In India, the sparse air quality monitoring infrastructure beyond urban centers limits our understanding of fine particulate matter (PM_2.5) spatiotemporal variability, exposure dynamics, and their health and ecological impacts. To address this challenge, the Ambient Air Quality Monitoring in Rural Areas using Indigenous Technology (AMRIT) project was launched, deploying 1,400 low-cost air quality sensors (LCS) across diverse demographics and land-use settings in the states of Uttar Pradesh and Bihar, within the Indo-Gangetic plains (IGP). Additionally, the Dynamic Hyper-local Source Apportionment (DHSA) project was initiated to explore the potential of LCS for real-time source apportionment, facilitating pollution source identification and providing policymakers with critical data for effective air pollution control. Together, these initiatives aim to capture regional pollution dynamics and impacts beyond urban centers for the first time in India.

Our investigation showed that the AMRIT-LCS network effectively captured fine-scale pollution patterns across urban and rural areas of Bihar, with a mean concentration of 135 µg/m³. Rural areas exhibited 6-8% higher pollution levels than urban settings. Within urban areas, pollution levels were notably higher in suburban and small-town regions, highlighting the need for targeted pollution management in these emerging cities. Leveraging machine learning (ML) frameworks, the village-level exposure assessment revealed significant spatiotemporal heterogeneity in PM_2.5 exposure, with consistently high levels in the northwestern districts and a mortality rate (per lakh) of 50 (95% CI: 33–64) in the region. Data-driven techniques were applied to delineate air sheds for future air quality management. Five distinct air-sheds were identified, with three (in the north) and two (in the south) of the Ganges River, flowing west to east and dividing Bihar into two unequal parts. Consistent with the exposure model, the air-sheds over the northwestern and north-central regions were more polluted. Additionally, the LCS network was used to identify pollution hotspots by leveraging satellite-driven datasets within a deep learning framework, across various temporal scales.

These findings underscore the critical need for high-density monitoring networks to capture local variability and generate spatially resolved estimates. Under the DHSA project, ML techniques enabled real-time, accurate predictions of pollution source contributions using LCS datasets, with a mean absolute error of less than 5%. This approach strengthens the potential for deploying widespread LCS networks capable of high-resolution source apportionment with spatiotemporal precision. The data-driven approach provides a solid foundation for designing decentralized mitigation strategies and comprehensive policy frameworks aimed at improving air quality and public health in the IGP. Thus, the portable LCS technology offers a promising alternative to conventional air quality monitoring methods, presenting a viable solution not only for India but also for data-sparse regions globally, contributing to the achievement of sustainable development goals.

Keywords: PM_2.5, Low-Cost Sensors, Indo-Gangetic Plains, Machine Learning, Exposure Assessment, Urban-Rural Disparity, Airsheds, Hotspot Analysis, Source Apportionment

How to cite: Tripathi, S.: Empowering Data-Driven Air Quality Management through low-cost sensors: Insights from the Indo-Gangetic Plains, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-1317, https://doi.org/10.5194/egusphere-egu25-1317, 2025.

The ocean interacts with the atmosphere, ice, and the solid earth, and the properties transferred across these boundaries are moved and mixed in the ocean interior by a variety of processes.  Some of these processes have been known for just a few decades and act in curious and surprising ways which are difficult to understand. 

The lecture will outline the thermodynamic theory and the mixing processes which underpin our oceanographic practices, concentrating on some counter-intuitive examples.  For example, thermodynamic reasoning has recently led to clear but initially surprising interpretations of the temperature and salinity variables that are carried by our ocean and climate models. 

The observed bottom intensification of diapycnal mixing in the abyssal ocean implies that the diapycnal velocity in the ocean interior is downwards towards denser water, and it follows that the upwelling occurs in thin bottom boundary layers.  The use of simple buoyancy budgets shows that the upwards diapycnal transport in these thin boundary layers is twice or even three times the formation rate of Antarctic Bottom Water. 

How to cite: McDougall, T.: Looking under the hood of Physical Oceanography: Curiosities and Surprises , EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-1430, https://doi.org/10.5194/egusphere-egu25-1430, 2025.

In recent years, our ability to model the coupled evolution of the tectonics, mantle dynamics and core cooling of Earth and terrestrial planets has improved dramatically, with corresponding improvements in our understanding of these. Simultaneously, the discovery of many rocky exoplanets plus increasingly detailed observations of Earth and solar system planets such as Mars and Venus have given additional motivation to such studies.

While planetary tectonics has generally been thought of in terms of the endmembers plate tectonics and stagnant lid (perhaps alternating), we now realise that there is a spectrum of planetary tectonic modes influenced by effective lithospheric strength (~yield stress), intrusive and extrusive magmatism, and other factors. While a simple rheological description of temperature-dependence + plastic yielding can give Earth-like plate tectonics (Tackley, 2000), indicated by reproducing the oceanic plate age-area distribution (Coltice+, 2012) and plate size-frequency distribution (Mallard+, 2016), melting and magmatism facilitate further tectonic modes and greatly influence planetary evolution. While vigorous extrusive magmatism can act as an important “heat pipe” heat transport mechanism (Nakagawa+Tackley, 2012), vigorous intrusive magmatism, which is probably volumetrically larger, can produce a soft, deformable lithosphere resulting in a “plutonic squishy lid” mode (Lourenco+, 2018; 2020) that matches observations of Venus’ lithosphere (Byrne+, 2023; Tian+, 2023). Combinations of these various modes can also exist (Tackley, 2023; Lourenco+Rozel, 2023).

Melting and magmatism also have key influences on mantle structure and evolution due to the compositional differentiation that they produce, which tends to result in a build-up of recycled basaltic crust above the core-mantle boundary (influencing core heat flow and evolution (Nakagawa+Tackley, 2014) and at the base of the transition zone (Yan+, 2020), creating partial layering between upper and lower mantles. Indeed, the latter “basalt barrier” effect is found to be much stronger than layering induced by the negative Clapeyron slope of the ringwoodite to bridgmanite+ferropericlase transition.

Further important influences include impacts, which may strongly influence early Earth/planetary tectonics (Borgeat+Tackley, 2022) and Mars crustal dichotomy (Cheng+, 2024), grain-size evolution, which strongly influences viscosity and may produce feedback as well as “surprising” behaviour (Shierjott +, 2020; Paul+, 2024) and differential heating due to tidal locking (Meier+, 2021).

In this talk, the application of these concepts and mechanisms to the evolution of Earth, Venus, Mars and exoplanets will be discussed.

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How to cite: Tackley, P.: Tectonics, Mantle Dynamics and Coupled Lithosphere-Mantle-Core Evolution of Earth and Other Rocky Worlds, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-19527, https://doi.org/10.5194/egusphere-egu25-19527, 2025.

Some years ago, I began giving lectures with both "Geology" and "Atmospheres" in the title. In part, this was to emphasize that atmospheres are dynamic entities, evolving in response to volatile cycling between the outer envelope of a planet and planetary interiors. Understanding atmospheres, whether of Solar System planets or exoplanets, requires an intimate understanding of the geochemistry of the interior, and of the physical processes mediating exchange between the interior and envelope.  Another "geological" aspect of exoplanet atmospheres is that many exoplanets are hot enough that substances ordinarily thought of as rocks or minerals exist as condensible vapours in the envelope, leading to a manifestation of mineralogical processes in situ in the envelope itself.  Unprecedented atmospheric characterizations from the James Webb Space Telescope (JWST) have accelerated the realization that addressing the grand challenge problems of planetary structure and evolution must erase the traditional boundaries between atmospheric physics and Earth science disciplines dealing with geodynamics and mineral physics. The demands of these problems call for an integrated approach to training the next generation of researchers to meet the emerging challenges.

In this lecture, I will highlight some examples of the interplay between planetary envelopes and planetary interiors, focusing on lava planets, "hot rocks" (rocky planets too hot to support surface liquid water but not hot enough to have molten surfaces), the deep carbon cycle on habitable rocky worlds, and subNeptunes. Recent JWST data driving these inquiries will be surveyed. The general programme is to determine the extent to which astronomical observations -- which probe only the outer skin of a planet's volatile envelope (if present)-- together with mass, radius and age data can constrain the composition and structure of the interior, which cannot be directly observed.  subNeptunes present an especially interesting case, because mony currently accessible targets have a predominantly rocky composition (by mass), surrounded by a lower molecular weight envelope which interacts physically and chemically with a permanent magma ocean at the silicate/envelope interface.  For subNeptunes with a sufficiently massive envelope, the interface with the silicate mantle can be hot enough to drive the silicate itself supercritical, blurring the distinction between mantle and envelope.  Lack of experimental data on equations of state, geochemical reaction constants and opacities currently constitutes a serious impediment to progress in modelling subNeptune thermochemical structure and evolution. 

How to cite: Pierrehumbert, R.: The geology of planetary atmospheres, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-3283, https://doi.org/10.5194/egusphere-egu25-3283, 2025.

Long Short-Term Memory networks (LSTMs) have been around since the early 90’s but only in the last few years have LSTMs gained significant popularity in the hydrological sciences. Related publication counts have grown exponentially, and LSTMs power some of the largest-scale operational flood forecasting systems.

In this presentation, I'll look back at my relatively short career as a student and researcher at the intersection of hydrology and machine learning. I don't claim to have introduced LSTMs to hydrology, but I'll share my own experience helping to develop this modeling approach into what it is today. We will look at what I saw in this neural network architecture, and why I thought it was well suited for hydrologic applications.

The tale goes as follows: Once upon a time, in a land (not so) far far away, a (not so young) master student of environmental engineering was teaching himself the dark arts of machine learning (ML). While studying ML for automated fish detection, he stumbled upon the LSTM architecture. Having just concluded a course on the design of conceptual hydrological models, he noticed the underlying similarity between the LSTM and these established approaches — and more generally, the conceptual approach for modeling the water cycle. With one of his dearest colleagues and friends, he started to work night and day (actually more nights than days) to see if the LSTM is indeed suitable for hydrology. From initial attempts at emulating the ABC and HBV models, to first real-world experiments in individual catchments, the LSTM was showing great potential. But it was not until he discovered the CAMELS dataset and started experimenting with large-sample hydrology that he fully understood the potential of LSTMs for applications in hydrology. Equipped with nothing more than his first GPU, he embarked on a quest to explore the wondrous lands of academia. Countless nights were spent on the computer, forging transatlantic friendships, conducting experiments and writing publications. Eventually, he ascended to the ranks of PhDs by defending his research against Reviewer #2 and the high council of the PhD committee. Fast forward in time, today, LSTMs are widely used and among others, power Google’s current operational, global-scale flood forecasting model. And thus, the now (not so) old research scientist lived happily ever after with his wife and his children, and continues, to this day, to do much the same as he had in those earlier years.

If there is one thing that I would like for you to take away from this talk, it is that I hope my presentation will motivate young scientists to stay curious, to follow their own ideas, to not get demotivated by initial pushback and to not be afraid of reaching out to more senior researchers. I want to advocate strongly the importance of open science, of reproducibility, of collaborations, of benchmarking and of open data sharing to advance science.

How to cite: Kratzert, F.: Long Short-Term Memory networks in hydrology: From free-time project to Google’s operational flood forecasting model, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-5863, https://doi.org/10.5194/egusphere-egu25-5863, 2025.

Climate extremes, such as droughts, floods, and heatwaves, often trigger compound and cascading impacts due to interdependencies between coupled natural and social systems. Yet, our knowledge of these interactions remains limited mainly due to the lack of comprehensive impact data. Research typically considers only one isolated impact, system, socioeconomic sector, and/or hazard at a time, often ignoring dependencies between impacts as well as how they interact with response and adaptation measures.

Against this backdrop, the unprecedented abundance of digital texts and cutting-edge machine-learning tools has opened new research avenues for impact assessment research. In this talk, I will demonstrate how we can leverage natural language processing (NLP) and large language models on different text types to infer how climate extremes impact society. I will discuss the potential of unconventional data sources, such as meeting minutes, newspaper articles, and reports, to monitor the consequences of extreme events in near real-time.

How to cite: Madruga de Brito, M.: Climate impacts and where to find them: insights from text mining, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-1930, https://doi.org/10.5194/egusphere-egu25-1930, 2025.

Women make up for half of the world’s population. Women have gained significant rights almost everywhere. They are not a minority in any sense, but they remain underrepresented where and when decisions are taken, especially in the highest offices. 

After centuries of progress, gender inequality persists. Women still enjoy less opportunities, earn less and have less power than men. Despite the absolutely vital nature of women’s roles in the family and economic spheres, they are marked by a persistent and systemic lack of recognition. So far, no country in the world has reached gender equality.

The world we know is changing fast, and not necessarily for the better. Across the Atlantic, equality, diversity and inclusion (EDI) policies are being rolled back by leading companies and globally known brands, sending a strong message to the rest of the world. EDI has become a dirty word, which some now associate loudly with a path to societal mediocrity. 

Election results of recent years in western democracies show an appetite for drastic political changes. Even if some people seem to have been caught by surprise,  a careful and attentive analysis of socio-political consciousness reveals that clear signals of desire for change were impossible to miss. Since before the pandemic, the populist and far right movements are on the rise. Many progressive players scorned and intentionally ignored the facts and insisted on policies that alienated portions of the population who prefer moderate views, leaving them lost and confused at times. 

The new socio-political order presents many challenges. The risk for reduction of women’s rights and freedom in general is undeniable, but it appeals to an increasing number of the population, women included. Political conservatives work hard and effectively to seduce women with potential women’s rights, family and motherhood policies. The payback is simple: women's capabilities are reduced to the traditional value of their reproductive dimension, and made invisible or secondary with regard to other productive activities. 

Denying or ignoring reality is not helpful. Acknowledging it can at least ignite a discussion on what counter-movements might need to look like, as we endure the storm and work to bring about a brighter future. The present is unchangeable, but the future is unwritten.

How to cite: Jesus-Rydin, C.: The unwritten future of women in the 21st century, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-12557, https://doi.org/10.5194/egusphere-egu25-12557, 2025.

Geoscience plays a vital role in shaping our sustainable future, yet the discipline is at a critical crossroads. Declining student enrolments, reduced course offerings, and the closure of university departments threaten its survival. Key challenges include public perceptions of geoscience and associated industries, its lack of visibility in school curricula, outdated branding and stereotypes, and issues related to diversity and inclusion. As students increasingly seek altruistic, sustainability-focused careers, geoscience must respond rapidly or risk further decline. A more strategic, impact-driven approach to geoscience communication is essential to address the discipline’s struggling brand image. This presentation takes you behind the scenes of the Earth Futures Festival, an international geoscience film and video festival. The festival bridges the arts and sciences to demonstrate how geoscience, combined with long-standing cultural knowledge of the Earth, offers solutions to pressing global challenges. We will explore the impact-focused approach underpinning the festival’s design, including forging value-aligned partnerships, providing communication skills training for geoscientists, and amplifying the visibility of typically underrepresented groups. This talk will provide a step-by-step practical guide to illustrate how impact-focused design can be effectively applied to geoscience communication and outreach.

How to cite: Handley, H.: An impact-driven approach to geoscience communication, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-13520, https://doi.org/10.5194/egusphere-egu25-13520, 2025.

During the past 15 years I and my colleagues have studied the dynamics of free (gravity-driven) subduction using a twofold approach: numerical simulations using the boundary-element method (BEM), and interpretation of the solutions using the theory of thin viscous shells. The basic model comprises a shell with thickness h and viscosity η₁ subducting in a mantle with viscosity η₂. The mantle has a finite depth H (in 3-D Cartesian geometry) or an outer radius R₀ (in spherical geometry). The key length scale governing subduction is the 'bending length' l_b, the sum of the slab length and the lateral extent of the  seaward flexural bulge. A dimensionless 'flexural stiffness' St = (η₁/η₂)(h/l_b)³ determines whether the subduction rate is controlled by η₁ or η₂. 3-D BEM simulations closely reproduce laboratory experiments, and reveal the physical mechanisms underlying the different modes of subduction observed.   In spherical geometry, subduction is controlled by St and a 'dynamical sphericity number' Σ = (l_b/R₀) cotθ_t, where θ_t is the angular radius of the trench. Spherical BEM solutions demonstrate the 'sphericity paradox' that the effect of sphericity on flexure is greater for small (more nearly flat) plates than for large ones  (e.g. hemispherical). Another surprising result is that state of stress in a doubly-curved slab is dominated by the longitudinal normal ('hoop') stress. BEM predictions of hoop stresses in slabs with positive and negative Gaussian curvature agree well with earthquake focal mechanisms in the Mariana slab. Linear stability analysis shows that a slab under compressive hoop stress is unstable to longitudinal buckling, which may explain the peculiar geomery of the Mariana slab. Finally, I will describe a new hybrid boundary-integral/thin-shell approach to coupling mantle flow with the deformation of a thin shell having non-Newtonian rheology. 

How to cite: Ribe, N.: Thin-shell dynamics of subduction, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-1740, https://doi.org/10.5194/egusphere-egu25-1740, 2025.

Venus is often called Earth’s sister planet due to its similar size and mass. Apart from that, however, the two planets are wildly different, with surface temperatures on Venus that easily melt lead and a Venusian surface pressure that is almost a hundred times larger than that of Earth. Additionally, Venus is completely covered in clouds; obscuring its surface and shrouding the entire planet in mystery. 

How did the observed topographic features form? Is there still some form of tectonics ongoing? Are there earthquakes - or indeed: venusquakes? 

These are just a few of the questions that Venus scientists would love to know the answer to. Luckily, several planetary missions will explore Venus in the coming decade. Focusing on tectonics, volcanism, and Venus’ atmosphere, missions like EnVision, VERITAS, and DAVINCI will likely provide rich new datasets to start answering the multitude of questions we have about Venus’ current and past state.

Until then, modelling is a useful tool to gain a first-order understanding of the physical processes on Venus. In addition, models can be used to make predictions and end-member hypotheses that can be directly tested by the upcoming missions. 

To gain first insights on how the observed rifting structures on the Venusian surface could have formed, we adapted 2-D thermomechanical numerical models of continental rifting on Earth to Venus-like environments. Our results show that a strong crustal rheology such as dry diabase is needed to localise strain and develop rifts under the high surface temperature and pressure of Venus. Models with different crustal thicknesses fit the topography profiles of the Ganis and Devana Chasmata well, indicating that the differences in these rift features on Venus might be due to different crustal thicknesses.

The rifts of Venus are potentially still seismically active and so could the fold belts and a subset of the coronae be. Scaling the seismicity of the Earth to Venus by identifying potential analogues for different tectonic settings, allowed us to provide several end-member estimates of the potential seismicity on Venus. Our most realistic estimate for a moderately active Venus results in a prediction of a few thousand venusquakes with magnitude 4 or higher per Earth year.

To assess the feasibility of measuring this seismicity with future missions, we estimated the seismic wave detectability of different ground-based, atmospheric, and orbital techniques. Airglow imagers, which can measure seismic wave patterns in the airglow of the upper atmosphere from orbit, appear to be the most promising technique due to their long mission duration, although they are limited to detecting larger magnitude events. 

In summary, since we are faced with many unknowns when it comes to Venus, this interdisciplinary approach that combines modelling aspects from both geodynamics and seismology and integrates observational techniques is the way forward to exploring the tectonics and seismicity of Venus and unravel the mysteries of this planet. 

How to cite: van Zelst, I., Garcia, R. F., Regorda, A., Maia, J., De Toffoli, B., Plesa, A.-C., Thieulot, C., Erdős, Z., and Buiter, S. and the ISSI team #566 - Seismicity on Venus: Prediction & Detection: Exploring the tectonics and seismicity of Venus , EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-6949, https://doi.org/10.5194/egusphere-egu25-6949, 2025.

Ground Penetrating Radar (GPR) is a diagnostic tool that well assessed in a variety of areas, including geophysics, archaeological prospection, civil engineering, and planetary exploration, just to mention few examples.

Notwithstanding the simplicity of the underlying principle, a significant limitation of GPR is concerned with the interpretability of the raw data, mostly presented under the form of radargrams, particularly in scenarios that are complicated and characterised by a multitude of embedded targets. 

To enhance the interoperability of radar images, it is crucial to reliably model the electromagnetic scattering, so that the radar imaging is conceptualised as an inverse scattering problem. For such an inverse problem, the geometric and electromagnetic properties of the targets are retrieved by the field scattered by the target when an incident field impinges on it. Despite the simplicity of the underlying principle, this inverse problem is inherently complex due to its non-linear nature and ill-posedness. These mathematical difficulties have a detrimental effect on the effectiveness of GPR diagnostics in real cases. To facilitate the application of inverse scattering approaches in real-world scenarios, it is necessary to resort to approximate models of electromagnetic scattering. Microwave tomography exploits the linearization of the inverse scattering problem, so that reconstruction approaches can be developed that operate under realistic conditions with the aim of estimating the position and geometry of targets, albeit with limitations on the class of unknowns that can be reconstructed (i.e. resolution limitations) and the impossibility of quantitatively estimating the electromagnetic properties of targets.

In the talk, microwave tomography will presented under a unified mathematical framework based on the solution of an integral equation accounting for arbitrary measurement configurations and background scenarios for both contact and contactless GPR measurements. Furthermore, the investigation of the reconstruction performance of the microwave tomographic approach for different measurement configurations and background scenarios will be presented.

Finally, several cases of exploitation of the microwave tomographic approach in real cases will be shown.

How to cite: Soldovieri, F.: Microwave tomography for subsurface prospecting, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-21957, https://doi.org/10.5194/egusphere-egu25-21957, 2025.

The strength of the ocean carbon sink is maintained by the physical, biological, and chemical processes. Any change in these processes may alter the carbon-climate feedbacks and affect the rate of global change. Our predictive understanding of the susceptibility of these feedbacks to global change is heterogeneous: some responses are well quantified, whilst for some, even the direction of change is unclear. This makes representing ocean biogeochemical cycles as an interactive component of Earth system models (ESMs) a key scientific challenge. This challenge unfolds in resolving the critical marine biological and physical processes, as well as their feedbacks in high spatial resolutions on climate-relevant time scales. Thereby, advancements in ocean biogeochemical ESM components need to embrace emerging observational and laboratory evidence, together with novel computational technologies. This lecture will discuss the current progress, challenges and opportunities in addressing knowledge gaps in our predictive understanding of the changing ocean carbon sink, its variability and feedbacks in the Earth system.

How to cite: Ilyina, T.: Predictability and feedbacks of the changing ocean carbon sink – insights from Earth system models, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-6396, https://doi.org/10.5194/egusphere-egu25-6396, 2025.

The Atlantic Meridional Overturning Circulation (AMOC) is crucial for global ocean carbon and heat uptake, and controls the climate around the North Atlantic. Despite its importance, quantifying the AMOC’s past changes and assessing its vulnerability to climate change remains highly uncertain. Understanding past AMOC changes has relied on proxies, most notably sea surface temperature anomalies over the subpolar North Atlantic. Here, we use 24 Earth System Models from Coupled Model Intercomparison Project Phase 6 (CMIP6) to demonstrate that these sea surface temperature anomalies cannot robustly reconstruct the AMOC on annual, decadal or centennial timescales. Instead, we find that the net air-sea heat flux anomaly between the Arctic and any given latitude between 26.5°N and 50°N in the North Atlantic is tightly linked to the AMOC anomaly at that latitude on decadal and centennial timescales. On these timescales, the air-sea heat flux proxy works through the conservation of energy, in which energy transferred laterally into the region is typically released to the atmosphere through surface heat fluxes. On annual timescales, however, air-sea heat flux anomalies are modulated more so by atmospheric variability and less by AMOC anomalies. Based on the here identified relationship and observation-based estimates of the past air-sea heat flux in the North Atlantic from reanalysis products, we show the decadal averaged AMOC at 26.5°N has not weakened from 1963 to 2017 although substantial variability exists. Furthermore, we find no decline in the AMOC at any other latitude, though the decadal variability appears distinct between subtropical and subpolar latitudes. This result aligns with previous work that has shown the lack of meridional coherence in the AMOC, and the presence of distinct overturning cells.

How to cite: Terhaar, J., Vogt, L., and Foukal, N. P.: Atlantic overturning inferred from air-sea heat fluxes indicates no decline since the 1960s, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-8323, https://doi.org/10.5194/egusphere-egu25-8323, 2025.

The abrupt transient centennial to millennial coolings of the North Atlantic region first described in Greenland ice core isotope records by Hans Oeschger and Willy Dansgaard are now widely recognized as recurrent, abrupt weakenings of the Atlantic meridional overturning circulation (AMOC). A hierarchy of climate models has shown that freshening in the North Atlantic can trigger AMOC collapse or condition unforced AMOC variability.  Yet, the existence of a freshwater trigger is largely untested for most events, and it is also uncertain whether a reduction in freshwater fluxes was necessary to permit the recovery of AMOC.  Decadally resolved stalagmite oxygen isotope records from coastal caves in NW Iberia record changes in the δ¹⁸O of the surface eastern North Atlantic which are highly sensitive to the freshwater balance.   Careful refinement of stalagmite carbon isotope proxies to correct for in-cave fractionation effects, has provided an indicator of the abrupt temperature changes caused by AMOC in this region.  These dual indicators resolve the detailed phasing of freshening and past AMOC variations. In stalagmite records spanning late MIS 7 and MIS 6, nearly half of the abrupt coolings have no significant freshening event within a hundred years of the onset of cooling.  In contrast, the millennial coolings at the start of Termination II deglaciation are synchronous with abrupt freshening events.  Thus, triggers of abrupt AMOC weakenings and recoveries may be diverse, and the sensitivity to different triggers may change with the evolution of climatic boundary conditions.  A longer set of stalagmite records provide evidence for more dynamic variations of Northern Hemisphere ice sheets and a succession of positive and negative feedbacks on ice melting rate during deglaciations. 

The recognition of past variation in atmospheric CO₂ in ice core archives, first characterized by Hans Oeschger, catalyzed efforts to estimate past atmospheric CO₂ from indirect proxies in the deeper past, to better estimate the earth system and cryosphere sensitivity to atmospheric CO₂ in warmer than preindustrial periods.  Over the last decades, the challenging path of deriving proxy CO₂ records has led to numerous paradoxes in the relationship between climate variables and estimated CO_2.  From the marine alkenone-based CO₂ proxy, a better representation of the biological processes imprinted on the proxy has improved the relationship between CO₂ and climate trends since the mid Miocene.  Such a representation allows more robust estimates of the scope of changes in atmospheric CO₂ across climate transitions, although estimates of absolute CO₂ still feature high uncertainty.  As orbital resolution CO₂ proxy records emerge for past warmer time periods, we are presented with new questions about the relationship between ice growth on Antarctica and CO₂, and the carbon cycle processes shifting carbon into and out of the atmosphere on orbital timescales.

How to cite: Stoll, H.: Clarifying past AMOC and climate sensitivity with paleoclimate archives, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-4861, https://doi.org/10.5194/egusphere-egu25-4861, 2025.

Darcy’s experiments for the public fountains in Dijon in the 1850s aimed at estimating a single parameter value, namely the saturated hydraulic conductivity (Ksat). Lumped hydrological models that are nowadays used to simulate streamflow at the catchment scale use at least a handful of model parameters. These parameters can not be measured in the field and are typically poorly defined. Therefore, despite all our efforts, catchment hydrological modelling still faces equifinality issues that can not be solved by the dramatically increased computational opportunities since Darcy’s work. In addition to the increased computational power, data availability for hydrological modelling has dramatically improved as well. Especially in the last decade, the emergence of large-sample datasets for various regions around the globe has enable modelling studies using data from hundreds of catchments. This has helped to ensure more generally applicable findings. These new data sets also allow us to study the value of data in more detail. This is interesting, for instance, when we want to evaluate the potential value of different datasets, including those of public observations in citizen science projects, such as CrowdWater. In this lecture, I will present findings of recent modeling studies based on large samples of catchments with a focus on the value of different types of data and the question how to best simulate (almost) ungauged catchments.

How to cite: Seibert, J.: Developments in hydrological modelling: from Darcy’s work on public fountains to observations by the public  , EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-10709, https://doi.org/10.5194/egusphere-egu25-10709, 2025.

Data are a fundamental building block of science. Ever-increasing volumes and diversity of data are allowing us to solve ever more complicated research questions; yet they are also creating new challenges around efficient data management and storage. This talk focuses on geochemical data, that are relatively low in volume compared to other Earth System Science disciplines, but are highly diverse due to the large range of materials analysed and analytical techniques employed. Modern geochemical research increasingly draws on large compilations of data previously collected by multiple authors using multiple analytical methods, over years and decades. Harmonising data from such diverse sources, and ensuring consistency and comparable data quality, is a non-trivial task that requires significant investment of time and resources. As a consequence, data compilations are increasingly published in high-ranking journals. Yet often they are singular, one-time efforts for specific projects by individual authors that quickly become outdated and lose relevance. In contrast, curated synthesis databases, such as the GEOROC database for igneous geochemical rock and mineral compositions, are continuously being updated and can offer long-term consistent curation over decades. By providing free access to, and customisable search of, their comprehensive data and metadata collections, they enable the compilation of a diverse range of smaller, targeted datasets that can form the basis of many different research projects across multiple (sub)disciplines. Long-term synthesis databases are an invaluable resource for the geochemical and broader scientific community. However, despite their broad relevance and usage, many such community databases struggle to secure the required resources for database maintenance and continuous technical developments to cater to changing scientific demands. This burden can be partly alleviated through integration of databases with curated, domain data repositories. Data harmonisation is greatly aided by adherence to best practices and standards during data publication. Repositories that publish curated, discipline-specific datasets, therefore, play an important role in ensuring new analyses are sufficiently well documented to allow quality assessment and reuse by third parties. They also support data rescue and the alignment of legacy data with modern data requirements. These standards and best practices should in turn be developed based on community expertise and consensus, which requires international collaboration. In geochemistry, data providers and services from three different continents formed the OneGeochemistry initiative. OneGeochemistry promotes exchange and agreement on minimum common variables between researchers from all geochemical sub-disciplines and the more than 15 international societies, associations and science unions that govern different types of geochemical data. As a participant in the WorldFAIR project, OneGeochemistry aims to reconcile cross-domain solutions for data interoperability with domain-specific geochemical requirements. The implementation of geochemical data standards in repositories, and their broad adoption by the geochemical community, will enhance the value of data and services provided by synthesis databases, which will lead to better access to comprehensive data compilations and, ultimately, better science.

How to cite: Klöcking, M.: The importance of curated domain repositories and synthesis databases as evolving community resources for modern Earth System Science research, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-9936, https://doi.org/10.5194/egusphere-egu25-9936, 2025.

Earth System Science datasets have been acquired for centuries across five broad spheres: geosphere, cryosphere, hydrosphere, biosphere and atmosphere. They vary from human observations to sensor-derived measurements ranging from nanoscale laboratory data to large-volume petascale datasets collected remotely by satellites, drones, etc. Across all spheres most datasets have their roots in three core disciplines: Geology, Geophysics and Geochemistry. Today we are generating unprecedented volumes of data and when combined with computer capacity, now at exascale, our capability to integrate and analyse data should be unparalleled.

Digital data repositories emerged around 1980 and the internet soon after. Initially data was shared by shipping on hard media. The internet soon enabled globally data sharing data, including by web services (e.g., OneGeology In 2008). Multiple global data sharing networks were envisioned, but few moved beyond those that proposed them. Machine-to-machine data sharing is still a challenge. Many spheres cannot utilise the existing capacity of computers, including the full potential of AI applications, because these cannot read the volumes of available data. 

History has repeatedly shown that revolutionary infrastructures can take decades to realise their full potential and change from being a new way of doing things to multiple ways of doing new things. 

The FAIR principles were specifically designed to increase machine-to-machine interoperability of data: they are the blueprint of WHAT needs to be done but the HOW will involve rethinking 3 key steps. 

Firstly, shift the onus on aggregating data from the consumer to repositories capable of implementing discipline-centric FAIR (meta)data standards. 

Secondly, as recommended by the WorldFAIR Second Policy Brief to the European Open Science Cloud (EOSC), change from a bibliographic approach to data stewardship to one of data engineering, where richer and more comprehensive standardised (meta)data at the datum level enables machine-to-machine access of specific variables of interest across multiple disciplinary datasets. Take a more holistic approach to standards development (e.g., Observation, Measurement and Samples Standard (ISO 19156:2023)) and identify common universals across disciplines (e.g., time, place, units of measure). Initiatives like OneGeology and Geochemistry and hopefully soon OneGeophysics can support higher--level discipline centric (meta)data standards. Standards coordination groups (e.g., CODATA, Research Data Alliance) are critical. PIDS at the object level will be essential.

Thirdly, prioritise which datasets are made fully FAIR compliant and fund their curation in repositories that offer discipline based curation. The 2019 Beijing Declaration on Research Data notes that ‘publicly funded research data should be interoperable, and preferably without further manipulation or conversion, to facilitate their broad reuse in scientific research’. The myriad of data products generated from these primary data sources can go to generalist and institutional repositories.

Revolutionary infrastructures do take time to realise their full potential. It is nearly 25 years since the early experiments using the internet to globally network data repositories. The WorldFAIR Second EOSC Policy Brief emphasises that the change to machine-actionable FAIR data ‘is one of a magnitude which will necessitate considerable resourcing, investment, and upskilling; but it will also achieve significant benefits, including creating a digitally integrated Earth to support sustainable development of our planet.

How to cite: Wyborn, L.: Rethinking HOW We Create Global Networks of Earth and Environmental Datasets to Maximise Their Potential to Underpin Integrated Research for a Sustainable Planet., EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-16237, https://doi.org/10.5194/egusphere-egu25-16237, 2025.

Conventional neo-Darwinian theory views organisms as responsive to their environments on neontological timescales, and able to readily change size or shape due to selection pressures (as exemplified by the famous case of Galápagos finches). But since 1863, it has been well established that Pleistocene animals and plants show limited morphologic change in response to the glacial-interglacial cycles. Rancho La Brea tar pits in Los Angeles, California, preserves a large and diverse fauna from many well-dated deposits, spanning 37,000 years. Pollen evidence shows that climate changed from oak-chaparral about 37 ka to snowy piñon-juniper-ponderosa pine forests during the peak glacial about 18 ka, then returned to the modern chaparral since the glacial-interglacial transition. We have studied all the sufficiently abundant mammals (dire wolves, saber-toothed cats, giant lions, Harlan’s ground sloths, camels, bison, and horses) and all the common birds (28 species, ranging from eagles, hawks, vultures, condors, owls, to yellow-billed magpies, ravens, and Western meadowlarks). We found complete stasis in size and robustness as measured by the major limb bones in all 28 species. There was no significant response even at 20 ka to 18 ka, during the peak glacial period, when climate and vegetation were very different at La Brea. The larger species might be so wide-ranging and versatile that they would not respond to environmental changes, but this is inadequate to explain stasis in even the smallest birds, such as meadowlarks and burrowing owls. While the Galápagos finch model suggests rapid morphological change in response to environmental change, the fossil record shows that such small-scale changes are transient and do not accumulate to result in speciation.

How to cite: Prothero, D. R.: Patterns of Evolution in late Pleistocene Mammals and Birds from La Brea Tar Pits, California, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-21959, https://doi.org/10.5194/egusphere-egu25-21959, 2025.

The increasing water demand by human societies raises concerns on the extent to which it is possible to feed the world with the limited freshwater resources of the planet. The growing competition for water between human uses and environmental needs limits the development of suitable water security scenarios for a sustainable future.  Human appropriation of water resources is for large part instrumental to the enjoyment of human rights to food. To what extent can such rights be reconciled with other human needs as well as the needs of Nature? This seminar will show how humanity is placing unprecedented pressure on the global agricultural system and the water resources it relies on. Through a suite of ecohydrological and socio-environmental analyses, we evaluate the biophysical and social justice limits to the sustainable use of water resources through a variety of perspectives accounting for hydrologic constraints, human needs, environmental flows, and globalization.

How to cite: D'Odorico, P.: The ‘safe operating space’ for global and local water use under climate and societal change, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-13721, https://doi.org/10.5194/egusphere-egu25-13721, 2025.

The glacier surface forms a vital boundary where snow and ice mass exchange occurs through climatic processes. In addition to the visible upper surface, glaciers are bounded by other interfaces, including the underlying base of bedrock/sediment, the front of a calving glacier facing an ocean or lake, and the ice-shelf base in contact with sub-shelf seawater. These unseen boundaries are venues of glacial sliding, hydrology, calving and underwater melting, which play critical roles in glacier dynamics and mass change. These processes are also essential for understanding how glaciers affect surrounding environments through erosion, sedimentation, ice and meltwater discharge. Despite their importance, these boundaries are largely unexplored, in contrast to the increasing amount of data available on the glacier surface. As they are covered by ice and water, special techniques and tools are required for direct observation. For example, hot-water drilling and borehole measurements provide crucial information regarding subglacial processes, and in-situ observations of the ice-water interface can be carried out with uncrewed vehicles or underwater survey devices near the calving front. Based on our experiences in the Alps, Patagonia, Greenland and Antarctica, this presentation highlights the importance of the processes taking place at the hidden glacier boundaries.

How to cite: Sugiyama, S.: On the dark side: Exploring hidden boundaries of glaciers and ice sheets, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-5296, https://doi.org/10.5194/egusphere-egu25-5296, 2025.

Polar ice sheets and glaciers worldwide are rapidly losing mass, acting as major contributors to global sea-level rise. This mass loss trend is expected to continue and further accelerate in a warming climate. Besides solid ice discharge of calving icebergs, mass loss is driven by a declining glacier surface mass balance (SMB), i.e., the difference between mass gained from snowfall accumulation and lost from meltwater runoff to the ocean. Reconstructions of past and projections of future glacier SMB often rely on global or regional climate models typically running on 5 to 100 km grids. Such spatial resolution remains, however, insufficient to accurately capture local SMB processes over small glaciers and ice caps.

To bridge this resolution gap, statistical downscaling has proven an efficient tool to spatially refine SMB outputs from coarse global and regional climate models to high-resolution (sub-)kilometer grids. In this presentation, we will assess the added value of statistical downscaling to accurately resolve local SMB processes, notably the high accumulation and melt rates generated over rugged mountain ranges and narrow outlet glaciers, respectively. We will discuss how high-resolution products proved essential to reconcile recent in situ and remote sensing mass change records, and to yield reliable future SMB projections. This talk will highlight the role of statistical downscaling in identifying mechanisms that currently drive, and may further accelerate, mass loss of polar ice sheets and glaciers across the globe.

How to cite: Noël, B.: Capturing high-resolution ice sheets and glacier surface mass balance in a changing climate, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-5980, https://doi.org/10.5194/egusphere-egu25-5980, 2025.

The radiation belts of the Earth and magnetised planets include high energy electrons reaching energies of up to 50 MeV.  Observations at the Earth show that the electron flux is highly variable, and that acceleration must take place inside the planetary magnetic field.   Soon after the radiation belts were discovered it was thought that inward radial diffusion was the main process responsible for the acceleration, but it was difficult to reproduce the timescale for some of the observed variations in the electron flux.  Local electron acceleration via Doppler shifted cyclotron resonance with chorus waves was proposed as an alternative mechanism and has been shown to play a major role in forming the outer electron belt at the Earth reaching energies of several MeV.  Here we review some of the evidence for local acceleration and describe the process of chorus wave acceleration at the Earth.  We review other types of plasma waves, such as magnetosonic waves, that could contribute to electron acceleration and describe the conditions necessary to reach electron energies of several MeV.  We show examples of chorus and other types of plasma waves at Jupiter and Saturn and show how they play an important role in accelerating electrons to form the radiation belts at those planets.  We suggest that wave acceleration is the missing link in a set of process that starts with volcanic gasses from the moon Io and results in the emission of synchrotron radiation from Jupiter.  We suggest that wave acceleration is a universal process operating at the magnetised planets.  Finally, we show how wave acceleration is included into space weather forecasting models to help ensure the safe and reliable operation of satellites on orbit around the Earth.

How to cite: Horne, R.: Electron Acceleration by Wave-Particle Interactions at the Earth and Magnetised Planets, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-11783, https://doi.org/10.5194/egusphere-egu25-11783, 2025.

Tipping points (TPs) are usually understood as bifurcations due to a slow parameter shift in a bistable system, where the system's state is diffusing around a fixed point in an underlying climate potential. As the shape of the climate potential changes towards the bifurcation, universal early-warning signals (EWS) due to critical slowing down appear.

How reliable is it to transfer this conceptual view to high-level risk assessments of climate change? We set out to test the anatomy and predictability of TPs in the complex system of the global ocean circulation, where changes in ice melt is a control parameter. Several findings highlight the need for more realistic methods to address the risk of TP:

1. The critical threshold of the control parameter can be fuzzy due to sensitive dependence on initial conditions and rate of non-adiabatic forcing changes.

2. In this spatially extended system, there is a high degree of multistability. This leads to a multitude of critical thresholds and abrupt changes in deterministic variability, which can interfer with EWS stemming from noise-driven fluctuations.

3. The universality of EWS in the high-dimensional case is compromised in practise, which may be mitigated by deriving system-specific observables from the properties of an edge state related to the TP.

How to cite: Lohmann, J.: Anatomy and predictability of tipping points in the high-dimensional climate system , EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-21955, https://doi.org/10.5194/egusphere-egu25-21955, 2025.

Stable water isotopes (δ¹⁸O) in precipitation are one of the most abundant paleoclimate proxies and have been used to infer temperature changes at high latitude and hydrological changes in the tropics. In spite of much progress, however, fundamental questions on the paleoclimate interpretation of stable water isotopes still remain open. Combing water isotope observations and an isotope-enabled TRAnsient ClimatE simulation of the last 21,000 years (iTREACE-21), I will discuss some recent progresses towards the understanding of paleoclimatic inferences of  δ¹⁸O.

I will first discuss the δ¹⁸O for the pan-Asian monsoon region. We show that the widespread δ¹⁸O variability that is coherent over the Asian monsoon continental region is accompanied by a coherent hydroclimate footprint, with spatially opposite signs in rainfall. This footprint is generated as a dynamically coherent response of the Asian monsoon system to meltwater forcing and insolation forcing, reinforced by atmospheric teleconnections. As such, a widespread δ¹⁸O depletion in the Asian monsoon region is accompanied by a northward migration of the westerly jet and enhanced southwesterly monsoon wind, as well as increased rainfall from South Asia to northern China, but decreased rainfall in southern China. 

I will then discuss the temperature effect of polar ice core δ¹⁸O, quantitatively, in a new framework called the Unified Slope Equations (USE) that illustrates the general relationship between spatial and temporal δ¹⁸O-temperature slopes. The application of USE to the Antarctica in model simulations and observations shows that the comparable Antarctica-mean spatial slope with deglacial temporal slope in δ¹⁸O-surface temperature is caused accidentally by the compensation responses between the δ¹⁸O-inversion layer temperature relation and the inversion layer temperature itself.  This finding further leads us to propose a paleothermometer that is more accurate and robust than the spatial slope as the present day seasonal slope of -inversion layer temperature, suggesting the possibility of reconstructing past polar temperature changes using present observations.

I will finally discuss the climate interpretation of tropical alpine ice core δ¹⁸O by combining proxy records with climate models, modern satellite measurements and radiative-convective equilibrium theory. I show that the tropical ice core δ¹⁸O is an indicator of the temperature of the middle and upper troposphere, with a glacial cooling of ~7oC . Furthermore, it severs as a Goldilocks indicator of global mean surface temperature change, providing the first estimate of glacial stage cooling that is independent of marine proxies as ~6oC .

How to cite: Liu, Z.: Understanding Paleoclimatic Inference of Stable Water Isotopes using iTRACE Simulation, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-1813, https://doi.org/10.5194/egusphere-egu25-1813, 2025.

Over the past 25 years, satellite observations have revolutionised our understanding of Earth’s magnetic field. The pioneering Ørsted and CHAMP satellite missions marked the beginning of continuous magnetic field monitoring from space, offering invaluable insights into Earth’s interior and its geospace environment. Building on these missions, the Swarm satellite trio, launched in 2013, introduced simultaneous measurements from nearby spacecraft, enabling improved separation of the various magnetic sources.

The field continues to advance with the launch of the first "Macau Science Satellite" (MSS-1) in May 2023, operating in a low-inclination orbit, and the forthcoming NanoMagSat constellation that is currently in preparation. These missions present exciting opportunities to address longstanding scientific questions and explore new frontiers in geomagnetic research.

This talk will highlight the scientific challenges of utilising satellite magnetic data to investigate Earth’s magnetic field, from disentangling overlapping sources to advancing data interpretation techniques. It will also explore the opportunities offered by current and upcoming missions, emphasizing their potential to enhance our understanding of Earth’s interior dynamics, magnetospheric processes, and geospace interactions.

How to cite: Olsen, N.: Exploring Earth's Magnetic Field from Space: Challenges and Opportunities, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-2598, https://doi.org/10.5194/egusphere-egu25-2598, 2025.

Fault mechanics predicts that fault reactivation and slip occur when the shear stress exceeds the fault strength, potentially nucleating earthquakes. Following Anderson’s legacy, the evolution of tectonic stress over the seismic cycle results in different couplings between normal and shear stress. This coupling depends on (1) the fault’s orientation relative to the maximum principal stress and (2) the tectonic faulting style. Reverse faults, loaded by an increase in maximum principal stress, experience increases in both normal stress and shear stress during the interseismic phase. In contrast, normal faults, loaded by a decrease in minimum principal stress, undergo a reduction in normal stress as shear stress builds up. For instance, low-angle normal faults experience larger increases in normal stress for the same shear stress increment compared to Andersonian 60°-dipping normal faults.

Despite this rich variety of stress field evolution observed in nature, laboratory deformation experiments have predominantly focused on a single stress-field scenario: a reverse fault optimally oriented for reactivation. The choice of reversed faults is dictated by the geometry of the apparatus, and the optimal orientation is the simplest system to generate recurrent lab-quakes. This simple laboratory approach describes faults as planes embedded in elastic media.

Here, I summarize results we have collected in the past years by systematically investigating in the laboratory the role of fault orientation and tectonic faulting style under triaxial saw-cut configuration—broadening the range of scenarios beyond the single one described above. The results reveal the impact of stress field on both fault zone and surrounding host rock deformation.

For fault zones, our results on gouge-bearing faults show clear discrepancies when compared with theoretical reactivation based on Coulomb-Mohr criterion. Faults at higher angles to the maximum principal stress appear weaker, suggesting potential stress field rotation within the fault zone. Additionally, when the normal stress for reactivation is comparable, reverse faulting tends to promote stable creep, while normal faulting—due to greater compaction and stiffness of the fault zone—favors slip acceleration and instabilities.

Fault orientation also affects the stress state of the surrounding host rock over the seismic cycle. Optimally oriented faults behave like ideal spring-slider system: elastic energy accumulates in the host rock during the interseismic phase and is released via on-fault slip during the co-seismic phase, accompanied by precursor acoustic activity. In contrast, unfavorably oriented faults produce a more complex picture. The host rock becomes critically stressed, acoustic activity spreads throughout the host rock, and precursors to lab-quakes become undetectable.

These results highlight the potential of investigating in the laboratory the role of stress field on fault zone deformation and its interplay with the surrounding host rock during earthquake nucleation. By expanding laboratory observations to include a wider range of stress-field scenarios, we take one small step toward bridging the gap between simplified experiments and the complex fault systems observed in nature.

How to cite: Giorgetti, C.: The Role of Stress Field on Fault Reactivation: What We Can Learn from Experimental Rock Deformation, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-17929, https://doi.org/10.5194/egusphere-egu25-17929, 2025.

About 30% of our soils are degraded, mostly due to unsustainable land use. These soils took centuries or millennia to form. Are they lost for generations, or can they be regenerated quickly? And how can these options cope with climate change?

The first part of the talk explains how long-term agricultural use degrades soils and how their properties can recover through management changes. It will discuss options for quickly regenerating such soils for agriculture and the challenges involved. History offers valuable insights: indigenous peoples in the tropics and early agricultural societies improved soils using biochar and organic residues with remarkable results. However, today these methods carry risks, such as yield reductions in temperate zones or the spread of antibiotic resistance from intensive organic fertilisation. The second part of the talk explores, therefore, the balance between opportunities and risks in sustainable soil use, concluding with recent findings on how subsoils might help resolve this conflict.

How to cite: Amelung, W.: Ways out of the global soil crisis: opportunities and risks, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-3696, https://doi.org/10.5194/egusphere-egu25-3696, 2025.

Managing soils to increase organic carbon storage presents a potential opportunity to mitigate and adapt to global change challenges, while providing numerous co-benefits and ecosystem services. However, soils differ widely in their potential for carbon gains and losses, and advancing knowledge of biophysical limits to carbon accumulation may aid in informing priority regions for management. There is thus increasing interest in assessing whether soils exhibit a maximum capacity for storing organic carbon (i.e., carbon saturation), especially as mineral-associated organic carbon given its presumed greater persistence and the finite nature of reactive minerals in soils. In this award lecture, I will summarize my ongoing work on the controls and limits of mineral-associated organic carbon and its representation in process-based soil carbon models. First, I will provide an overview of the concept of soil carbon saturation at both micro- and macro-scales, address common misconceptions, and present a quantification of the maximum observed capacity of mineral-associated organic carbon globally. Next, I will show that organo-mineral associations can moderate the vulnerability of a soil to lose carbon under climate or land-use change. Finally, I will review the landscape of current ecosystem- to global-scale soil carbon models and highlight next steps for improving their structure and parameterizations in this context.

How to cite: Georgiou, K.: Limits, controls, and vulnerability of mineral-associated soil organic carbon, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-14372, https://doi.org/10.5194/egusphere-egu25-14372, 2025.

Integrated flood risk management requires an extension from hazard to risk analysis and an involvement of various stakeholders including the general public. Since no standard protocols for collecting data about flood-affected societies are in place, post-disaster surveys have been initiated to gain information from affected residents and companies. Using the most damaging flood events that have occurred in Germany since 2000 as examples, the lecture will address how data collected from flood-affected people have been used a) to develop and improve loss models, b) to better understand how and why people adapt to flood risk, c) to evaluate how people respond to warnings, d) to provide insights into flood-related health impacts and e) to comprehend how people recover from flood impacts. Since flood processes in Germany between 2002 to 2024 differed considerably, it will be addressed how much the flood type – in particular slow-onset river flooding, flash floods and pluvial floods – influence impacts and coping mechanisms. Research outcomes have informed flood early warning systems, risk communication and recovery programs in Germany and beyond. However, surveying or interviewing flood-affected people might also put an additional burden on them. Hence, the lecture will discuss some ethical considerations about collecting data in (highly) affected areas as well as some pros and cons of cross-sectional versus longitudinal survey designs. Finally, transfer to other regions and hazards will be highlighted.

How to cite: Thieken, A.: More than two decades of post-disaster household surveys to improve flood risk management, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-6429, https://doi.org/10.5194/egusphere-egu25-6429, 2025.

In this Ralph Alger Bagnold medal lecture I will present a tour of the world’s mighty and kilometers-thick ice sheets that existed in the last glacial. The journey will take us to palaeo ice sheets of North America, Greenland, Britain and Ireland, Scandinavia, northern Europe, Russia and Antarctica.  Having looked at glacial landforms in all these locations I will attempt to show what they tell us about processes of formation and the functioning of ice sheets.  There are some important lessons to help us forecast future ice sheets and sea level. For example, to what extent does the history of an ice sheet matter for its future dynamics and change? A theme will be on my four-decade journey, riding the wave of increasing spatial resolution which started with peering into the gloom of fuzzy satellite images. I will show that the renaissance in mapping, description and untangling of landform patterns have been pivotal in advancing knowledge. Further themes will include: the troublesome problem of scale; building large geomorphological and geochronological databases; reconciling field to continental-scale observations; numerical modelling of landform creation; and recent advances on integrating numerical ice sheet modelling approaches with empirical data sets.

I am likely to reflect (or rant) on some diversions such as on the third referee, the freedom of PhD research against grant deliverables, the need to study nature not books, that it takes a long time and many people to make progress on hard problems, and on the importance to geomorphology of a wide diversity of researchers in how they think.

How to cite: Clark, C. D.: Landforms in focus; riding the wave of increasing spatial resolution, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-6235, https://doi.org/10.5194/egusphere-egu25-6235, 2025.

Water is everywhere on the surface of Earth.  Water is also a key ingredient in geochemical processing of Earth.  Through plate tectonics water is cycled through the mantle and behaves as a flux for production of magmas.  The provenance of water on Earth appears straightforward.  Hydrogen and oxygen are the two commonest elements capable of forming molecules and so water is an expected species in the molecular cloud forming the solar system.  Water on Earth has been ascribed to late stage infall (comets and asteroids) although there are details that are only now being revealed.  Water can be characterised through its abundance, but also through isotopic compositions (D/H, 18O/16O, 17O/16O).

Our instrument of choice for carrying out these analyses is a large-radius secondary ion mass spectrometer, SHRIMP-SI, that was designed and built with water and oxygen isotopes specifically in mind.  The large radius allows high mass dispersion for separation of 16OH from 17O allowing coupled measurements of OH abundance and oxygen isotope compositions.  Much of the development of this instrument centered around excluding atmospheric water contamination, through differentially pumped chambers.  In rocks, water can be present from trace quantities to major contributions (>10 wt%) and so the detection system must be capable of a large dynamic range.  The charge-mode Faraday cup system was developed for this type of analysis.  Finally, the water background from mounting systems had to be controlled.  Epoxy mounts, thin sections, and even indium metal mounts can all show contamination.  Mounting of samples in molten BiSn allows a robust mounting material capable of being repolished and low inherent water background.

Our analytical work has followed two different routes: terrestrial geochemistry and solar system cosmochemistry.  Work in terrestrial samples has ranged from water concentrations in volcanic glasses through to low level water analyses in mantle and lower crustal melts.  But it is in the analysis of extraterrestrial samples where the coupled isotopes and water concentrations allow the greatest insight.  The low-level water concentrations in high-temperature objects like chondrules shows distinct three-oxygen isotope compositions and water concentrations.  

The ultimate question of where did water on Earth come from appears to have been solved through the recent sample return missions of Hayabusa 2 and Osiris REx.  These missions visited C-type asteroids, which were thought to be related to the carbonaceous chondrites.  But the C-type asteroids dominate the main asteroid belt and carbonaceous chondrites are quite rare.  Both Hayabusa 2 and Osiris REx recovered CI chondrite-like material, amongst the rarest subtype of carbonaceous chondrite.  The resolution of the abundance paradox comes down to the friability of the asteroid-return samples.  These materials simply do not survive atmospheric entry.  As such, it is likely that Earth received a large contribution of carbonaceous chondrite material during its formation and ongoing accretion of extraterrestrial material.

How to cite: Ireland, T.: The Provenance of Earth's Water, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-7562, https://doi.org/10.5194/egusphere-egu25-7562, 2025.

This presentation highlights some advancements in understanding plasma wave generation and wave-particle interactions in space plasmas. Utilizing data from the Van Allen Probes, we conducted a comprehensive analysis of whistler-mode chorus waves, revealing key properties such as source regions, element durations, and the role of magnetic field inhomogeneity. Further comparative studies of plasma waves across different planets provided crucial evidence supporting the universality of the TaRA model. Additionally, we discovered two distinct forms of energy coupling between plasma waves: between whistler-mode waves through wave beating, and between high-frequency electromagnetic ion cyclotron (EMIC) waves and magnetosonic (MS) waves, driven by anisotropic low-energy protons. These findings significantly enhance our understanding of space plasma dynamics and have broad implications for theoretical models and future research in the field.     

How to cite: Teng, S., Tao, X., and Yao, Z.: Advancements in Plasma Wave Generation and Wave-Particle Interactions in Space Plasmas , EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-1765, https://doi.org/10.5194/egusphere-egu25-1765, 2025.

In recent decades, an increasing number of spacecrafts have explored the Solar System with a wide range of on-board instruments that have acquired very different types of data to characterize planetary surfaces (topography, spectroscopy, optical imaging...). The best example is Mars, where several orbiters have explored its surface with a wide variety of instruments. These complementary instruments are the key to unravel the geological history of a planet, for which we need constraints on the age of the surface, its composition and its quantitative geomorphology.  Managing and combining this large and diverse dataset is challenging, but we can build on recent advances that now allow a virtual geological investigation of the surface of Mars. From these combined datasets, global and local studies have revealed the complex geological evolution of Mars, in particular the inventory of habitable sites across space and time. Virtual Martian geology is used not only to understand the evolution of Mars, but also to guide the selection of landing sites for in-situ rover missions. We will see how the combination of orbital data is used to down select a landing site for a rover mission, using the Exomars mission as an example, and how it also drives the long-term strategy of the rovers. With a particular focus on the Mars2020 mission, we will see how the combination of orbital data contributes to the diversity and relevance of the sample cache currently being collected on the surface of Mars by Perseverance for Mars Sample Return Program. 

How to cite: Quantin-Nataf, C.: Mars Geology: Virtual to real, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-15583, https://doi.org/10.5194/egusphere-egu25-15583, 2025.

This lecture provides a critical analysis of drought indices, emphasizing their role in evaluating drought severity while addressing the challenges associated with their application. It highlights the inherent complexity of drought assessment, given the multifaceted nature of drought phenomena, the various types of drought, and the intricate mechanisms underlying their development. A central focus is the distinction between drought and aridity, as well as between drought metrics and indices—concepts that are frequently misunderstood or conflated.

Particular attention is given to atmospheric drought indices, especially those incorporating atmospheric evaporative demand (AED). These indices are crucial for assessing water stress but have faced criticism for certain limitations. One notable issue is the "index-impact gap," where atmospheric drought indices often indicate more severe droughts than those reflected in hydrological and ecological metrics derived from Earth System Models (ESMs), particularly in future climate scenarios. Atmospheric indices do not directly account for soil moisture or vegetation dynamics. Nonetheless, AED reflects atmospheric conditions rather than direct water reservoirs and fluxes, making AED-based indices valuable for understanding atmospheric drivers of drought. This value is reinforced by AED's critical role in intensifying drought through increased evaporation, heightened plant water stress, and reduced photosynthesis.

The lecture further focuses into the uncertainties inherent in ESM projections of ecological and hydrological variables, such as soil moisture and runoff. These uncertainties arise because ESMs often underestimate drought severity due to challenges in simulating complex hydrological and physiological processes. The difficulties stem from limitations in modelling plant physiology, water cycles, and ecosystem responses, compounded by biases in key variables such as evapotranspiration. While ESM outputs are valuable for drought assessments, relying exclusively on them risks producing misleading conclusions.

This issue connects with the role of rising atmospheric CO₂ concentrations, a factor commonly incorporated into ESM simulations, which adds another layer of complexity. Elevated CO₂ levels can enhance plant water-use efficiency and photosynthesis but also introduce uncertainties regarding their impacts on evapotranspiration and soil moisture. These dynamics generate complex feedbacks with AED and other variables, further complicating drought severity assessments, particularly in future ESM simulations.

To address these challenges, the lecture advocates for an integrated approach that combines atmospheric drought indices with hydrological and ecological metrics. Such an approach ensures that the intensifying role of AED under global warming is neither overlooked nor overstated, thereby improving the accuracy of drought assessments, especially in the context of future climate scenarios.

How to cite: Vicente Serrano, S. M.: On the Use of Drought Indices for Drought Severity Assessment, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-1572, https://doi.org/10.5194/egusphere-egu25-1572, 2025.

Tectonic-scale geological phenomena are fundamentally controlled by nanoscale physiochemical mineral processes. Understanding these processes across multiple length scales is crucial for determining how mass and stress are transferred during tectonism. Minerals exhibit complex structure-property relationships that govern their mechanical and chemical behaviour, yet these relationships have been historically underexplored in Earth sciences. Advances in nanotechnology and instrumentation, including techniques such as high-resolution electron backscatter diffraction, electron channeling contrast imaging, transmission electron microscopy, and atom probe tomography, now enable unprecedented investigations of nanoscale features in geomaterials. The correlative approach has given rise to the emerging field of nanogeology, which helps bridge the gap between nanoscale and tectonic-scale processes. Recent nanoscale investigations have demonstrated the fundamental role of structural defects and element mobility in controlling the mechanical properties and deformation behaviour of minerals in the brittle-ductile regime. For example, detailed microanalyses of garnet reveal a novel precipitation hardening mechanism where Fe diffused along grain boundaries of recrystallized garnet, nucleating Fe-rich nanoclusters. These clusters act as barriers to dislocation migration, resulting in localized strain hardening. This process provides a potential mechanism for mechanical strengthening in the lower continental crustsubsequently influencing large scale geodynamic processes. Similar investigations of pyrite, a critical metal-bearing sulfide mineral, reveal nanoscale fluid inclusions that facilitate the diffusion of trace elements into crystalline defects, such as dislocations, inhibiting their movement, and leading to mineral hardening. Such findings are particularly significant, as the brittle-to-ductile behaviour of sulfides has been directly linked to the upgrading of critical metal deposits. These discoveries highlight the dynamic interplay between nanoscale element mobility and the rheology of minerals, and by consequence, larger mass transfer dynamics. Moreover, deformation-driven element redistribution raises questions about the reliability of deformed minerals as petrological tools. For instance, the deformation of zircon may compromise its use as a robust geochronometer, whereas the deformation of garnet may influence its reliability as a thermobarometer. A deeper understanding of element mobility in the presence of defects is essential for accurately interpreting geochemical data and reconstructing tectonic histories. Overall, these breakthroughs highlight the pivotal role of nanoscale processes in shaping tectonic phenomena, emphasizing the need for a multi-scale approach to understanding Earth's dynamic behaviour.

How to cite: Dubosq, R., Schneider, D., Rogowitz, A., and Gault, B.: Scaling up: Nanoscale insights into tectonic phenomena , EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-4567, https://doi.org/10.5194/egusphere-egu25-4567, 2025.

Understanding the physical processes and interactions that govern the dynamics of the seafloor is key to unraveling the fundamental mechanisms of the marine lithosphere and its boundaries. These processes not only shape the ocean floor but also influence a variety of geohazards that pose significant risks to coastal communities.

One of the greatest challenges in marine geosciences is to identify the locations and underlying causes of marine geohazards. To achieve this, we need a multidisciplinary approach and comprehensive, multi-sensor geophysical measurements that integrate observations of the seafloor conditions and the complex interactions of sub-seafloor processes that lead to these events. This includes a detailed understanding of the physical, chemical, and mechanical factors that drive natural hazards including earthquakes, tsunamis, and volcanic eruptions. Seafloor processes, from tectonic movements to crustal deformation to magmatic activity, are central to understanding how these phenomena occur.

Recent advancements in marine geophysical research, particularly in seafloor geodesy, ocean bottom array seismology, and micro-bathymetry have allowed for the quantification of seafloor processes and their dynamic changes under tectonic stress. The majority of large (magnitude Mw>8.5) earthquakes occur in subduction zones. The associated surface deformation is concentrated at the seafloor and is often coupled with the triggering of tsunamis. The seabed therefore harbors information about tectonic stress and elastic deformation. This information is crucial for early warning concepts and can be methodically analyzed using seafloor geodesy in conjunction with seismic and earthquake studies. The plate boundary offshore northern Chile is one of the seismically most active regions on the globe and is the site of comprehensive multi-sensor seafloor monitoring. The integrated data analysis revealed co-seismic stress changes and aftershock activation of extensional faulting of the upper continental plate, indicative of active subduction erosion during the co-seismic and post-seismic phase. One of the most striking findings is the correlation of the seismogenic up-dip limit with a pronounced decrease in plate boundary reflectivity. High-resolution in-situ strain measurements from seafloor geodetic arrays monitor the tectonic stress build-up across the subduction zone, which is characterized by very low rates during the interseismic phase. Tectonic stress build-up across a plate boundary was also monitored along the offshore segment of the North Anatolian Fault Zone in the Sea of Marmara, revealing a significant slip on this fully locked segment.   

Looking ahead, marine geophysical research is poised to expand significantly, addressing new challenges and utilizing new technologies and methods across disciplines. The next generation of seabed monitoring systems will use real-time data analysis and underwater acoustic communication in autonomous ‘smart’ networks for targeted monitoring. On a broader scope, the utilization of existing telecommunication systems has the potential to profoundly change solid earth monitoring. These observations may also elucidate potential preparatory phases of major subduction earthquakes, detect landslides on coastal slopes, and monitor largely unknown submarine volcanic activity. Operational real-time access will reduce earthquake and tsunami early warning delays significantly.

How to cite: Kopp, H.: The Dynamic Seafloor: Enhancing Our Knowledge of Seafloor Processes, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-4841, https://doi.org/10.5194/egusphere-egu25-4841, 2025.

Very Long Baseline Interferometry (VLBI) is a truly global scientific effort that demands rigorous coordination among a network of telescopes distributed worldwide. Central to this collaboration is the generation and distribution of a synchronized observation plan, a task typically called scheduling. Given a network of telescopes, a catalog of celestial sources, and a constrained time window, the goal of scheduling is to find an optimal sequence of observations to achieve the best possible scientific outcomes.

The complexity of this task arises from the virtually infinite number of potential schedules, making it practically impossible to find the most perfect solution. Instead, the objective is to generate a schedule that balances quality with practical constraints. Additionally, numerous optimization criteria must be considered, such as maximizing the number of observations for increased redundancy, ensuring a well-distributed coverage in azimuth and elevation angles to mitigate atmospheric effects, and achieving a balanced distribution of observations across the network and sources to enhance the parameter estimation process. Unfortunately, many of these criteria are in direct conflict with each other, further complicating the optimization process.

However, the importance of optimized scheduling cannot be overstated, as it directly determines the data available for analysis and, consequently, the quality of the scientific results. In recent years, significant progress has been made in VLBI scheduling algorithms. State-of-the-art practices involve generating hundreds of potential schedules for each experiment and using simulations to evaluate and select the optimal one. Nowadays, developing advanced scheduling algorithms requires a multifaceted approach, encompassing the creation of logical observation sequences, the generation of high-quality simulations, and the application of cutting-edge analysis and parameter estimation techniques. Additionally, new observing scenarios emerging from upcoming satellite missions, e.g. Genesis, combined with the more interdisciplinary application of VLBI resources, are fundamentally changing scheduling optimization objectives.

In this lecture, I will give a brief introduction to VLBI scheduling, highlighting its unique and exciting challenges. I will discuss recent advancements in scheduling algorithms and their impact on VLBI science. Furthermore, I will provide insights into future challenges and opportunities.

How to cite: Schartner, M.: The art of VLBI scheduling, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-6899, https://doi.org/10.5194/egusphere-egu25-6899, 2025.

Gravity measurements and geoid determination is a fundamental pillar of geodesy, and despite of roots going back more than two centuries, it is still a very active research field, with satellite and airborne data collection finally making global detailed gravity field coverage and thus a few-cm accuracy geoid within reach, a holy grail of geodesy for decades. Recent years have seen major efforts to cover the most inaccessible areas of the planet with gravity, especially the polar and mountainous areas, thanks to the development of airborne gravity sensors and long-range data campaigns. Parallel with this, climate applications of gravity measurements, both in space and in situ, have made gravity field change measurements more relevant than ever, especially for understanding global sea level rise and the melting of the large icesheets. Ongoing R&D in developing quantum methods for both in-situ, kinematic and space applications further points to new directions and applications for geodetic, geophysical and environmental applications of gravity field data, securing gravity field science key developments in the years to come. The Vening-Meinesz talk will address many recent developments in the above fields, and highlights the new opportunities for the next generation of geodesists.   

How to cite: Forsberg, R.: Gravity, Climate and Quantum, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-14370, https://doi.org/10.5194/egusphere-egu25-14370, 2025.

The process of new particle formation from gas-phase precursors holds significant importance in Earth's atmosphere and introduces a notable source of uncertainty in climate change predictions. Typical conditions for new particle formation are moderate temperatures, clear sky and low background aerosol contamination. This general paradigm was challenged by the puzzling observation of frequent new particle formation in megacities. The pre-existing aerosol loadings in such environments seemed to be too high to allow clusters of being formed and grow fast enough before they encounter a collision with a background particle and get lost from the number budget.

Here, we show how nanoparticle growth in urban atmospheres is facilitated enabling efficient survival of nanoclusters providing an explanation for the occurrence of NPF in heavily polluted environments. We outline the tool set, which we have developed over the recent years to address this puzzle. Significant uncertainty in the particle number size distribution measurements and growth rate estimates were addressed through new instrumentation and analysis approaches. At the same time, we refined growth models to account for the challenges of a wide variety of potentially condensable vapors and updated our understanding of particle survival in the atmosphere.

We could demonstrate that new particle formation takes a decisive role in air quality issues in megacities, especially as nanoparticles seem to grow at surprisingly constant rates even when no new particle formation is observed. The “unique atmospheric experiment” of the Covid-19 lockdowns finally provided the chance to estimate how sensitive the urban environment is to changes in the atmospheric chemistry, especially with respect to new particle formation. While we speculated that other condensable vapors than previously thought could be part of the puzzle, we can finally show that also the population dynamics are crucial for more efficient nanoparticle survival than previously thought. However, severe challenges remain, as the outlined methodological improvements also revealed that sometimes the little ones even grow slower than expected.

How to cite: Stolzenburg, D.: How do the little ones grow? Solving the puzzling occurrence of new particle formation in megacities, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-2853, https://doi.org/10.5194/egusphere-egu25-2853, 2025.

Clouds are fascinating objects because of their myriad shapes and the optical phenomena that they cause. They are also scientifically challenging to understand because their formation and dissipation require knowledge about both the large-scale meteorological environment as well as about the details of cloud droplet and ice crystal formation on the microscale. While we have reduced the uncertainty in the radiative forcing of aerosol-cloud interactions over the last decades, the effect of climate change on clouds, precipitation forecasts and cloud dynamics still pose lots of open questions.

With the advancement of better in-situ and remote sensing instruments, unprecedented observations of clouds are now possible. Simultaneously, the increasing amount of computing power enables us to simulate clouds at increasingly finer scales over larger domains, making convection parameterizations obsolete and allowing us to resolve larger eddies. Cloud research is also being revolutionized by machine learning. We have used machine learning in combination with satellite data to disentangle the response of stratocumulus clouds to aerosol perturbations, for understanding how cirrus clouds respond to the presence of mineral dust as well as for classifying ice crystals down to aggregated monomer scale in in-situ measurements.

We have exploited these advancements in our CLOUDLAB project, where we employed cloud seeding technology to better our understanding of mixed-phase cloud processes: by releasing silver iodide-containing particles from uncrewed aerial vehicles in supercooled low stratus clouds over the Swiss plateau, we were able to observe and measure downstream ice crystals in a controlled way. From these measurements, we quantifed their diffusional growth rates, aggregation rates and riming rates. Additional high-resolution modeling supported the experiments and provided insights for weather forecasts and climate projections. The CLOUDLAB results can also be translated to the potential climate mitigation idea of thinning mixed-phase clouds.

I have great hope that the open questions in cloud research will be tackled by a combination of advanced measurement devices, AI-driven methods, and further advances in computing power enabling high-resolution modeling.

How to cite: Lohmann, U.: From the microscale to climate: combining observations, laboratory data, and numerical simulations for aerosol-cloud interactions, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-5678, https://doi.org/10.5194/egusphere-egu25-5678, 2025.

The amount of CO₂ taken up by plants (gross primary production) is the largest flux in the terrestrial carbon cycle. However, the uncertainty in how much CO₂ plants absorb is larger than annual anthropogenic CO₂ emissions. This means that small changes in plant uptake could drastically alter the carbon balance, making climate predictions more challenging. A better understanding of the terrestrial carbon cycle is essential for predicting future climate conditions and atmospheric CO₂ mole fractions. Stable isotope measurements of CO₂ (δ¹³C and δ¹⁸O) provide valuable insights into the magnitude of CO₂ fluxes between the atmosphere and biosphere.

Recent advancements in measurement techniques have made it possible to measure ∆^′17O in atmospheric CO₂ with high precision. These high-precision measurements provide valuable constraints on terrestrial carbon fluxes that δ¹³C and δ¹⁸O alone could not achieve. This is because ∆^′17O(CO₂) has a known stratospheric source, its variations are much smaller than those of δ¹⁸O, and conventional biogeochemical processes follow a well-defined three-isotope fractionation slope. Additionally, the triple oxygen isotope fractionation slopes for specific processes are independent of source water isotope composition, insensitive to temperature, and process specific.

In this talk, I will discuss the broader applications of ∆^′17O in atmospheric CO₂ research, the challenges associated with high precision ∆^′17O measurements, the latest advancements in measurement techniques, and future implications for studying the terrestrial carbon cycle.

How to cite: Adnew, G. A.: ∆′17O of Atmospheric CO2 as a tracer for gross fluxes of terrestrial carbon cycle, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-3819, https://doi.org/10.5194/egusphere-egu25-3819, 2025.

The ocean carbon cycle is a critical component of the climate system. Each year, the ocean absorbs approximately a quarter of the CO₂ emitted to the atmosphere from human activities, playing a vital role in mitigating climate change. The ocean will ultimately sequester the majority of these emissions over centuries and beyond, thus regulating atmospheric CO₂ concentration and climate stabilisation in the long term. Understanding the mechanisms and drivers of the observed trends and variability in ocean carbon storage is therefore essential for reducing uncertainty in long-term climate projections.

Trends and variability in ocean carbon storage arise from a complex interplay of factors, including atmospheric CO₂ growth, warming, ocean acidification, physical ocean dynamics, and marine ecosystem changes. While the physico-chemical effects of warming and ocean acidification on the ocean carbon cycle are well-known, the impacts of large-scale changes in ocean circulation remain less well understood. Notably, shifts in surface winds over the Southern Ocean and a weakening Atlantic Meridional Ocean Circulation could induce important changes in carbon storage that are poorly quantified. Changes in marine ecosystems under multiple stressors and their effect on the marine carbon cycle remain poorly constrained and were categorized as a “known-unknown” in the last four assessment reports of the Intergovernmental Panel on Climate Change (IPCC).

In this lecture, I will synthesise recent understanding of the drivers of trends and variability in ocean carbon storage, focusing on timescales ranging from years to centuries. I will present new insights into how marine ecosystem shape carbon dynamics and discuss how changes in ecosystems could influence the ocean carbon storage well beyond 2100. These insights underscore the need to develop new and better integrated “Ocean Systems Models” that include more detailed representations of marine ecosystems and their interactions with biogeochemical cycles.

How to cite: Le Quéré, C.: Carbon storage by the ocean in a changing climate, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-9776, https://doi.org/10.5194/egusphere-egu25-9776, 2025.

Accurately modeling emerging physical climate risks to natural and societal systems—such as global supply chains, the food system, health, and critical infrastructures—is essential for effective preparedness and honest discussions about the consequences of rising greenhouse gas emissions.

A series of anomalous weather events that shattered previous records by wide margins has —yet again—highlighted the need for an improved understanding of the physical processes behind weather and climate extremes, their statistical characteristics, and our ability to project them under future emission scenarios using climate models.

In this Award lecture, I will present an overview of recent studies and preliminary findings that explore the mechanisms and physical drivers of high-impact climate extremes, as well as their statistical characteristics, such as simultaneous or sequential occurrences, which can lead to high societal impacts under current and future climate conditions and will reflect on our capacity to reproduce such events in climate models.

How to cite: Kornhuber, K.: Physical drivers and statistical properties of high impact climate extremes , EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-16597, https://doi.org/10.5194/egusphere-egu25-16597, 2025.

Induced seismicity is likely a major obstacle in front of the widespread deployment of geoenergy applications, such as geothermal energy or geologic carbon storage (GCS), which are indispensable components of efforts to mitigate the climate change emergency. Induced earthquakes may jeopardize the integrity of subsurface structures and, if felt at the surface, negatively impact the public perception of geoenergy projects. Thus, the effective and safe use of the subsurface to provide clean and sustainable energy and reduce atmospheric carbon emissions needs to properly address the risks and hazards posed by induced seismicity. In this Outstanding Early Career Scientist ‎Award Lecture of the ERE‎ Division, I discuss some important topics of induced seismicity in low-carbon geoenergies. First, I explain the potential mechanisms of seismic events that are unexpectedly induced far away from and/or long after operations related to geothermal energy developments. Such seismic sequences have been found problematic because of partial loss of control over their management. In particular, ‎thermal stress is key in reactivating distant faults from a fluid circulation doublet after several years ‎of operation in hydraulically bounded and unbounded hot deep sedimentary aquifers. The observed delays can be explained by the relatively large characteristic time scales of thermal effects (small thermal diffusivity). In enhanced ‎geothermal systems, a sequence of processes, which can be identified when explicitly including fractures in numerical models, may give rise to post-injection seismicity. The stabilizing effect of poroelastic stress generated during reservoir ‎stimulation rapidly attenuates after stopping injection, while the injection overpressure gradually diffuses ‎away, which could bring distant faults to slip conditions with time delays as long as several months. Interestingly, bleed-off, i.e., ‎flow back to relieve wellbore pressure,‎ as an industrial practice to prevent post-injection seismicity may not effectively work under certain conditions. This is because the ‎stimulated fractures become progressively less responsive to hydraulic perturbations with distance from ‎the wellbore. In the second part of my presentation, I discuss induced seismicity within GCS at the gigatonne scale. Analysis of data from the global, multiphysics database of induced seismicity underscores some similarities between large-scale GCS and massive wastewater disposal that led to a drastic rise in seismic activity in central and eastern US in the 2010s – not to negate fundamental differences between the two technologies. Although GCS at the megatonne scale has been extensively demonstrated, its scale-up could face elevated risk of induced seismicity. We have developed the open-source tool CO2BLOCKSEISM that employs simplified physics models for screening subsurface CO₂ storage resources at regional scales constrained by the risk of induced seismicity. The tool’s application is shown within the Utsira storage unit in the North Sea. Induced seismicity draws a more restrictive and ‎realistic limit to the storage resource use at regional than at single-site scales. I conclude that reliable methodologies for induced seismicity forecasting and mitigation should be developed in light of the underlying physics and continuous characterization of the subsurface during operations to safely unlock the huge potential of the subsurface for a timely approach toward climate targets.

How to cite: Rahimzadeh Kivi, I., Makhnenko, R., Min, K.-B., Rutqvist, J., Carrera, J., Krevor, S., and Vilarrasa, V.: Energy transition and the challenge of induced seismicity, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-13579, https://doi.org/10.5194/egusphere-egu25-13579, 2025.

High mountain environments are disproportionately affected by climate change. Around the world, mountain glaciers are retreating, leaving unstable sediments behind. Thawing permafrost and changing rainfall conditions make many mountain slopes unstable and increase natural hazards. Plants colonize the newly available terrain, but also need to shift upslope to survive rising temperature, threatening biodiversity. What will happen in the future? Might unstable sediments and moving slopes limit plant colonization and shifts? Or can colonizing and shifting plants actually stabilize moving sediments and slopes? This depends on biogeomorphic feedbacks!

In this award lecture, I will take you on a journey through recent finding and advances in “mountain biogeomorphology”, the discipline investigating feedbacks between moving mountain slopes and dynamic mountain plants. Our journey will start in the front of retreating glaciers. Here, I will illustrate the strong biogeomorphic feedbacks between paraglacial geomorphic processes and vegetation succession, mediated by “ecosystem engineer” plants that not only stabilize moving moraine slopes but also promote periglacial landform development, soil formation and vegetation succession.

In a second part, I will evaluate the role of biogeomorphic feedbacks in a changing climate. Using a “biogeomorphic balance” concept, we will assess how biogeomorphic feedbacks can influence future slope movements, vegetation shifts, natural hazards and biodiversity in different scenarios. Finally, I will take you to the current research frontiers in mountain biogeomorphology. I will illuminate the yet not fully understood role of plant traits and sediment properties as key controls for biogeomorphic feedbacks. Subsequently, we will explore how increasing data availability and novel methods, including artificial intelligence (AI) techniques, can help to unravel biogeomorphic feedback mechanisms and dynamics. Thereby, mountain biogeomorphic research can advance understanding and mitigation of climate change impacts on high mountain environments.

How to cite: Eichel, J.: Feedbacks between moving mountain slopes and dynamic mountain plants, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-16685, https://doi.org/10.5194/egusphere-egu25-16685, 2025.

The geological water cycle (or the deep water cycle) consists of water-rock interactions between the hydrosphere/atmosphere and lithosphere. This water plays a critical role in geological processes, for example, promoting melting and the formation of new continental crust, the mobilisation of economic metals, rock reactivity and rheology, and seismic activity. In the modern day, the most dominant form of the geological water cycle is the uptake of water in mantle-derived rocks in the oceans, and release of this water during subduction to melt overlying lithologies and form volcanic arcs. In the Archean, however, the geological water cycle is less well understood. This is particularly because (i) there are rare ophiolites from this timeframe, and lithologies responsible for water uptake and release may have been different and (ii) because the mode of tectonics is argued, meaning that the geodynamics and therefore conditions of water release are not well understood.

This presentation will focus on the processes of hydration and dehydration of ultramafic to mafic rocks from Archean greenstone belts (komatiites and komatiitic basalts). Geochemical evidence suggests that these rocks were initially hydrated on an Archean oceanic plateau after their eruption. During this process, they sequestered mobile elements such as boron from the seawater, and produced molecular H₂ by the oxidation of Fe, a possible source of energy for early chemosynthetic life. Most greenstone belts have been metamorphosed to greenschist-amphibolite facies, indicating that they experienced some form of burial during Earths earlier history. Phase equilibria modelling shows that if komatiites are buried to higher temperature conditions (>750 °C), the breakdown of hydrous phases could release significant quantities of water into the surrounding rocks, promoting fluid-fluxed melting of surrounding lithologies. In the case of the Barberton Greenstone Belt, which contains ~8 % komatiite and ~20% basalt by volume, fluid release from the komatiite into the basaltic lithology would promote wet melting of basalts to form tonalite-trondhjemite-granodiorite (TTG) series rocks, important constituents of Archean continental crust.  While not abundant in the geological record, the role of ultramafic rocks in the Archean geological water cycle is evident, as is their importance in ocean floor processes and the formation of the Earth’s first TTG crust.

How to cite: Tamblyn, R. and Hermann, J.: The Archean geological water cycle , EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-13998, https://doi.org/10.5194/egusphere-egu25-13998, 2025.

Seismic anisotropy -- the directional dependence of seismic wave speeds -- provides a unique view into the past and present deformation of Earth's interior. However, constraining Earth's anisotropic heterogeneity remains a challenge primarily due to imperfect data coverage combined with the increased number of free parameters required to describe elastic anisotropy. And yet, exploring this more complex model space is critical for the interpretation of seismic velocity anomalies which may be significantly distorted if anisotropy is neglected. In this presentation, I will review new imaging strategies, developed by myself and colleagues, for constraining 3D anisotropic structures and their application to studying subduction zone dynamics and volcanic processes. Key developments include moving beyond simplified assumptions regarding the orientation of anisotropic fabrics (i.e. from azimuthal and radial parameterisations to tilted-transversely isotropic models), the integration of multiple and complementary seismic observables (P and S body wave arrivals, shear wave splitting measurements, and surface wave constraints), and the use of probabilistic inversion algorithms that allow for rigorous exploration of model uncertainty and parameter trade-offs. I will discuss how applying these imaging approaches to subduction systems in the central Mediterranean and Western USA yields new insights into the geometry of mantle flow, the nature of seismic velocity heterogeneity, and trade-offs between isotropic and anisotropic features. At smaller scales, I will highlight how new anisotropic tomography reveals the structure of the magmatic plumbing system beneath Mt. Etna (Italy) and provides constraints on the geologic processes controlling crustal stresses.

How to cite: VanderBeek, B.: Improved Strategies for Seismically Imaging Earth's Anisotropic Interior with Applications to Subduction Zones and Volcanic Systems, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-17444, https://doi.org/10.5194/egusphere-egu25-17444, 2025.

Coronal mass ejections (CMEs) are large-scale eruptions of magnetized plasma from the Sun's lower atmosphere, significantly influencing space weather and planetary environments. To improve predictions of CME arrival and their impacts on Earth and its surroundings, a deeper understanding of their origins, initiation, and complex early evolution is crucial. While coronagraphic observations have been essential for studying the dynamics of CMEs, they cannot capture the initial, critical phase of CME development. Consequently, investigating indirect phenomena in the lower solar atmosphere has become essential. One of the most prominent indirect indicators associated with CMEs is coronal dimming. These are localized, sudden decreases in coronal emission observed at extreme ultraviolet and soft X-ray wavelengths, which evolve rapidly during the lift-off and early expansion phases of CMEs. Coronal dimmings have been interpreted both as “footprints” of the erupting magnetic structure and as indicators of coronal mass loss in the lower corona.

I will review recent advancements in using coronal dimmings to diagnose CMEs. Topics covered will include statistical studies linking dimming characteristics to CME mass and speed, the use of dimmings as early indicators of CME propagation direction, and insights into the magnetic topology and reconfiguration of the early CME stages based on dimming locations and fine structure. Additionally, the potential role of dimmings in the pre-event phase preceding CME onset will be discussed. Finally, I will highlight future research directions and underexplored areas in CME science, emphasizing the untapped potential of coronal dimmings in advancing our understanding of these dynamic solar events.

How to cite: Dissauer, K.: Footprints of Giants – Exploring Early Diagnostics of Coronal Mass Ejections Through Coronal Dimmings, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-17289, https://doi.org/10.5194/egusphere-egu25-17289, 2025.