Fiches info

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. We show that following current policies this century would commit to a 45% tipping risk by 2300 (median, 10–90% range: 23–71%), even if temperatures are brought back to below 1.5 °C. We find that tipping risk by 2300 increases with every additional 0.1 °C of overshoot above 1.5 °C and strongly accelerates for peak warming above 2.0 °C. Achieving and maintaining at least net zero greenhouse gas emissions by 2100 is paramount to minimise tipping risk in the long term. Our results underscore that stringent emission reductions in the current decade are critical for planetary stabili

Le Shift Project présente son rapport intermédiaire "Pour une agriculture bas carbone, résiliente et prospère"

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

Over the past 50 years, humans have extracted the Earth’s groundwater stocks at a steep rate, largely to fuel global agro-economic development. Given society’s growing reliance on groundwater, we explore ‘peak water limits’ to investigate whether, when and where humanity might reach peak groundwater extraction. Using an integrated global model of the coupled human–Earth system, we simulate groundwater withdrawals across 235 water basins under 900 future scenarios of global change over the twenty-first century. Here we find that global non-renewable groundwater withdrawals exhibit a distinct peak-and-decline signature, comparable to historical observations of other depletable resources (for example, minerals), in nearly all (98%) scenarios, peaking on average at 625 km3 yr−1 around mid-century, followed by a decline through 2100. The peak and decline occur in about one-third (82) of basins, including 21 that may have already peaked, exposing about half (44%) of the global population to groundwater stress. Most

Global projections of macroeconomic climate-change damages typically consider impacts from average annual and national temperatures over long time horizons1–6. Here we use recent empirical findings from more than 1,600 regions worldwide over the past 40 years to project sub-national damages from temperature and precipitation, including daily variability and extremes7,8. Using an empirical approach that provides a robust lower bound on the persistence of impacts on economic growth, we find that the world economy is committed to an income reduction of 19% within the next 26 years independent of future emission choices (relative to a baseline without climate impacts, likely range of 11–29% accounting for physical climate and empirical uncertainty). These damages already outweigh the mitigation costs required to limit global warming to 2 °C by sixfold over this near-term time frame and thereafter diverge strongly dependent on emission choices. Committed damages arise predominantly through changes in average tempe

Taking into account all known factors, the planet warmed 0.2 °C more last year than climate scientists expected. More and better data are urgently needed. Taking into account all known factors, the planet warmed 0.2 °C more last year than climate scientists expected. More and better data are urgently needed.

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

All local communities affected by mining projects should have the right to have a say on whether mining activities will start or continue in their backyard. This belief in community involvement in political, economic, and environmental decision-making is epitomised in a Right to Say No (RTSN), which is the inalienable and collective right of a community to say no (or yes) to extractive projects on the territories/lands they are living within. Currently, there is no real ‘Right’ to Say No outside of iterations of the indigenous right to free, prior and informed consent (FPIC) — it is a right we are asserting, not something we can yet claim. This toolbox will elaborate on the rights local communities already have and those rights that still need to be recognised and enforced, to establish a Right to Say No.

The sunlight bids farewell to the mountains. The clouds hang in a sky tinged with pink and purple. The birds fly in flocks, returning to their trees. We, too, are returning home after another afternoon spent in the communal lands

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

Les températures atteignent de nouveaux sommets, mais le monde ne réduit (toujours) pas ses émissions - Résumé analytique

Financité ... éclairer le débat par des analyses chiffrées et documentées mais aussi le guider, en réaffirmant des principes non pas moraux mais juridiques fondamentaux, à commencer par les droits humains les plus élémentaires). Le présent document s’inscrit pleinement dans ce rôle de force de propositions démocratiques qui est le nôtre.

Organisme indépendant chargé d'évaluer la mise en œuvre des politiques et mesures publiques pour réduire les émissions de gaz à effet de serre de la France.

6 priorités, 32 propositions pour préserver l’accès à la terre pour nos agriculteur.rice.s et une Agriculture Durable et Nourricière (ADN)

Mis en lumière par la chercheuse Elinor Ostrom à la fin du XXe siècle, les communs sont un modèle de gouvernance à part, évitant les écueils de la propriété privée ou de la gestion publique. Une ressource naturelle, un espace public, une forêt, un service, des œuvres créatives, ou l’information peuvent être gérés de façon originale par et pour des citoyen·ne·s d’horizons divers.

Grâce au développement économique et technologique rapide du secteur du transport de marchandises, il est aujourd’hui possible de consommer facilement des biens provenant des quatre coins de la planète. Cette accélération constante de la mondialisation n’est pas sans conséquence sur le réchauffement climatique car les émissions associées au transport de marchandises sont considérables. Lorsqu’on parle de transport de marchandises et de climat, on est confronté à un florilège d’idées reçues qui suscitent souvent des réponses contradictoires. Avec cette FAQ, Carbone 4 cherche à éclairer le débat pour démêler le vrai du faux en proposant une approche scientifique et chiffrée pour chaque idée reçue. Ces questions sont les premières d'une plus longue série.

PFAS: Une contamination importante du sol, de l’air et de l’eau par des composés perfluorés

Life on planet Earth is under siege. We are now in an uncharted territory. For several decades, scientists have consistently warned of a future marked by extreme climatic conditions because of escalating global temperatures caused by ongoing human activities that release harmful greenhouse gasses into the atmosphere. Unfortunately, time is up. We are seeing the manifestation of those predictions as an alarming and unprecedented succession of climate records are broken, causing profoundly distressing scenes of suffering to unfold. We are entering an unfamiliar domain regarding our climate crisis, a situation no one has ever witnessed firsthand in the history of humanity.

Ocean-driven melting of floating ice-shelves in the Amundsen Sea is currently the main process controlling Antarctica’s contribution to sea-level rise. Using a regional ocean model, we present a comprehensive suite of future projections of ice-shelf melting in the Amundsen Sea. We find that rapid ocean warming, at approximately triple the historical rate, is likely committed over the twenty-first century, with widespread increases in ice-shelf melting, including in regions crucial for ice-sheet stability. When internal climate variability is considered, there is no significant difference between mid-range emissions scenarios and the most ambitious targets of the Paris Agreement. These results suggest that mitigation of greenhouse gases now has limited power to prevent ocean warming that could lead to the collapse of the West Antarctic Ice Sheet. The authors use a regional ocean model to project ocean-driven ice-shelf melt in the Amundsen Sea. Already committed rapid ocean warming drives increased melt, regard

Le MIT Technology Review a révélé cette semaine qu’une expérience de géo-ingénierie solaire s’était tenue au mois de septembre au Royaume-Uni. Cette expérience, à l’occasion de laquelle une petite quantité de soufre a été diffusée dans la stratosphère par ballon, s’est tenue en toute confidentialité, et en l’absence de tout...