Earth System Research Articles

The Influence of Climate Variability and Future Climate Change on Atlantic Hurricane Season Length

AbstractAtlantic hurricane season length is important for emergency management preparation, motivating the need to understand its variability and change. We investigated the influence of ocean variability on Atlantic hurricane season length in observations and a future climate simulated by the Energy Exascale Earth System Model (E3SM). We found that multiple factors influence hurricane season length, through their influence on season start and end. Warm western subtropical Atlantic sea‐surface temperature anomalies (SSTAs) during boreal spring (before the official hurricane season start) drive early starts to the hurricane season, and vice versa for cool SSTAs. Meanwhile, La Niña in autumn (before the official hurricane season end) drives late ends to the hurricane season, and vice versa for El Niño. E3SM projects a 27‐day increase in future Atlantic hurricane season length given La Niña and warm northern tropical Atlantic SSTAs. This research documents sources of predictability for Atlantic hurricane season length.

Large transboundary health impact of Arctic wildfire smoke

Rapid warming at high latitudes, particularly in Siberia, has led to large wildfires in recent years that cause widespread smoke plumes. These fires lead to substantial deterioration in summer air quality in the region, with a factor 4 increase in summer fine particulate matter (PM2.5) concentrations in parts of Siberia during 1998–2020. Exposure to PM2.5 is associated with increased risk of mortality due to cardiovascular and respiratory disease, and the atmospheric lifetime of PM2.5 means that it can be efficiently transported between regions and nations. We used the Community Earth System Model to quantify the fraction of PM2.5 attributed to high latitude wildfires that occur in the Arctic Council member states and estimated the attributable health impact locally and in neighbouring countries. During 2001–2020 we attribute ~21,000 excess deaths to Arctic Council wildfires on average each year, of which ~8000 occur in countries outside the Arctic Council. Our analysis shows that the health impact of Arctic wildfires decreased during 2001–2020, despite the increase of wildfire-sourced PM2.5, which we suggest is due to a northwards shift in the average latitude of Siberian wildfires, reducing their impact on more densely populated regions.

An Intelligent Network Method for Analyzing Corporate Consumer Repurchase Behavior Using Deep Learning Neural Networks

Earth system models (ESMs) are our key tools for analyzing the planet's existing state and predicting its evolution in the next continuing human-caused events. However, the use of artificial intelligence (AI) approaches to augment or even replace conventional ESM functions has expanded in recent years, raising hopes that AI will be able to overcome some of the major difficulties in climate research. We address the advantages and disadvantages of neural ESM neurons, as well as the unsolved question of whether AI will eventually replace ESMs. Dynamic geophysical events are the foundation of Earth and environmental studies. Given the widespread acceptance of AI and the growing amount of Earth data, the geoscientific community may wish to seriously explore using artificial intelligence (AI) approaches at a much deeper level. Although it is a tall ambition to integrate hybrid physics and AI approaches from a fresh perspective, geology has yet to figure out how to make such methods feasible. This research is an important step towards realising the concept of combining physics and artificial intelligence to address problems with the Earth's system.  

Rapid Laurentide Ice Sheet growth preceding the Last Glacial Maximum due to summer snowfall

There has been extensive research into the nonlinear responses of the Earth system to astronomical forcing during the last glacial cycle. However, the speed and spatial geometry of ice sheet expansion to its largest extent at the Last Glacial Maximum 21 thousand years ago remains uncertain. Here we use an Earth system model with interactive ice sheets to show that distinct initial North American (Laurentide) ice sheets at 38 thousand years ago converge towards a configuration consistent with the Last Glacial Maximum due to feedbacks between atmospheric circulation and ice sheet geometry. Notably, ice advance speed and spatial pattern in our model are controlled by the amount of summer snowfall, which is dependent on moisture transport pathways from the North Atlantic warm pool linked to ice sheet geometry. The consequence of increased summer snowfall on the surface mass balance of the ice sheet is not only the direct increase in accumulation but the indirect reduction in melt through the snow/ice–albedo feedback. These feedbacks provide an effective mechanism for ice growth for a range of initial ice sheet states and may explain the rapid North American ice volume increase during the last ice age and potentially driving growth during previous glacial periods.

Persistent climate model biases in the Atlantic Ocean's freshwater transport

Abstract. The Atlantic Meridional Overturning Circulation (AMOC) is considered to be one of the most dangerous climate tipping elements. The salt–advection feedback plays an important role in AMOC tipping behaviour, and its strength is strongly connected to the freshwater transport carried by the AMOC at 34° S, below indicated by FovS. Available observations have indicated that FovS has a negative sign for the present-day AMOC. However, most climate models of the Coupled Model Intercomparison Project (CMIP, phase 3 and phase 5) have an incorrect FovS sign. Here, we analyse a high-resolution and a low-resolution version of the Community Earth System Model (CESM) to identify the origin of these FovS biases. Both CESM versions are initialised from an observed ocean state, and FovS biases quickly develop under fixed pre-industrial forcing conditions. The most important model bias is a too fresh Atlantic Surface Water, which arises from deficiencies in the surface freshwater flux over the Indian Ocean. The second largest bias is a too saline North Atlantic Deep Water and arises through deficiencies in the freshwater flux over the Atlantic Subpolar Gyre region. Climate change scenarios branched from the pre-industrial simulations have an incorrect FovS upon initialisation. Most CMIP phase 6 models have similar biases to those in the CESM. Due to the biases, the value of FovS is not in agreement with available observations, and the strength of the salt advection feedback is underestimated. Values of FovS are projected to decrease under climate change, and their response is also dependent on the various model biases. To better project future AMOC behaviour, an urgent effort is needed to reduce biases in the atmospheric components of current climate models.

Deep carbon recycling viewed from global plate tectonics

Abstract Plate tectonics plays an essential role in the redistribution of life-essential volatile elements between Earth's interior and surface, whereby our planet has been well tuned to maintain enduring habitability over much of its history. Here we present an overview of deep carbon recycling in the regime of modern plate tectonics, with a special focus on convergent plate margins for assessing global carbon mass balance. The up-to-date flux compilation implies approximate balance between deep carbon outflux and subduction carbon influx within uncertainty but remarkably limited return of carbon to convecting mantle. If correct, carbon would gradually accumulate in the lithosphere over time by (i) massive subsurface carbon storage occurring primarily in continental lithosphere from convergent margins to continental interior and (ii) persistent surface carbon sinks to seafloors sustained by high-flux deep CO2 emissions to the atmosphere. Further assessment of global carbon mass balance requires updates on fluxes of subduction-driven carbon recycling paths and reduction in uncertainty of deep carbon outflux. From a global plate tectonics point of view, we particularly emphasize that continental reworking is an important mechanism for remobilizing geologically sequestered carbon in continental crust and sub-continental lithospheric mantle. In light of recent advances, future research is suggested to focus on a better understanding of the reservoirs, fluxes, mechanisms, and climatic effects of deep carbon recycling following an integrated methodology of observation, experiment, and numerical modeling, with the aim of decoding the self-regulating Earth system and its habitability from the deep carbon recycling perspective.

Inclusion of bedrock vadose zone in dynamic global vegetation models is key for simulating vegetation structure and function

Abstract. Across many upland environments, soils are thin and plant roots extend into fractured and weathered bedrock where moisture and nutrients can be obtained. Root water extraction from unsaturated weathered bedrock is widespread and, in many environments, can explain gradients in vegetation community composition, transpiration, and plant sensitivity to climate. Despite increasing recognition of its importance, the “rock moisture” reservoir is rarely incorporated into vegetation and Earth system models. Here, we address this weakness in a widely used dynamic global vegetation model (DGVM; LPJ-GUESS). First, we use a water flux-tracking deficit approach to more accurately parameterize plant-accessible water storage capacity across the contiguous United States, which critically includes the water in bedrock below depths typically prescribed by soil databases. Secondly, we exploit field-based knowledge of contrasting plant-available water storage capacity in weathered bedrock across two bedrock types in the Northern California Coast Ranges as a detailed case study. For the case study in Northern California, climate and soil water storage capacity are similar at the two study areas, but the site with thick weathered bedrock and ample rock moisture supports a temperate mixed broadleaf–needleleaf evergreen forest, whereas the site with thin weathered bedrock and limited rock moisture supports an oak savanna. The distinct biomes, seasonality and magnitude of transpiration and primary productivity, and baseflow magnitudes only emerge from the DGVM when a new and simple subsurface storage structure and hydrology scheme is parameterized with storage capacities extending beyond the soil into the bedrock. Across the contiguous United States, the updated hydrology and subsurface storage improve annual evapotranspiration estimates as compared to satellite-derived products, particularly in seasonally dry regions. Specifically, the updated hydrology and subsurface storage allow for enhanced evapotranspiration through the dry season that better matches actual evapotranspiration patterns. While we made changes to both the subsurface water storage capacity and the hydrology, the most important impacts on model performance derive from changes to the subsurface water storage capacity. Our findings highlight the importance of rock moisture in explaining and predicting vegetation structure and function, particularly in seasonally dry climates. These findings motivate efforts to better incorporate the rock moisture reservoir into vegetation, climate, and landscape evolution models.

Foundational guiding principles for a flourishing Earth system

AbstractIn this perspectives article, we maintain that the current local to global sustainable development predicaments we face are the result of humanity's impact on the Earth System (ES)—that is to say, on the very systemic fabric of the ES (i.e., its functioning and configuration), combined with an insufficiently coherent application of sustainable development policy to address and resolve this systemic problem. In response to what is an urgent crisis, we propose four foundational guiding principles, which we contend provide an overarching framing that, if implemented, would offer an approach to steer global sustainable development policy in a manner that would be to the benefit of the ES and the securing of a flourishing future for all. Our principles are applicable at the levels from a local business ecosystem, national‐regional networks, to global policy.

Predictability of the upper ocean heat content in a Community Earth System Model ensemble prediction system

Predictability of the upper ocean heat content in a Community Earth System Model ensemble prediction system

A machine learning approach for evaluating Southern Ocean cloud radiative biases in a global atmosphere model

Abstract. The evaluation and quantification of Southern Ocean cloud–radiation interactions simulated by climate models are essential in understanding the sources and magnitude of the radiative bias that persists in climate models for this region. To date, most evaluation methods focus on specific synoptic or cloud-type conditions that do not consider the entirety of the Southern Ocean's cloud regimes at once. Furthermore, it is difficult to directly quantify the complex and non-linear role that different cloud properties have on modulating cloud radiative effect. In this study, we present a new method of model evaluation, using machine learning that can at once identify complexities within a system and individual contributions. To do this, we use an XGBoost (eXtreme Gradient Boosting) model to predict the radiative bias within a nudged version of the Australian Community Climate and Earth System Simulator – Atmosphere-only model, using cloud property biases as predictive features. We find that the XGBoost model can explain up to 55 % of the radiative bias from these cloud properties alone. We then apply SHAP (SHapley Additive exPlanations) feature importance analysis to quantify the role each cloud property bias plays in predicting the radiative bias. We find that biases in the liquid water path are the largest contributor to the cloud radiative bias over the Southern Ocean, though important regional and cloud-type dependencies exist. We then test the usefulness of this method in evaluating model perturbations and find that it can clearly identify complex responses, including cloud property and cloud-type compensating errors.

An Ensemble Learning Model Reveals Accelerated Reductions in Snow Depth Over Arctic Sea Ice Under High‐Emission Scenarios

AbstractThere are significant differences in snow depth predictions among different earth system models, and many models underestimate snow depth, restricting their application. Here, major factors influencing snow depth changes in the Coupled Model Intercomparison Project Phase 6 (CMIP6) were identified and evaluated. Based on satellite‐derived snow depth and CMIP6 data, an ensemble learning model based on multiple deep learning methods (hereafter referred to as the Multi‐DL model) was developed to predict future snow depth. According to satellite observations and two Operation IceBridge products, the Multi‐DL model yielded root mean square errors of 7.48, 6.20, and 6.17 cm. A continuous decrease in snow depth was observed from 2002 to 2100, and the rate of decrease accelerated with increasing emissions. Under the highest emission scenario, the first snow‐free year occurred in 2047, within the same decade as the first ice‐free year (2056). The predicted warm season snow depth was sensitive to sea ice velocity, sea ice concentration (siconc), precipitation, sea surface temperature (tos) and albedo, while the predicted cold season snow depth was sensitive to tos, air temperature, and siconc. The above parameters introduce some snow depth uncertainty. This method provides new ideas for predicting snow depth, and the generated snow depth records can provide data support for formulating Arctic‐related policies.

Watermass architecture of the Ordovician-Silurian Yangtze Sea (South China) and its palaeogeographic implications

During the Late Ordovician Hirnantian Ice Age, the South China Craton experienced large changes in climate, eustasy, and environmental conditions, but their impact on the watermass architecture of the Yangtze Sea has not been thoroughly evaluated to date. Here, we reconstruct the salinity-redox structure of the Yangtze Sea based on five Upper Ordovician-lower Silurian shale successions representing a lateral transect, from a deep-water area of the Inner Yangtze Sea (IYS; Shuanghe section) across the shallow Hunan-Hubei Arch (Pengye, Jiaoye, and Qiliao sections) to the relatively deep-water Outer Yangtze Sea (OYS; Wangjiawan section). Carbon-isotope ( δ 13 C org ) profiles show that the Guanyinqiao Bed (recording peak Hirnantian glaciation) thins and is less completely preserved at sites on the flanks of the Hunan-Hubei Arch than in deeper-water areas to the SW and NE, reflecting bathymetric influences. Watermass salinities were mainly marine at Shuanghe and brackish at the other four study sites, with little variation between Interval I (pre-glaciation), Interval II (Hirnantian glaciation), and Interval III (post-glaciation). Redox proxies document mainly euxinia at Shuanghe and Wangjiawan and suboxia at the other sites during Interval I, with shifts toward more reducing (mostly euxinic) conditions at most sites during Intervals II and III, which shows that all study sections were deep enough to remain below the redoxcline during the glacio-eustatic lowstand. Two features of the Shuanghe section mark it as being unusual: it alone exhibits fully marine salinities, implying greater proximity to the open ocean than for the other four sites, and it exhibits an especially large shift toward more reducing conditions during Interval III (i.e., the post-Hirnantian transgression), implying greater water depths. These features are difficult to reconcile with the standard palaeogeographic model for the Ordovician-Silurian South China Craton, which is characterized by a geographically enclosed and restricted IYS and a more-open OYS, arguing instead for the SW end of the IYS having been connected to the global ocean and the OYS having been a restricted oceanic cul-de-sac. A review of sedimentologic and facies data for the IYS region suggests that our re-interpretation of the Ordovician-Silurian palaeogeography of the South China Craton is viable, although further vetting of this hypothesis will be needed. Thematic collection: This article is part of the Chemical Evolution of the Mid-Paleozoic Earth System and Biotic Response collection available at: https://www.lyellcollection.org/topic/collections/chemical-evolution-of-the-mid-paleozoic-earth-system Supplementary material: https://doi.org/10.6084/m9.figshare.c.7170648

The Effect of Physically Based Ice Radiative Processes on Greenland Ice Sheet Albedo and Surface Mass Balance in E3SM

AbstractA significant portion of surface melt on the Greenland Ice Sheet (GrIS) is due to dark ice regions in the ablation zone, where solar absorption is influenced by the physical properties of the ice, light absorbing constituents (LACs), and the overlying crustal surface or melt ponds. Earth system models (ESMs) typically prescribe the albedo of ice surfaces as a constant value in the visible and near‐infrared spectral regions. This work advances ESM ice radiative transfer modeling by (a) incorporating a physically based radiative transfer model (SNow, ICe and Aerosol Radiation model Adding‐Doubling Version 4; SNICAR‐ADv4) into the Energy Exascale Earth System Model (E3SM), (b) determining spatially and temporally varying bare ice physical properties over the GrIS ablation zone from satellite observations to inform SNICAR‐ADv4, and (c) assessing the impacts on simulated GrIS albedo and surface mass balance associated with modeling of more realistic bare ice albedo. GrIS‐wide bare ice albedo in E3SMv2 is overestimated by ∼4% in the visible and ∼7% in the near‐infrared wavelengths compared to the Moderate Resolution Imaging Spectroradiometer. Our bare ice physical property retrieval method found that LACs, ice crustal surfaces, and melt ponds reduce visible albedo by 30% in the bare ice region of the GrIS ablation zone. The realistic bare ice albedo reduces surface mass balance by ∼145 Gt, or 0.4 mm of sea‐level equivalent between 2000 and 2021 compared to the default E3SM. This work highlights the importance of simulating bare ice albedo accurately and realistically to improve our ability to quantify changes in the GrIS surface mass and radiative energy budgets.

An overview of the E3SM version 2 large ensemble and comparison to other E3SM and CESM large ensembles

Abstract. This work assesses a recently produced 21-member climate model large ensemble (LE) based on the U.S. Department of Energy's Energy Exascale Earth System Model (E3SM) version 2 (E3SM2). The ensemble spans the historical era (1850 to 2014) and 21st century (2015 to 2100), using the SSP370 pathway, allowing for an evaluation of the model's forced response. A companion 500-year preindustrial control simulation is used to initialize the ensemble and estimate drift. Characteristics of the LE are documented and compared against other recently produced ensembles using the E3SM version 1 (E3SM1) and Community Earth System Model (CESM) versions 1 and 2. Simulation drift is found to be smaller, and model agreement with observations is higher in versions 2 of E3SM and CESM versus their version 1 counterparts. Shortcomings in E3SM2 include a lack of warming from the mid to late 20th century, likely due to excessive cooling influence of anthropogenic sulfate aerosols, an issue also evident in E3SM1. Associated impacts on the water cycle and energy budgets are also identified. Considerable model dependence in the response to both aerosols and greenhouse gases is documented and E3SM2's sensitivity to variable prescribed biomass burning emissions is demonstrated. Various E3SM2 and CESM2 model benchmarks are found to be on par with the highest-performing recent generation of climate models, establishing the E3SM2 LE as an important resource for estimating climate variability and responses, though with various caveats as discussed herein. As an illustration of the usefulness of LEs in estimating the potential influence of internal variability, the observed CERES-era trend in net top-of-atmosphere flux is compared to simulated trends and found to be much larger than the forced response in all LEs, with only a few members exhibiting trends as large as observed, thus motivating further study.

Modulation of regional carbon uptake by AMOC and alkalinity changes in the subpolar North Atlantic under a warming climate

IntroductionThe slowdown of the Atlantic Meridional Overturning Circulation (AMOC) and associated consequences on ocean carbon uptake could have large implications for the Earth’s climate system and its global carbon cycle.MethodsThis study analyzes ten Earth System Models from the Coupled Model Intercomparison Project Phase 6 (CMIP6) and reveals that the regional carbon uptake in the subpolar North Atlantic under a high CO2 emission scenario moderately correlates with the decline in AMOC at 40°N. AMOC transports warm and salty subtropical waters to the subpolar regions.ResultsModels with stronger AMOC slowdown generally exhibit weaker surface warming and larger decline of surface salinity and alkalinity. We consider two plausible mechanisms linking the AMOC slowdown to the decline of regional CO2 uptake: the reduction in surface alkalinity and diminished subduction. The decline of surface salinity and alkalinity reduces the ocean’s capacity to buffer acids leading to a reduced CO2 uptake. This important contribution is unique to the North Atlantic. Diminished convective mixing and subduction of surface water can further decrease the downward transport of anthropogenic carbon, as also shown in previous research. The centennial trends of pCO2 are decomposed into four components driven by temperature, salinity, alkalinity and dissolved inorganic carbon, revealing that alkalinity and dissolved inorganic carbon are both significant contributors. The alkalinity-driven pCO2 essentially follows surface salinity, establishing the linkage between AMOC slowdown and alkalinity decline.DiscussionOur results indicate that alkalinity changes are important for the interplay between AMOC and the regional carbon sequestration ability across the late 20th and the entirety of the 21st century in the subpolar North Atlantic.

The Location of Large‐Scale Soil Moisture Anomalies Affects Moisture Transport and Precipitation Over Southeastern South America

AbstractSoutheastern South America (SESA) is a highly productive agricultural region and a hot spot for land‐atmosphere interactions. To evaluate the impact of dry soil moisture anomalies (SMAs) on SESA climate and the sensitivity of the regional climate response to the location of SMAs, we perform three experimental simulations using the Community Earth System Model (CESM) with prescribed dry SMAs over (a) SESA, (b) western SESA, and (c) eastern SESA. The dry SESA and eastern SESA simulations show widespread negative precipitation anomalies. In contrast, the dry western SESA simulation shows positive precipitation anomalies over northeastern Argentina, which are associated with the enhanced southward moisture flux co‐located with the South American low‐level jet exit region. A composite analysis of extremely dry cases over western SESA using reanalysis data agrees with the findings from our CESM experiment. These findings have potential implications for subseasonal forecasting in this region.

Manure fertilizer divergently affects organic and inorganic carbon in a dryland agricultural soil

AbstractSoil carbon (C) is important to support sustainable agriculture, affect global C cycling, and influence the climate system. Manure fertilization is an important and widely used practice to increase agricultural productivity and soil organic carbon (SOC) pools, whereas its effect on soil inorganic carbon (SIC) and total C in deep soils is not reported. This knowledge gap restricts our ability to accurately evaluate C budget in agricultural soils because SIC in deep soils accounts for more than half of the global soil C pools, while current earth system models rarely take them into account. Herein, we examined changes of soil C along 0‐ to 3.0‐m depth after 35 years of application of manure in a dryland agricultural ecosystem. We also measured C concentrations in soil samples (0–0.2 m) from 1985 to 2019 to evaluate C dynamics in topsoils. The objective was to understand how SIC and SOC in deep soils respond to manure fertilization in semiarid ecosystem, where SIC accounts for a large fraction of total C. We showed a divergent effect of 35 years of manure application on SOC and SIC in 0–3.0 m soil from a dryland agricultural ecosystem. Either within or across the two cropping systems examined, manure increased SOC in top 0.8 m layer but decreased SIC in 0.8–3.0 m layer, which offset SOC increase and resulted in 63.8 Mg ha−1 decrease of total C in 0–3.0 m soil layer. Given the importance of soil C for sustainable agriculture and that drylands contain 80% of the global SIC and ∼50% of world cropland, immediate attention should be paid to such divergent effects in both mechanisms understanding and model prediction.

Marine redox dynamics and biotic response to the mid-Silurian Ireviken Extinction Event in a mid-shelf setting

The early Silurian Llandovery–Wenlock boundary interval was marked by significant marine perturbations and biotic turnover, culminating in the Ireviken Extinction Event (IEE) and the Early Sheinwoodian Carbon Isotope Excursion (ESCIE). Here, we apply multiple independent redox proxies to the early Wenlock Buttington section, which was deposited in a mid-shelf location in the Welsh Basin, UK. To account for regional geochemical variability in marine sediments due to factors such as sediment provenance, we first define oxic baseline values for the Welsh basin, utilizing deeper water, well-oxygenated intervals of late Llandovery age. Our approach documents unstable, oscillating redox conditions on the mid shelf at Buttington. We suggest that these dynamic redox fluctuations are likely to relate to changes in the position of the chemocline or a migrating oxygen minimum zone. Benthic biota such as trilobites, brachiopods, bivalves and gastropods appear to have been relatively unaffected by fluctuating oxic-ferruginous conditions, but were more severely impacted by the development of euxinia, highlighting the inhibiting role of toxic sulfides. By contrast, the redox perturbations appear to have placed extreme stress on graptolites, causing many extinction losses regardless of the specific development of euxinia. Thematic collection: This article is part of the Chemical Evolution of the Mid-Paleozoic Earth System and Biotic Response collection available at: https://www.lyellcollection.org/topic/collections/chemical-evolution-of-the-mid-paleozoic-earth-system Supplementary material: https://doi.org/10.6084/m9.figshare.c.7165009

Modelling sulfate concentrations in the global ocean through Phanerozoic time

Understanding the long-term variance of seawater sulfate concentrations ([SO 4 2- ] sw ) is critical to understanding the dynamic relationship between the sulfur, carbon, calcium, and oxygen cycles, and their influence on Earth's habitability. Here, we explore how [SO 4 2- ] sw has changed throughout the Phanerozoic, and its impact on other elemental cycles. We do this by utilising the biogeochemical box model GEOCARBSULFOR. The model suggests that [SO 4 2- ] sw rose throughout the Paleozoic, declined during the Mesozoic, and then rose once more in the Cenozoic, generally matching geochemical proxies. Atmospheric oxygen mirrors [SO 4 2- ] sw changes during the Paleozoic and Mesozoic, but intriguingly, decouples during the Cenozoic. We further explored controls on [SO 4 2- ] sw by modifying the modelled gypsum fluxes via the incorporation of evaporite data from the geological record. We find that forcing gypsum burial with the observed evaporite deposition data causes the model to better match proxy records at some times, but worsens predictions at others. Finally, we investigate model reliance on a prescribed record of marine calcium concentrations, finding that it is a dominant control on modelled Phanerozoic [SO 4 2- ] sw , and that removing this control seriously degrades model predictions. We conclude that no model can yet simulate a reasonable evolution of both the calcium and sulfur cycles. Thematic collection: This article is part of the Sulfur in the Earth system collection available at: https://www.lyellcollection.org/topic/collections/sulfur-in-the-earth-system Supplementary material: https://doi.org/10.6084/m9.figshare.c.7164928

Anthropocene, planetary boundaries and tipping points: interdisciplinarity and values in Earth system science

Earth system science (ESS) and modelling have given rise to a new conceptual framework in the recent decades, which goes much beyond climate science. Indeed, Earth system science and modelling have the ambition “to build a unified understanding of the Earth”, involving not only the physical Earth system components (atmosphere, cryosphere, land, ocean, lithosphere) but also all the relevant human and social processes interacting with them. This unified understanding that ESS aims to achieve raises a number of epistemological issues about interdisciplinarity. We argue that the interdisciplinary relations in ESS between natural and social / human sciences are best characterized in terms of what is called ‘scientific imperialism’ in the literature and we show that this imperialistic feature has some detrimental epistemic and non-epistemic effects, notably when addressing the issue of values in ESS. This paper considers in particular the core ESS concepts of Anthropocene, planetary boundaries and tipping points in the light of the philosophy of science discussions on interdisciplinarity and values. We show that acknowledging the interconnections between interdisciplinarity and values suggests ways for ESS to move forward in view of addressing the climate and environmental challenges.