Mastodon

L’année 2025 a été l’une des plus sèches depuis trente-cinq ans en matière de débits fluviaux, constate l’organisme des Nations unies dans son bilan mondial annuel de l’état des ressources en eau publié jeudi.

Global energy and materials are essential to the functioning of the economy and have significant implications for macroeconomics and the environment. At the same time, the world is not on track to meet Paris Agreement goals. This paper documents two stylized facts that connect these observations. First, the world economy is characterized by large embedded emissions and materials: different energies and materials are deeply entwined and interdependent. This has historically led to additive – rather than substitution – dynamics in energy and materials on a global scale. Second, historically there has been a strong positive correlation between efficiency in resource use and total resource use at a global scale. We synthesize these observations by introducing the Generalized Jevons Paradox (GJP). We argue that the GJP reflects the direct and indirect energy/material demand effects of long-term energy and material interdependencies, themselves shaped by market and geoeconomic power, trade arrangements, and financi

Climate models show considerable discrepancies in their future projections around the Atlantic, mainly due to uncertainties in the fate of the Atlantic Meridional Overturning Circulation (AMOC). Climate models suggest a reduction in AMOC strength of 32 ± 37% by 2100 (90% probability, Shared Socioeconomic Pathways 2-4.5 scenario, Coupled Model Intercomparison Project Phase 6). To refine this estimate and reduce its uncertainty, we use four different observational constraint methods. The best one, which provides the lowest leave-one-out error, integrates a large set of observable variables using ridge-regularized linear regression—a method unusual in climate science. It gives an estimate of the AMOC slowdown of 51 ± 8% (90% probability), i.e., a weakening ∼ 60% stronger than suggested by the multimodel mean. This refinement mainly results from correcting a bias in South Atlantic surface salinity, consistent with recent studies emphasizing its role in the proximity to an AMOC tipping point. This more substantial

Climate models simulate a wide range of 21st century warming for a given forcing scenario. Constraining this uncertainty is a central challenge in climate science because of its implications for climate policy and adaptation. The Transient Climate Response (TCR) is a key idealized metric used to quantify future warming in response to an exponentially increasing CO2 concentration. Climate models span a range of 1.3–3 K for TCR. In attempts to constrain this range, emergent constraints on TCR based on historical temperature trends consistently pointed towards TCR values at the lower end of the range of models. However, recent evidence from trends in the short-wave and long-wave components of Earth's energy imbalance (EEI) at the top-of-atmosphere suggests that models with higher TCR lie closer to the observed EEI trends. Here, we reconcile this discrepancy and provide a revised range for TCR of 1.9–2.6 K. Using a statistical variability-filtering approach, we show that previous temperature-based constraints we

Exclusive: UCL scientists find large swathes of southern Europe are drying up, with ‘far-reaching’ implications

Il faut absolument se passer des délétères énergies fossiles car les coûts directs et indirects (dérèglement climatique, pollution, biodiversité, destruction de l'environnement,...) de leurs usages ne sont absolument pas soutenables. Mais s'en passer à des implications socio-économiques importantes qu'il y a lieu de comprendre et d'anticiper afin qu'une transition hors des énergies fossiles puisse se dérouler sans heurts.

The Implications of Oil and Gas Field Decline Rates

L'hashtag #IEA a publié cette semaine un rapport peu commenté mais aux enseignements majeurs, "The Implications of Oil and Gas Field Decline Rates" On y apprend notamment que 90% des investissements du secteur Oil and Gas servent à maintenir la production, face à un taux de déclin de plus en plus important. En 2025, le "déclin naturel" annuel des champs pétroliers représente 6 millions de barils/jour.

Much attention today focuses on uncertainties affecting the future evolution of oil and natural gas demand, with less consideration given to how the supply picture could develop. However, understanding decline rates – the annual rate at which production declines from existing oil and gas fields – is crucial for assessing the outlook for oil and gas supply and, by extension, for market balances. The International Energy Agency (IEA) has long examined this issue, and a detailed understanding of decline rates is at the heart of IEA modelling and analysis, underpinning the insights provided by the scenarios in the World Energy Outlook. This new report – based on analysis of the production records of around 15 000 oil and gas fields around the world – explores the implications of accelerating decline rates, growing reliance on unconventional resources, and evolving project development patterns for the global oil and gas supply landscape, for energy security and for investment. It also provides regional insights

Satellite data processing algorithms developed by ICM-CSIC have played a crucial role in detecting this significant shift in the Southern Hemisphere, which could accelerate the effects of climate change.