références en Anglais

Antarctica's remote and mysterious current has a profound influence on the climate, food systems and Antarctic ecosystems. Can we stop it weakening by 2050?

Lenton, the founding director of the Global Systems Institute at the University of Exeter, was the lead author of the 2008 paper that formally introduced the idea of tipping points in the Earth’s climate system.

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.

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.

A new report from U.K. actuaries and climate scientists "shows a 50% GDP contraction between 2070 and 2090 unless an alternative course is chartered," said the lead author.​

A new report explores a framework for global climate risk management and includes contributions from an actuary at the Government Actuary's Department.

A panel of international scientists has moved their symbolic “Doomsday Clock” closer to midnight than ever before, citing Russian nuclear threats amid its invasion of Ukraine, tensions in other world hotspots, military applications of artificial intelligence and the climate crisis as factors underlying the risks of global catastrophe.

The 20th edition of the Global Risks Report 2025 reveals an increasingly fractured global landscape, where escalating geopolitical, environmental, societal and technological challenges threaten stability and progress. This edition presents the findings of the Global Risks Perception Survey 2024-2025 (GRPS), which captures insights from over 900 experts worldwide. The report analyses global risks through three timeframes to support decision- makers in balancing current crises and longer-term priorities.

Actuaries are calling for more realistic climate risk assessments. This includes the “risk of ruin”: the point past which global society can no longer adapt to climate change. Today’s report from the Institute and Faculty of Actuaries (IFoA) and the University of Exeter – “Climate Scorpion: the sting is in the tail” – puts forward the case for using financial services risk management to evaluate and communicate climate risk. It advocates for “worst-case” scenario thinking around climate change.

The abrupt loss of many species from a system is generally attributed to a breakdown in ecological functioning. As species are sequentially knocked out, the whole community becomes unstable, and it all comes crashing down. Another mechanism that may be at play. My colleagues and I argue that despite the fact life on Earth displays such great variety, many species that live together appear to share remarkably similar thermal limits. That is to say, individuals of different species can tolerate temperatures up to similar points.

Every December, people ask us how severe the year’s extreme weather events were. To answer this question, we’ve partnered with Climate Central to produce a report that reviews some of the most significant events and highlights findings from our attribution studies. It also includes new analysis looking at the number of dangerous heat days added by climate change in 2024 and global resolutions for 2025 to work toward a safer, more sustainable world.

Experts warn that mirror bacteria, constructed from mirror images of molecules found in nature, could put humans, animals and plants at risk of lethal infections

This report describes the technical feasibility of creating mirror bacteria and the potentially serious and wide-ranging risks that they could pose to humans, other animals, plants, and the environment. It accompanies the Science Policy Forum article titled “Confronting risks of mirror life”, published December 12, 2024.

All known life is homochiral. DNA and RNA are made from “right-handed” nucleotides, and proteins are made from “left-handed” amino acids. Driven by curiosity and plausible applications, some researchers had begun work toward creating lifeforms composed entirely of mirror-image biological molecules. Such mirror organisms would constitute a radical departure from known life, and their creation warrants careful consideration. The capability to create mirror life is likely at least a decade away and would require large investments and major technical advances; we thus have an opportunity to consider and preempt risks before they are realized. Here, we draw on an in-depth analysis of current technical barriers, how they might be eroded by technological progress, and what we deem to be unprecedented and largely overlooked risks (1). We call for broader discussion among the global research community, policy-makers, research funders, industry, civil society, and the public to chart an appropriate path forward.

The big question: Would climate engineering like sending reflective particles into the stratosphere or brightening clouds help reduce the national security risks of climate change or make them worse?

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.

Simultaneous harvest failures across major crop-producing regions are a threat to global food security. Concurrent weather extremes driven by a strongly meandering jet stream could trigger such events, but so far this has not been quantified. Specifically, the ability of state-of-the art crop and climate models to adequately reproduce such high impact events is a crucial component for estimating risks to global food security. Here we find an increased likelihood of concurrent low yields during summers featuring meandering jets in observations and models. While climate models accurately simulate atmospheric patterns, associated surface weather anomalies and negative effects on crop responses are mostly underestimated in bias-adjusted simulations. Given the identified model biases, future assessments of regional and concurrent crop losses from meandering jet states remain highly uncertain. Our results suggest that model-blind spots for such high-impact but deeply-uncertain hazards have to be anticipated and acc

Sharp declines in critical mineral prices mask risks of future supply strains as energy transitions advance - News from the International Energy Agency

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

Dangers of wildfires, extreme weather and other factors outgrowing preparedness, European Environment Agency says