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A seismic stratigraphic framework and basin fill geohistory for Arctic Ocean basins is presented based on data collected by several Russian Government organized expeditions to the Arctic Ocean. This analysis tied together seismic stratigraphic interpretations for the shelf and the deep-water part of the ocean. The stratigraphic framework is based on age data derived from linear magnetic anomalies in the Eurasia Basin, borehole data for the Lomonosov Ridge and Alaska Shelf, and correlations with various regional geological events. Six seismic boundaries were identified and traced regionally over large areas. We present as a hypothesis that the Arctic Ocean probably was formed during four phases with different kinematics: 133-125 Ma – Canada Basin opening, 125-80 Ma – superplume-related tectonics and magmatism in the Alpha-Mendeleev Rise area and adjacent basins, 80-56 Ma - strike-slip fault tectonics, and 56-0 Ma – Eurasia Basin opening. The time interval of 45-20 Ma appears to be a period of large-scale vertical intraplate movements and normal faulting. Climatic events are recorded in the sedimentary cover of the Arctic Ocean. The analyses were based on a comprehensive dataset that included more than 23,000 km of 2D seismic lines, which were acquired in the deep-water part of the ocean, supplemented by a large number of federal and commercial seismic lines, which were acquired for the Russian shelves during the past 10-15 years. In addition, special multiple Russian expeditions collected samples on scarps of the Mendeleev Rise that served as ground truth for the seismic interpretation. • New seismic stratigraphy of the Arctic Ocean region. • Great Aptian to Albian continental rift and magmatic epoch. • SDRs and volcanoes in the Mendeleev Rise region. [ABSTRACT FROM AUTHOR]

Effective selection of climate predictors is a fundamental aspect of climate modeling research. Predictor Screening (PS) plays a crucial role in identifying regional climate drivers, reducing noise, expediting convergence, and minimizing time consumption, ultimately leading to the development of robust models. This review delves into the complex landscape of PS techniques within the context of Numerical Climate Modeling (NCM), with a specific focus on their applicability across various Köppen climate classifications and PS model structures. The analysis revealed substantial variations in the performance of PS methods, shedding light on their ability to capture –and prioritize predictors related to precipitation and temperature within distinct climate contexts. Furthermore, the provided methods have been categorized into two subsections: Feature Selection (FS) and Feature Extraction (FE), with FS encompassing filter, wrapper, embedded, and ensemble/hybrid techniques, and FE covering Linear Feature Extraction (LFE), Time-Domain Analysis (TDA), deep learning, and clustering methods. The initial compilation of papers, acquired through a keyword search on Scopus, consisted of 3650 documents. Following a meticulous evaluation process, 206 papers were identified as fitting for inclusion in the literature review, covering the time frame from 1974 to November 3, 2023. In conclusion, the results provide a detailed understanding of the strengths and limitations of each approach, establishing a hierarchy of effectiveness contingent upon the specific climate context. Additionally, insights into promising avenues for future research in this field are offered. This review follows the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) standard as its foundation. [ABSTRACT FROM AUTHOR]

Desertification in karst is an effect of climate change and not sustainable anthropogenic activities, the combination of which, however, causes the gradual loss of karst natural resources, such as soil, vegetation, and groundwater. A considerable percentage of global karst areas is found in drylands, characterized by negative water balance and scarce presence of soils. High fragility of the karst environment, and its vulnerability to land degradation and pollution because of the peculiar anisotropic setting, environmental dynamics, and of the direct connection between the surface and the subsurface, are at the origin of the severe problems deriving from desertification processes in karst. In addition to natural drivers, such as geology and topography, karst desertification is generally due to four main factors, mostly or partly related to human activity: deforestation, improper land use, groundwater overexploitation, and climate changes. Through the analysis of a collection of studies conducted in several karst territories around the world, the present paper aims to provide an overview of the processes leading to desertification risks in karst areas. Emphasizing the need to preserve these fragile environments, characterized by peculiar features and precious freshwater resources, this review summarizes the main situations at the global scale of rocky desertification in karst, at the same time providing indications for developing innovative and multi-disciplinary approaches addressed toward mitigation of the risk related to desertification in karst. [ABSTRACT FROM AUTHOR]

Water erosion, a notorious major threat to food security and ecosystem sustainability, is strongly conditioned by spatial and temporal scale effects. This paper systematically reviews the scale issues in runoff and sediment delivery (SIRSD) as a research field by integrating the traditional review approach and bibliometric analysis. This review summarises SIRSD's roots and the scale effect on runoff and sediment delivery. Then, we provide quantitative insights into the SIRSD domain's development history, thematic structure, geographic distribution, international cooperation, and methodologies. Findings show that: i) SIRSD arises from the gap between the non-linearity of runoff and sediment delivery across scales and our ability to measure it. Point-based and short-term measurements cannot capture the non-linearities from the spatio-temporal heterogeneities and cross-scale interactions of factors or processes. ii) Previous literature provides evidence that the spatial scaling of specific runoff (r), soil erosion (SE), sediment yield (SSY), or sediment delivery ratio (SDR) with drainage area (A) or slope length (L) exhibits contrasting patterns due to distinct mechanisms. Infiltration-excess and saturation-excess processes account for inverse and positive r - A relations, respectively. Interrill-erosion and rill-erosion cause inverse and positive SE-L relations. Hillslope-erosion and channel/bank-erosion explain inverse and positive SSY-A relations. Downstream increasing deposition and additional sediment inputs drive inverse and positive SDR-A relations. These scaling relationships can be nonlinear or complex due to spatial heterogeneities in land use, vegetation, topography, climate, lithology, and soil characteristics. Hence, applying an empirical scaling equation developed from the region with distinct environmental contexts is not recommended. Furthermore, the existing scaling patterns or equations may require updating given global climate and land use change. iii) SIRSD is a complex and multidisciplinary issue investigated by scientists from 93 countries since 1928. International research has substantially facilitated the understanding of SIRSD; still, more collaboration should focus on less-developed countries with high soil and water loss risks and urgent conservation needs, such as those in Africa and South America under cropland expansion. iv) Scale mismatch and scale break have discredited large-scale erosion and sediment assessments. Incorporating gully and bank erosion into modelling, extending the scale range of the L factor, and expanding the sediment scaling scope from watershed to slope may make a difference. Therefore, more research with nested design incorporating multiple scales is necessary for cross-scale analysis and scalable modelling. Addressing global climate change requires improving real-time urban flood forecasting and integrating downscaled climate models with hydrology, erosion, and sediment transport models. • A bibliometric review of the global SIRSD research for the first time. • SIRSD is rooted in the gap between natural nonlinearity and our measuring ability. • Scaling of specific runoff, erosion, sediment yield, and SDR has diverse patterns. • Scale mismatch and scale break discredit large-scale modelling and assessments. [ABSTRACT FROM AUTHOR]

Radon can pose a serious risk on human health. At present, radon has been considered as the second leading cause of lung cancer after smoking. The potential risk of radon exposure in cold regions of Northern Hemisphere is increasing due to climate-induced permafrost degradation. In this paper, we took permafrost regions in the Northern Hemisphere as our study area. We performed an extensive literature review on the Web of Science (WoS), China National Knowledge Infrastructure (CNKI), and Google Scholar (GS). We divided these selected literatures into three groups: Group uranium, Group radon and Group permafrost and tried to reveal the impacts of distribution of uranium deposits/u-rich rocks and permafrost/permafrost degradation on radon concentration/migration in permafrost regions. Based our research, it is evident that uranium deposits or U-rich rocks provides an abundant source of U (Ra) for soils and groundwaters in permafrost regions, resulting in abnormally high concentrations of radioactive elements in soils and groundwaters. As a natural barrier, permafrost soils could screen the radon gas from migrating into underground dwellings and work-space in cold regions. However, permafrost degradation has been extensively observed and this trend is projected to continue under a warming climate. Permafrost degradation and ground ice melting, water exchange, gas emissions and thaw settlement have enhanced the ability of radon migration into dwellings and work space, which substantially endangers human health if long exposed. Our synthesis results also underline that the related research of radon migration and relation in permafrost regions are grossly inadequate and urgently needed. Research priorities include the mechanisms of radon migration in freezing, frozen, thawing and thawed soils/rocks, responses of release of radon sequestered in permafrost soils and radon migration in groundwater systems, among many others, to permafrost degradation. [ABSTRACT FROM AUTHOR]

Soil erosion is part of the erosion-sedimentation cycle and a type of land degradation that can be caused by poor land management. This is expected to be exacerbated by climate change. The rainfall erosivity factor (R) of the Universal Soil Loss Equation (USLE) family of soil erosion models is one of the most important parameters being studied because it is heavily influenced by climate change. The determination of the R factor necessitates high-frequency precipitation data, which are unavailable for a significant portion of the globe. For decades, researchers in data-sparse regions have estimated the R factor using empirical equations that required only monthly or annual rainfall data. Unfortunately, many of these equations are outdated and susceptible to misuse. This study presents an empirical R equation based on the Modified Fournier Index (MFI) that has caused probably one of the most widespread and unnoticed errors in soil erosion research for at least 33 years. Our exhaustive literature search and analysis uncovered 125 papers with 28 incorrect R equation formulations. We discovered that the earliest incorrect publication dates back to 1989, and most of the studies were conducted in Asia (China and India). The 125 published papers have similar citation characteristics (three citations per year per paper) as other papers in the field of soil erosion modelling, and many of the 125 papers were published in well-known scientific journals. Together, they have been cited over 3300 times by international researchers. In addition, the number of incorrect papers has increased dramatically over the past few years (2015–2021), indicating that the equation is spreading more frequently than the general publication trend. Since using an incorrect R equation can result in a significant bias in estimating the R factor and, consequently, soil erosion, the incorrect use could significantly bias numerous studies. The inaccuracy also hinders global efforts like the "Global Applications of Soil Erosion Modelling Tracker (GASEMT)" to synthesize soil erosion studies worldwide to shed light on the global problem of soil erosion and to promote environmental education. Consequently, the primary objective of this paper is to contribute to the recognition of the use of incorrect R equations, thereby reducing or even preventing their further spread and thus limiting the number of studies publishing biased results. [ABSTRACT FROM AUTHOR]

This paper discusses the potential response of fluvial processes and landforms to the projected permafrost degradation and related hydrological change. Fluvial system structure is presented in the first section of the paper along with permafrost controls over its functioning, which vary across fluvial system compartments. The distinction is drawn between primarily fluvial landforms that are expected to adjust to future hydrology with less permafrost constraints, and primarily cryogenic landforms evolving in line with permafrost disturbances. The influence of permafrost on fluvial action varies across compartments: on hillslopes, permafrost mostly controls the occurrence of surface runoff, in river valleys and channels, sediment erodibility, while thermal interaction is essential for growing thermo-erosional gullies. Observed and projected changes in permafrost and hydrology are outlined, and their relevance for cryo-fluvial evolution of fluvial systems is reviewed. Based on these projections, future changes in fluvial action in each compartment are discussed. On hillslopes, where permafrost exerts important controls on hillslope hydrology, fluvial activity of overland flow is expected to decrease following the active layer deepening and decreased overland flow duration. In erosional networks, controlled by thermal interaction between runoff and permafrost terrain, higher water temperature is expected to increase the occurrence and rates of thermo-erosional gully development. In river valleys and channels, where permafrost controls the erodibility of bed and bank material, the expected fluvial feedbacks vary across scales and stream orders, and include changes in seasonality of channel deformations, increased retreat rates in lower river banks and decreased, in higher banks, along with floodplain subsidence, and minor potential for complete destabilization of existing channel patterns. Future collateral effects of fluvial change include alterations of terrestrial biogeochemical cycles and societal impact that must be accounted for in climate change adaptation and mitigation strategies. [ABSTRACT FROM AUTHOR]

Abstract: The development of a genomics-derived discipline within geology is timely, as a result of major advances in acquiring and processing geologically relevant genetic data. This paper articulates the emerging field of “geogenomics”, which involves the use of large-scale genetic data to constrain geological hypotheses. The paper introduces geogenomics and discusses how hypotheses can be addressed through collaboration between geologists and evolutionary biologists. As an example, geogenomic methods are applied to evaluate competing hypotheses regarding the timing of the Andean uplift, the closure of the Isthmus of Panama, the onset of trans-Amazon drainage, and Quaternary climate variation in the Neotropics. [Copyright &y& Elsevier]

In mountainous regions, climate change threatens cryospheric water resources, and understanding all components of the hydrological cycle is necessary for effective water resource management. Rock glaciers are climatically more resilient than glaciers and contain potentially hydrologically valuable ice volumes, and yet have received less attention, even though rock glacier hydrological importance may increase under future climate warming. In synthesising data from a range of global studies, we provide the first comprehensive evaluation of the hydrological role played by rock glaciers. We evaluate hydrological significance over a range of temporal and spatial scales, alongside the complex multiple hydrological processes with which rock glaciers can interact diurnally, seasonally, annually, decadally and both at local and regional extents. We report that although no global-extent, complete inventory for rock glaciers exists currently, recent research efforts have greatly elaborated spatial coverage. Using these research papers, we synthesise information on rock glacier spatial distribution, morphometric characteristics, surface and subsurface features, ice-storage and hydrological flow dynamics, water chemistry, and future resilience, from which we provide the first comprehensive evaluation of their hydrological contribution. We identify and discuss long-, intermediate- and short-term timescales for rock glacier storage, allowing a more balanced assessment of the contrasting perspectives regarding the relative significance of rock glacier-derived hydrological contributions compared to other water sources. We show that further empirical observations are required to gain a deeper hydrological understanding of rock glaciers, in terms of (i) their genesis and geomorphological dynamics (ii) total ice/water volume; (iii) water discharge; and (iv) water quality. Lastly, we hypothesise that at decadal and longer timescales, under future climate warming, degradation of ice within rock glaciers may represent an increasing hydrological contribution to downstream regions, and thus increased hydrological significance while rock glacier water stores persist. [ABSTRACT FROM AUTHOR]

Since its first use in the late 80's, the term chevron has been employed in numerous studies to describe large U- and V-shaped ridges found in or near shorelines worldwide. Most studies have so far focused on Bahamian chevrons that are exclusively of Late Pleistocene age, and on the supposed Holocene chevrons found in S-Madagascar and Australia. In the Bahamas, these deposits have been interpreted as the product of extreme storms at the end of the last interglacial (LIG) warm period. In contrast, the extensive chevrons complex exposed in S-Madagascar and on the western coast of Australia have been associated with a tsunami induced by a meteorite impact. Finally, several authors have also proposed a non-catastrophic (i.e. eolian) origin based on the recognized importance of wind-related processes in these coastal areas, and term such deposits parabolic dunes. In this paper, we collect and synthesize existing data on the morphology, sedimentology and age of these chevrons, and review the different interpretations proposed in the literature with the aim to lay out a consistent database to assist further investigations on these important coastal morphologies. In addition, we generated a synthesis of wind data at the three study areas, which highlights the relationship between present wind regimes and chevrons morphologies. The ubiquity of chevrons (likely actually parabolic dunes) in coastal areas around the globe and their relationship with coastal processes makes them crucial archives for reconstructing past wind regimes. [ABSTRACT FROM AUTHOR]

Abstract This paper reviews the impacts of permafrost change on hydrological and related hydrochemical, particulate and organic fluxes in small Arctic catchments. While the emphasis is directed at High Arctic systems, literature and recent developments from other Arctic regions are also included. Hydrological change, particularly a shift from nival (snowmelt) dominance to increasing pluvial (rainfall) runoff contributions has important consequences for the timing and magnitude of hydrological fluxes. A key distinction is made between thermal perturbation , where changing melt season thaw conditions result in deep thaw with minimal geomorphic or surface hydrological effects, in contrast to physical perturbation , where permafrost change results in some form of thermokarst or physical disturbance such as mass movement or enhanced erosion. The latter disturbances are commonly expressed as localized thermo erosional gullies, active layer detachments and retrogressive thaw slumps. Results from recent research emphasise the importance of hydrological connectivity in terms of the downstream effect of a particular permafrost perturbation. Well-connected systems, either at the surface as channelized flows, or in the subsurface, through new or altered active layer flow pathways, result in substantial changes in downstream fluvial fluxes. Surface hydrological connectivity of localized permafrost disturbances increases transport of suspended sediment and particulate organic matter, the latter of which is often old and comparatively labile. Exposed ice in retrogressive thaw slumps sustains discharge during the melt season, further increasing fluxes. Thermal perturbation holds a substantially greater potential downstream impact due to widespread mobilization of solutes and dissolved organic carbon and nitrogen, and several studies point to rapid microbial alteration of carbon and inorganic nitrogen transformation in the shallow subsurface. Collectively, these results point to altered runoff, sediment transport and hydrochemical fluxes with spatial and hydrological controls. [ABSTRACT FROM AUTHOR]

Abstract Global warming has already had a significant impact on social ecosystems. The Tibetan Plateau (TP), which is characterized by a cryosphere, is also recognized to have a profound influence on regional and global climate systems, as well as the ecological economy. Therefore, research on the cryosphere is of significant importance. This paper comprehensively reviews the current status and recent changes of the cryosphere (e.g., glacier, snow cover, and frozen ground) in the TP from the perspectives of observations and simulations. Because of enhanced climate warming in the TP, a large portion of glaciers have experienced significant retreat since the 1960s, with obvious regional differences. The retreat is the smallest in the TP interior, and gradually increases towards the edges. Glacier simulations are comparatively few and still under development. Snow cover is a highly sensitive element of the cryosphere and decreases with large interdecadal variations from the 1960s to the 2010s in general. Simulations of snow cover mostly focus on the mutual feedback between the snow cover anomaly, climate and atmospheric circulation. In situ observations and simulations both indicate that the mean annual temperature of frozen ground increases, causing permafrost thaw and degradation and decreasing the seasonal freeze depth of seasonally frozen ground. Under future climate warming, the cryospheric elements in the TP will continue to diminish on the whole. Studies of climate and the cryosphere are ongoing. To date, the lack of observations is the biggest challenge on the TP, resulting in a divergence of cryosphere dynamics and its simulation being a bottleneck. To overcome these issues, a strategy that combines sets of in situ and remote sensing measurements and improved numerical models is of great importance for achieving breakthroughs with respect to research on the TP cryosphere and its interaction with climate. [ABSTRACT FROM AUTHOR]

Abstract The Pontocaspian (Black Sea - Caspian Sea) region has a very dynamic history of basin development and biotic evolution. The region is the remnant of a once vast Paratethys Sea. It contains some of the best Eurasian geological records of tectonic, climatic and paleoenvironmental change. The Pliocene-Quaternary co-evolution of the Black Sea-Caspian Sea is dominated by major changes in water (lake and sea) levels resulting in a pulsating system of connected and isolated basins. Understanding the history of the region, including the drivers of lake level and faunal evolution, is hampered by indistinct stratigraphic nomenclature and contradicting time constraints for regional sedimentary successions. In this paper we review and update the late Pliocene to Quaternary stratigraphic framework of the Pontocaspian domain, focusing on the Black Sea Basin, Caspian Basin, Marmara Sea and the terrestrial environments surrounding these large, mostly endorheic lake-sea systems. [ABSTRACT FROM AUTHOR]

Developing a comprehensive understanding of the interactions between the atmosphere and the geosphere is an ever-more pertinent issue as global average temperatures continue to rise. The possibility of more frequent volcanic eruptions and more therefore more frequent volcanic ash clouds raises potential concerns for the general public and the aviation industry. This review describes the major processes involved in short- and long-term volcano–climate interactions with a focus on Iceland and northern Europe, illustrating a complex interconnected system, wherein volcanoes directly affect the climate and climate change may indirectly affect volcanic systems. In this paper we examine both the effect of volcanic inputs into the atmosphere on climate conditions, in addition to the reverse relationship – that is, how global temperature fluctuations may influence the occurrence of volcanic eruptions. Explosive volcanic eruptions can cause surface cooling on regional and global scales through stratospheric injection of aerosols and fine ash particles, as documented in many historic eruptions, such as the Pinatubo eruption in 1991. The atmospheric effects of large-magnitude explosive eruptions are more pronounced when the eruptions occur in the tropics due to increased aerosol dispersal and effects on the meridional temperature gradient. Additionally, on a multi-centennial scale, global temperature increase may affect the frequency of large-magnitude eruptions through deglaciation. Many conceptional models use the example of Iceland to suggest that post-glacial isostatic rebound will significantly increase decompression melting, and may already be increasing the amount of melt stored beneath Vatnajökull and several smaller Icelandic glaciers. Evidence for such a relationship existing in the past may be found in cryptotephra records from peat and lake sediments across northern Europe. At present, such records are incomplete, containing spatial gaps. As a significant increase in volcanic activity in Iceland would result in more frequent ash clouds over Europe, disrupting aviation and transport, developing an understanding of the relationship between the global climate and volcanism will greatly improve our ability to forecast and prepare for future events. [ABSTRACT FROM AUTHOR]

China is the country with the most population in the world, and its climate is extremely diverse due to tremendous differences in latitude, longitude, and altitude, ranging from tropical in the far south to subarctic in the far north and alpine in the higher elevations of the Qinghai-Tibetan Plateau. Accurate assessment of its modern climate change is conductive to addressing global warming threat. Along with the development of Past Global Changes (PAGES) research, the focus has changed from paleo-climate reconstructions to using paleo-data for assessing the present and predicting the future. Previous studies have been devoted to climate change assessment using modern climate observations and simulations. This paper presents a new assessment approach based on the mid-Holocene, which provides a naturally oriented warming that can be compared to modern human-made global warming. A variety of climatic data, including modern observations, paleo-climate records, CMIP5 (Coupled Model Intercomparison Project Phase 5) and PMIP3 (Paleoclimate Modelling Intercomparison Project 3) simulations, as well as lake level models, were applied in this synthesis. Numerical climate classification was introduced to evaluate climate change impacts to Chinese climate zones on various time scales. The results show that winter and summer seasons have different response to the naturally oriented mid-Holocene warming but human-made global warming makes the warming trend appear in all seasons. Temperate and continental dry winter climates expand dramatically during the mid-Holocene warm period; however, the future global warming could have few impacts to Chinese climate zones. Furthermore, the East Asian summer monsoon was strengthened obviously by the mid-Holocene warm climate and strong low-latitude insolation. There is no consistent trend both for the winter and summer monsoon on the background of human-made global warming. In this study, a new benchmark was established based on paleo-climate to evaluate the impacts of human-made global warming. [ABSTRACT FROM AUTHOR]

The ability to predict future variability of groundwater resources in time and space is of critical importance to drought management. Periodic control on groundwater levels from oscillatory climatic systems (such as the North Atlantic Oscillation) offers a potentially valuable source of longer term forecasting capability. While some studies have found evidence of the influence of such climatic oscillations within groundwater records, there is little information on how periodic signals propagate between a climatic system and a groundwater resource. This paper develops a conceptual model of this relationship for groundwater resources in Europe, based on a review of current research. The studies reviewed here reveal key spatial and temporal signal modulations between climatic oscillations, precipitation, groundwater recharge and groundwater discharge. Generally positive correlations are found between the NAO (as a dominant influence) and precipitation in northern Europe indicating a strong control on water available for groundwater recharge. These periodic signals in precipitation are transformed by the unsaturated and saturated zones, such that signals are damped and lagged. This modulation has been identified to varying degrees, and is dependent on the shape, storage and transmissivity of an aquifer system. This goes part way towards explaining the differences in periodic signal strength found across many groundwater systems in current research. So that an understanding of these relationships can be used by water managers in building resilience to drought, several research gaps have been identified. Among these are improved quantification of spatial groundwater sensitivity to periodic control, and better identification of the hydrogeological controls on signal lagging and damping. Principally, research needs to move towards developing improved predictive capability for the use of periodic climate oscillations as indicators of longer term groundwater variability. [ABSTRACT FROM AUTHOR]

River temperature has a major influence on biophysical processes in lotic environments. River temperature is expected to increase due to climate change, with potentially adverse consequences for water quality and ecosystems. Consequently, a better understanding of the drivers of river temperature space-time variability is important for developing adaptation strategies. However, existing river temperature archives are often of low resolution or short timespans, and the analysis of patterns or trends can therefore be difficult. In light of these limitations, researchers have increasingly used models to generate river temperature estimates suitable for addressing fundamental and applied questions in river science. Of these models, process-based approaches are well suited to helping improve knowledge of the mechanisms controlling river temperature, because of their ability to explore the energy (and water) fluxes responsible for temperature patterns. While process-based modelling approaches can often be more data intensive than their statistical counterparts, they offer significant advantages with regard to simulating the impacts of projected land-use or climate change, and can provide valuable insights for informing the development of statistical models at larger scales. However, a wide range of process-based river temperature models exist, and choosing the most appropriate model for a given investigation requires careful consideration. In this paper, we review the foundations of process-based river temperature modelling and critically evaluate the features and functionality of existing models with a view to helping river scientists better understand their utility. In conclusion, we discuss key considerations and limitations of currently available process-based models and advocate directions for future research. We hope that this review will enable river researchers and managers to make informed decisions regarding model selection and spur the continued refinement of process-based temperature models for addressing fundamental and applied questions in the river sciences. [ABSTRACT FROM AUTHOR]

The present paper addresses driving mechanisms of global monsoon (GM) variability and outstanding issues in GM science. This is the second synthesis of the PAGES GM Working Group following the first synthesis “The Global Monsoon across Time Scales: coherent variability of regional monsoons” published in 2014 (Climate of the Past, 10, 2007–2052). Here we introduce the GM as a planetary scale circulation system and give a brief accounting of why it exhibits regional structure. The primary driver of the GM is solar insolation, and the specific features in the underlying surface, such as land-sea distribution, topography, and oceanic circulations, are mainly responsible for the differences among regional monsoon systems. We then analyze the monsoon formation mechanisms, together with the major processes that drive monsoon variations at various timescales, including external forcings and internal feedbacks. On long time scales, external forcings often induce variability on a global scale, whereas short-term variability in regional monsoon systems is usually caused by internal feedbacks within the climate system. Finally, a number of debatable issues are discussed, with an emphasis on time scales beyond the instrumental record. These include the dual nature of the monsoon as wind and rain, the meaning of oxygen isotope in hydrological cycle, in particular of speleothem δ 18 O, the role of ice-sheet in monsoon variations, etc. In general, the GM as a system comprises a hierarchy of regional and local monsoons with various degrees of similarity, though all show coherent variability driven by a common solar forcing. The goal of the GM concept, therefore, is by no means to replace or diminish research on the regional monsoons, but to help dissect the mechanisms and controlling factors of monsoon variability at various temporal-spatial scales. [ABSTRACT FROM AUTHOR]

Soil erosion is expected to be affected by climate change. Climate changes in temperature and precipitation patterns will impact plant biomass production, infiltration rate, soil moisture, land use and crop management, and hence affect runoff and soil erosion. Close links between climate change and soil erosion have been observed in the past decades. This paper reviews the achievements regarding the impacts of climate change such as changed rainfall, vegetation cover, and land management on water erosion. More climate change models with climate scenarios and land use models should be coupled with hydrologic/erosion models to accurately predict climate change impacts. Soil erosion is expected to be affected adversely under future climate change in most case studies, although direct and indirect impacts can promote or suppress soil erosion. However, uncertainties are still involved with respect to specific influencing mechanisms and actual damages, and the impacts vary with different regions. The representation of extreme climate events should be improved in climate models. Relevant erosion processes including rill erosion, gully erosion or channel erosion need to be incorporated and differentiated in erosion models. Additionally, more research is needed to explore the impacts of crop management practices on soil erosion under future climate change. This review is intended to introduce the achievements and to point out the critical research needs to better understand and predict the responses of soil erosion to a changing climate in the future. [ABSTRACT FROM AUTHOR]

Drylands, a critical terrestrial system of the Earth due to low water availability, are known for their extensive global reach, estimated by most scientific sources at approximately 41% of the world's land area, or ~ 60 mil km 2 . However, the analysis of the global dryland areas, using new climate data, suggests a total of ~ 45% of the Earth's terrestrial area, almost 7 mil km 2 more than initially estimated. This new spatial dimension involves a wide range of environmental issues, some of which have yet to be associated with these critical global systems. This paper primarily aims to accurately quantify the global, continental and national extent of drylands by using a high-resolution climate database presently available at global level. Also, based on relevant scientific literature, this approach attempts to briefly highlight the main environmental issues (natural and anthropogenic) of the major continental and regional dryland areas. In this respect, special attention was given to the land degradation processes (water and wind erosion, vegetation degradation, salinization, soil compaction and nutrient loss), as it is known to be the main environmental perturbation in almost all dryland systems. Research shows that, given the fact that Africa and Asia have the most extensive dryland systems on Earth (each of them has almost 23 mil km 2 , or ~ 15% of the global land area), these continents are especially threatened by major environmental perturbations (desertification, in addition to other ecological and climatic disturbances such as drought, dust storms, heat waves, water stress, extreme rainfall events, wildfire, dzud, or disease emergence), which are currently affecting 46 African states (37% of the 126 states affected by aridity worldwide) and 38 Asian states (30%). Given this context, anthropogenic systems are indirectly severely threatened by the crisis generated by soaring poverty, food insecurity, population migration, and escalating conflicts and regional political instability. Moreover, in the current context of large-scale aridity identified at high latitudes, another critical threat reviewed was the cryosphere's destabilization, which can potentially accelerate climate warming by means of positive feedback mechanisms that can be triggered in the global climate system. In this respect, a major concern is attributed to permafrost melting that, against the background of a significant expansion in the terrestrial northern hemisphere (in Russia, Alaska and Canada), can generate a massive acceleration of climate warming due to the potential release of large quantities of carbon dioxide (CO 2 ) and methane (CH 4 ), which are currently stored in these frozen soils in the Arctic and sub-Arctic regions. [ABSTRACT FROM AUTHOR]

Floods do have multiple aspects: they are integral phenomena by nature. In this paper we deal with the meteorological aspects, which need to be adequately understood in order to understand the occurrence and development of floods. This holds the more as different meteorological environments and accompanying mechanisms can result in different types of heavy precipitation and so in different flood responses. In this paper, the meteorological aspects of floods are described from the perspective of a precipitation event. The characteristics, the categorisations and the ingredients of the storm systems are presented. The influences of global warming on heavy precipitation events will be discussed as well. The sequence of these aspects reads as a logical succession of the distinct topics of the meteorological aspects of a heavy precipitation event. Since floods commonly have a profound impact on environment and society, the understanding of the meteorological aspects is a first and necessary step in a challenge of dealing with floods. The ultimate goal of this step is to diminish the harmful consequences of floods as adequately as possible. [ABSTRACT FROM AUTHOR]

Known as the "third pole" and "water tower of Asia", the Tibetan Plateau (TP) is the home to the largest number of glaciers in the mid-latitudes and one of the most sensitive areas to global climate change due to its special geographical location and powerful thermodynamic effects. In recent years, the TP has been affected by exogenous pollutants and the concentrations of some pollutants have shown an increasing trend, especially light-absorbing aerosols (LAAs), when ice core records, ground- and aircraft-based field campaigns and satellite technology enabled synthesized monitoring. The enhanced warming of the vast majority of regions in TP, together with Arctic warming, and snow/ice decline, represents credible evidence of anthropogenic climate change. This paper provides a comprehensive review of studies on the sources, characteristics and climate impacts of LAAs over the TP. Adjacent to the two major emission sources of LAAs in East Asia and South Asia, the unique geographical location and climatic characteristics of the TP make it possible for TP LAAs to cause atmospheric warming and accelerated glacier melting, affecting the hydrological cycle in South Asia, East Asia and even the Northern Hemisphere, thus causing a series of serious environmental and social problems. LAAs, such as black carbon and dust, can strongly absorb solar radiation and and have significantly influence on climate change. Moreover, light-absorbing impurities (LAIs) on snow/ice can reduce the snow/ice albedo and further accelerate the snow/ice melting. Both LAAs and LAIs over the TP can induce thermodynamic feedback processes, cause significant warming of the TP and then lead to a strengthening of the early monsoon and affect the subsequent evolution of the monsoon. Many mechanisms have been proposed forth regarding how TP LAAs modulate the phase, intensity, and amplitude of the Asian climate system. A wide range of theoretical, observational, and modeling findings on TP LAAs and their climate impacts are synthesized, in which dust aerosols from drylands and black carbon from biomass burning are considered leading components. By coupling an integrated approach with state-of-the-art modeling, high temporal and fine spatial resolution remote sensing observations with increasing sampling over the TP will provide further insights into TP aerosols. • Light-absorbing aerosols warm the Tibetan Plateau, further influence climate system • The external input of light-absorbing aerosols over the Tibetan Plateau is dominant • Climate effects of light-absorbing aerosols or impurities in snow is divergent [ABSTRACT FROM AUTHOR]

Natural chemical tracers contained in moisture within unsaturated zone (USZ) sediments have very significant potential as a novel archive of past climate and palaeoenvironmental conditions in dryland environments. However, this potential has yet to be fully realised. The tracer signature is established in the near-surface zone, with evapotranspiration processes enriching the concentration inherited from input from atmospheric deposition (predominantly rainfall). This pore-moisture tracer signature then moves vertically through the USZ sediments toward the water table, producing a hydrostratigraphy that, with increasing depth, records changes to the moisture balance at the surface through time. The small fluxes of water through the USZ in dryland climates means that this hydrostratigraphy approach is particularly valuable in these environments for providing climate records longer than the instrumental data period. This paper sets out the current state of the art in the use of the USZ as an archive. We explain the nature of the USZ, the basis of the tracer technique and also the field and sampling methodologies employed. Examples of application worldwide by broad geographic region are also evaluated. This shows that the USZ hydrostratigraphy approach can be used across three key timescales: (i) decadal to multi-decadal resolution records covering hundreds of years that provide information about recent climate fluctuations and patterns of land-use change; (ii) multi-decadal through to millennial scale length records which may record wetter and drier events down to decadal scale resolution and (iii) Last Interglacial through to the Holocene records of lower resolution that indicate broad shifts over multi-millennial timescales. We also explore the questions and challenges surrounding the depositional flux of tracer inputs and the extent to which infiltration is non-uniform, before setting the agenda for their future potential use alongside related proxies for palaeohydrology. [ABSTRACT FROM AUTHOR]

Debate over what influence (if any) solar variability has had on surface air temperature trends since the 19th century has been controversial. In this paper, we consider two factors which may have contributed to this controversy: 1. Several different solar variability datasets exist. While each of these datasets is constructed on plausible grounds, they often imply contradictory estimates for the trends in solar activity since the 19th century. 2. Although attempts have been made to account for non-climatic biases in previous estimates of surface air temperature trends, recent research by two of the authors has shown that current estimates are likely still affected by non-climatic biases, particularly urbanization bias. With these points in mind, we first review the debate over solar variability. We summarise the points of general agreement between most groups and the aspects which still remain controversial. We discuss possible future research which may help resolve the controversy of these aspects. Then, in order to account for the problem of urbanization bias, we compile a new estimate of Northern Hemisphere surface air temperature trends since 1881, using records from predominantly rural stations in the monthly Global Historical Climatology Network dataset. Like previous weather station-based estimates, our new estimate suggests that surface air temperatures warmed during the 1880s–1940s and 1980s–2000s. However, this new estimate suggests these two warming periods were separated by a pronounced cooling period during the 1950s–1970s and that the relative warmth of the mid-20th century warm period was comparable to the recent warm period. We then compare our weather station-based temperature trend estimate to several other independent estimates. This new record is found to be consistent with estimates of Northern Hemisphere Sea Surface Temperature (SST) trends, as well as temperature proxy-based estimates derived from glacier length records and from tree ring widths. However, the multi-model means of the recent Coupled Model Intercomparison Project Phase 5 (CMIP5) climate model hindcasts were unable to adequately reproduce the new estimate — although the modelling of certain volcanic eruptions did seem to be reasonably well reproduced. Finally, we compare our new composite to one of the solar variability datasets not considered by the CMIP5 climate models, i.e., Scafetta and Willson, 2014's update to the Hoyt and Schatten, 1993 dataset. A strong correlation is found between these two datasets, implying that solar variability has been the dominant influence on Northern Hemisphere temperature trends since at least 1881. We discuss the significance of this apparent correlation, and its implications for previous studies which have instead suggested that increasing atmospheric carbon dioxide has been the dominant influence. [ABSTRACT FROM AUTHOR]

Damming rivers to generate hydropower can help mitigate the world's energy crisis and reduce the risk of global climate change; however, damming can also produce enormous negative effects on the environment and ecosystems. The mainstream Lancang-Mekong River within China has been planned as one of the thirteen state hydropower bases. To date, there have been six operational dams along the mainstream Lancang River, and the 15 remaining dams of the proposed Lancang cascade will be completed in the next decades. In this paper, we examined several crucial environmental changes and ecological responses that have resulted from the construction and operation of the existing dams of the Lancang cascade. The current literature and observational data suggest that the commissioned dams have led to a decline in the flood season water discharge and annual sediment flux within China's borders, reservoir aggradations, and water quality degradation in the reservoirs, which has negatively affected riverine aquatic biological communities and fish assemblages. In contrast, the dams have only had small unfavorable effects on downstream environments and ecosystems outside of China. Because of the potential environmental and geopolitical risks of the Lancang cascade dams, a long-term basin-wide terrestrial and aquatic monitoring program is urgently required to ensure that regional sustainable development occurs in the Lancang-Mekong River Basin. [ABSTRACT FROM AUTHOR]

Increasing anthropogenic pressures coupled with climate change impacts on natural resources have promoted a quest for innovative tracing techniques for understanding soil redistribution processes and assessing the environmental status of soil resources. Among the different existing tracers, the fallout component of the radioisotope lead-210, also termed unsupported or excess lead-210 ( 210 Pb ex ) when referring to its presence in soil or sediment, arguably offers the broadest potential for environmental applications, due to its origin and relatively long half-life. For more than five decades, 210 Pb ex has been widely used for dating sediments, to investigate sedimentation processes and, since the 1990s, to provide information on the magnitude of soil and sediment redistribution. The aim of this review is to provide a comprehensive evaluation and discussion of the various applications of 210 Pb ex as a tracer in terrestrial and aquatic environments, with particular emphasis on catchment sediment budget investigations. This paper summarizes the state-of-the-art related to the use of this tracer, the main assumptions, the requirements (including the need for accurate analytical measurements and for parallel validation), and the limitations which must be recognised when using this fallout radionuclide as a soil and sediment tracer. Lessons learned and current and future research needs in the environmental and radiochronological application of 210 Pb ex are also presented and discussed. [ABSTRACT FROM AUTHOR]

While global sea level has risen by 20 cm since the mid-19th century, the role of this process in present-day and past shoreline mobility is still debated. In this paper, we review previous studies that explored the relations between sea-level rise and shoreline changes over the last few decades. Existing methods can be classified into two groups: (1) approaches based on the analysis of trends and variability in shoreline change observations, which investigate whether a correlation with the temporal or spatial patterns sea level changes can be established; and (2) approaches based on the comparison of shoreline observations with a coastal model outcome, which attempt to evaluate the contribution of sea-level rise to shoreline mobility using coastal evolution modeling tools. The existing applications of these methods face two common difficulties: first, shoreline data are often lacking or insufficiently resolved temporally to capture the dynamics of coastlines; and second, relative sea level along the coast is generally only known in a limited number of areas where tide gauges are available. These two challenges can be met, owing to the increasing amount of shoreline change observations and complementary geodetic techniques. The wide range of different interpretations regarding the role of sea-level rise in recent shoreline changes highlights the necessity to conduct specific studies that rely on local observations and models applicable in the local geomorphological context. [ABSTRACT FROM AUTHOR]

Mt. Everest (Qomolangma or Sagarmatha), the highest mount on Earth and located in the central Himalayas between China and Nepal, is characterized by highly concentrated glaciers and diverse landscapes, and is considered to be one of the most sensitive area to climate change. In this paper, we comprehensively synthesized the climate and environmental changes in the Mt. Everest region, including changes in air temperature, precipitation, glaciers and glacial lakes, atmospheric environment, river and lake water quality, and vegetation phenology. Historical temperature reconstruction from ice cores and tree rings revealed the distinct features of 20th century warming in the Mt. Everest region. Meteorological observations further proved that the Mt. Everest region has been experiencing significant warming (approximately 0.33 °C/decade) but relatively stable precipitation during 1961−2018 AD. Projected results (during 2006−2099 AD) under different representative concentration pathway scenarios showed a general warming trend in the region, with larger warming occurring in winter than in summer. Meanwhile, the precipitation projections varied spatially with no significant trends over the region. Intensive glacier shrinkage was characterized by decreasing glacier areas, while glacier-fed river runoff increased. Glacial lakes expanded with increasing glacial lake areas and numbers. These findings indicated a clear regional hydrological response to climate warming. Owing to the remote location of Mt. Everest, the present atmospheric environment remained relatively clean; however, long-range transport of atmospheric pollutants from South Asia and West Asia may have substantially influenced the Mt. Everest region, resulting in increasing concentrations of pollutants since the Industrial Revolution. Anthropogenic activities have been shown to influence river and lake water quality in this remote region, especially in the downstream. The end of the vegetation growing season advanced in the northern slope and did not change in southern slope region of the Mt. Everest, and there was no significant change in start date of the growing season in the region. This review will enhance our understanding of climate and environmental changes in the Mt. Everest region under global warming. • Climate and environmental changes were synthesized in the Mt. Everest region. • Glaciers have retreated significantly, posing impacts to river runoff and glacial lakes. • Transboundary transport of atmospheric pollutants influenced the region. • TThere was no significant change in start date of the growing season. [ABSTRACT FROM AUTHOR]

The Early 20th Century Warming (ETCW) in the northern high latitudes was comparable in magnitude to the present-day warming yet occurred at a time when the growth in atmospheric greenhouse gases was rising significantly less than in the last 40 years. The causes of ETCW remain a matter of debate. The key issue is to assess the contribution of internal variability and external natural and human impacts to this climate anomaly. This paper provides an overview of plausible mechanisms related to the early warming period that involve different factors of internal climate variability and external forcing. Based on the vast variety of related studies, it is difficult to attribute ETCW in the Arctic to any of major internal variability mechanisms or external forcings alone. Most likely it was caused by a combined effect of long-term natural climate variations in the North Atlantic and North Pacific with a contribution of the natural radiative forcing related to the reduced volcanic activity and variations of solar activity as well as growing greenhouse gases concentration in the atmosphere due to anthropogenic emissions. [ABSTRACT FROM AUTHOR]

From the latest Cretaceous (late Campanian to Maastrichtian, ~75–66 Ma) to the earliest Paleogene, fluctuations in greenhouse climate, inferred primarily from marine sediments, have been linked to volcanism, the Chicxulub asteroid impact, and the Cretaceous-Paleogene (K-Pg) mass extinction. In this paper, we summarize terrestrial climate records in mid-latitude East Asia during the latest Cretaceous and across the K-Pg boundary, based on a multi-proxy approach from the geochronologically well-constrained Sifangtai and Mingshui formations (SMF), accessed by scientific drilling of the Songliao Basin in northeastern China. Evolution of sedimentary environments is characterized by five depositional units of fluvial-deltaic-lacustrine facies. Development of four types of paleosols, including Inceptisols, Aridisols, Vertisols and Alfisols, is interpreted to primarily reflect climatic changes. Correlations among sedimentary facies, paleosol features, illite chemistry index, chemical index of alteration, as well as stable and clumped isotopes of pedogenic carbonates and clay minerals of the SMF validate their reliability for paleoclimate reconstruction, and indicate significant fluctuations in terrestrial climate and sedimentary environment. During global warming intervals possibly triggered by volcanism (e.g. ~69.5–68.5 Ma), the Songliao Basin experienced a warmer and wetter climate with stronger terrestrial chemical weathering and more monsoon-derived moisture sourced from the Pacific. In contrast, during global cooling intervals (e.g. ~70.5–69.5 Ma and ~ 68.5–66.5 Ma), the SMF record a cooler and drier climate with less intensive chemical weathering and more westerlies-derived moisture. Across the K-Pg boundary, dramatic changes in land temperatures and hydroclimate correspond to the latest Maastrichtian warming episode (~66.4–66.1 Ma), the transient cooling preceding the K-Pg boundary (~66.1–66.0 Ma), and the earliest Paleogene warming interval (~66.0–65.7 Ma). Temporal correlation of weathering index changes with the Deccan Traps volcanism suggests that volcanism and subsequent intensified weathering played a major role for climatic changes across the K-Pg boundary. The integrated records of sedimentological and geochemical datasets from the Songliao Basin robustly demonstrate that the terrestrial climate of mid-latitude East Asia responded strongly to greenhouse climate changes and to the catastrophic geological events from the latest Cretaceous to the earliest Paleogene. [ABSTRACT FROM AUTHOR]

Global climate change and anthropogenic impacts lead to alterations in the water cycle, water resource availability and the frequency and intensity of floods and droughts. As a result, developing effective techniques such as hydrological modeling is essential to monitor and predict water storage changes. However, inaccuracies and uncertainties in different aspects of modeling, due to simplification of meteorological physical processes, data limitations and inaccurate climate forcing data limit the reliability of hydrological models. Satellite remote sensing datasets, especially Terrestrial Water Storage (TWS) data which can be obtained from Gravity Recovery and Climate Experiment (GRACE), provide a new and valuable source of data which can augment our understanding of the hydrologic cycle. Merging these new observations with hydrological models can effectively enhance the model performance using advanced statistical and numerical methods, which is known as data assimilation. Assimilation of new observations constrain the dynamics of the model based on uncertainties associated with both model and data, which can introduce missing water storage signals e.g., anthropogenic and extreme climate change effects. Assimilation of GRACE TWS data into hydrological models is a challenging task as provision should be made for handling the errors and then merging them with hydrological models using efficient assimilation techniques. The goal of this paper is to provide an in-depth overview of recent studies on assimilating GRACE TWS data into hydrological models and shed light on their limitations, challenges and progress. We present a comprehensive review of some challenges with GRACE TWS data assimilation into a hydrological model including GRACE TWS errors e.g., the correlated noise of high-frequency mass variations and spatial leakage errors, and how to work with GRACE TWS data errors to use the potential of GRACE TWS data as much as possible. We provide a review of the benefits and limitations of available data assimilation techniques with emphasis on the capability of sequential methods for hydrological applications. Unlabelled Image • We provide an in-depth overview of recent studies on assimilating GRACE TWS data into hydrological models. • We present a comprehensive review of some challenges with GRACE TWS data assimilation into a hydrological model. • We provide an extended review of the benefits and limitations of data assimilation methods for hydrological applications. [ABSTRACT FROM AUTHOR]

With a depositional history spanning the early Aptian to early Albian (~19 mys), the Lower Cretaceous Xinminpu Group in Jiuquan, NW China provides detailed record of an inland ecosystem responding to global climatic and environmental changes. The Xinminpu Group exhibits the most typical elements of the Jehol Biota found outside NE China, a highly diverse avifauna and a mid-Cretaceous angiosperm flora. The absence of a comprehensive stratigraphical framework for this area however limits the degree to which the unit can be interpreted relative to coeval sections and the geological records in genera. Recent fossil discoveries and radio-isotopic age data can provide a more detailed biostratigraphical and chronostratigraphical framework for Lower Cretaceous units around Jiuquan. The data complied here indicate that the Chijinpu Formation correlates with the middle-upper Yixian and lower Jiufotang formations of NE China making it early Aptian in age, and the Xiagou Formation correlates with the upper Jiufotang and Shahai formations making it late early Aptian-early Albian in age. This research further reports a novel zircon U-Pb age constraint of 112.4 ± 0.3 Ma for a basalt sample from the lowermost Zhonggou Formation, which is supported to be correlated with the Fuxin Formation of early Albian age. The Chijinpu Formation contains typical elements of the Jehol Biota, i.e. the Eosestheria - Lycoptera - Ephemeropsis trisetalis assemblage, confirming the interpretation that the Jehol Biota had reached Jiuquan during its second evolutionary stage. The Xiagou Formation contains the amphibious avifauna appearing just above OAE1a, indicating a close link between the early Ornithuromorpha evolution and early Aptian global climate changes. The Zhonggou Formation in Jiuquan records the first appearance of an angiosperm flora above OAE1b. Depositional indicators suggest a humid climate with a gradual shift to arid conditions during this time. This review paper laid foundation for the systematic study of the well-preserved Early Cretaceous ecosystem in Jiuquan, allowing to understand correlations between inland and marine environments as recorded in sediments from this critical period. • We establish the stratigraphy and time scales for the Lower Cretaceous in Jiuquan. • We review how a Cretaceous inland ecosystem responded to global climatic change. • This study summarizes the detailed fossil records for the Jehol Biota in NW China. • Robust age for the less-studied outcrops allows to test the Jehol radiations. • A close link existed between early Ornithuromorpha evolution and OAE1a. [ABSTRACT FROM AUTHOR]

This paper presents a review of Late Quaternary climatic changes and glacier variability in the Himalaya and East Africa, focusing on the role of Indian Summer Monsoon (ISM), East African monsoon, and Westerlies monsoons. Multi-proxy studies which are based on five different archives (lakes, peat bogs, speleothems, marine sediments, and ice cores) including sixty-six records from India and nearby regions, particularly in the Himalaya and in addition to six archives from the equatorial Eastern part of Africa encompasses with high-resolution published and unpublished records for the last 50 ka BP. The proxy data is discussed towards REMO-ESM model Coupled Model Intercomprasion Project phase 5 (CMIP5 Project) results. Our results indicate that both Western Himalaya and East Africa had undergone mega-droughts from ~17.0–15.0 ka BP, and precipitation had increased during the Early Holocene (10.0–7.0 Ka BP) during the time span when the Westerlies dominated regions. The model results suggest that the Westerlies monsoon has significantly contributed to the Northwestern Himalaya and somewhat to a lesser degree to the Western Himalaya and lower solar insolation in the winters did support the glacier advance during the LGM. The time series from the proxy data are compared with glacier fluctuations in different valleys to understand the response of the aforementioned monsoon system including other forcing factors which drive these variabilities. The review results indicate that the Westerlies was the main driver of the climate and glacier fluctuations in Northwestern Himalaya during the Late Quaternary. The Early and Late Holocene glacier fluctuation was mainly controlled by Westerlies precipitation in Northwestern Himalaya and the ISM controlled the glacier fluctuations in the Western Himalaya during Late Quaternary. [ABSTRACT FROM AUTHOR]

Fossil pollen records are well-established indicators of past vegetation changes. The prevalence of pollen across environmental settings including lakes, wetlands, and marine sediments, has made palynology one of the most ubiquitous and valuable tools for studying past environmental and climatic change globally for decades. A complementary research focus has been the development of statistical techniques to derive quantitative estimates of climatic conditions from pollen assemblages. This paper reviews the most commonly used statistical techniques and their rationale and seeks to provide a resource to facilitate their inclusion in more palaeoclimatic research. To this end, we first address the fundamental aspects of fossil pollen data that should be considered when undertaking pollen-based climate reconstructions. We then introduce the range of techniques currently available, the history of their development, and the situations in which they can be best employed. We review the literature on how to define robust calibration datasets, produce high-quality reconstructions, and evaluate climate reconstructions, and suggest methods and products that could be developed to facilitate accessibility and global usability. To continue to foster the development and inclusion of pollen climate reconstruction methods, we promote the development of reporting standards. When established, such standards should 1) enable broader application of climate reconstruction techniques, especially in regions where such methods are currently underused, and 2) enable the evaluation and reproduction of individual reconstructions, structuring them for the evolving open-science era, and optimising the use of fossil pollen data as a vital means for the study of past environmental and climatic variability. We also strongly encourage developers and users of palaeoclimate reconstruction methodologies to make associated programming code publicly available, which will further help disseminate these techniques to interested communities. [ABSTRACT FROM AUTHOR]

Developing future projections of shoreline change requires a good understanding of the driving coastal processes. These processes result primarily from the combination of mean sea level, waves, storm surges and tides, which are affected by global and regional climate change, and whose uncertainty increases with time. This paper reviews the current state of the art of methods used to model climate change-induced coastal erosion focusing on how climate change-related drivers and the associated uncertainty are considered. We identify research gaps, describe and analyse the key components of a comprehensive framework to derive future estimates of shoreline change and make suggestions for good practice. Within the scope of the review, we find that although significant progress has been made over the last decade, most of the studies limit uncertainty sampling to considering ranges of variation of forcing variables and ensembles of emissions scenarios, and applications with high level of probabilistic development remain few. Further research is necessary to fully (a) incorporate projected time series of coastal drivers into the erosion models, including bias correction; (b) sufficiently sample the uncertainty associated with each step of the top-down approach, including the consideration of different emission scenarios, inter- and intra-model variability, and multiple runs of erosion models or model ensembles; and (c) reduce uncertainty in shoreline change estimates by developing better datasets and model parameterisations, and progressing in detection and attribution. [ABSTRACT FROM AUTHOR]

• This study reviews and lists all Chinese papers on Devonian miospores. • The Late Devonian miospore diversity was greatly overestimated. • The rise of land plants and the oxygenation event are discussed. • The spore diversity is affected by both climate and sea-level changes. The microfossil-based pattern of the Devonian land plants of China is revised and discussed based on a new, comprehensive dataset. This dataset compiles the chronostratigraphical distribution of 1677 species belonging to 190 genera of spores and pollen from the primary literature, which covers the history of fossil Chinese terrestrial palynofloras. From this, we describe the patterns and biodiversity dynamics using both range-based and sample-based data to illustrate the main fluctuations of Devonian taxonomic richness, including rarefaction by filtering out uneven sampling. Results show that the apparent terrestrial palynofloral diversity of China increases progressively from the Early to Middle Devonian, with a genuine Givetian peak followed by a plateau persisting during the Late Devonian. Results further suggest that sampling effects may strongly influence the perception of biodiversity trends in China, as well as that the observed Late Devonian taxonomic diversification may have been greatly overestimated. Compiled evidence is discussed in the light of the global evolution of marine-terrestrial ecosystems. We hypothesize that the rise of Devonian floras may have played a remarkable role in an oceanic oxygenation event during this Period. [ABSTRACT FROM AUTHOR]

The world's primary energy requirements are supplied to a large extent by non-renewable energy resources, which has resulted in significant anthropogenic greenhouse gas emissions, leading to global warming and climate change. This issue can only be overcome by using low-emission energy means such as natural gas, geothermal energy, and solar energy. Although there is enormous potential for power generation with geothermal energy, to date commercial geothermal energy production has mostly been limited to geothermal areas with accessible heat sources, where significant amounts of fluids are available (conventional geothermal reservoirs). In recent decades, the geothermal industry has moved to utilize more challenging unconventional resources, and of these, enhanced geothermal systems (EGSs) have been steadily improving worldwide. Although knowledge of reservoir geomechanics has developed substantially thus far, technical challenges specific to EGS technology (high-temperature and -pressure environments, accelerated chemical characteristics) and critical environmental concerns have prevented the widespread utilization of EGSs. A number of research areas in geotechnical engineering, including understanding the coupled thermo-hydro-mechanical and chemical interactions in intact and fractured rock mass, the initiation and propagation of natural and artificially-induced rock fractures, the mechanisms of induced seismicity and mitigation techniques, and the exploration of non-water-based fracturing fluids, can provide crucial information on reservoir stimulation, long-term performance and the sustainability of EGS. This paper critically reviews the state-of-art of the technology, including major geotechnical and environmental concerns in EGS development. The current study aims to stimulate the discussion of sustainable EGS development among the geothermal community, highlighting the future research needs for exploration, stimulation, and long-term production. [ABSTRACT FROM AUTHOR]