Future Global Warming Scenarios Research Articles

Stronger aggregation reduces temperature sensitivity of soil organic carbon decomposition in croplands

AbstractThe temperature sensitivity (Q10) of soil organic C (SOC) decomposition is an important parameter to predict C dynamics under climate change. Given that SOC is mainly protected by aggregates and minerals, differentiating the Q10 of the two C fractions helps to explain bulk soil C dynamics. In the present study, we collected agricultural soils from adjacent paddy and upland areas in mid‐temperate (Mollisols) and subtropic (Ultisols) regions of China. We employed density fractionation to separate aggregate‐protected and free mineral‐associated C fractions of soil samples and determined the Q10 of SOC and the two C fractions at 15 and 25°C incubated conditions. Results showed that the Q10 of SOC for Mollisols were lower than that for Ultisols, with an exception of aggregates in upland soils. Aggregate‐protected C had lower Q10 than free mineral‐associated C, except in the upland Mollisols. The Q10 of SOC was negatively correlated with the proportion of C protected in aggregates, whereas it was positively correlated with the proportions of mass or C of free minerals. Given that the mass and C proportion of aggregates in bulk soils of Mollisols were 271% and 80% higher than of Ultisols, respectively, the SOC of Mollisols exhibited lower Q10 than Ultisols. Therefore, stronger soil aggregation and higher proportion of aggregate‐protected C contributed to the lower temperature sensitivity of SOC in Mollisols. Consequently, agricultural practices aimed at promoting soil aggregation will alleviate SOC loss under future global warming scenarios.

Non-linear radiative response to patterned global warming due to convection aggregation and non-linear tropical dynamics

Abstract Climate responses to global warming exhibit large dependence on the spatial pattern of sea surface temperature (SST) changes. A Green’s function (GF) approach - predicting the global climate response to a complex SST pattern change as the linear superposition of the response to finite-area SST perturbations evaluated in isolation – has been used to systematically evaluate and understand the top of atmosphere (TOA) radiation response to patterned warming. However, in general the linear GF approach fails for TOA radiation reconstruction under future global warming scenarios in coupled models. Here we show that the linear superposition of global mean TOA radiation responses to large SST warming perturbations at multiple patches (the GF approach prediction) overestimates the actual response to simultaneous multi-patch perturbation. This is because the linear superposition overestimates tropical large-scale convection aggregation strengthening upon localized heating that enhances longwave radiative cooling, which is further explained by the overestimation of circulation response and associated horizontal water vapor transport. The non-additivity of TOA radiation response is caused by the non-additivity of convection aggregation, ultimately rooted in non-linear tropical dynamics. We also demonstrate that the prediction error of the GF approach grows with decreasing patch size (equivalently, increasing patch number). We conclude that using the GF approach to predict future climate change could overestimate longwave radiative cooling and underestimate (effective) climate sensitivity. Numerical experiments may be used to identify specific perturbation patterns where the errors are smaller than the signal. Our research also highlights that an increase in the degree of large-scale convection aggregation has a non-linear and negative feedback for mean warming.

First observations on airborne prokaryotes in a subArctic Atlantic marine area

Among extreme environments, bioaerosol includes a wide range of primary atmospheric organic particles associated with and emitted by living and dead organisms. Bioaerosol samples were collected along two transects at a subArctic Atlantic spatial scale, including the eastern Fram Strait and the Greenland, Norwegian, and North Seas. This study was aimed at first estimating microscopically the prokaryotic abundance, biomass and phenotypic traits, along with the number of potential viable and respiring cells. Moreover, physiological profiles at community level were assessed. Prokaryotic abundance ranged from 104 to 107 cells m−3, with the predominance of small sized cells (0.1 μm3). Prokaryotic biomass reached higher values (mean value 233 μg C m−3) in relation to the occurrence of large sized rods. Overall, the percentage of the viable cells was lower than the dead ones, while respiring cells were in lower abundance than total cells. The physiological profiles revealed various potential metabolic pathways among the samples, highlighting the utilization of phosphate-carbon, carboxylic and amino acids. These first results on the metabolism and physiology of microbes, which survived transport in the atmosphere of the Northern Hemisphere, suggest that bioaerosol constitutes an extremely dynamic environment of remarkable ecological interest, also considering future global warming scenarios.

High thermodynamical sensitivity of CO2 emissions from a large oligotrophic-hardwater lake (Nam Co) on the Tibetan Plateau

The Tibetan Plateau (TP) has the world's largest distribution of high-alpine and saline (generally hardwater) lakes, which are expected to affect regional carbon cycling profoundly. However, the variability, and especially underlying factors controlling CO2 dynamics, across widespread hardwater lakes is poorly understood on the TP. Here, we present year-round records of surface water pCO2 from a representative hardwater lake (Nam Co) on the TP, and analyze relationships between ambient variables and pCO2 during open water (i.e., ice-free) and ice-covered months. Surface pCO2 (233.3 μatm on average) was a little oversaturated to atmosphere (219 μatm on average) during the open water season. As a CO2 source, Nam Co emitted 8.73 ± 1.06 Gg C annually, but this flux only accounted for 0.53 ± 0.06 ‰ of its total dissolved inorganic carbon pool (1.64 × 1013 g C). Regression results indicate that, during open water months, both seasonal and diurnal varying patterns of surface pCO2 were influenced predominantly by water temperature, in a quasi-marine mode, by controlling gas solubility and dissolved carbonate equilibria. Therefore, CO2 evasion was elevated during summer months, despite the lake being autotrophic (i.e., CO2 consumption via photosynthesis). By contrast, during ice-covered months the surface pCO2 was strongly related to under-ice thermodynamics, and declined nonlinear with increased inversed stratification. In the hypolimnion, as a result of extremely weak metabolism (as indicated by low dissolved oxygen depletion rates) and a combined high carbonate buffering effect, accumulation of CO2 was negligible, leading to an absence of peak effluxes of CO2 during turnover periods, compared to eutrophic freshwater lakes. We argue that, under future global warming scenarios, consideration of the impact of gradually warming lake water on thermodynamics and dissolved carbonate equilibria are vital in order to understand the future CO2 dynamics of these widespread high-altitude oligotrophic-hardwater lakes situated across the TP.

Effect of coastal hypoxia on bacterial diversity as elucidated through 16S rRNA amplicon sequencing

The formation of oxygen-depleted zones in the bottom waters is one of the most widespread phenomena in coastal areas. Upwelling episodes along India’s west coast due to the southwest monsoon increase biological productivity, further lowering the dissolved oxygen in the upwelled waters, which intensifies annually between June and October. Here, we have determined the changes in the microbial community in response to the varying oxygen levels and other physicochemical parameters at the Candolim Time Series Station using high-throughput sequencing. Amplicon Sequence Variants across all the samples collected in different seasons were mostly affiliated to the phyla Proteobacteria, Actinobacteria, Bacteroidetes, Verrucomicrobia, Chloroflexi, Firmicutes and Planctomycetes, with the most dominant being Proteobacteria (21-41%). Statistical analysis revealed that microbial diversity differed significantly with changing DO, ammonia, nitrate and nitrite concentrations during different seasons. The microbial community shift due to seasonal hypoxia results in the differential biogeochemical cycling of essential nutrients, with certain years seeing redox conditions up to sulphate reduction while certain years seeing only nitrogen loss. Future global warming scenarios will serve as a big challenge for understanding the role of microbial diversity and its implications in the cycling of natural elements.

Increased late Holocene dust activity revealed by loess accumulation rates in Central Asia

Dust from the vast arid and semi-arid regions of arid Central Asia (ACA) makes a large contribution to global-scale dust cycles. However, systematic and regional-scale reconstructions of dust activity in ACA are lacking, thus hindering the exploration of its relationship with climate change. Aeolian loess deposits provide valuable records of past dust activity and its linkages to climate. We constructed a stacked, normalized dust mass accumulation rate (MAR) record from 17 loess sections with high-resolution dating, together with a probability density record based on 189 absolute ages from 39 Holocene loess sections. These records were used to reconstruct the temporal pattern of Holocene dust activity in ACA, which shows a pronounced increase during the late Holocene. After evaluating the temporal variation of moisture conditions at different altitudes in ACA, we conclude that while dust activity during the early and middle Holocene was driven predominantly by climate change, this was not the case in the late Holocene. Taking the mountain-basin system of the Yili Basin in Xinjiang as an example, we propose that dust activity on a large spatial scale was not completely controlled by changes in moisture conditions, and that regional factors, such as fluvial geomorphic processes, played an important role in increasing the materials supply to the areas of dust accumulation. We speculate that dust activity may intensify in ACA under future global warming scenarios.

Modeling of Human Rabies Cases in Brazil in Different Future Global Warming Scenarios.

Bat species have been observed to have the potential to expand their distribution in response to climate change, thereby influencing shifts in the spatial distribution and population dynamics of human rabies cases. In this study, we applied an ensemble niche modeling approach to project climatic suitability under different future global warming scenarios for human rabies cases in Brazil, and assessed the impact on the probability of emergence of new cases. We obtained notification records of human rabies cases in all Brazilian cities from January 2001 to August 2023, as reported by the State and Municipal Health Departments. The current and future climate data were sourced from a digital repository on the WorldClim website. The future bioclimatic variables provided were downscaled climate projections from CMIP6 (a global model ensemble) and extracted from the regionalized climate model HadGEM3-GC31-LL for three future socioeconomic scenarios over four periods (2021-2100). Seven statistical algorithms (MAXENT, MARS, RF, FDA, CTA, GAM, and GLM) were selected for modeling human rabies. Temperature seasonality was the bioclimatic variable with the highest relative contribution to both current and future consensus models. Future scenario modeling for human rabies indicated a trend of changes in the areas of occurrence, maintaining the current pace of global warming, population growth, socioeconomic instability, and the loss of natural areas. In Brazil, there are areas with a higher likelihood of climatic factors contributing to the emergence of cases. When assessing future scenarios, a change in the local climatic suitability is observed that may lead to a reduction or increase in cases, depending on the region.

Predicting the potential distribution of 12 threatened medicinal plants on the Qinghai-Tibet Plateau, with a maximum entropy model.

Climate change is a vital driver of biodiversity patterns and species distributions, understanding how organisms respond to climate change will shed light on the conservation of endangered species. In this study, the MaxEnt model was used to predict the potential suitable area of 12 threatened medicinal plants in the QTP (Qinghai-Tibet Plateau) under the current and future (2050s, 2070s) three climate scenarios (RCP2.6, RCP4.5, RCP8.5). The results showed that the climatically suitable habitats for the threatened medicinal plants were primarily found in the eastern, southeast, southern, and some parts of the central regions on the QTP. Moreover, 25% of the threatened medicinal plants would have reduced suitable habitat areas within the next 30-50 years in the different future global warming scenarios. Among these medicinal plants, RT (Rheum tanguticum) would miss the most habitat (98.97%), while the RAN (Rhododendron anthopogonoides) would miss the least habitat (10.15%). Nevertheless, 33.3% of the threatened medicinal plants showed an increase in their future habitat area because of their physiological characteristics which are more adaptable to a wide range of climates. The climatic suitable habitat for 50% of the threatened medicinal plants would migrate to higher altitudes or higher latitudes regions. This study provides a data foundation for the conservation of biodiversity and wild medicinal plants on the QTP.

Early warning and management of invasive crop pests under global warming: estimating the global geographical distribution patterns and ecological niche overlap of three Diabrotica beetles.

Invasive alien pests (IAPs) pose a major threat to global agriculture and food production. When multiple IAPs coexist in the same habitat and use the same resources, the economic loss to local agricultural production increases. Many species of the Diabrotica genus, such as Diabrotica barberi, Diabrotica undecimpunctata, and Diabrotica virgifera, originating from the USA and Mexico, seriously damaged maize production in North America and Europe. However, the potential geographic distributions (PGDs) and degree of ecological niche overlap among the three Diabrotica beetles remain unclear; thus, the potential coexistence zone is unknown. Based on environmental and species occurrence data, we used an ensemble model (EM) to predict the PGDs and overlapping PGD of the three Diabrotica beetles. The n-dimensional hypervolumes concept was used to explore the degree of niche overlap among the three species. The EM showed better reliability than the individual models. According to the EM results, the PGDs and overlapping PGD of the three Diabrotica beetles were mainly distributed in North America, Europe, and Asia. Under the current scenario, D. virgifera has the largest PGD ranges (1615 × 104 km2). In the future, the PGD of this species will expand further and reach a maximum under the SSP5-8.5 scenario in the 2050s (2499 × 104 km2). Diabrotica virgifera showed the highest potential for invasion under the current and future global warming scenarios. Among the three studied species, the degree of ecological niche overlap was the highest for D. undecimpunctata and D. virgifera, with the highest similarity in the PGD patterns and maximum coexistence range. Under global warming, the PGDs of the three Diabrotica beetles are expected to expand to high latitudes. Identifying the PGDs of the three Diabrotica beetles provides an important reference for quarantine authorities in countries at risk of invasion worldwide to develop specific preventive measures against pests.

Distribution of denitrifiers predicted by correlative niche modeling of changing environmental conditions and future climatic scenarios across the Baltic Sea

Denitrifying microbial communities provide an important ecosystem function in aquatic systems. Yet, knowledge on predictive and modeling of these complex and changing communities is limited. The emergently challenging question of how the geographical distribution of denitrifiers responds to ongoing and future environmental change is not yet fully understood. In our study we use metadata-based correlative niche modeling to analyze the geographical distribution of selected putative denitrifiers in the genus Sphingomonas, Mycoplana, Shewanella, and Alteromonas at different predicted environmental conditions and future climatic scenarios across the Baltic Sea. Using the predictive power of an ensemble modeling approach and eight different machine-learning algorithms, habitat suitability and the distribution of the selected denitrifiers were evaluated using geophysical and bioclimatic variables, benthic conditions, and four Representative Concentration Pathway (RCP) trajectories of future global warming scenarios. All algorithms provided successful prediction capabilities both for variable importance, and for habitat suitability with Area Under the Curve (AUC) values between 0.89 and 1.00. Model findings revealed that salinity and nitrate concentrations significantly explained the variation in distribution of the selected denitrifiers. Rising temperatures of 0.8 to 1.8 °C at future RCP60–2050 trajectories are predicted to diminish or eliminate the bioclimatic suitable habitats for denitrifier distributions across the Baltic Sea. Multi-collated terrestrial and marine environmental variables contributed to the successful prediction of denitrifier distributions within the study area. The correlative niche modeling approach with high AUC values presented in the study allowed for accurate projections of the future distributions of the selected denitrifiers. The modeling approach can be used to improve our understanding of how ongoing and predicted future environmental changes may affect habitat suitability for organisms with denitrification capacity across the Baltic Sea.

Holocene extreme hydroclimate events in the Asian monsoon region were more frequent during cooler intervals

The areas affected by the East and South Asian monsoons contain almost half the world’s population. Understanding natural variability in these monsoons under warmer climates is critical for managing future changes. Here we present a high-resolution record of Holocene drought events derived from lake level changes in the South Asian monsoon region. By combining the published storm events in the East Asian monsoon region, we demonstrate that extreme hydroclimate events frequently occurred within a ca. 500-year cycle during the cool early-late Holocene, exhibiting a fierce Asian monsoon. In contrast, there were fewer extreme hydroclimate events during the warm mid-Holocene period. We propose that tropical temperatures and air-sea interaction in the Indo-Pacific Oceans are responsible for the occurrences of centennial-scale extreme events. Our findings suggest that tropical influences can module climate responses in monsoon regions, and the Asian monsoon may be more peaceful than hitherto expected under future global warming scenarios.

Drought‐tolerant succulent plants as an alternative crop under future global warming scenarios in sub‐Saharan Africa

AbstractGlobally, we are facing an emerging climate crisis, with impacts to be notably felt in semiarid regions across the world. Cultivation of drought‐adapted succulent plants has been suggested as a nature‐based solution that could: (i) reduce land degradation, (ii) increase agricultural diversification and provide both economic and environmentally sustainable income through derived bioproducts and bioenergy, (iii) help mitigate atmospheric CO2 emissions and (iv) increase soil sequestration of CO2. Identifying where succulents can grow and thrive is an important prerequisite for the advent of a sustainable alternative ‘bioeconomy’. Here, we first explore the viability of succulent cultivation in Africa under future climate projections to 2100 using species distribution modelling to identify climatic parameters of greatest importance and regions of environmental suitability. Minimum temperatures and temperature variability are shown to be key controls in defining the theoretical distribution of three succulent species explored, and under both current and future SSP5 8.5 projections, the conditions required for the growth of at least one of the species are met in most parts of sub‐Saharan Africa. These results are supplemented with an analysis of potentially available land for alternative succulent crop cultivation. In total, up to 1.5 billion ha could be considered ecophysiologically suitable and available for succulent cultivation due to projected declines in rangeland biomass and yields of traditional crops. These findings may serve to highlight new opportunities for farmers, governments and key stakeholders in the agriculture and energy sectors to invest in sustainable bioeconomic alternatives that deliver on environmental, social and economic goals.

What distribution models of alligator weed in its native and invaded ranges tell us about its invasion story and biological control

AbstractEcological niche models of species occurrence have gained interest in biological control programs to improve efficiency, reduce risks, and to inform when and how control agents may be released and/or surveyed. Alligator weed, Alternanthera philoxeroides (Mart.) Griseb. (Amaranthaceae), is an amphibious aquatic plant native to southern South America that has invaded several countries around the world. In this study, our aim was to quantify the current and to model the future alligator weed geographical distributions in its native range in South America, and in its introduced range (USA, the country where biological control of the weed was first implemented). Additionally, we modelled the current and potential distribution of its biocontrol agent Agasicles hygrophila Selman & Vogt (Coleoptera: Chrysomelidae), released in the USA in 1964, and other potential biocontrol agents, including the flea beetles Disonycha argentinensis Jacoby and Systena sp. In total, 19438 occurrence records of alligator weed, 253 of A. hygrophila, 48 of D. argentinesis, and 19 of Systena sp. were compiled. Niche models predicted expanded distributions of alligator weed, particularly in northern regions of South America. However, the models of the flea beetles A. hygrophila, D. argentinensis, and Systena sp. did not predict geographic range expansion and the future scenarios are similar to current distributions. Our study predicts an increase in the suitable areas for alligator weed in South America in future scenarios of global warming, whereas these new areas would not be as favourable for the biocontrol agents historically used.

Increasing compound drought and hot event over the Tibetan Plateau and its effects on soil water

Climate extremes, such as droughts and hot events, are expected to become more frequent and intense as the Earth’s climate continues to change. Indeed, they will likely pose increasingly serious threats to both humanity and the sustainability of natural ecosystems. Compound climate extremes may significantly impact regions sensitive to climate change, such as the Tibetan Plateau (TP), although there is currently a notable lack of research on compound extreme drought and hot events (CEDHs) that affect this region. We employed the copula model using the standardized precipitation index (SPI), standardized temperature index (STI), and standardized soil moisture index (SSMI) to explore patterns of changes in CEDHs and assess the risk of soil water scarcity under CEDHs. Our results showed that the probability of CEDHs increased significantly across the TP over time, mainly due to hot events becoming more common. The conditional probability of soil water scarcity (SSMI < -0.8) under moderate CEDHs (defined as SPI < − 0.8 and STI > 0.8) increased by 81.8% and 21.4% over time compared with those under individual hot and dry conditions, respectively. Our findings have important implications for mitigating the impacts of CEDHs under future global warming scenarios.

Hawaiian coral holobionts reveal algal and prokaryotic host specificity, intraspecific variability in bleaching resistance, and common interspecific microbial consortia modulating thermal stress responses

Historically, Hawai‘i had few massive coral bleaching events, until two consecutive heatwaves in 2014–2015. Consequent mortality and thermal stress were observed in Kāne‘ohe Bay (O‘ahu). The two most dominant local species exhibited a phenotypic dichotomy of either bleaching resistance or susceptibility (Montipora capitata and Porites compressa), while the third predominant species (Pocillopora acuta) was broadly susceptible to bleaching. In order to survey shifts in coral microbiomes during bleaching and recovery, 50 colonies were tagged and periodically monitored. Metabarcoding of three genetic markers (16S rRNA gene ITS1 and ITS2) followed by compositional approaches for community structure analysis, differential abundance and correlations for longitudinal data were used to temporally compare Bacteria/Archaea, Fungi and Symbiodiniaceae dynamics. P. compressa corals recovered faster than P. acuta and Montipora capitata. Prokaryotic and algal communities were majorly shaped by host species, and had no apparent pattern of temporal acclimatization. Symbiodiniaceae signatures were identified at the colony scale, and were often related to bleaching susceptibility. Bacterial compositions were practically constant between bleaching phenotypes, and more diverse in P. acuta and M. capitata. P. compressa's prokaryotic community was dominated by a single bacterium. Compositional approaches (via microbial balances) allowed the identification of fine-scale differences in the abundance of a consortium of microbes, driving changes by bleaching susceptibility and time across all hosts. The three major coral reef founder-species in Kāne‘ohe Bay revealed different phenotypic and microbiome responses after 2014–2015 heatwaves. It is difficult to forecast, a more successful strategy towards future scenarios of global warming. Differentially abundant microbial taxa across time and/or bleaching susceptibility were broadly shared among all hosts, suggesting that locally, the same microbes may modulate stress responses in sympatric coral species. Our study highlights the potential of investigating microbial balances to identify fine-scale microbiome changes, serving as local diagnostic tools of coral reef fitness.

Threatened birds face new distribution under future climate change on the Qinghai-Tibet Plateau (QTP)

The Qinghai-Tibet Plateau (QTP) contains a significant amount of biodiversity which provides a wide range of habitats for a great quantity of wildlife, especially various birds, on account of the unique climatic conditions and geography. However, the QTP has shown more sensitivity and vulnerability to global climate change than other regions, and the change pose a threat to the birds. Here, we used the MaxEnt and the barycenter shift analysis for analyzing the effects of global warming on the potential future habitat of the threatened birds on the QTP by using the ACCESS-ESM1-5 global climate model of the Coupled Model Intercomparison Projects Phase 6 (cmip6) climate pattern with three Shared Socioeconomic Pathway (SSP). The results demonstrated that the climatically suitable habitats for the threatened birds are mainly distributed in the eastern and central regions of the QTP. Moreover, over 81% of the threatened birds would experience a reduction in suitable habitat area within the next 30–50 years in the different future global warming scenario. Satyr tragopan (Tragopan satyra) would lose the most habitat (57.15%), while the Tibetan babax (Pterorhinus koslowi) would lose the least (0.35%) in comparing to these birds. Nonetheless, some threatened birds showed an increase in their future habitat area because of their physiological characteristics which are more adaptable to a wide range of climate. The climatic suitable habitat for all the threatened birds, except for the Tibetan eared pheasant (Crossoptilon harmani), would move to higher altitudes or higher latitudes regions. Simultaneously, the threatened birds in the order of Galliformes had a higher risk of extinction due to their weak flight and extended migratory distances on the QTP in the future. Our study provides provide a data foundation for the conservation of biodiversity and wild birds on the QTP.

Nitrogen availability mediates soil carbon cycling response to climate warming: A meta-analysis.

Global climate warming may induce a positive feedback through increasing soil carbon (C) release to the atmosphere. Although warming can affect both C input to and output from soil, direct and convincing evidence illustrating that warming induces a net change in soil C is still lacking. We synthesized the results from field warming experimentsat165sites across the globe and found that climate warming had no significant effect on soil C stock. On average, warming significantly increased root biomass and soil respiration, but warming effects on root biomass and soil respiration strongly depended on soil nitrogen (N) availability. Under high N availability (soil C:N ratio < 15), warming had no significant effect on root biomass, but promoted the coupling between effect sizes of root biomass and soil C stock. Under relative N limitation (soil C:N ratio > 15), warming significantly enhanced root biomass. However, the enhancement of root biomass did not induce a corresponding C accumulation in soil, possibly because warming promoted microbial CO2 release that offset the increased root C input. Also, reactive N input alleviated warming-induced C loss from soil, but elevated atmospheric CO2 or precipitation increase/reduction did not. Together, our findings indicate that the relative availability of soil C to N (i.e., soil C:N ratio) critically mediates warming effects on soil C dynamics, suggesting that its incorporation into C-climate models may improve the prediction of soil C cycling under future global warming scenarios.

Late Cenozoic cooling restructured global marine plankton communities.

The geographic ranges of marine organisms, including planktonic foraminifera1, diatoms, dinoflagellates2, copepods3 and fish4, are shifting polewards owing to anthropogenic climate change5. However, the extent to which species will move and whether these poleward range shifts represent precursor signals that lead to extinction is unclear6. Understanding the development of marine biodiversity patterns over geological time and the factors that influence them are key to contextualizing these current trends. The fossil record of the macroperforate planktonic foraminifera provides a rich and phylogenetically resolved dataset that provides unique opportunities for understanding marine biogeography dynamics and how species distributions have responded to ancient climate changes. Here we apply a bipartite network approach to quantify group diversity, latitudinal specialization and latitudinal equitability for planktonic foraminifera over the past eight million years using Triton, a recently developed high-resolution global dataset of planktonic foraminiferal occurrences7. The results depict a global, clade-wide shift towards the Equator in ecological and morphological community equitability over the past eight million years in response to temperature changes during the late Cenozoic bipolar ice sheet formation. Collectively, the Triton data indicate the presence of a latitudinal equitability gradient among planktonic foraminiferal functional groups which is coupled to the latitudinal biodiversity gradient only through the geologically recent past (the past two million years). Before this time, latitudinal equitability gradients indicate that higher latitudes promoted community equitability across ecological and morphological groups. Observed range shifts among marine planktonic microorganisms1,2,8 in the recent and geological past suggest substantial poleward expansion of marine communities even under the most conservative future global warming scenarios.

Evaluation and projection of precipitation extremes under 1.5°C and 2.0°C GWLs over China using bias-corrected CMIP6 models

China is facing an increasing challenge from severe precipitation-related extremes with accelerating global warming. In this study, using a bias-corrected CMIP6 ensemble, future responses of precipitation extreme indices at 1.5°C and 2.0°C global warming levels (GWLs) under the SSP245, SSP370 and SSP585 scenarios are investigated. Despite different change magnitudes, extreme precipitation events will be more frequent and more intense over China as a whole under higher emissions and GWLs. The increase in annual total precipitation could attribute to a sharp increase in the intensity and days of very heavy precipitation in future global warming scenarios. Limiting global warming to 1.5°C and low emission pathways (i.e., SSP245) instead of 2°C and high emission pathways (i.e., SSP585) would have substantial benefits for China in terms of reducing occurrences of extreme precipitation events.

Spatiotemporal evolution of global long-term patterns of soil moisture

Surface soil moisture (SM) is essential for existence of biotic lifeform and geophysical processes. However, with increasing global warming due to climatic changes, its spatiotemporal evolution is uncertain and largely unknown. In this study we detected long-term (40 years; 1981–2020) SM patterns of global vegetated areas through spatial timeseries clustering using the state-of-the-art ERA5-Land dataset. In addition, we also analyzed long-term patterns of precipitation (P), evapotranspiration (bare soil evaporation (BSe) and vegetation transpiration (VT)), and normalized difference vegetation index (NDVI). Our results indicate that surface SM (0–7 cm depth) of about 48 % and 9 % of the global vegetated area is showing drying and wetting pattern over the past 40 years, respectively. The detected soil drying, and wetting patterns were largely consistent across different soil depth, with 90 % and 80 % pattern similarity of surface soil layer with 2nd soil layer (7–28 cm) and 3rd soil layer (28–100 cm), respectively. About 80 % of areas with drying soil pattern also showed increasing evapotranspiration and/or decreasing precipitation. Specifically, decreasing P, increasing BSe and VT pattern were detected for 11 % of the soil drying pattern area. Similarly, increasing BSe and VT pattern, only decreasing P and only increasing VT pattern were detected for 17 %, 25 % and 12 % of soil drying areas, respectively. Both decreasing precipitation and increasing evapotranspiration patterns showed about 40 % similarity with decreasing soil moisture patterns. Across different landcover types, broadleaved forests, and cropland areas showed largest drying pattern. Under the future global warming scenario, the global soil water is expected to decrease as evapotranspiration would increase with inconsistent trend of global precipitation change. Our findings are of utmost importance for global soil water resource conservation and management.