énergétique The Shift Project nous abordons l’inexorable épuisement des ressources fossiles et ses conséquences géopolitiques (Golfe Persique, Irak, Ukraine) La dépendance de l’Europe au pétrole et au gaz. Les grands moments historiques du pétrole (pic de 1970, Mer du Nord, boom du shale aux USA) Les premiers accords climatiques (Protocole de Kyoto) et la croissance paradoxale de la consommation de gaz L’analogie du corps humain pour montrer que l’énergie est l’« organe vital » de nos sociétés Les pistes de sortie de la « marriage pétrolier » : sobriété organisée, souveraineté industrielle, transition vers les renouvelables Et un appel à l’élaboration d’un plan clair et collectif pour réduire la dépendance aux énergies carbonées « Decarbonons la France ! »

Societies increasingly rely on scientists to guide decisions in times of uncertainty, from pandemic outbreaks to the rise of artificial intelligence. Addressing climate change is no different. For governments wanting to introduce ambitious climate policies, public trust in climate scientists is pivotal, because it can determine whether voters support or resist those efforts.

Small particulate matter (PM2.5) in air pollution raises the risks of respiratory problems, cardiovascular disease, and even cognitive decline. Heat waves, which are occurring more often with climate change, can cause heatstroke and exacerbate conditions such as asthma and diabetes. When heat and pollution coincide, they can create a deadly combination.

Earth’s albedo (reflectivity) declined over the 25 years of precise satellite data, with the decline so large that this change must be mainly reduced reflection of sunlight by clouds. Part of the cloud change is caused by reduction of human-made atmospheric aerosols, which act as condensation nuclei for cloud formation, but most of the cloud change is cloud feedback that occurs with global warming. The observed albedo change proves that clouds provide a large, amplifying, climate feedback. This large cloud feedback confirms high climate sensitivity, consistent with paleoclimate data and with the rate of global warming in the past century.

Climate change is driving rising global temperatures, ecological degradation, and widespread human suffering. Yet, as a collective, humanity has failed to implement sufficient changes to mitigate these threats. This paper introduces the concept of “global narcissism” as a speculative lens to analyze the psychological barriers to climate action. By examining different levels of narcissism and their manifestations in human responses to climate change, this framework highlights key obstacles to meaningful action. While humanity is diverse, and lived experiences vary greatly, this perspective offers a way to discuss patterns of response and resistance. A central challenge lies in humanity’s difficulty in recognizing its symbiotic relationship with the non-human world. Through the metaphor of “global narcissism” this paper explores how humanity’s response to ecological crisis mirrors narcissistic defense mechanisms and suggests a collapse is taking place. This framework provides insights into how psychological int

Paper in Nature Climate Change journal reveals major role wealthy emitters play in driving climate extremes. The world’s wealthiest 10% are responsible for two-thirds of global heating since 1990, driving droughts and heatwaves in the poorest parts of the world, according to a study.

Springtails illustrate in new research how global warning and antibiotic resistance creates synergistic effects: warming increases pesticide toxicity, triggering antibiotic resistance which spreads through horizontal gene transfer and predation.

2023 set a number of alarming new records. The global mean temperature also rose to nearly 1.5 degrees Celsius above the preindustrial level, another record.A team led by the Alfred Wegener Institute puts forward a possible explanation for the rise in global mean temperature: our planet has become less reflective because certain types of clouds have declined. The work is published in the journal Science.

A superpower in the fight against global heating is hiding in plain sight. It turns out that the overwhelming majority of people in the world – between 80% and 89%, according to a growing number of peer-reviewed scientific studies – want their governments to take stronger climate action.

We investigate the probabilities of triggering climate tipping points under five Shared Socioeconomic Pathways (SSPs) and how they are altered by including the additional carbon emissions that could arise from tipping points within the Earth's carbon cycle. The crossing of a climate tipping point at a threshold level of global mean surface temperature (threshold temperature) would commit the affected subsystem of the Earth to abrupt and largely irreversible changes with negative impacts on human well-being. However, it remains unclear which tipping points would be triggered under the different SSPs due to uncertainties in the climate sensitivity to anthropogenic greenhouse gas emissions, the threshold temperatures and timescales of climate tipping points, and the response of tipping points within the Earth's carbon cycle to global warming. We include those uncertainties in our analysis to derive probabilities of triggering for 16 previously identified climate tipping points within the Earth system.

La Suisse et le Nord de l’Italie ont subi des précipitations exceptionnelles, qui ne se produisaient avant qu’une fois par siècle. Un courant du sud très humide est monté vers les Alpes où un front froid est arrivé mercredi (MétéoSuisse 14 avril). Une pluie torrentielle a suivi ce choc de masses d’air.

Global temperature for 2025 should decline little, if at all, from the record 2024 level. Absence of a large temperature decline after the huge El Nino-spurred temperature increase in 2023-24 will provide further confirmation that IPCC’s best estimates for climate sensitivity and aerosol climate forcing were both underestimates. Specifically, 2025 global temperature should remain near or above +1.5C relative to 1880-1920, and, if the tropics remain ENSO-neutral, there is good chance that 2025 may even exceed the 2024 record high global temperature.

Tipping elements within the Earth system are increasingly well understood. Scientists have identified more than 25 parts of the Earth’s climate system that are likely to have “tipping points” – thresholds where a small additional change in global warming will cause them to irreversibly shift into a new state. The “tipping” of these systems – which include the Atlantic Meridional Overturning Circulation (AMOC), the Amazon rainforest and the Greenland ice sheet – would have profound consequences for both the biosphere and people. More recent research suggests that triggering one tipping element could cause subsequent changes in other tipping elements, potentially leading to a “tipping cascade”. For example, a collapsed AMOC could lead to dieback of the Amazon rainforest and hasten the melt of the Greenland ice sheet.

Les températures de la Planète augmenteront pendant les prochaines décennies. Les catastrophes climatiques s’aggraveront au cours de cette période. A 2°C, il y aura beaucoup plus d’inondations et des vagues de chaleur plus fortes. Nous les subirons de plein fouet, probablement au cours des vingt prochaines années (James E.Hansen).

Eat-Lancet report recommended shift to more plant-based, climate-friendly diet but was extensively attacked online [...] The report recommended that if global red meat eating was cut by 50%, the “planetary health diet” would provide nutritious food to all while tackling the harms caused by animal agriculture, which accounts for over 14% of all greenhouse gas emissions worldwide. It suggested individuals – particularly in wealthy countries – should increase their consumption of nuts, pulses and other plant-based foods while cutting meat and sugar from their diets.

Dans cet épisode, Arnaud reçoit Laurent Testot, journaliste, historien et vulgarisateur scientifique reconnu pour ses travaux sur l’histoire globale et les grands changements environnementaux. Auteur de plusieurs ouvrages, dont « Cataclysme » et « Omokanis », il nous livre une réflexion fascinante sur l’impact humain sur la Terre. Avec Laurent, nous explorons l'impact de l'humanité sur la Terre, de la domestication des chiens aux mutations écologiques du Sahara, en décryptant les grands défis de l'Anthropocène : l'accélération de la crise climatique, la sixième extinction de masse et l'influence des politiques mondiales. C'est une réflexion urgente pour repenser notre rapport à la nature, à l'agriculture et aux écosystèmes.

Morgan Stanley, JPMorgan and an international banking group have quietly concluded that climate change will likely exceed the Paris Agreement’s 2 degree goal.Top Wall Street institutions are preparing for a severe future of global warming that blows past the temperature limits agreed to by more than 190 nations a decade ago, industry documents show.

L’Organisation Météorologique Mondiale a publié son rapport annuel (OMM2024). L’année 2024 a été la plus chaude de l’Histoire. Elle a apporté de nombreux événements extrêmes. Le cyclone Yagi a causé des dégâts étendus en Chine, au Philippines et au Vietnam, et le cyclone Chido a dévasté Mayotte et le Mozambique. De nombreux affluents de l’Amazone se sont taris par une chaleur inhabituelle, et plus de mille pèlerins ont succombé à la chaleur à la Mecque.

Countries must move rapidly to slash CO2 emissions from homes, offices, shops and other buildings—a sector that accounts for a third of global greenhouse gas pollution, the United Nations said Monday. Carbon dioxide emissions from the building sector rose around 5% in the last decade when they should have fallen 28%, according to a new report by the United Nations Environment Program (UNEP).

The clear signs of human-induced climate change reached new heights in 2024, which was likely the first calendar year to be more than 1.5°C above the pre-industrial era, with a global mean near-surface temperature of 1.55 ± 0.13 °C above the 1850-1900 average.

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.

Global temperature leaped more than 0.4°C (0.7°F) during the past two years, the 12-month average peaking in August 2024 at +1.6°C relative to the temperature at the beginning of last century (the 1880-1920 average). This temperature jump was spurred by one of the periodic tropical El Niño warming events, but many Earth scientists were baffled by the magnitude of the global warming, which was twice as large as expected for the weak 2023-2024 El Niño.

The world is warming despite natural fluctuations from the El Niño cycle.

The Antarctic Circumpolar Current (ACC) is the world's strongest ocean current and plays a disproportionate role in the climate system due to its role as a conduit for major ocean basins. This current system is linked to the ocean's vertical overturning circulation, and is thus pivotal to the uptake of heat and CO2 in the ocean. The strength of the ACC has varied substantially across warm and cold climates in Earth's past, but the exact dynamical drivers of this change remain elusive. This is in part because ocean models have historically been unable to adequately resolve the small-scale processes that control current strength. Here, we assess a global ocean model simulation which resolves such processes to diagnose the impact of changing thermal, haline and wind conditions on the strength of the ACC. Our results show that, by 2050, the strength of the ACC declines by ∼20% for a high-emissions scenario. This decline is driven by meltwater from ice shelves around Antarctica, which is exported to lower latit

Où en est l’effort environnemental des États européens ? Les 27 États membres de l’UE se sont fixés des engagements pour réagir au changement climatique et à ses conséquences, aux problèmes de qualité de l’air qui provoquent des décès précoces, à la chute de la biodiversité.

... An “acid” test of our interpretation will be provided by the 2025 global temperature: unlike the 1997-98 and 2015-16 El Ninos, which were followed by global cooling of more than 0.3°C and 0.2°C, respectively, we expect global temperature in 2025 to remain near or above the 1.5°C level. Indeed, the 2025 might even set a new record despite the present weak La Nina. There are two independent reasons. First, the “new” climate forcing due to reduction of sulfate aerosols over the ocean remains in place, and, second, high climate sensitivity (~4.5°C for doubled CO2) implies that the warming from recently added forcings is still growing significantly.

Les événements centennaux, vagues de chaleurs qui frappaient tous les cent ans par le passé, se produisent maintenant tous les dix ou vingt ans. Dans le futur, des épisodes plus graves, aux températures plus élevées, se produiront, et atteindront des températures fatales pour les populations. Les canicules comportent d’autres dangers qui incluent la sécheresse, la mort du bétail et les incendies.

Un nouvel article du grand climatologue James Hansen affirme que le réchauffement a accéléré il y a quelques années. La réduction des aérosols liés au fuel des navires en serait la cause. La fonte du Groenland dépasse les prévisions et mènera à un arrêt de la circulation océanique dans 20 -30 ans, ce qui provoquera plus tard une importante montée du niveau de la mer. Il suggère des prévisions climatiques complémentaires à celles du GIEC, qui s’appuieraient plus sur les observations de la réalité.

January 2025 was the 18th month in a 19-month period with a global-average surface air temperature exceeding 1.5ºC above pre-industrial levels. According to the Copernicus Climate Change Service…