Abstract Several studies have shown sub‐surface warming in the Southern Ocean via an increase in meltwater flux from the Antarctic Ice Sheet (AIS), which can lead to a positive feedback through enhanced basal melting. In this study, we investigate how the feedback strength is related to the prevailing climate in a coupled climate–ice‐sheet model. We find that sub‐surface temperature increase due to Antarctic meltwater is more pronounced under pre‐industrial climate compared to a strong global warming scenario. This is explained by a climate‐change induced reduction of vertical overturning in the Southern Ocean, which already leads to strong sub‐surface warming without additional meltwater. While in the pre‐industrial climate additional meltwater substantially reduces vertical mixing, the additional ice‐sheet mass flux into the ocean has less impact when the overturning is already suppressed by climate change. Sub‐surface warming due to meltwater flux increase thereby shows a saturation effect under climate warming.

ABSTRACT The concept of sustainability has been shaped by the history of environmental problems and ecological crises, and the scientific value of studying the past has long been recognized. However, the relevance of studying Earth's past in the context of the sustainability debate goes beyond testing Earth‐system models used for future climate projections and looking for past analogues of future climate states or modern biodiversity loss. The past is also important for communicating the climate and ecological crisis in terms of enhancing scientific credibility and illustrating the extent of human interference with our planet. Finally, teaching and communicating the past evolution of the Earth system can help guide our thinking toward a more sustainable future by overcoming two root problems of the sustainability crisis, the perceived disconnect between humans and the environment, and the lack of long‐term thinking.

Low friction at subduction zones is essential for modern-style plate tectonics, and sediments are widely discussed to help keep this friction low by lubricating the plate interface. This mechanism allows the climate to exert an influence on geodynamics via erosion and sediment flux to subduction zones. Conversely, geodynamics affects climate via carbon outgassing and weathering. However, the resulting feedbacks between climate and geodynamics and their effects on the Earth system remain poorly understood. Here, we present a conceptual model developed to quantify these mechanisms, revealing two stable states: a state with fast tectonic plates and well-lubricated subduction zones and a "slow" state with sediment-depleted subduction zones. We find that supercontinent assembly can lead to bifurcation tipping from the fast into the slow state. Conversely, Snowball Earth events act as a large sediment source, pushing the model from the slow into the fast state. These mechanisms offer plausible mechanisms for the beginning and end of the mid Proterozoic "Boring Billion" period. We furthermore show that the climate of the slow state is likely warmer than that of the fast state, in line with the absence of glaciations during the Boring Billion.

Many model studies show that a shutdown of the Atlantic meridional overturning circulation (AMOC) causes reduced northward heat transport into the North Atlantic and a warming Southern Ocean in addition to shifts in large-scale atmospheric circulations. How these changing climate conditions could influence the present-day state of the Antarctic Ice Sheet is little studied even though observational data of AMOC strength show a slowdown trend over the last decades. The ocean current as well as the Antarctic Ice Sheet might reach climate tipping points triggering irreversible processes with consequences already on human time-scales. It's unclear whether increasing Southern Ocean temperatures due to a AMOC shutdown could accelerate basal melting rates, the critical parameter which in turn may induce tipping of the West Antarctic Ice Sheet.Here, a freshwater hosing that forces the shutdown of the AMOC is applied to the North Atlantic in a global climate model with an interactive ice sheet model for Antarctica. This model framework consists of the Parallel Ice Sheet Model (PISM) that is coupled to the CM2Mc global Earth system model via the ice shelf cavity model PICO (Potsdam Ice-shelf Cavity mOdel). PISM is interactively coupled to the ocean module in order to investigate feedbacks at the ice-ocean boundary, while the atmospheric forcing is prescribed. Preliminary results show that an AMOC shutdown results in warming sea surface temperatures in the southern hemisphere along with a small shift in the mid-latitude westerlies due to reduced northward heat transport, which is in line with previous studies. Antarctic marginal temperatures decrease, however, resulting in a reduction of Antarctic mass through increased calving and decreased basal melting.

While the term "Anthropocene" is well established across scientific disciplines and social spheres, interpretations are diverse. Taking account of the 2024 rejection by a geological commission to accept the Anthropocene as a geological epoch and the related scientific debate, here we offer a future-oriented perspective from the viewpoint of Earth system science. We describe different pathways in the Anthropocene up to the year 3,000, systematically characterizing them according to impacts and causes. We discuss the enormous global consequences of anthropogenic pressures on the Earth system and quantify the corresponding long-term commitment to change. Regarding the causes, we conservatively explore best-case and middle-of-the road emission scenarios, in combination with climate sensitivities drawn from within the IPCC likely range. We also discuss implications for Earth system resilience that could result in what we call worst case scenarios for Anthropocene outcomes. We conclude that, beyond the slow pace of natural climate recovery spanning many millennia, even minimal, unavoidable residual emissions like from the food sector risk perpetuating global warming in the absence of other human forcing. One implication is that if climate or carbon cycle feedbacks shift toward reinforcing warming, they risk not only exacerbating climate impacts but to also surpassing human forcing in relevance. At that point, human influence on the Anthropocene would no longer play the dominant role.

The shift from the climate of the “boring billion” without evidence for major glaciations to the globally ice-covered “Snowball Earth” events of the Cryogenian (720–635 million years ago, Ma) remains enigmatic. Various factors have been suggested to drive the cooling in the early Neoproterozoic (1000–539 Ma), most prominently decreasing carbon-dioxide levels due to enhanced weathering of tropical continents or fresh volcanic material. However, these processes should have operated during the boring billion as well, triggering the quest for alternative explanations. It has been suggested, for example, that the increase in both the diversity and the biomass of eukaryotic algae around 800 Ma could have contributed to the cooling via the emission of dimethyl sulfide (DMS), a source of cloud condensation nuclei instrumental in forming bright clouds over dark ocean surfaces. Here, we investigate this hypothesis with a coupled climate–ocean biogeochemistry model, allowing for the first time the quantification of the relevant marine carbon cycle feedbacks. We confirm that the increase in cloud condensation nuclei cools the Neoproterozoic climate and can lead to global glaciation at low atmospheric carbon-dioxide concentrations. Our analysis sheds light on the positive and negative feedback loops associated with the rise of algae and demonstrates that changes in cloud cover remain a plausible contribution to Neoproterozoic cooling.

Monsoon systems transport water and energy across the globe, making them a central component of the global circulation system. Each monsoon system has its own regional characteristics ranging from particular continental shapes to dynamic vegetation patterns and the influence of mountain ranges. This individuality makes it difficult to access the common core meridional monsoon dynamics by only using observations or realistic simulations. Idealized frameworks have proven to be useful approaches to study monsoon systems with regard to their commonalties. Here, we present the latest insight of our work on the Monsoon Planet – an aquaplanet setup with an idealized circumglobal land stripe.

The potential impact of the increased rates of tidal energy dissipation on the climate on early Earth is usually assessed in terms of the global contribution to the energy balance which is small compared to the incoming solar radiation. However, tidal energy dissipation depends strongly on the distribution of landmasses, and regional energy input could, in principle, impact the local and global climate state via changes in circulation patterns and feedbacks in the Earth system. Here we investigate these effects by calculating tidal energy dissipation for a randomly generated continental distribution representative of early Earth, and three different rotation rates, and feeding it into a coupled climate model. Despite marginal global impacts, tidal energy dissipation can have significant regional effects caused by changes in ocean circulation and amplified by the ice-albedo feedback. These effects are strongest in climate states and regions where meridional heat transport close to the sea-ice margin is altered. This suggests that tidal heating could have contributed to sustaining regions with no significant ice cover.

The field of Geomorphology covers the essential link between climate and geological processes such as tectonics. Because both of these processes operate on planetary scales, and over million year periods, landscape evolution models must, by necessity, do the same. With the advent of modern computing and the reduction in computational complexity of the Stream Power Law algorithm (SPL), it has become much easier to conduct investigations of landscape evolution on these scales. By doing so we can test model interactions between Earth system processes such as geodynamics, weathering, sediment flux, and erosion. In this work we aim to conduct landscape evolution modelling with the SPL algorithm on pre-industrial Earth, using high resolution climate models (CMIP – Coupled Model Intercomparison Project) and topographic maps with uplift histories as input. This model has already been used for planetary scale modelling on ancient Mars, and now we aim to use it to conduct a broad sensitivity analysis of the landscape evolution of pre-industrial Earth. We will compare the model outputs to established datasets and to other landscape evolution studies to best constrain the input parameters of the model (e.g., incision coefficient) to reproduce known water and sediment fluxes for the period. Once the model is calibrated, we aim to use it to look at periods of deep time where landscape evolution was perturbed by tectonic and climate excursions such as supercontinent assembly, and transitions to and from icehouse climate states. As with the pre-industrial study, this work would also include coupling to climate models but furthermore would be coupled to a global geodynamic model to produce topography, reducing reliance on paleo-topographical maps and allowing for comparison to previous studies that used those maps as topographic input.

Abstract A mismatch of species’ thermal preferences to their environment may indicate how they will respond to future climate change. Averaging this mismatch across species may forewarn that some assemblages will undergo greater reorganization, extirpation, and possibly extinction, than others. Here, we examine how regional warming determines species occupancy and assemblage composition of marine bivalves, brachiopods, and gastropods over one-million-year time steps during the Early Jurassic. Thermal bias, the difference between modelled regional temperatures and species’ long-term thermal optima, predicts a gradient of species occupancy response to warming. Species that become extirpated or extinct tend to have cooler temperature preferences than immigrating species, while regionally persisting species fell midway. Larger regional changes in summer seawater temperatures (up to +10 °C) strengthen the relationship between species thermal bias and the response gradient, which is also stronger for brachiopods than for bivalves, while the relationship collapses during severe seawater deoxygenation. At +3 °C regional seawater warming, around 5 % of pre-existing benthic species in a regional assemblage are extirpated, and immigrating species comprise around one-fourth of the new assemblage. Our results validate thermal bias as an indicator of immigration, persistence, extirpation, and extinction of marine benthic species and assemblages under modern-like magnitudes of climate change.

Declines in resilience have been observed in several climate tipping elements over the past decades, including the Atlantic Meridional Overturning Circulation (AMOC) and the Amazon rainforest (AR). Large-scale nonlinear and possibly irreversible changes in system state, such as AMOC weakening or rainforest-savanna transitions in the Amazon basin, would have severe impacts on ecosystems and human societies worldwide. In order to improve future tipping risk assessments, understanding interactions between tipping elements is crucial. The AMOC is known to influence the Intertropical Convergence Zone, potentially altering precipitation patterns over the AR and affecting its stability. However, AMOC-AR interactions are currently not well understood. Here, we identify a previously unknown stabilising interaction pathway from the AMOC onto the Southern AR, applying an established causal discovery and inference approach to tipping element interactions for the first time. Analysing observational and reanalysis data from 1982-2022, we show that AMOC weakening leads to increased precipitation in the Southern AR during the critical dry season, in line with findings from recent Earth system model experiments. Specifically, we report a 4.8% increase of mean dry season precipitation in the Southern AR for every 1 Sv of AMOC weakening. This finding is consistent across multiple data sources and AMOC strength indices. We show that this stabilising interaction has offset 17% of dry season precipitation decrease in the Southern AR since 1982. Our results demonstrate the potential of causal discovery methods for analysing tipping element interactions based on reanalysis and observational data. By improving the understanding of AMOC-AR interactions, we contribute toward better constraining the risk of potential climate tipping cascades under global warming.

Human activities have had a significant impact on Earth's systems and processes, leading to a transition of Earth's state from the relatively stable Holocene epoch to the Anthropocene. The planetary boundary framework characterizes major risks of destabilization, particularly in the core dimensions of climate and biosphere change. Land system change, including deforestation and urbanization, alters ecosystems and impacts the water and energy cycle between the land surface and atmosphere, while climate change can disrupt the balance of ecosystems and impact vegetation composition and soil carbon pools. These drivers also interact with each other, further exacerbating their impacts. Earth system models have been used recently to illustrate the risks and interacting effects of transgressing selected planetary boundaries, but a detailed analysis is still missing. Here, we study the impacts of long-term transgressions of the climate and land system change boundaries on the Earth system using an Earth system model with an incorporated detailed dynamic vegetation model. In our centennial-scale simulation analysis, we find that transgressing the land system change boundary results in increases in global temperatures and aridity. Furthermore, this transgression is associated with a substantial loss of vegetation carbon, exceeding 200 Pg C, in contrast to conditions considered safe. Concurrently, the influence of climate change becomes evident as temperatures surge by 2.7–3.1 °C depending on the region. Notably, carbon dynamics are most profoundly affected within the large carbon reservoirs of the boreal permafrost areas, where carbon emissions peak at 150 Pg C. While a restoration scenario to reduce human pressure to meet the planetary boundaries of climate change and land system change proves beneficial for carbon pools and global mean temperature, a transgression of these boundaries could lead to profoundly negative effects on the Earth system and the terrestrial biosphere. Our results suggest that respecting both boundaries is essential for safeguarding Holocene-like planetary conditions that characterize a resilient Earth system and are in accordance with the goals of the Paris Climate Agreement.

A mismatch of species thermal preferences to their environment may forewarn that some assemblages will undergo greater reorganization, extirpation, and possibly extinction, than others under climate change. Here, we examined the effects of regional warming on marine benthic species occupancy and assemblage composition over one-million-year time steps during the Early Jurassic. Thermal bias, the difference between modelled regional temperatures and species’ long-term thermal optima, predicted species responses to warming in an escalatory order. Species that became extirpated or extinct tended to have cooler temperature preferences than immigrating species, while regionally persisting species fell midway. Larger regional changes in summer seawater temperatures (maximum + 10°C) strengthened the relationship between species thermal bias and the escalatory order of responses, which was also stronger for brachiopods than bivalves, but the relationship was overridden by severe seawater deoxygenation. At + 3°C seawater warming, our models estimate that around 5% of an assemblage’s pre-existing benthic species was extirpated, and around one-fourth of the new assemblage being immigrated species. Our results validate thermal bias as an indicator of future extinction, persistence, and immigration of marine species under modern magnitudes of climate change.

Monsoon systems are transporting water vapour and energy across the globe, making them a central component of the global circulation system. Changes in different forcing parameters have the potential to fundamentally change the monsoon characteristics as indicated in various paleoclimatic records. Here, we use the Atmosphere Model version 2 developed at the Geophysical Fluid Dynamics Laboratory (GFDL-AM2) and couple it with a slab ocean to analyse the monsoon's sensitivity to changes in different forcing parameters on a planet with idealized topography. This Monsoon Planet concept of an Aquaplanet with a broad zonal land stripe allows to reduce the influence of topography and to access the relevant meridional monsoon dynamics. In the simulations that enable monsoon dynamics, a bimodal rainfall distribution develops during the monsoon months with one maximum over the tropical ocean and the other one over land. The intensity and expansion of the land monsoon depends on the relative height of a local maximum in the surface pressure field that is acting as a barrier and determines the landward moisture transport. This dynamic is emerging during the course of one year, but also occurs when varying different parameters in a sensitivity analysis (slab ocean depth, sulfate aerosols, carbon dioxide, solar constant, land albedo). This structure of a bimodal rainfall distribution and a pressure-barrier located between the two maxima is also present in the Westafrican monsoon.

A potential shutdown of the Atlantic meridional overturning circulation (AMOC) is commonly recognized to have a significant impact on the Northern hemispheric climate, notably in Northern Europe. The collapse of the northbound heat transport by the AMOC is supposed to cool down surface air temperatures at the Scandinavian coast by up to 6 K accompanied by a concomitant nutrient starvation of phytoplankton in Subarctic and Arctic regions. However, besides local and regional impacts, tipping the AMOC into a weaker state by anthropogenic carbon dioxide (CO _2 ) and associated freshwater forcing could also have surprising remote effects. In order to investigate possible long-term impacts of an AMOC shutdown on ocean biogeochemistry, we employ an Earth system model of intermediate complexity using idealized scenarios of century-scale atmospheric 2×CO _2 and 4×CO _2 pulses combined with North Atlantic freshwater forcing. The results show a continued increase in primary production, in particular in the Eastern equatorial Pacific, due to a decrease in iron limitation following the AMOC shutdown. Tracer simulations indicate that bioavailable dissolved iron brought by Aeolian dust into the subtropical gyres of the Atlantic Ocean is transported to the Southern Ocean and from there enters the Indian Ocean and the Pacific. Thereby, the additionally introduced iron fertilizes the phosphate-rich high-nutrient, low chlorophyll waters, giving a lasting boost to phytoplankton growth, especially in the Eastern equatorial Pacific.

On early Earth increased rates of tidal energy dissipation are likely, but depend on the (unknown) distribution of continents. A stronger tidal heating could provide an additional energy source during times of substantially lower solar input. So far, the problem has been assessed in terms of the negligible contribution to Earth's global energy budget. Here we present a spatially resolved investigation of the impact of tidal heating, mixing, and geothermal heat on early Earth's climate. Using a random landmass distribution, tidal heating is calculated for three different rotation periods (12, 18, 24 hr) and fed into a climate model. For each rotation rate, three climate states with different atmospheric CO2 levels are simulated. We find that, depending on the climate state, tidal heating can affect regional ocean dynamics and sea-ice cover. The impact is strongest when tidal heating alters sea-ice dynamics and meridional heat transport close to the sea-ice edge, but its global impact remains negligible with only small global mean changes in ice cover (0.3%) and temperature (<0.05 degrees C). Adding tidal mixing and geothermal heat, however, leads to significant reduction in sea-ice cover of similar to 11% and similar to 19%, respectively, and thus to larger global warming. As we do not consider the dynamical effects of a higher rotation rate or different landmass distributions, this is only a first glimpse at the importance of tides for the climate of early Earth. Nevertheless, our results suggest that tides and geothermal heat are important for understanding regional climates and could have contributed to warming early Earth.

Current and upcoming large optical and near-infrared astronomical surveys have fundamental science as their primary drivers. To cater to those, these missions scan large fractions of the entire sky at multiple wavelengths and epochs. These aspects make these data sets also valuable for investigations into astronomical hazards for life on Earth. The Netherlands Research School for Astronomy (NOVA) is a partner in several optical / near-infrared surveys. In this paper we focus on the astronomical hazard value for two sets of those: the surveys with the OmegaCAM wide-field imager at the VST and with the Euclid Mission. For each of them we provide a brief overview of the astronomical survey hardware, the data and the information systems. We present first results related to the astronomical hazard investigations. We evaluate to what extent the existing functionality of the information systems covers the needs for the astronomical hazard investigations

&lt;p class=&quot;western&quot; align=&quot;left&quot;&gt;Global warming has been implicated as a trigger of mass extinctions in the past. Although species track their thermal niches as isotherms move poleward, systematic changes in the area of habitable space (i.e., their thermal habitat) are expected to influence their extinction risk. Quantifying thermal habitat changes is difficult in the geological past, where information about geography and the distributions of species are highly incomplete. We therefore present a formalized model of thermal habitat change, resulting from the interaction of spherical geometry, thermal niche preference, latitudinal temperature profile, and global temperature change. Our results suggest an overall decrease in available thermal habitat during global warming. Thermal habitat is lost primarily from lower latitude and polar areas, whereas temperate areas are less affected. Although patterns of extinction are ultimately dependent on the geography of available habitat space, the extent to which species occupy their thermal niches, additional abiotic parameters, and biotic interactions, our simple theoretical model provides the basic expectation for spatial patterns of habitat loss, and therefore potentially species loss, during global warming.&lt;/p&gt;

Increased sub-shelf melting and ice discharge from the Antarctic Ice sheet has both regional and global impacts on the ocean and the overall climate system. Additional meltwater, for example, can reduce the formation of Antarctic Bottom Water, potentially affecting the global thermohaline circulation. Similarly, increased input of fresh and cold water around the Antarctic margin can lead to a stronger stratification of coastal waters, and a potential increase in sea-ice formation, trapping warmer water masses below the surface, which in turn can lead to increased basal melting of the ice shelves.So far these processes have mainly been analysed in simple unidirectional cause-and-effect experiments, possibly neglecting important interactions and feedbacks. To study the long-term and global effects of these interactions, we have developed a bidirectional offline coupled ice-ocean model framework. It consists of the global ocean and sea-ice model MOM5/SIS and an Antarctic instance of the Parallel Ice Sheet Model PISM, with the ice-shelf cavity module PICO representing the ice-ocean boundary layer physics. With this setup we are analysing the aforementioned interactions and feedbacks between the Antarctic Ice Sheet and the global ocean system on multi-millenial time scales.