Flux continu

Jean-Marc Jancovici, ingénieur spécialiste du changement climatique et président du think tank Shift Project, alerte sur des plans d'adaptation encore trop peu contraignants.

High-level policy discussions have built momentum for “food system transformation” that would help farmers address the climate crisis.

An extensive new multi-proxy database of paleo-temperature time series (Temperature 12k) enables a more robust analysis of global mean surface temperature (GMST) and associated uncertainties than was previously available. We applied five different statistical methods to reconstruct the GMST of the past 12,000 years (Holocene). Each method used different approaches to averaging the globally distributed time series and to characterizing various sources of uncertainty, including proxy temperature, chronology and methodological choices. The results were aggregated to generate a multi-method ensemble of plausible GMST and latitudinal-zone temperature reconstructions with a realistic range of uncertainties. The warmest 200-year-long interval took place around 6500 years ago when GMST was 0.7 °C (0.3, 1.8) warmer than the 19th Century (median, 5th, 95th percentiles). Following the Holocene global thermal maximum, GMST cooled at an average rate −0.08 °C per 1000 years (−0.24, −0.05). The multi-method ensembles and th

Abstract. Intergovernmental Panel on Climate Change (IPCC) assessments are the trusted source of scientific evidence for climate negotiations taking place under the United Nations Framework Convention on Climate Change (UNFCCC). Evidence-based decision-making needs to be informed by up-to-date and timely information on key indicators of the state of the climate system and of the human influence on the global climate system. However, successive IPCC reports are published at intervals of 5–10 years, creating potential for an information gap between report cycles. We follow methods as close as possible to those used in the IPCC Sixth Assessment Report (AR6) Working Group One (WGI) report. We compile monitoring datasets to produce estimates for key climate indicators related to forcing of the climate system: 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 activit

Annually updated, IPCC AR6 consistent indicators of human-induced global warming, greenhouse gas emissions, and the remaining global carbon budget.

Mitigating climate change necessitates global cooperation, yet global data on individuals’ willingness to act remain scarce. In this study, we conducted a representative survey across 125 countries, interviewing nearly 130,000 individuals. Our findings reveal widespread support for climate action. Notably, 69% of the global population expresses a willingness to contribute 1% of their personal income, 86% endorse pro-climate social norms and 89% demand intensified political action. Countries facing heightened vulnerability to climate change show a particularly high willingness to contribute. Despite these encouraging statistics, we document that the world is in a state of pluralistic ignorance, wherein individuals around the globe systematically underestimate the willingness of their fellow citizens to act. This perception gap, combined with individuals showing conditionally cooperative behaviour, poses challenges to further climate action. Therefore, raising awareness about the broad global support for climat

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

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

As we mark 100 days until the COP28 UN climate summit, the urgency of addressing the climate crisis has never been more palpable. Global failures to mitigate emissions and adapt to the impacts continue to wreak havoc on the planet, and we’re seeing this in a range of ways. Unprecedented extreme weather events have occurred with frightening regularity in 2023. In March, over 500 people lost their lives when Cyclone Freddy struck Malawi. Last month, flooding in the Philippines caused by Typhoons Doksuri and Khanun displaced more than 300,000 people, and the recent wildfires that ravaged Hawaii – in part exacerbated by climate change – continue to make for distressing headlines. This list is likely to become even longer by the end of the year, when COP28 gets underway in the United Arab Emirates (UAE).

Een internationaal team van wetenschappers werkt aan een systeem dat de achtjaarlijkse rapporten van het VN-klimaatpanel aanvult met een actuele stand van zaken per jaar. Klimaatexpert Piers Forster van de Universiteit van Leeds legt uit waarom dat zo belangrijk is, en wat de laatste bevindingen zijn.

Abstract. Intergovernmental Panel on Climate Change (IPCC) assessments are the trusted source of scientific evidence for climate negotiations taking place under the United Nations Framework Convention on Climate Change (UNFCCC), including the first global stocktake under the Paris Agreement that will conclude at COP28 in December 2023. Evidence-based decision-making needs to be informed by up-to-date and timely information on key indicators of the state of the climate system and of the human influence on the global climate system. However, successive IPCC reports are published at intervals of 5–10 years, creating potential for an information gap between report cycles. We follow methods as close as possible to those used in the IPCC Sixth Assessment Report (AR6) Working Group One (WGI) report. We compile monitoring datasets to produce estimates for key climate indicators related to forcing of the climate system: emissions of greenhouse gases and short-lived climate forcers, greenhouse gas concentrations, radia

Climate change has important implications for the health and futures of children and young people, yet they have little power to limit its harm, making them vulnerable to climate anxiety. This is the first large-scale investigation of climate anxiety in children and young people globally and its relationship with perceived government response.

Increasing risks posed by climate change are causing rare extreme events that can kill more than 10 million people or lead to damages of $10 trillion-plus, posing threats of total societal collapse, a UN report finds.

Flying is a highly controversial topic in climate debates. It accounts for around 2.5% of global CO₂ emissions, but 3.5% when we take non-CO₂ impacts on climate into account.

Cette première partie de conférence traite de l'histoire de nos sociétés de consommation à la mode occidentale grâce aux énergies modernes esssentiellement f...

Concerns about climate change shrank across the world last year, with fewer than half of those questioned in a new survey believing it posed a “very serious threat” to their countries over the next 20 years.

L’introduction du concept d’Anthropocène – sous ce terme et avec les arguments scientifiques de la recherche contemporaine, en glaciologie et paléoclimatologie notamment – se situe significativement dans le cadre du Programme International Géosphère-Biosphère (IGBP), c’est-à-dire au cœur de la coopération scientifique internationale mobilisée autour du fameux « Global Change » : expression d’origine américaine (proche des « recherches biosphériques » et atmosphériques de la Nasa) qui désigne la problématique des transformations environnementales, naturelles et anthropogéniques (d’origine humaine), à l’échelle du Globe, notre « globe terraqué » (composé de terre et d’eau), comme disait les naturalistes et natural philosophers de l’Europe chrétienne classique, ou si l’on préfère préindustrielle et encore néolithique. ...

A la fin du mois de juin 2021, le nord-ouest des États-Unis et l’ouest du Canada ont connu une vague de chaleur exceptionnelle. Si la tendance de fond au réchauffement climatique augmente l’intensité de ce type d’événement, les valeurs atteintes ont surpris les scientifiques. Une analyse du World Weather Attribution – un consortium d’experts climatiques du monde entier travaillant sur l’attribution d’événements extrêmes – évalue l’impact du réchauffement climatique dans la survenue de cet épisode caniculaire.