références en Anglais

The world has been too optimistic about the risk to humanity and planet – but devastation can still be avoided, says Timothy Lenton

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.

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.

Mark Lynas has spent decades pushing for action on climate emissions but now says nuclear war is even greater threat Climate breakdown is usually held up as the biggest, most urgent threat humans pose to the future of the planet today. But what if there was another, greater, human-made threat that could snuff out not only human civilisation, but practically the entire biosphere, in the blink of an eye?

What if the rules of the game have already sealed our fate? This is a brutal mathematical reality: an unstoppable, self-reinforcing chain reaction in the Earth’s climate system is now underway.

The exponential rise in microplastic pollution over the past 50 years may be reflected in increasing contamination in human brains, according to a new study. It found a rising trend in micro- and nanoplastics in brain tissue from dozens of postmortems carried out between 1997 and 2024. The researchers also found the tiny particles in liver and kidney samples.

Metals and metalloids are ubiquitous in soils, originating from bedrock and from human activities and infrastructure. These compounds can be toxic to humans and other organisms, and their soil distribution and concentrations at global scale are not well known. Hou et al. analyzed data from more than 1000 regional studies to identify areas of metal toxicity and explore drivers of these trends. They estimate that 14 to 17% of cropland exceeds agricultural thresholds for at least one toxic metal.

Recent projections suggest that large geographical areas will soon experience heat and humidity exceeding limits for human thermoregulation. The survivability limits modeled in that research were based on laboratory studies suggesting that humans cannot effectively thermoregulate in wet bulb temperatures (Twb) above 26 to 31 °C, values considerably lower than the widely publicized theoretical threshold of 35 °C. The newly proposed empirical limits were derived from the Twb corresponding to the core temperature inflection point in participants exposed to stepped increases in air temperature or relative humidity in a climate-controlled chamber. Despite the increasing use of these thermal-step protocols, their validity has not been established. We used a humidity-step protocol to estimate the Twb threshold for core temperature inflection in 12 volunteers.

Microplastics have been found for the first time in human ovary follicular fluid, raising a new round of questions about the ubiquitous and toxic substances’ potential impact on women’s fertility. The new peer-reviewed research published in Ecotoxicology and Environmental Safety checked for microplastics in the follicular fluid of 18 women undergoing assisted reproductive treatment at a fertility clinic in Salerno, Italy, and detected them in 14.

https://www.ucs.org/resources/1992-world-scientists-warning-humanity - Some 1,700 of the world's leading scientists, including the majority of Nobel laureates in the sciences, issued this appeal in November 1992. The World Scientists' Warning to Humanity was written and spearheaded by the late Henry Kendall, former chair of UCS's board of directors.

Il y a vingt-cinq ans, l'Union of Concerned Scientists et plus de 1700 scientifiques indépendants, dont la majorité des lauréats scientifiques du prix Nobel d’alors, ont scellé l'Avertissement des scientifiques du monde à l'humanité de 1992 (voir le texte en annexe S1). Ces scientifiques s’adressaient à l'humanité afin d’endiguer la destruction de l'environnement et avertissaient « Si nous voulons éviter une misère humaine à grande échelle, il est indispensable d’assurer un changement profond de notre gestion des ressources et de la vie sur Terre ».

An international group of scientists, led by King's College London, has revealed how continued global warming will lead to more parts of the planet becoming too hot for the human body over the coming decades. the amount of landmass on our planet that would be too hot for even healthy young humans (18 to 60-year-olds) to keep a safe core body temperature will approximately triple (to 6%)—an area almost the size of the US—if global warming reaches 2°C above the preindustrial average.

Climate projections versus population projections - There is a puzzling disconnect at the core of climate science between climate projections and population projections. Indeed, comparing the two, one might be forgiven for thinking that population scientists and climate scientists live in two completely different worlds.

Microplastics and nanoplastics may be present in food, primarily from environmental contamination where foods are grown or raised.

Microplastics are ubiquitous environmental contaminants for which there are documented human exposures, but there is a paucity of research evaluating their impacts on human health. We conducted a rapid systematic review using the “Navigation Guide” systematic review method. We searched four databases in July 2022 and April 2024 with no restriction on the date.

Human pressures have pushed the Earth system deep into the Anthropocene, threatening its stability, resilience and functioning. The Planetary Boundaries (PB) framework emerged against these threats, setting safe levels to the biophysical systems and processes that, with high likelihood, ensure life-supporting Holocene-like conditions. In this Review, we synthesize PB advancements, detailing its emergence and mainstreaming across scientific disciplines and society. The nine PBs capture the key functions regulating the Earth system. The safe operating space has been transgressed for six of these. PB science is essential to prevent further Earth system risks and has sparked new research on the precision of safe boundaries. Human development within planetary boundaries defines sustainable development, informing advances in social sciences. Each PB translates to a finite budget that the world must operate within, requiring strengthened global governance. The PB framework has been adopted by businesses and informed

Record emissions, temperatures and population mean more scientists are looking into possibility of societal collapse, report says

Global average surface temperatures shattered all-time records in 2023 at 1.45 ± 0.12 ◦C above pre- industrial levels (WMO 2024). Worsened by climate change-induced drought, Canadian wildfires burned 18.5 million hectares, nearly three-times more land area than in any previous year on record (NRC 2023).

Greece, Italy, Spain, Portugal, France and Morocco experienced extreme heat in July 2024, causing at least 23 fatalities, widespread wildfires and bringing public life to a hold.

Scientists now fear that there is little more than five years left to prevent irreversible climate damage and stark changes to the Earth’s weather patterns from global carbon emissions, Minister for Climate Eamon Ryan has warned.