With rising anthropogenic pressures, there is an increasing risk of the human-Earth system hitting the ceiling of some of the self-regulating feedbacks of the Earth System, and of crossing tipping points in the large ice sheets, atmosphere-ocean circulation systems (e.g. the Atlantic Meridional Overturning Circulation) and biomes such as the Amazon rainforest. Transgressing these critical thresholds in human pressures such as greenhouse gas emissions and land-use changes could trigger large-scale and often abrupt and irreversible impacts on the biosphere and the livelihoods of millions of people. Potential domino effects or tipping cascades could arise due to the interactions between these tipping elements and lead to a further decline of Earth resilience. At the same time, there is growing evidence supporting the potential of positive (social) tipping points that could propel rapid decarbonization and transformative change towards global sustainability.
In this session, we invite contributions on all topics relating to Earth resilience, tipping points in the Earth system, positive (social) tipping, as well as their interactions and potential cascading domino effects. We are particularly interested in diverse methodological and quantitative approaches, from Earth system modelling to conceptual modelling and data analysis of nonlinearities, tipping points and abrupt shifts in the Earth system.
Orals: Mon, 28 Apr | Room F1
Palaeorecords indicate that global temperatures have been relatively stable for the past ~10,000 years of the Holocene epoch, in contrast to cooling trends during previous interglacials and multiple abrupt shifts during past glacials. Hypotheses for this seeming stability range from early anthropogenic emissions to orbital factors or the timing of carbon cycle feedbacks. An alternative suggestion grounded in dynamical systems theory is that Holocene stability reflects the Earth system residing in a climate ‘attractor’, with strong negative feedbacks acting to stabilise the climate’s state, and glacial/interglacial cycling representing either a limit cycle or tipping between interglacial and glacial attractors. This in turn has led to the more recent hypothesis that human actions are eroding the resilience of the Earth system’s current state, and at some level could be sufficient to tip the whole Earth system into a warmer “Hothouse Earth” attractor. However, despite multiple hypotheses for Holocene stability, that the Earth system is close to the edge of a dynamical attractor is often assumed rather than demonstrated. Here, I review the basis for the Holocene climate attractor hypothesis in the literature, and assess to what extent there is sufficient evidence to support it versus other possibilities. I then outline what additional evidence might be needed, and consider how Earth system states and resilience can be alternatively conceptualised.
How to cite: Armstrong McKay, D.: Holocene stability: climate attractor, or lucky break?, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-19647, https://doi.org/10.5194/egusphere-egu25-19647, 2025.
Recently, Wunderling et al., (2024) reviewed the current knowledge on climate tipping interactions and cascades, which highlighted lacking knowledge on the interaction between the AMOC and northern high-latitude permafrost carbon loss – labeled with ‘very limited/missing evidence’ for their interaction strength and direction. Here, we investigate the response of permafrost-carbon to idealized climate stabilization and overshoot scenarios with different modeling approaches ranging from complex to simplified Earth system models (ESM, LSM and SCM). Net warming in these mitigation scenarios results in irreversible loss of soil carbon from permafrost regions, even after achieving net-zero emissions. However, Northern Hemisphere regional cooling from a temporary slowdown or collapse of the AMOC partially negates the release of permafrost carbon. Our modeling approach allows for the first time to illustrate and quantify a stabilizing negative feedback loop between the AMOC and permafrost, whose effectiveness ranges between 30-60% of permafrost carbon loss reduction if the critical temperature for AMOC tipping is crossed.
[Wunderling, N., von der Heydt, A. S., Aksenov, Y., Barker, S., Bastiaansen, R., Brovkin, V., Brunetti, M., Couplet, V., Kleinen, T., Lear, C. H., Lohmann, J., Roman-Cuesta, R. M., Sinet, S., Swingedouw, D., Winkelmann, R., Anand, P., Barichivich, J., Bathiany, S., Baudena, M., Bruun, J. T., Chiessi, C. M., Coxall, H. K., Docquier, D., Donges, J. F., Falkena, S. K. J., Klose, A. K., Obura, D., Rocha, J., Rynders, S., Steinert, N. J., and Willeit, M.: Climate tipping point interactions and cascades: a review, Earth Syst. Dynam., 15, 41–74, https://doi.org/10.5194/esd-15-41-2024, 2024.]
How to cite: Steinert, N. J., Burke, E., Schwinger, J., Zhu, B., Gasser, T., Munday, G., Mathison, C., and Lee, H.: Negative AMOC tipping feedback on permafrost carbon in climate mitigation scenarios , EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-18398, https://doi.org/10.5194/egusphere-egu25-18398, 2025.
Climate tipping elements like the Atlantic Meridional Overturning Circulation (AMOC) and the Amazon Rainforest (AR) are critical components of the Earth system that currently both show declining trends in their resilience due to anthropogenic climate change and other human disturbances such as deforestation. A shutdown of the AMOC or a large-scale dieback of the AR would have severe impacts on a global scale. Additionally, AMOC and AR are not independent from each other but disturbances from one system can propagate to the other. The sign and strength of this interaction has so far been classified as unknown by recent literature surveys. Using causal discovery and inference methods on observational and reanalysis data, we find that AMOC weakening increases precipitation in the Southern Amazon during the critical dry season. Specifically, a 1 Sv AMOC weakening results in 4.8% additional dry season precipitation, amounting to a 16.5% increase under the current estimated 3.45 Sv AMOC weakening since 1950. These findings, supported by multiple data sources, suggest that the Southern AR drying trend due to global warming and deforestation, which amounts to 4 mm/year since 1982, would be even more severe without concurrent AMOC weakening. Our results demonstrate the potential of causal discovery in the data-driven study of tipping element interactions and contribute to the understanding of coupled AMOC-AR dynamics, with the potential to improve assessments of climate tipping risk under ongoing global warming.
How to cite: Högner, A., Di Capua, G., Donges, J. F., Donner, R. V., Feulner, G., and Wunderling, N.: Causal pathway from AMOC to Southern Amazon Rainforest indicates stabilising interaction between two climate tipping elements, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-8514, https://doi.org/10.5194/egusphere-egu25-8514, 2025.
The Amazon rainforest and the Atlantic Meridional Overturning Circulation (AMOC) are two crucial components of the Earth system that may be on tipping course. As the world’s largest tropical rainforest, the Amazon is a major carbon sink and biodiversity reservoir. Therefore, its transition into a savanna under the pressure of climate change may have large-scale consequences. The AMOC plays an important role in the global meridional heat transport and may collapse due to greenhouse gas emissions. This would, among other consequences, alter the ocean-induced moisture inflows over the Amazon rainforest, where precipitation over certain areas may increase and decrease over other areas.
Resilience of the Amazon is here defined as the ability of the Amazon rainforest to remain in a rainforest regime or to return to this state, against perturbations that may bring it towards a savanna-like state. Our objective is to analyse the resilience of the Amazon rainforest with respect to a collapse of the AMOC. More precisely, we study the interaction between the Amazon rainforest and AMOC in a conceptual coupled. We have estimated parameter values (such as mean annual precipitation) of the Amazon rainforest dynamics from a AMOC collapse experiment carried out in a CMIP5 global model (CESM1).
The notion of resilience we consider here is solely based on footprints extracted from an ensemble of AMOC tipping trajectories. It is difficult to simulate many instances of an AMOC collapse because of the rarity of such event. We overcome this problem using a rare-events algorithm, Transition-Adaptive Multilevel Splitting (TAMS), that iteratively pushes trajectories towards a tipping, however unlikely it is, until obtaining an ensemble of tipped trajectories and the corresponding probability of tipping. This algorithm allows us to obtain an ensemble of simulations where the Amazon rainforest tips (i.e. loses resilience) under the influence of the AMOC, at a much lower computational cost than with Monte-Carlo simulations. From this ensemble, we can then extract from this ensemble, footprints characterizing the behaviour of the system as it is losing resilience. With this approach, we can precisely quantify the resilience of the Amazon rainforests to changes induced by an AMOC collapse.
How to cite: Jacques-Dumas, V. and Dijkstra, H. A.: Resilience of the Amazon rainforest to an AMOC collapse, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-13909, https://doi.org/10.5194/egusphere-egu25-13909, 2025.
Deforestation in the Amazon has been predicted to cause irreversible forest dieback, primarily due to significant reductions in mean precipitation driven by decreased evapotranspiration. However, these results are based on conventional climate models that use convective parameterizations and/or limited boundaries, leading to precipitation with high sensitivity to evapotranspiration and restricted large-scale interactions. To overcome these limitations, we use a storm-resolving global climate model run at a 5km grid spacing to simulate the response of precipitation to complete deforestation over the Amazon basin. We find no significant change in annual precipitation and a distinct spatial pattern of precipitation change compared to previous studies. This suggests that the Amazon may be more resilient to deforestation than previously thought. However, we do observe an increase in the intensity of extreme hourly precipitation at both ends – no rain and violent rain – after deforestation, indicating potential risks to the forest ecosystem. We identify key mechanisms that differentiate the storm-resolving model from previous conventional models, highlighting the missed basic physical processes in previous studies, which distorted their response to precipitation to Amazon deforestation. Additionally, we underscore the importance of considering short-term precipitation, often masked by long-term averages, to more accurately evaluate the impacts of deforestation.
How to cite: Yoon, A. and Hohenegger, C.: The fate of Amazon precipitation after massive deforestation, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-3432, https://doi.org/10.5194/egusphere-egu25-3432, 2025.
Tropical forest and savanna frequently coexist under the same climatic conditions, which has led to the hypothesis that they could represent alternative ecosystem states, stabilized by internal feedbacks. An implication of this hypothesis is that forest and savanna may be bistable and exhibit tipping behavior in response to changing conditions. However, we pose that the local presence of forest and savanna within coexistence landscapes is not sufficient evidence that these are alternative stable states at larger ecosystem scales. Therefore, we explore forest-savanna coexistence and bistability at landscape scale in Central Africa. Using remote sensing data on tree cover, we classify 10 x 10 km landscapes as homogeneous forest, homogeneous savanna, or coexistence, and analyze the factors driving their distributions. We find that the precipitation ranges for which homogeneous forest and savanna occur have only limited overlap, and that this overlap can largely be explained by other external drivers, such as seasonality, soil sand content, and elevation. Conversely, local coexistence of forest and savanna under the same climatic and edaphic conditions is common within landscapes. In these coexistence landscapes, however, the spatial configuration of tree cover can often be predicted based on topographic variables, indicating that the apparent bistability of forest and savanna is likely caused by local redistribution of resources, rather than internal feedbacks. Considering the limited evidence found for forest and savanna as true alternative ecosystem states, particularly at landscape scale, we conclude that the likelihood of tipping between both states may be lower than previously thought. Intermediate coexistence states, facilitated by topographic heterogeneity, may lead to more gradual and reversible transitions between tropical forest and savanna, increasing the resilience of these ecosystems to changing drivers and disturbances.
How to cite: Zwaan, A., Staal, A., te Beest, M., and Rietkerk, M.: Widespread forest-savanna coexistence but limited bistability at a landscape scale in Central Africa, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-2758, https://doi.org/10.5194/egusphere-egu25-2758, 2025.
The intricate interplay of the Earth system’s biophysical processes provides the basis for Earth resilience and human wellbeing. While this interplay has been systematically studied on a global scale, a better understanding of the sub-global interactions is crucial in order to fully assess the systemic environmental impact of human activities.
Building on the quantitative framework provided by the Earth system impact metric (Lade et al. 2021), we present a bottom-up spatial pattern of cross-scale Earth system interactions. In this study, we focus on the processes of change in carbon dioxide concentration, vegetation cover, and surface water runoff. These processes lie at the critical interface between human pressures and the major Earth system components of climate, land, and water. Interactions are quantified using the spatially resolved dynamical global vegetation model LPJmL (Lund-Potsdam-Jena managed Land). A comparison of the resulting spatial patterns to established climate- and vegetation-based divisions of the Earth reveals that parts of the patterns are already explained by the simple combination of vegetation types being naturally prevalent in an area. The effects of climate change on runoff are for example particularly high in areas originally covered by cool seasonal grasses only. In contrast, the effects of changes in vegetation cover on climate more closely follow the Köppen-Geiger climate classification, showing a particularly high interaction strength under tropical rainforest climate. Eventually, we derive an integrative world map of interaction zones using multivariate spatially constrained clustering.
With this study, we provide a refined local assessment of cross-scale interactions between three crucial Earth system processes. By aggregating the results into larger regions, we aim to facilitate its applicability in decision support and communication.
Steven J Lade et al., A prototype Earth system impact metric that accounts for cross-scale interactions, Environ. Res. Lett. 16 115005 (2021).
How to cite: Zoller, H., Rocha, J., Fetzer, I., Gotangco Gonzales, C. K., Chaudhary, N., and Lade, S.: A bottom-up spatial pattern of Earth system interactions, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-12239, https://doi.org/10.5194/egusphere-egu25-12239, 2025.
Worldwide, developments towards highly industrialized, conventional agriculture systems have led to ecological deterioration, as well as societal problems. On the ecological side, many Planetary Boundary transgressions can - in substantial parts - be attributed to agricultural developments: Land System Change, Biosphere Integrity, Climate Change, Freshwater Change, and Biogeochemical Flows were all found to be majorly impacted by agriculture. Social issues like worker health and unstable livelihoods add to the dire picture.
Many approaches towards sustainable agriculture exist, among them Regenerative Agriculture (RA). While RA practices, according to most definitions, center on improving soil health, broader interpretations of the term exist. Some include factors like agrobiodiversity and water cycles, others additionally include social aspects like farmer well-being. While studies assessing the biophysical potential of different RA practices exist, the question how a wide-spread, up-to-global adoption of RA practices can unfold, remains understudied.
To tackle this key research question, we developed the Integrated Social Ecological rEsilient lanD Systems (InSEEDS) model (v0.2), an agent-based dynamic global vegetation model (AB-DGVM). InSEEDS is a World-Earth Model that comprises an environmental and a socio-cultural component. Through a bidirectional tight coupling facilitated by the novel copan:lpjml framework (Breier et al., in prep), the Lund Potsdam Jena managed Land (LPJmL) is integrated as the Environmental component of InSEEDS. The model’s socio-cultural component is represented by an agent-based model (ABM) to simulate farmers’ management decisions for or against conservation tillage, which is a RA practice.
This presentation introduces the InSEEDS model and describes its model set-up and design. It delineates the ABM structure, focussing on the farmers’ decision-making process, as well as the different farmer types. It lays out results regarding the co-evolutionary interactions in which the adoption and spreading dynamics are rooted in, the role of social and ecological heterogeneity in the model, as well as the interplay of factors in the agent decision-making.
The development and application process of the InSEEDS model points to future research directions for our model development team. In future model versions, the integration of qualitative and quantitative empirical knowledge for the ABM structure as well as parameterization could be an asset in comparison to the purely theoretical approach v0.2 follows. To capture more broad management options in the ecological component, the implementation as well as bundling of further RA practices like cover crops and agroforestry is planned (Breier et al., in prep). Furthermore, loop learning processes, more diverse agent types, non-local farmer networks, and higher levels of social organisation are envisioned as extensions of the farmer ABM component (Schwarz et al., in prep; Prawitz et al., in prep).
How to cite: Schwarz, L., Breier, J., Prawitz, H., Constantino, S., Bechthold, M., Gerten, D., Müller, C., Rockström, J., Hotz, R., von Bloh, W., Heitzig, J., and Donges, J.: Investigating transitions to regenerative agriculture using the InSEEDS World-Earth model – foundations, first results, and research directions, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-19136, https://doi.org/10.5194/egusphere-egu25-19136, 2025.
The planetary boundaries framework is a cornerstone for assessing Earth's resilience and stability, with significant traction in academia and policy-making. However, despite its relevance, many boundaries remain provisional and require rigorous refinement. This study introduces a comprehensive, data-driven methodology to determine planetary boundaries for locally variable Earth system processes. By integrating empirical approaches with advanced analytical techniques, we aim to improve the framework’s precision and applicability. Our approach utilizes spatially explicit binary outcome indicators—such as ecosystem degradation—to identify grid-level thresholds for control variables like Human Appropriation of Net Primary Production (HANPP).
Thresholds are optimized using Receiver Operating Characteristic (ROC) curves for each indicator, and the final local threshold is defined as the median of these values. Widely used in engineering and other disciplines to evaluate model performance and decision thresholds, ROC analysis provides a robust statistical framework for identifying optimal boundaries. Aggregating grid cells exceeding local thresholds enables the derivation of robust global boundaries. We demonstrate this methodology by refining the functional biosphere integrity boundary and propose its application to other locally variable boundaries, including biogeochemical flows, freshwater change, and land-use change.
Additionally, the ROC-based approach allows for the systematic comparison of control variables by quantifying their predictive strength using the Area Under the Curve (AUC). Like ROC analysis, AUC is extensively applied in engineering, data science, and other fields to evaluate the accuracy and performance of predictive models. The AUC is particularly valuable for expanding the planetary boundaries framework to new frontiers, such as the current endeavor to incorporate ocean processes. By providing a robust and empirical means of assessing the compatibility of different proposed control variables, AUC helps ensure that the framework remains both scientifically rigorous and adaptable. This approach also facilitates the evaluation of how well various control variables encompass the breadth of the processes they represent, guiding their selection and potential refinement.
Building on this foundation, we leverage AI algorithms to explicitly predict outcome indicators using one or multiple control variables. This enables a deeper analysis of different regimes of the control variable, as well as spatial variations in behavior, by examining how prediction statistics vary across values. Furthermore, these predictive models offer an opportunity to reframe planetary boundaries, directly based on empirical outcome indicators. Such a reframing allows for clearer, outcome-oriented definitions of boundaries while retaining the ability to simulate and assess their behavior under various scenarios using the original control variables.
Our findings provide a robust, empirically validated methodology for determining planetary boundaries and offer new tools for understanding thresholds and spatial dynamics in Earth system processes. By integrating advanced analytical techniques and predictive models, this approach supports the development of a more precise framework for assessing resilience and stability in a rapidly changing Earth system.
How to cite: Ben Uri, L., Stenzel, F., Shmuel, A., and Milo, R.: An Empirically Grounded Data-Driven Methodology for Setting Planetary Boundaries thresholds with A Case Study on Biosphere Integrity, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-14767, https://doi.org/10.5194/egusphere-egu25-14767, 2025.
Reducing environmental pressure from food systems is critical to limiting environmental degradation and the risk of irreversibly destabilizing the Earth system, but an integrated framework that sets out the safe operating space for food systems is lacking. We assess the current state of food systems across all Planetary Boundaries and propose Food System Boundaries, which are specific shares of the Planetary Boundaries delineating environmental limits for food systems. Our findings reaffirm that food systems are the single largest driver of Planetary Boundary transgressions, and are dominating at least four Planetary Boundary transgressions (i.e. biosphere integrity, land system change, freshwater change, biogeochemical flows). Food systems are beyond all proposed food system boundaries. Returning to the safe operating space for food requires rapidly eliminating CO2 emissions associated with food systems, halting intact land conversion from agriculture, redistribution of fertilizer input, and (regionally) limiting water, pesticide and antibiotic use.
How to cite: te Wierik, S., Rockström, J., Norberg, A., Vermeulen, S., van Vuuren, D., DeClerck, F., de Vries, W., Schulte-Uebbing, L., Beusen, A., Springmann, M., Gerten, D., Maggi, F., Tang, F., and Noone, K.: Identifying the safe operating space for food systems, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-16769, https://doi.org/10.5194/egusphere-egu25-16769, 2025.
Posters on site: Mon, 28 Apr, 10:45–12:30 | Hall X5
The way life on Earth adapts to the climate can change the climate. In the Anthropocene, humans have become a planetary force dominating the biosphere. Could human climate adaptation therefore have substantial feedback effects on the Earth system? We work out the bio-geo-physical mechanisms of adaptation within a new Earth system-based framework of human climate adaptation. Thereby we can for the first time approximate the contribution of climate adaptation to the current state of affected planetary boundaries. By establishing what we call artificial climate niches, Homo sapiens is the only known species able to fully emulate all recorded climates on Earth at a small scale. Many of those niches exceed the human scale by orders of magnitude but still remain small at Earth system scales. Yet climate adaptation-Earth system-feedbacks are extremely disproportional to scale. Linking research from various domains, we find that human climate adaptation currently contributes ≥25.7 percent of annual greenhouse gas emissions and ≥73.2 percent of human freshwater withdrawals. Climate adaptation even affects the stratosphere: the ozone hole is largely a product of climate adaptation. The large majority of those impacts likely still results from adaptation to mostly stable Holocene climates and not yet from adaptation to climate change. This proves both the importance and the urgency of establishing a safe and just operating space for human climate adaptation.
How to cite: Grudde, B.: The human climate: towards an Earth system-based perspective on human climate adaptation, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-1992, https://doi.org/10.5194/egusphere-egu25-1992, 2025.
When assessing prerequisites for the resilience or collapse of present and future societies in the Anthropocene, computational models of ancient civilizations can provide valuable insights. The Classic Maya are a common example for a civilization that has experienced spectacular growth in population and technology before apparently undergoing catastrophic reorganization. The MayaSim social-ecological model was conceived by Heckbert (2013) to test conflicting theories on these events and has since been further developed and evaluated in several studies (Heckbert et al. 2014, 2019; Kolb 2020). It is the first spatially explicit, agent-based computational model of the ancient Maya, and the first one to incorporate trade. Within the scope of a master thesis, we thoroughly revisited MayaSim on multiple levels. A full technical revision revealed that the model does not inherently produce large scale population collapses. On the aggregate level, the model system will converge to long-term population stability under all tested parameter settings. From what is set up in the model, even a climate forcing could only lead to either full recovery or extinction, which is confirmed by results from previous model versions. Both cases, however, do not apply to the Mayan Classic-to-Post-Classic transition. That transition, despite a significant decrease in population numbers, did not feature a full population collapse, but was mainly characterized by a collapse of the established societal structure and a spatial reorganization from the inland to the coasts of the Yucatán peninsula. Mayan culture, however, continued to flourish and is still present around Yucatán today. Hence, despite an ambitiously comprehensive approach taken in the development of MayaSim, the model does not appear fit to explain the dynamics at hand. For this contribution, the modeling approach that lead to MayaSim is therefore critically reviewed, adopting new perspectives on how the Maya timeline can be insightful for present-day societies. Especially, the role of societal dynamics in the Classic-to-Post-Classic transition is explored, aiming to account for the influence of colonial history and “western” ideas of development on our view of the Classic Maya. How did the societal organization before and after the famous "collapse" differ? Is the Classic era state really a more desirable one, given that it did not persist? And is the concept of social tipping helpful in the interpretation of that transition? Drawing from these perspectives, how could MayaSim 2.0 be re-conceived from scratch? How can dynamics of power, inequality and centralization be explored in a simple, conceptual model? What are further examples of such a hypothesized revolution in human history that this model might apply to?
How to cite: Kühlein, F., Soliev, I., and Donges, J.: Social tipping towards revolution? New perspectives for the MayaSim model, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-21249, https://doi.org/10.5194/egusphere-egu25-21249, 2025.
The existence of large-scale tipping points - thresholds where small changes can trigger drastic, often irreversible shifts in the climate system - has been a major concern of climate science in the past two decades. The ability to evaluate tipping risks using computationally manageable models is crucial to assess the resilience of the climate system and also to identify safe global warming trajectories for tipping elements. Here, we present an approach to estimate parameters of a simple tipping model based on complex Earth system model output. We validate our results by reproducing simulations that have not been used in the training process and apply the model to major earth system tipping elements such as the Greenland Ice Sheet. A simple model that captures essential behaviour of complex earth system models provides an important step towards a tipping point emulator for extensive tipping risk analyses.
How to cite: Krönke, J., Donges, J. F., Rockström, J., Bochow, N., and Wunderling, N.: Estimating parameters for a simple tipping model from complex Earth system model output, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-15832, https://doi.org/10.5194/egusphere-egu25-15832, 2025.
There is increasing interest in understanding how the collapse of the Atlantic Meridional Overturning Circulation (AMOC) impacts global climate, yet its effects on the carbon cycle remain underexplored. While previous studies have focused on these impacts under preindustrial conditions, our research takes a novel approach by examining equilibrium states under different CO2 levels, offering a perspective not previously addressed.
Using the intermediate-complexity Earth system model CLIMBER-X, we conducted a series of hosing experiments to simulate AMOC collapse under various CO2 equilibrium conditions. Our analysis focuses on the carbon cycle and global climate changes resulting from AMOC collapse, while also exploring the roles of ocean dynamics and carbon cycle during this process.
Our findings highlight that under a warming climate, a potential AMOC collapse could result in significant oceanic carbon release to the atmosphere, amplifying global warming. Although it would take hundreds to thousands of years for the AMOC to reach equilibrium after collapse and fully produce these effects, the rate of this process can vary depending on the CO2 levels of the equilibrium. Furthermore, certain scenarios may even trigger additional warming before the AMOC collapse is fully realized.
How to cite: Nian, D., Willeit, M., Wunderling, N., Ganopolski, A., and Rockström, J.: Global temperature and carbon cycle changes after AMOC collapse, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-13351, https://doi.org/10.5194/egusphere-egu25-13351, 2025.
The present-day Atlantic Meridional Overturning Circulation (AMOC) is considered to be a prominent tipping element and its collapse would have grave consequences on the global climate. Its dynamics are partly determined by the Bering Strait Throughflow where fresh Antarctic Intermediate Water from the Pacific Basin enters the Arctic Ocean through the Bering Strait and eventually joins the lower branch of the AMOC through deep-water formation in the North Atlantic. The Throughflow's net effect is a freshening of the North Atlantic. Closure of the Bering Strait produces therefore a strengthening of the AMOC. Various studies have indicated that the AMOC is weakening and may even collapse before the end of this century. As the Bering Strait is only 80 km wide and on average 50 m deep an enclosure dam is technically feasible as a measure to strengthen the AMOC and prevent its tipping. In this work we use a hierarchy of climate models including CESM1 to study the effect of a Bering Strait closure on the AMOC under various climate and freshwater forcings. It shows that for low freshwater forcings to the North Atlantic a closure can mitigate the weakening of the AMOC and even prevent an AMOC tipping due to climate forcing. However, for larger freshwater forcings a Bering Strait closure destabilizes the AMOC and would make a tipping more likely as now the additional freshwater can no longer directly be exported out off the North Atlantic to the Pacific via the Bering Strait. Additionally, a small conceptual model is employed in order to illuminate these results further.
How to cite: Soons, J. and Dijkstra, H. A.: Closure of the Bering Strait to prevent an AMOC tipping, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-8987, https://doi.org/10.5194/egusphere-egu25-8987, 2025.
Anthropogenic disturbances to ecosystems on the boundary between tropical savannas and forests may lead to changes in vegetation cover that are difficult to reverse. Given a sufficiently large disturbance, feedback mechanisms between forest tree cover and fire frequencies could trigger a transition between forest and savanna. Tree cover suppresses grass fires that maintain savanna, and thus tropical forest recruitment drives forest resilience against critical transitions. Tree seed dispersal strategies may be important determinants of spatial patterns of forest recruitment. However, their role in shaping forest resilience is not well understood. We therefore investigate the influence of tree seed dispersal strategies on tropical forest resilience. To this end, we introduce a novel individual-based model of Seed Dispersal in Savanna-Forest ecosystems (SDSF), simulating the interaction between tree dispersal strategies, spatial patterns of tree cover, and fire percolation. We find that seed dispersal by birds induces lower recruitment rates and more heterogeneous seed deposition patterns than dispersal by wind. In addition, forest recruitment rates and resilience are more sensitive to spatial pattern morphology when dispersed by birds than by wind. This effect is more pronounced for coarser spatial patterns containing larger forest patches that are spaced further apart. Our findings demonstrate for the first time that tree seed dispersal strategies interact with spatial patterns of tree cover and fire percolation, affecting tropical forest resilience against tipping toward a savanna state. Thus, efforts to understand the impact of global change on critical transitions in savanna-forest boundaries should account for the different effects of seed dispersal strategies.
How to cite: van der Ree, M., Barkema, G. T., and Staal, A.: Tree seed dispersal strategies affect resilience of savanna-forest boundary ecosystems, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-11367, https://doi.org/10.5194/egusphere-egu25-11367, 2025.
Terrestrial ecosystems worldwide are under increasing stress due to changing climate and weather regimes, as well as direct anthropogenic influences such as land use changes. The combination of stressors can erode an ecosystem’s ability to resist and recover from external shocks and pressures.
Vegetation resilience loss is often assessed by applying temporal early warning signals (EWS) based on dynamical systems theory to remotely sensed time series of different vegetation indices. The global coverage and regular measurement intervals of the satellite data in combination with easily computable EWS such as temporal autocorrelation and variance make this an appealing approach. Recent studies have confirmed that common EWS are good indicators of recovery rates after small disturbances in global ecosystems. However, to be useful in real-world applications, EWS need also be able to provide warning signals before a major upcoming ecosystem collapse, as driven for example by drought or heat stress. This has been evaluated for local case studies of specific ecosystems, but a global assessment of EWS accuracy and sensitivity for predicting terrestrial ecosystem collapses is lacking.
Here, we evaluate the performance of different EWS in predicting forest dieback events recorded in situ and on manually assessed satellite data around the world. We compare different frequently used remote sensing datasets, vegetation indices, and a range of EWS. This work highlights limitations of commonly applied resilience loss assessment methods for real-world applications and aims to contribute to the discussion on how to reliably evaluate changes in large-scale ecosystem resilience.
How to cite: Knecht, N., Lotcheris, R., Fetzer, I., and Rocha, J.: Limitations of early warning signals: evaluating the performance of resilience loss detection methods to predict forest die-back events from remote sensing data, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-18547, https://doi.org/10.5194/egusphere-egu25-18547, 2025.
Advanced warning of catastrophic changes in ecosystem function and composition are fundamental to protect and restore nature, particularly from novel climate threats. Critical slowing down (CSD) has been proposed as an early warning system for ecosystem critical transition and, alongside other state measurements, for defining a system’s ecological resilience. These concepts are based on the idea of stable states, which are difficult to define in ecological systems, and have not been demonstrated empirically because reference states are inherently static in field data. Using remote sensing data we show the dynamic regime of real-world ecological systems by mapping trajectories as a surface to quantify the geometry governing transitions between locally stable states. We find different attractor landscapes between ecosystems with extremes in biodiversity. Sites with high diversity (such as nature reserves) show a single local minima representing a single stable state - a resilient system, while ecosystems with low diversity exhibit multiple local stable states and trajectories between states after perturbation (drought), showing a critical transition. Our results evidence the theory of resilience and stability of ecological systems. We anticipate the use of our approach to better understand and visualize ecosystem resilience and as a tool for identifying ecosystems in critical transition that can be targets for intervention, such as ecological restoration.
How to cite: Rust, W., Stojanovic, M., Corstanje, R., Simms, D., and Harris, J.: Attractor landscapes for characterising ecological resilience in real-world systems, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-19409, https://doi.org/10.5194/egusphere-egu25-19409, 2025.
The Planetary Boundaries (PBs) framework identifies nine essential Earth system processes that are critical for maintaining global stability and resilience. These include climate regulation, biosphere integrity, land system dynamics, and freshwater availability. However, recent studies reveal that six of these boundaries have already been crossed, posing significant threats to Earth's sustainability. In this context, satellite-based Earth Observation (EO) has emerged as a powerful tool for monitoring PBs, offering global-scale data with rich temporal, spatial, and spectral insights. In particular, EO missions such as Sentinel, Landsat, and Aqua/Terra play a critical role in tracking PB-related control variables (CVs), such as atmospheric CO2 concentrations and land-use changes. While these EO missions provide valuable insights, significant challenges remain. Monitoring certain boundaries, such as biogeochemical flows, is still beyond the capabilities of current EO technologies. Additionally, the exponential growth in EO data acquisition creates difficulties in data processing, requiring advanced analytical techniques, substantial computational power, and effective harmonization of multi-scale and multi-sensor datasets. Accessibility to EO resources is another critical issue, particularly in remote or underdeveloped regions that are vital for PBs monitoring. Programs such as Copernicus, with its free data access policy, are addressing these disparities. At the same time, emerging technologies like machine learning (ML) and deep learning (DL) are revolutionizing data processing, enabling the development of indicators aligned with PBs.
This study aims to explore the potential of satellite-based EO for PBs monitoring. By integrating EO capabilities with cutting-edge computational tools and fostering interdisciplinary collaboration, stakeholders can develop actionable strategies for sustainable planetary management. Continued innovation and equitable access to EO resources are essential to preserving Earth’s stability and resilience.
How to cite: Rafiezadeh Shahi, K., Caesar, L., Sakschewski, B., and Rockström, J.: Exploring the Potential of Satellite-Based Earth Observation for Monitoring Planetary Boundaries, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-9141, https://doi.org/10.5194/egusphere-egu25-9141, 2025.
The planetary boundaries (PBs) framework defines a "safe operating space" based on nine key Earth system processes. Out of these, four are terrestrial and their primary driver of transgression is agriculture. To better understand how agricultural activities might further influence the terrestrial PBs, it is essential to model their drivers and interactions over time. A helpful tool for studying complex dynamic relationships like these are World-Earth models, in particular FRIDA because of its aim to provide an internally consistent representation of many societal and Earth system processes. In this study, we included within FRIDA the PBs for: biosphere integrity, land system change, freshwater use, biogeochemical flows and climate change. This allows us to quantify their temporal trajectories, identify drivers of their transgression, and explore their main interactions. In total, seven different PB control variables are implemented across the five PBs studied, using both directly related variables in FRIDA and proxies related to the calculations using assumed relationships based on literature. By running the FRIDA model in a scenario governed by endogenous model behaviour, the PB quantifications are validated against values documented in the literature. Since FRIDA is still under active development, this study should be seen as a first effort to integrate PB status quantification and analysis into such a model.
The results show strong agreement with independent, earlier, estimates of PB trajectories and in particular whether the PB’s control variables are in the safe operating space, the zone of increasing risk or the high risk zone. However, some notable differences still occur, which may be attributed to the proxies developed to account for some relevant processes not currently represented in FRIDA. We also explore the role of certain drivers of (single or joint) PB transgressions centred around agriculture and associated societal processes and behaviours such as diet. As a part of this, we illustrate that an unambiguous attribution of PB transgressions to any given driver is challenging given that the coupling of drivers leads to non-linear and dynamically evolving feedback processes. Overall, we demonstrate the general suitability of the FRIDA model for simulating PB trajectories, their drivers and interactions. For future studies potentially using the model to inform decision-making, we recommend implementing all PB control variables, if possible in a more spatially explicit manner and without the aforementioned proxies.
How to cite: Eriksson, A., Gerten, D., Nilsson, L. J., Breier, J., and Schoenberg, W. A.: Assessing Planetary Boundary Transgressions and Their Causes - Using the FRIDA System Dynamics Model, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-16810, https://doi.org/10.5194/egusphere-egu25-16810, 2025.
Direct and indirect human pressures have notably changed the global freshwater cycle. The recently updated planetary boundary for freshwater change (PB-FW) illustrates the extent and degree of freshwater change in the Earth system by reporting the share of global land area experiencing anomalous streamflow and soil moisture conditions. However, analysis underlying the new PB-FW remains ambiguous in distinguishing the different drivers of water cycle change and offers no look into how future climate change may affect the PB-FW status. Here, we fill these missing pieces of the recent PB-FW research.
We adopt the methodology introduced in the new PB-FW definition while utilising an updated state-of-the-art global hydrological model ensemble from ISIMIP 3a and 3b simulation rounds. Scenarios in ISIMIP 3a offer a way to separate between direct human forcing (DHF) and climate related forcing (CRF), whereas ISIMIP 3b allows for projecting the status of the PB-FW into the future with respect to Shared Socioeconomic Pathway (SSP) scenarios. Furthermore, we enrich the metrics of PB-FW transgressions by considering also the magnitude of previously identified deviations from stable (unaffected) conditions at the local (grid-based) scale.
Our tentative results show that CRF generally dominates over DHF in determining the PB-FW status at the global scale during the historical period (1901–2019), both for streamflow and soil moisture. However, DHF has a stronger contribution to increasing dry streamflow deviations, which is particularly visible at smaller scales in regions under heavy anthropogenic influences. Quantifying the magnitude of local deviations shows how certain areas, such as Central Africa and the Mediterranean, have experienced the strongest dry local deviations, whereas the strongest wet local deviations locate to the northernmost latitudes and southern South America.
In line with the domination of CRF over DHF in the historical period, analysing future climate projections emphasises the strong dependence of the PB-FW status on climate action. Both for streamflow and soil moisture, the PB-FW transgression plateaus in the low-emission scenario (SSP1-2.6) projections, while high-emission scenarios (SSP3-7.0 and SSP5-8.5) project a continuously increasing trajectory of PB-FW transgression towards the end of the 21st century.
The results are largely in line with the existing PB-FW and related studies on past and projected global water cycle change. By resolving the drivers of PB-FW transgressions with updated scenario simulations and better quantifying PB-FW transgressions by considering the magnitude of local deviations, this study makes the new PB-FW more tangible and actionable.
How to cite: Virkki, V. and Porkka, M.: Planetary boundary for freshwater change: past drivers and future projections, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-15604, https://doi.org/10.5194/egusphere-egu25-15604, 2025.
In tourism-oriented coastal regions, maintaining water quality is critical amidst growing anthropogenic pressures. Balancing the natural auto-purification capacity of coastal waters with human interventions requires innovative approaches to mitigate and manage pollution. This study presents a multidisciplinary and integrated framework for assessing auto-purification potential, demonstrated through a case study in the Brač Channel and Kaštela Bay in the Eastern Adriatic Sea. Using the results of atmospheric-oceanographic modelling with WRF-ROMS, Lagrangian particle tracking was applied to simulate non-conservative pollutant transport under varying hydrodynamic conditions. Stochastic ensemble analysis and spatially integrated statistics were utilized to develop a novel, scale-adaptive methodology for quantifying auto-purification potential. Results revealed significant differences in pollutant dispersion during characteristic Bora and Sirocco events, offering actionable insights for monitoring strategies and managing additional pressure inputs. While focused on this case study, the framework provides a scalable approach for evaluating and sustaining water quality in other critical recreational coastal zones.
How to cite: Galešić Divić, M., Divić, V., Koračin, D., and Andričević, R.: Integrated framework for assessing coastal water auto-purification potential, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-4777, https://doi.org/10.5194/egusphere-egu25-4777, 2025.
Climate change and biodiversity loss and are regarded as major global environmental issues. However, the interactions between these and other environmental issues, which vary in type and magnitude across regions, have not been adequately considered before measures for addressing each major issue are planned, decided, or implemented. To achieve the simultaneous resolution of multiple environmental issues without externalizing the problem (e.g., shifting "wrinkles" to other areas or regions), it is essential to enhance trans-scale integration of top-down management and bottom-up action planning, leveraging the advantages of both approaches.
To date, at the global level, targets for greenhouse gas (GHG) emission reductions and their timelines are typically determined first, followed by allocation to individual countries. This process often overlooks the "ripple effects" of GHG reduction measures on ecosystems and human well-being within each country.
On the other hand, at the local (national) level, policymakers generally possess a good understanding of societal constraints, demands, and capacities for implementing such measures. However, causal interactions among various issues and their cross-border effects are rarely considered or prioritized.
Here, a Double PDCA-cycle framework is proposed to bridge local action plans (bottom-up) with global evaluations and recommendations (top-down):
- First Cycle: Simulation-based assessment to evaluate the external and global impacts of the proposed local action plans before implementation.
- Second Cycle: Post-implementation assessment and iterative modifications based on observed outcomes.
A set of simple dynamic models incorporating the global system and two nations was analyzed under the following assumptions:
- Top-down: Global-scale goal-oriented approach,
- Bottom-up: National-scale goal-oriented approach, and
- Double PDCA-cycle: Integration of both approaches.
Preliminary results from the comparisons of these three assumptions demonstrate the following advantages of the Double PDCA-Cycle Framework:
- Each country can design its local action plan tailored to its unique natural and cultural conditions.
- Appropriate models can be employed to evaluate the globally integrated impacts of local action plans proposed by each country.
- Existing observation and assessment mechanisms can be effectively utilized.
How to cite: Ishii, R.: A new conceptual framework for integrating multiple problems at multiple spatial scales to achieve simultaneous solutions to global environmental issues, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-18634, https://doi.org/10.5194/egusphere-egu25-18634, 2025.
