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Pizolgletscher, Swiss Alps, was already a very small glacier when the monitoring of length change was initiated 130 years ago. In situ mass balance measurements at seasonal resolution began in 2006. During the last 18 years, the glacier has lost 98% of its volume and is considered extinct since 2022. However, a tiny remnant of ice of a few thousand square metres is preserved under rockfall debris. The case of Pizolgletscher allows tracking the extinction of a glacier with a comprehensive long-term observational series. Furthermore, the vanished glacier has a touristic and cultural significance, as exemplified by a commemoration ceremony held in 2019. Here, detailed monitoring data sets (mass balance, area, volume, length) are presented that shed light on the processes of glacier disintegration before ultimate disappearance. Comparison to regional mass balance variations indicates that the signal from very small glaciers can remain representative at larger scales even during the final phase of a glacier’s lifecycle.
Climate policy discussions often veer into questioning whether actions are worthwhile, if technological fixes are the solution, or if others should take responsibility instead. Interest groups can use these discussions – also known as ‘discourses of climate delay’ – to downplay the need for ambitious climate action. But in other contexts, such discussions can reflect the legitimate concerns of citizens. Here we examine possible ways to make such a distinction and judge when someone intends to delay climate policy.
Technical summary
We conduct a review of the climate policy discourse literature with a focus on how studies evaluate intent. We find that they usually refer to one of three actor-based categories: interest, behaviour, or track record. That is, actors are considered more likely to have intent when they have material or ideological connections to fossil interest groups, behave in ways that undermine climate policy (e.g. through voting or funding oppositional science), or have a track record of rhetorical opposition to climate policy (e.g. having previously articulated climate denial). We further suggest that argument density (e.g. the number of claims they make against climate policy), ambiguity (e.g. whether they leave room for an interpretation of delay), and professional context (e.g. whether they are professional communicators) matters. We summarise these categories to provide a companion to ‘discourses of climate delay’ that focuses on intent. We further consider how the evaluation of intent can support traditional fact and logic-based misinformation identification strategies.
Social media summary
Examine interests, behaviour and track record to evaluate intent in climate delay discourses.
Wall slip sensitivity and non-sphericity and orientation effects are investigated for a moving no-slip solid body immersed in a fluid above a plane slip wall with a Navier slip. The wall–particle interactions are examined for the body motion in a quiescent fluid (resistance problem) or when freely suspended in a prescribed ‘linear’ or quadratic ambient shear flow. This is achieved, assuming Stokes flows, by using a boundary method which reduces the task to the treatment of six boundary-integral equations on the body surface. For a wall slip length $\lambda$ small compared with the wall–particle gap $d$ a ‘recipe’ connecting, at $O((\lambda /d)^2),$ the results for the slip wall and another no-slip wall with gap $d+\lambda$ is established. A numerical analysis is performed for a family of inclined non-spheroidal ellipsoids, having the volume of a sphere with radius $a,$ to quantity the particle behaviour sensitivity to the normalised wall slip length $\overline {\lambda }=\lambda /a,$ the normalised wall–particle gap ${\overline {d}}=d/a$ and the particle shape and orientation (here one angle $\beta ).$ The friction coefficients for the resistance problem exhibit quite different behaviours versus the particle shape and $({\overline {d}}, \overline {\lambda },\beta ).$ Some coefficients increase in magnitude with the wall slip. The migration of the freely suspended particle can also strongly depend on $({\overline {d}}, \overline {\lambda },\beta )$ and in a non-trivial way. For sufficiently small $\overline {d}$ a non-spherical particle can move faster than in the absence of a wall for a large enough wall slip for the ambient ‘linear’ shear flow and whatever the wall slip for the ambient quadratic shear flow.
The generation of plastic waste and its dispersion across environmental compartments is largely attributable to the lack of circularity in the plastic economy; although enhancing circularity can mitigate such leakage, it does not entirely prevent it. Transitioning to a circular plastic economy requires a systemic approach that encompasses the entire lifecycle of plastics, with an urgent need to boost recycling technologies and integrate them into a long-term strategy covering design, production, use, and disposal. Enhanced recycling strategies are needed, as current practices, relying almost exclusively on mechanical recycling, are insufficient to achieve plastic circularity and are nearing their technical limits. Furthermore, the current recycling rates are generating a discrepancy between the legal requirements for recycled resins and their available supply. Available methods include thermal processes using established technologies, as well as dissolution recycling and chemical depolymerization, each at different stages of maturity. While these methods can separate polymers, with or without depolymerization, from complex feedstocks, they face significant technical and economic challenges. A key issue is the high cost of recycling infrastructure, which requires regulatory stability and global commitment to establish a fair set of rules that avoids unfair competition strategies. Additionally, markets for recycled materials remain underdeveloped, especially in countries with less advanced waste management systems. Another critical aspect is the need to design plastic products to facilitate recycling. This means using single materials or objects easy to disassemble, avoiding harmful additives and standardizing waste management practices.
For hypersonic inlets, buzz is a self-sustained oscillatory flow characterised by strong nonlinear and unsteady behaviour. Our recent study shows that, unlike conventional alterations in flow conditions at the inlet entrance or exit, flexible lip deformation is a newly identified trigger for buzz. However, the mechanism by which this fluid–structure interaction (FSI) behaviour induces buzz remains unclear. To clarify how FSI acts as a dominant factor in triggering flow instability leading to buzz, this study investigates a more general flexible plate model within the inlet. The results show that the plate FSI introduces a prolonged instability accumulation process for buzz evolution, resulting in a ‘gradual-onset’ characteristic differing from previous studies. During this process, plate FSI amplifies downstream flow oscillations while accumulating unstable energy. Eventually, the excessive unstable energy causes the shock train to destabilise and be disgorged from the inlet, initiating a complete instability process dominated by buzz. Notably, buzz induced by plate FSI exhibits unsteady characteristics similar to those observed in rigid inlets. Therefore, as an internal self-excited disturbance source, plate FSI produces relatively weaker disturbances than conventional flow modifications, but exhibits highly persistent accumulation effects and distinct multistage characteristics. This study reveals the buzz evolution mechanism under plate FSI, providing new insights into flow instability in hypersonic inlets.
Our ability to accurately quantify the total ice volume in glaciers and the loss of glacier volume, discharge and freshwater in response to climate change is limited by a paucity of ice thickness and bed topography observations. Consequently, glacial ice thickness is often inferred indirectly from more easily obtained surface measurements. Here, we present a simple inversion building on the assumption of perfect plasticity. In the traditional perfect-plastic approximation, the ice thickness (or bed) can be inferred from the surface elevation and yield strength. Here, we extend this to demonstrate that, provided glaciers are changing, we can simultaneously determine the yield strength and bed topography from observations of surface elevation alone. We demonstrate that the ice thicknesses and bed topographies we infer perform comparably to other inversions documented in the Ice Thickness Models Intercomparison eXperiment. Unlike other inversions, we do not require surface mass balance or glacier velocities, which can be inaccurate and difficult to obtain. Given the increasing availability of high-resolution surface elevation data, it may be possible to apply this method to glaciers worldwide to better constrain the ice thickness, bed topography and volume of glaciers globally.
India is rich in mica deposits, and, after extraction, ~75% of the mica material is discarded as waste during the cleaning and processing stages. Effective modification methods may enhance the properties of the waste mica, making it suitable for a number of environmental applications, but this has received limited attention despite its availability. The present study focused on mining-derived waste mica and was aimed specifically at assessing the effects of controlled acid modification on its structural and physico-chemical properties. To achieve this, waste mica was ground and activated using various concentrations of sulfuric acid (1 M, 2 M, and 3 M) under continuous shaking at room temperature for periods varying from 24 to 72 h. The physico-chemical characteristics of the waste mica and acid-treated waste mica were studied by X-ray fluorescence (XRF), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), Brunauer-Emmett-Teller (BET) method, scanning electron microscopy (SEM), zeta potential, thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). The molecular arrangement of the raw and acid-activated waste mica was elucidated using VESTA software. The waste mica was identified as biotite based on structural and compositional characteristics. The XRF and XRD studies indicated that acid activation leads to progressive expansion of the interlayer space of waste mica by way of cation leaching and the subsequent weakening of interlayer forces. After conversion to nanoform and treating the waste mica with 2 M sulfuric acid for 48 h, the characteristic mica peak shifted from 8.99 to 8.76°2θ, indicating the enlargement of interlayer space with a concomitant increase in the specific surface area from 4.32 to 228.02 m2 g–1. The structural and surface modifications achieved through acid treatment enhanced the functional characteristics of the waste mica, indicating its suitability as a cost-effective and sustainable alternative to conventional adsorbents for use in environmental remediation.
Reliably identifying and understanding temporal precursors to extreme wind gusts is crucial for early warning and mitigation. This study proposes a simple data-driven approach to extract key predictors from a dataset of historical extreme European winter windstorms and derive simple equations linking these precursors to extreme gusts over land. A major challenge is the limited training data for extreme events, increasing the risk of model overfitting. Testing various mitigation strategies, we find that combining dimensionality reduction, careful cross-validation, feature selection, and a nonlinear transformation of maximum wind gusts informed by Generalized Extreme Value distributions successfully reduces overfitting. These measures yield interpretable equations that generalize across regions while maintaining satisfactory predictive skill. The discovered equations reveal the association between a steady drying low-troposphere before landfall and wind gust intensity in Northwestern Europe.
Spacecraft assembly facilities (SAFs) house clean rooms where interplanetary spacecraft are built, thereby reducing the bioburden on spacecraft to protect planetary environments from terrestrial microbes that may interfere with the search for life or disturb potential native ecosystems. The most plausible environments for living systems on celestial bodies involve brines with depressed freezing points. Here, we specifically measure the abundance of salinotolerant microbes on SAF surfaces. Most probable number analyses performed with salty liquid media were applied to washes of SAF floor wipes. Microbial abundance was measured using Salt Plains medium at low salt or supplemented with (all w/v) 10% NaCl (1.7 M; aw = 0.92), 50% MgSO4 (2.0 M as epsomite; aw = 0.94), 5% NaClO3 (0.5 M; aw = 0.98), or 5% NaClO4 (0.4 M; aw = 0.98). The abundance of salinotolerant microbes was generally 1 to 10% (102 to 104 cells m−2) of the total population of microbes observed in low-salt medium (105 cells m−2). Microbes were isolated by repetitive streak-plating of positive enrichment cultures and then characterized. All of the 38 isolates were Gram-positive bacteria, mainly spore-forming Bacillaceae, with some Staphylococcus. The isolate collection showed strong tolerance to high concentrations of NaCl (to 30%), MgSO4 (to 50%) and sucrose (to 70%). There also was substantial tolerance to pH (5 to 10) and temperature (4 to 60 °C). Taken together, these SAF isolates are polyextremophiles that are in substantial abundance in the clean rooms where spacecraft are assembled.
We investigate the motion of a thin liquid drop on a pre-stretched, highly bendable elastic sheet. Under the lubrication approximation, we derive a system of fourth-order partial differential equations, along with appropriate boundary and contact line conditions, to describe the evolution of the fluid interface and the elastic sheet. Extending the classical analysis of Cox and Voinov, we perform a four-region matched asymptotic analysis of the model in the limit of small slip length. The central result is an asymptotic relation for the contact line speed in terms of the apparent contact angles. We validate the relation through numerical simulations. A key implication of this result is that a soft substrate retards drop spreading but enhances receding, compared to the dynamics on a rigid substrate. The relation remains valid across a wide range of bending modulus, despite the distinguished limit assumed in the analysis.
The timing of snowmelt onset (SMO) is a critical climate indicator in the Arctic. However, spaceborne, in-situ measurements, and model simulations yield different estimates for the timing. Understanding these discrepancies is essential for identifying the physical mechanisms driving SMO. In this study, SMO, snow, and sea ice thermodynamics were simulated using a single-column snow/ice model (HIGHTSI) along trajectories of 42 ice mass balance buoys operating in the period of 2010 to 2015. The results were compared with passive microwave remote sensing and ice mass balance observations. The modeled surface-SMO has a high inter-annual correlation (0.94) with the ice mass balance-derived results but occurred on average 5 days earlier than observations. The remote-sensing-derived Early-SMO was 12 days before the ice mass balance-derived surface-SMO, while the Continuous-SMO showed a 5 day lag. The modeled average snow depth, ice thickness, and snow/ice temperature captured the recorded seasonal variations. The modeled snow/ice temperature showed seasonal biases of 0.4°C/0.5°C between May–September, and −2.7°C/−4.6°C between October–April, respectively. The corresponding biases for average snow depth and ice thickness were −0.05 m/−0.15 m and 0.03 m/0.14 m, respectively. Accurate representation of air temperature forcing and solar radiation absorption is crucial for realistic simulation of SMO.
Quantum turbulence is characterised by the collective motion of mutually interplaying thin and discrete vortex filaments of fixed circulation which move in two mutually interacting fluid components. Despite this very peculiar nature determined by quantum-mechanical effects, turbulence in quantum fluids may exhibit very similar features to classical turbulence in terms of the vortex dynamics, energy spectrum and decay and intermittency. The recent work by Blaha et al. (2025 J. Fluid. Mech. 1015, A57) reveals an additional classical behaviour of quantum turbulence, by showing that the trajectories of starting vortices shed by accelerating airfoils in a quantum fluid are almost indistinguishable from their counterpart in classical viscous flows. These results strongly support the suggestive idea that turbulent flows, both classical and quantum, may be described by the collective dynamics of interacting, thin and discrete filaments of fixed circulation.
Microfluidic paper-based analytical devices (${\unicode{x03BC}}$PADs) have gained considerable attention due to their ability to transport fluids without external pumps. Fluid motion in ${\unicode{x03BC}}$PADs is driven by capillary forces through the network of pores within paper substrates. However, the inherently low flow speeds resulting from the small pore sizes in paper often limit the performance of ${\unicode{x03BC}}$PADs. Recent studies have introduced multilayered ${\unicode{x03BC}}$PADs composed of stacked paper sheets, which enable significantly faster fluid transport through inter-layer channels. In this study, we present a combined theoretical and experimental investigation of water imbibition dynamics through channels formed by multiple paper layers. Upon contact with water, the paper layers absorb water and undergo swelling, altering channel geometry and consequently affecting flow dynamics. We develop a mathematical model that extends the classical Washburn equation to incorporate the effects of water absorption and swelling. The model predictions show excellent agreement with experimental observations of water flow through multilayered paper channels. The results elucidate how water absorption and swelling influence capillary imbibition, and suggest potential strategies for regulating flow rates in multilayered ${\unicode{x03BC}}$PADs.
In discussions on European Neogene continental chronology, the Kastellios Hill section has played an important role because of the presence of strata with planktonic foraminifers and strata with mammalian remains. With the primary papers written in the 1970s and 1980s, the time is ripe for an update on age and taxonomy of the murid rodents from Kastellios Hill by comparing the fauna with time-equivalent southern and central European faunas. This comparison results in a partly revised faunal list consisting of the dominant Progonomys mixtus n. sp., the less common Cricetulodon cf. C. hartenbergeri Freudenthal, 1967 and P. cathalai Schaub, 1938, and the rare P. hispanicus Michaux, 1971 and cf. Hansdebruijnia neutra (de Bruijn, 1976). Based on the updated species list and magnetic polarity data, the most probable age of the Kastellios Hill mammal localities is 9.3–9.1 Ma (Chron C4Ar.1r, late Vallesian, MN10). The genus Hansdebruijnia is narrowed down to two species in an ancestor–descendant relationship: the ancestral type species H. neutra, which is restricted to southeastern Europe and Anatolia, and the descendant species H. magna (Sen, 1977), representing a new combination and including ‘Occitanomys alcalai’ Adrover et al., 1988 and ‘O. debruijni’ (Hordijk and de Bruijn, 2009). H. magna colonized both southeastern and southwestern Europe.
This study examines the enablers of progress towards net-zero emissions in emerging economies, focusing on the roles of renewable energy integration and energy policy support. Using structural equation modelling on survey data from 935 diverse respondents across India, the study finds that both renewable energy integration and energy policy support have significant positive impacts on net-zero progress. The analysis reveals two key mediating pathways: first, technology adoption and innovation mediate between renewable energy integration and net-zero progress; second, community awareness and participation mediate between energy policy support and net-zero progress. Economic and infrastructure constraints moderate the relationship between energy policy support and net-zero progress. Importance-performance map analysis indicates that while renewable energy, policy support and economic factors are highly important, their effectiveness may be limited by infrastructural and governance challenges. The findings suggest that policymakers should adopt a holistic approach that simultaneously addresses technological, social, economic and institutional dimensions. This study contributes to the net-zero transition literature by developing and validating an integrated model that incorporates technical, social, policy and institutional aspects. Limitations include the cross-sectional nature and single-country focus, suggesting opportunities for future longitudinal and cross-country studies.
Maurogemmiite, Ti10Fe3O3, and paulrobinsonite, Ti8Fe4O2, are two new mineral species in a fragment 0.45 mm × 0.8 mm in size extracted from chromitite orebody #31 in the Luobusa ophiolite near Luobusa Village, Tibet, China (29°13.86’N, 92°11.41’E). The fragment comprises (1) an alloy core consisting of a wangxibinite + ‘osbornite’ intergrowth, Ti and the new minerals; (2) an inner rim of Ti and (3) an outer rim of coesite, kyanite and amorphous Ti-aluminosilicate. Maurogemmiite forms irregular grains up to 30 μm across enclosed in paulrobinsonite, which isolated it from the wangxibinite (TiFe) + ‘osbornite’ intergrowth. Two standardless EDS analyses and O taken from the structurally refined model gave O 6.40, Al 0.26, Si 1.96, Ti 65.73, Fe 24.79, Ni 0.85, sum 100 wt.%. The empirical formula normalised to Ti = 10 is Al0.07Si0.51Ti10Fe3.23Ni0.11O2.91. Two standardless EDS analyses of paulrobinsonite gave O 3.73, Al 0.28, Si 1.82, Ti 56.50, Fe 35.65, Ni 2.03, sum 100 wt.%. The empirical formula normalised to Ti = 8 is Al0.07Si0.44Ti8Fe4.33Ni0.23O1.58. Three-dimensional electron diffraction (3DED) data on maurogemmiite delivered a primitive hexagonal cell, space group P63/mmc (#194) with a = 8.065(1) Å, c = 8.015(3) Å, V = 451.6(2) Å3 and Z = 2. The structure is a compact framework with Ti1, Ti3 and Fe1 in coordination 12 and Ti2 in coordination 13. Both Ti2 and Ti3 show a wide range of interatomic distances, which result in interstitial positions occupied predominantly by O and partially by non-stoichiometric Fe. The 3DED data on paulrobinsonite delivered an F-centred cubic cell, space group Fd$\bar 3$m (#227) with a = 11.388(4) Å, V = 1477.0(8) Å3 and Z = 8. The structure is also a compact framework with Ti1 and Fe1 in coordination 12 and Ti2 in coordination 14, whereas the remaining Fe and all O atoms occupy interstitial positions in nearly regular octahedral coordination with Ti2.
Earth’s lithospheric mantle is dominated (usually >90% vol.%) by a nominally volatile-free mineral paragenesis with peridotitic composition. The remaining lithologies are typically hydrous and/or carbonate-bearing assemblages (the latter mostly stable at P >2 GPa), representing the products of mantle metasomatism with, or without, involvement of subduction. Despite their importance, the modal compositions of these metasomes are poorly constrained, probably containing hydrous phases (amphibole and/or phlogopite), coupled with accessory minerals, such as apatite, ilmenite, rutile and/or carbonates. These assemblages are usually considered to be the source of unusual magmas, in particular ultrapotassic compositions, especially kamafugites (K2O-rich, commonly ultracalcic, basic/ultrabasic lithologies). To evaluate if partial melting of such metasomes could effectively produce kamafugites, we performed partial melting experiments at 2.7 and 5 GPa, and 1200°C to 1550°C on clinopyroxenites variably enriched in phlogopite, olivine and accessory phases (apatite, oxides, titanite), and on a clinopyroxene glimmerite (with apatite and magnetite).
At low degrees of melting, the glasses show extremely high TiO2 (<15 wt.%), CaO (<18 wt.%) and P2O5 (<7.4 wt.%), coupled with low SiO2 (>21.6 wt.%), as accessory minerals are the principal contributors in the melting reactions. Although there are no known natural counterparts for these low-degree melt compositions, they might play a key role in re-fertilisation events in the upper mantle. At increased degrees of partial melting (∼50 to ∼90%), the experimental melts approach the compositions of silica-poor, potassic/ultrapotassic and ultracalcic rocks. Indeed, experimental-produced glasses share several geochemical similarities with natural kamafugites, partially overlapping for most of the major oxides. Clinopyroxene- and phlogopite-rich lithologies, variably enriched in olivine and accessory phases (apatite, oxides, titanite) probably occur as veins pervading the lithospheric peridotitic matrix, and their partial melting, especially at high degrees, may be a plausible explanation for the genesis of SiO2-poor, K2O- and CaO-rich compositions.
Sea ice outflow through the Transpolar Drift (TPD) is essential in Arctic sea ice loss. Twenty-four buoys deployed in the Arctic Ocean during the summer of 2021 were used to analyse sea ice kinematics and deformation across the pack ice zone (PIZ) and marginal ice zone (MIZ), mainly focusing on the TPD region. Three stages were identified as sea ice transitions from melt to growth and to melt again. In Stage 1, sea ice exhibited active internal motion, with a high deformation rate (5.7 d−1) determined using the buoy trajectory-stretching exponents. In Stage 2, ice consolidation reduced wind response and deformation rates (2.3 d−1), but still with intermittently enhanced ice deformation over 6.0 d−1 caused by severe storms. In Stage 3, the combined impacts of a super cyclone, MIZ ice and oceanic conditions, and tidal dynamics north of Svalbard remarkably altered the ice kinematic regime. Variations in sea ice kinematics along the TPD region support the MIZ definition by the threshold of certain sea ice concentration variability. This study demonstrates how seasonal transitions, spatial heterogeneities of sea ice conditions, atmospheric or oceanic forcings, and extreme cyclones collectively shape sea ice dynamics in the TPD region, amplifying its seasonal changes relative to those in the central Arctic Ocean.
This study introduces a boundary element method to solve the three-dimensional problem of internal tide generation over arbitrary isolated seamounts in a uniformly stratified finite-depth fluid with background rotation, without assumptions on the size or slope of the topography. Focusing on linearly propagating waves with small tidal excursions, the approach employs a vertical mode decomposition to describe the wavefield and the wave energy flux. We apply the model to the generation of internal tides by a unidirectional barotropic tide interacting with an axisymmetric Gaussian seamount. We study the conversion rate and flow field for various topographic configurations. We qualitatively recover some of the two-dimensional results of Papoutsellis et al. (2023 J. Fluid Mech.964, A20), and find topographies with weak conversion rates, as discussed by Maas (2011 J.FluidMech.684, 5–24). Furthermore, our results reveal the previously underestimated influence of the Coriolis frequency on the wavefield and on the spatial distribution of radiated energy flux. Due to Coriolis effects, the energy fluxes are shifted slightly counter-clockwise in the northern hemisphere. We explain in detail how this shift increases with the magnitude of the Coriolis frequency and the topographic features and why such effects are absent in models based on the weak topography assumption.