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The densely populated coast of the Gulf of Guinea (GoG) is experiencing escalating erosion from climate change (CC). To assess Longshore Sediment Transport (LST) changes in the past and future, an empirical formula was used to model the GoG's LST. Nearshore wave conditions, crucial for LST estimation, were derived by projecting significant wave height, mean wave period, and mean wave direction from deep water to the breaker zone. These wave conditions were used as input for LST computation. Analysing three time slices: Past (1979–2005), mid-century (2026–2045), and end-century (2081–2100) under RCPs 4.5 and 8.5, results indicate continuous increase in LST in most locations, with local and seasonal variations. LST magnitudes range from 104 to 105 m3y−1 in the GoG, with the Cameroonian coast having the least. This aligns with the rising wave energy from CC. LST directions are predominantly eastward, though some locations, like off Lagos and Cameroon-Gabon coasts, show westward trend, correlating with coastal orientation influenced by southward wave directions. RCP 8.5 projections suggest mid-century increase, intensifying by end of century, with yearly rates of change around 103 m3y−1 and future LST changes up to 105 m3y−1. This situation implies accelerated sediment removal, heightening erosion. [ABSTRACT FROM AUTHOR]

This study identifies and summarizes potential risks to operations, regulatory compliance, supply chains, and infrastructure of the electric power industry from changing surface water conditions resulting from global climate change. The results help inform companies/utilities seeking to incorporate climate change risk in their planning and decision‐making processes by ranking risk severity and likelihood of occurrence on both a regional basis and by risk receptor. The assessment includes identification of potential risks to: (1) thermal generating, (2) hydroelectric, (3) land‐based renewable generating, and (4) transmission and distribution assets. These risks may result from such projected changes as reduced water availability (e.g., for hydroelectric or once‐through cooling), increased water temperatures (e.g., decrease in cooling efficiency, inability to meet discharge permit conditions), increased flood severity (e.g., increased streambank erosion and/or damage to river‐adjacent infrastructure), and decreased water quality (e.g., from increased transport of sediment and dissolved solids). The potential risks identified from this qualitative risk‐assessment are documented in a graphical format depicting both severity and likelihood. This approach allows for comparison of risks across a portfolio and for future prioritization of adaptation strategies. A total of 32 risks were identified in the study, including nine risks to infrastructure, six risks to operations, four risks to supply chain, and 13 environmental/regulatory risks. [ABSTRACT FROM AUTHOR]

Atolls islands are biogenic landforms that are intrinsically capable of adjusting their size, position, and elevation to changing sea levels. The vulnerability of atoll islands to sea level rise is not intrinsically due to their low elevation but primarily due to the loss of their island building capacity. The geophysical processes that control atoll island accretion are being impacted on global and local scales. Protecting and restoring the natural geophysical processes of atoll island accretion through local conservation actions is key to unlocking nature-based opportunities for enhancing atoll resilience to global change. Atoll islands are often perceived as inevitably lost due to rising sea levels. However, unlike other islands, atoll islands are dynamic landforms that have evolved, at least historically, to vertically accrete at a pace commensurate with changing sea levels. Rather than atoll islands' low elevation per se , the impairment of natural accretion processes is jeopardising their persistence. While global marine impacts are deteriorating coral reefs, local impacts also significantly affect accretion, together potentially tipping the scales toward atoll island erosion. Maintaining atoll island accretion requires intact sediment generation on coral reefs, unobstructed sediment transport from reef to island, and available vegetated deposition sites on the island. Ensuring the persistence of atoll islands must include global greenhouse gas emission reduction and local restoration of accretion processes. [ABSTRACT FROM AUTHOR]

Shorelines face growing threats due to climate change and diminishing sand supply. Coastal headlands, common rocky features along coastlines, are crucial in shaping hydrodynamics and sediment transport. Yet, the influence of future climate conditions, including sea‐level rise (SLR) and intensified storm energy on complex shorelines with headlands has remained relatively unexplored. In this study, we model changes in hydrodynamics and headland bypassing under different SLR and higher storm wave scenarios. Our findings reveal the formation of circulation cells on both sides of a headland, where wave energy converges around the headland zone. Future climate conditions result in larger storm waves on the beach. However, SLR enhances nearshore currents through a landward shifting of the circulation cells, while higher storm waves intensify offshore flow currents due to the seaward movement of the cells. This effect, in turn, increases the potential for headland sediment bypassing. Plain Language Summary: Coastal headlands, prominent rocky features along open coastlines, play a crucial role in protecting nearby beaches from strong waves and erosion. They also affect how sand is exchanged between different beaches. We use a model to explore how future climate conditions including sea‐level rise (SLR) and larger storm waves influence coastal waves, littoral currents, and the transport of sand around headlands. Our findings reveal that headlands converge wave energy forming circulation flow cells. SLR results in stronger nearshore currents, driven by the landward movement of the rotating flow cells. In contrast, larger storm waves can move the rotating flow cells seaward, thereby increasing offshore current strength and the potential for sand transport around the headland. Understanding how coastal waves, flow and sediment transport change under future climate conditions will help determine coastal resilience. Key Points: The formation of circulation cells and wave energy convergence around headlands during storms reduce bottom shear stress at the beachSea‐level rise increases wave heights, currents, and bed shear stress in the nearshore because of landward shifting of the circulation cellsHigher storm waves expand the surf zone, shift circulation cells seaward, and enhance potential headland sediment bypassing [ABSTRACT FROM AUTHOR]

Climate change affects cryosphere-fed rivers and alters seasonal sediment dynamics, affecting cyclical fluvial material supply and year-round water-food-energy provisions to downstream communities. Here, we demonstrate seasonal sediment-transport regime shifts from the 1960s to 2000s in four cryosphere-fed rivers characterized by glacial, nival, pluvial, and mixed regimes, respectively. Spring sees a shift toward pluvial-dominated sediment transport due to less snowmelt and more erosive rainfall. Summer is characterized by intensified glacier meltwater pulses and pluvial events that exceptionally increase sediment fluxes. Our study highlights that the increases in hydroclimatic extremes and cryosphere degradation lead to amplified variability in fluvial fluxes and higher summer sediment peaks, which can threaten downstream river infrastructure safety and ecosystems and worsen glacial/pluvial floods. We further offer a monthly-scale sediment-availability-transport model that can reproduce such regime shifts and thus help facilitate sustainable reservoir operation and river management in wider cryospheric regions under future climate and hydrological change. [ABSTRACT FROM AUTHOR]

During their flow through an area, the streams are used to erode, transport and re-deposit sediments in the number of cycles following the climatic variation in an area. This cycle in turn affect the chemistry of these sediments and hence the geochemical study of these sediments helps to understand the palaeo-climate, source-area weathering and provenance of the study area. In order to understand the geochemical classification of sediments, palaeo-climate, source-area weathering and provenance for stream sediments of the Eastern Ghats Mobile Belt (EGMB), 364 stream sediment samples were collected from the area around Daringbadi, Kandhamal district, Odisha, India and analyzed for major oxides, trace elements and rare earth elements. These sediments are geochemically classified as shaly and wacke type, moderately mature and derived through the high intensity of weathering of source rock under warm and humid climatic condition. The positive correlation between Al2O3 and Fe2O3, MnO, and MgO, indicates multiple sources for sediment and these oxides are associated with clay minerals. The discrimination function diagram suggests a felsic igneous as well as quartzo-sedimentary provenance for these sediments whereas the ratio of Al2O3/TiO2 and concentration of V-Ni-Th suggest a felsic igneous source rock. The high concentration of LREE, slight enrichment of HREE and negative Eu anomaly indicate terrestrial or continental crust source rock. Hence the source rock for these sediments are granite gneiss, charnokite and khondalite present in and around Daringbadi area. [ABSTRACT FROM AUTHOR]

Hydrological connectivity plays a major role in solving water resource and eco-environmental problems. However, this phenomenon has not been afforded the attention it deserves. The detailed analysis of connectivity in river systems could provide considerable insight into the structural and functional attributes of riverine landscapes. The current study used a graph theory approach and associated connectivity indicators to explore the characteristics and evolution of river systems and hydrological connectivity in a large catchment (Poyang Lake, China). The results revealed that the structure of the river system tended to be complex during 1990–2020, characterized by a dynamic evolution of tributaries in certain northern areas. Both river density and complexity exhibited an increasing trend by up to 15%, with the change rate after 2000 approximately twice as high as that of the preceding period. Overall, human activities across the catchment were more likely to play a key role in leading to significant changes in the quantity, morphometric, and structural characteristics of the river system. Additionally, the functional connectivity analysis indicated that the index of connectivity (IC) in the downstream catchment was stronger than that of the upstream vegetation areas, suggesting a strong contribution to the runoff sediment transport (r = 0.6–0.7). This study highlights the spatial and temporal evolution of both structural and functional connectivity in the large Poyang Lake catchment. The findings of this work will benefit future water resource management and applications by providing a strategy for protecting the surface hydrology and mass transport of large river basins under climate and land use changes. [ABSTRACT FROM AUTHOR]

Alluvial rivers aggrade, incise, and adjust their sediment‐transport rates in response to changing sediment and water supply. Fluvial landforms, such as river terraces, and downstream stratigraphic archives may therefore record information about past environmental change. Using a physically based model describing sediment transport and long‐profile evolution of alluvial rivers, we explore how their responses to environmental change depend on distance downstream, forcing timescales, and whether sediment or water supply is varied. We show that amplitudes of aggradation and incision, and therefore the likelihood of terrace formation, are greater upstream and in shorter and/or wetter catchments. Aggradation and incision, and therefore terrace ages, may also lag behind environmental change. How sediment‐transport rates evolve depends strongly on whether water or sediment supply is varied. Diverse responses to environmental change could arise in natural alluvial valleys, controlled by their geometry and hydrology, with important implications for paleo‐environmental interpretations of fluvial archives. Plain Language Summary: Rivers carry sediment from upland regions, where it is produced by weathering and erosion, to low‐lying areas where it is deposited and stored. This process is sensitive to climate: for example, wetter conditions enhance rivers' capacity to transport sediment, causing rivers to cut into their beds, which in turn remobilizes sediment that is transported downstream. Changing climate may also lead to enhanced sediment production and supply to rivers, causing them to accumulate sediment in their beds. Climate cycles can therefore produce alternating periods of sediment accumulation and removal, resulting in ancient floodplains being abandoned and preserved alongside modern rivers ("terraces"), and in variations in the amounts of sediment delivered downstream. Terraces and patterns of sediment accumulation downstream could therefore provide valuable records of past climatic change. We develop a mathematical model that describes the effects of climatic change on river‐bed height and sediment‐transport rates. We show how the amount and timing of river in‐filling and down‐cutting, and the timescales over which they occur, depend on the rate of climatic change, on river length and associated drainage‐basin area, and on the amount of water it carries. These predictions will facilitate more detailed interpretations of terrace records along rivers and of the sedimentary deposits that they leave behind. Key Points: Alluvial rivers respond in diverse ways to cyclical climatic change depending on their geometry and hydrology and on the forcing frequencyTerrace formation is favored upstream and in shorter and wetter catchments and may lag appreciably behind environmental changeVariation in sediment output lags variation in sediment supply but can lead and be amplified with respect to variation in water supply [ABSTRACT FROM AUTHOR]

Human intervention makes river channels adjust their slope and bed surface grain size as they transition to a new equilibrium state in response to engineering measures. Climate change alters the river controls through hydrograph changes and sea level rise. We assess how channel response to climate change compares to channel response to human intervention over this century (2000–2100), focusing on a 300‐km reach of the Rhine River. We set up a schematized numerical model representative of the current (1990–2020), non‐graded state of the river, and subject it to scenarios for the hydrograph, sediment flux, and sea level rise. We conclude that the lower Rhine River will continue to adjust to past channelization measures in 2100 through channel bed incision. This response slows down as the river approaches its new equilibrium state. Channel response to climate change is dominated by hydrograph changes, which increasingly enhance incision, rather than sea level rise. Plain Language Summary: Humans have modified rivers to enable boat traffic, to protect people against flooding, and to provide them with freshwater and energy. When the shape of a river changes, the amount of sand and gravel (sediment) that can move along its bed also changes. In response, rivers change their slope and bed characteristics, so that they can transport as much sediment as they receive from higher up in the basin. This results in changes in bed level, which becomes higher or lower, causing problems for navigation and flood protection. Climate change makes this worse, because it changes the amount of water flowing down the river, and sea level. This further affects the amount of sediment that can move down the river, therefore causing additional bed level change. Here we study how climate change affects the lower Rhine River (Germany‐Netherlands), over the 21st century. This river has been heavily modified by humans, and its bed has been lowering over hundreds of kilometers. With a computer model, we simulate how different scenarios of climate change affect this behavior. We foresee that the ongoing bed level lowering will continue in the upcoming decades, and that it will be enhanced by climate change. Key Points: Human intervention will continue to govern channel response in the lower Rhine River by 2100, mainly through channel bed incisionClimate change leads to sea level rise and hydrograph adjustment, the latter being dominant and causing enhanced incisionChannel response to human intervention slows down as the river approaches its equilibrium state, but response to climate change accelerates [ABSTRACT FROM AUTHOR]

The evolution of the East Asian winter monsoon (EAWM) during the Holocene remains controversial because of the lack of reliable proxies. In this study, a link between cross‐front transport and the EAWM was found in the North Yellow Sea, and the EAWM intensity could be imprinted in the leaked sediment, which permits reliable reconstruction of the EAWM on well‐preserved offshore deposition. By comparison with instrumental data, the wind speed of the EAWM since 4.4 ka was quantitatively reconstructed for the first time at high resolution (∼5 yr). The results show that the EAWM gradually weakened in the mid‐to‐late Holocene, which was likely controlled by solar insolation, and that there has been a negative relationship between the EAWM and temperature on the centennial scale since ∼2.0 ka; this relationship was reversed by increasing CO2 emissions during the Current Warm Period. Plain Language Summary: The East Asian monsoon is characterized by a distinct seasonal reversal of monsoon flow driven by temperature differences between the Pacific Ocean and the East Asian continent. It influences more than 2 billion people around East Asia by regulating the risk of drought or flooding. However, the evolution of the East Asian winter monsoon (EAWM) in the mid‐to‐late Holocene remains elusive, limiting our understanding of its driving force and projections under climate change. This study analyzed sediment transport dynamics under varying winter monsoons in the North Yellow Sea. It was found that coastal sediments could be transported offshore, and their pathways differed under different strengths of the winter monsoon. Based on the sedimentary records of offshore muddy deposition, the EAWM proxy was extracted, and the wind speed of the EAWM from 4.4 ka was quantitatively reconstructed. A gradual weakening trend during 4.4–0.7 ka and a dramatic strengthening after 0.2 ka were found in the EAWM; the EAWM was negatively related to the temperature on the centennial scale since ∼2.0 ka, but this relationship was reversed by an increase in CO2 emissions since ∼1800 CE, indicating a shift in the controlling mechanism. Key Points: A link between cross‐front transport and the East Asian winter monsoon (EAWM) was found in the shelf sea, and the leaked sediment was used to reconstruct the EAWMThe wind speed of the EAWM since 4.4 ka was quantitatively reconstructed at high resolution (∼5 yr) for the first timeCorrelation between the EAWM and the temperature on the centennial scale since ∼2.0 ka was reversed by the increasing CO2 at the Current Warm Period [ABSTRACT FROM AUTHOR]

Hybrid 2D/one-line shoreline models, which typically apply a finite volume approach to simulate sediment transport and the one-line theory to update the shoreline morphology, are being increasingly applied over meso timescales (101 to 102 years) to inform coastal management. The one-line theory assumption of a constant closure depth prevents these models from considering the effects of sea-level rise in the shoreline morphology update. Sea-level rise, an endogenous driving factor of meso timescale coastal behaviour, influences the closure depth through its effects on the wave climate. This paper presents a new hybrid 2D/one-line approach that enables a time-varying closure depth in response to annual variations in wave climate as a solution for mirroring the effects of sea-level rise on the coastal profile and associated shoreline evolution. This new hybrid approach is applied to hindcast meso timescale shoreline evolution in a sandy coastal system and compared against the traditional hybrid 2D/one-line approach. Results show that the traditional hybrid approach gives the most accurate predictions whereas the new hybrid approach overpredicts shoreline erosion. However, this overprediction is attributed to net closure depth overestimation. This attribution gives confidence that the shoreline response to the time-varying closure depth specified is within expectations since closure depth overestimation increases offshore sediment transport in shoreline models. Therefore, it is likely that enabling a time-varying closure depth in hybrid 2D/one-line models may improve meso timescale shoreline predictions under sea-level rise if closure depths can be accurately prescribed over time. [ABSTRACT FROM AUTHOR]

Algeria, a semi-arid Mediterranean country, is distinguished by a more marked interannual variability in solid inputs compared to liquid inputs. This study aimed to comprehensively analyze hydrometeorological variables, such as rainfall, suspended sediment load, and flood flows in the Wadi Mina basin (6048 km2), using both traditional and advanced statistical techniques. These techniques included the MK trend tests MMK, and TFPWMK, as well as newer methods such as ITA and IPTA. To identify breakpoints, the CUSUM test and the SQ-MK test were used. The study was based on monthly data covering 40 years of rainfall (1970–2010) and 41 years of data on flood flows and suspended sediment load (1969–2010). The results indicated stable annual rainfall across the stations, suggesting a consistent rainfall regime over time. However, notable variability in sediment loads and flood flows was observed, with stations like Ain Hamara, Sidi Aek Djilali, and Wadi El Abtal displaying marked decreases in annual sediment loads, hinting at effective erosion control or natural attenuation of erosive processes. In contrast, a significant increase in flood events was recorded at Ain Hamara, attributed to climatic fluctuations or land use changes affecting runoff. Monthly analyses further demonstrated the enhanced sensitivity of ITA and IPTA over traditional methods, effectively uncovering subtle trends not detected by MK, MMK, and TFPWMK. For example, increasing rainfall trends during winter at Takhmert station and significant sediment transport patterns at Ain Hamara during colder months suggested dynamic seasonal hydrological behaviors. Additionally, critical insights into abrupt changes were revealed through CUSUM and SQ-MK tests, such as a pivotal shift in flood regimes at Takhmert in 2003 and a critical change in rainfall patterns at Ain Hamara in 2008, necessitating adjustments in water management and agricultural practices. [ABSTRACT FROM AUTHOR]

This study reveals the morphological transformations of a deep-water channel system within the Rakhine Basin in the northeastern Bay of Bengal through a comprehensive analysis of high-resolution 3D seismic data integrated with drilling logs. Employing the "source-channel-sink" paradigm, this investigation examined the impact of various factors, including tectonic transformations, sediment influx, slope dynamics, climatic changes, and relative sea-level fluctuations, on the evolutionary trajectory of these channel systems. Applying precise time-slicing techniques integrating root-mean-square amplitude attributes, coherent amplitude attributes, and horizontal amplitudes on seismic profiles, this investigation recognized three distinct stages in the evolution of channel-levee complexes (CLCs): the Middle Miocene erosional deep-water channel-levee complex (CLC-1), the Pliocene erosional-depositional deep-water channel-levee complex (CLC-2), and the Pleistocene depositional deep-water channel-levee complex (CLC-3). Comparative analysis revealed that the CLC-3 exhibits unique characteristics, including shallower channel depth (D), wider channel width (W C), extensive U-shaped cross-sectional area (S), broader natural levee width (W L) and height (H), and the highest tortuosity coefficient (L C /L S) when contrasted with the other two CLCs. Furthermore, this study substantiated how tectonic processes, primarily the collision between the Indo-Eurasian plates, resulting in the Himalayan and Indo-Burma Range orogenies, have shaped the region's geological and climatic framework, thereby influencing monsoon circulation and precipitation patterns, which in turn augmented detrital material influx into the basin. Moreover, this tectonic collision has led to gradual changes in the slope gradient of the Rakhine Basin and its deep-water areas, impacting internal flow velocities and channel curvature, thus governing deep-water channel systems' development and spatial distribution. Also, episodic sea level fluctuations were identified as significant contributors to sediment transport from shelves to deep-water regions and sediment deposit reworking. Overall, this study underscores the role of tectonic changes after the Eocene in driving the evolutionary dynamics of the deep-water channel system within the Rakhine Basin, Myanmar. [Display omitted] • Indo-Eurasian plate collision shaped the deep-water channel systems in the Rakhine Basin. • 3D seismic data reveals three evolutionary stages in these deep-water channel systems. • Pleistocene depositional channel-levee complex exhibits unique physical characteristics. • Tectonically affected slope dynamics have directed the channels' evolutionary dynamics. • Episodic sea level fluctuations have also supported these morphological transformations. [ABSTRACT FROM AUTHOR]

The Holocene sedimentary history of the Turbio River valley in semi-arid north-central Chile and its relationship to climate variability is presented in this study. Fluvial landforms and sedimentary deposits serve as essential records for studying the long-term dynamics of fluvial systems in response to external factors such as tectonic and climatic influences. The study area, located in the Andean Mountain range, is highly sensitive to hydrodynamic changes and sediment transport processes, making it suitable for studying fluvial dynamics and their relationship to climate fluctuations over millennia. In particular, the transitional semi-arid conditions of this region provide an opportunity to link Holocene fluvial sediments to climatic shifts. This study presents the analysis of well-preserved sedimentary deposits that outcrop along the valley walls, including grain-size distribution, stratigraphy, geochemical composition and radiocarbon dating to establish the chronological context. Facies association analysis, along with geochemical data, allowed the interpretation of depositional sub-environments and their evolution through time. We interpret the Holocene sedimentary evolution for the Turbio River valley as six time periods that reflect shifts in sediment source, energy regime, flow types, and sedimentary processes linked to fluctuations between wet and dry climatic conditions. The sedimentary sequence is interpreted as reflecting an initial high-energy period with continuous surface runoff followed by two periods of formation of extensive lakes, likely separated by periods of runoff intensification. The later part of the sequence reflects a more stable fluvial landscape that led to the excavation of the sedimentary fill. This sedimentary record provides valuable insights into past climate variations and their impact on the hydrodynamic conditions of the fluvial system in the region. Comparisons with other regional records support a broader understanding of climate change in the semi-arid Andes of Chile. • Rio Turbio sedimentary record is studied to reconstruct Holocene river dynamics. • Fluctuations in fluvial processes are related to alternating wet and dry periods. • A new model explains how the river evolved in response to Holocene climate variations. • Fluvial record provide valuable insights into past climates. [ABSTRACT FROM AUTHOR]

Some of the most disruptive effects of climate change are projected to be felt along the coastlines. The combined effects of future changes in water levels and wave climate along coastal areas constitute one of the most serious threats to their sustainable evolution, compromising critical infrastructures, resources, ecosystems, and communities. Understanding long-term changes in coastal areas remains challenging, however, due to their multivariate and multi-time-and-space-scale nature. In this study, we propose an innovative methodology for a complete vulnerability assessment of sandy low-lying coastal areas, based on dynamic, ensemble-based projections from the Coupled Model Intercomparison Project phase 5 (CMIP5). In the current Part I study, the effects of sea level rise (SLR) and nearshore wave climate changes on future shoreline evolution are assessed at five key-locations along the Portuguese coastline. Longshore sediment transport (LST) projections are computed, and sedimentary imbalances are quantified. Overall, robust shoreline retreat of up to 300 m is projected, especially along the Portuguese northern and central coastal areas, with continued erosion driven mainly by sediment imbalance and SLR. The projected decrease in future nearshore wave energy is responsible for a slight alleviation in erosion trends, up to 6.33%, whereas the increase of northerly incoming waves is expected to lead to northward beach rotations along western Mainland Portugal. The resulting shoreline evolution, responsible for the loss of up to 0.786 km2 of dry land by 2100 along the 14 km of analysed coastline, is projected to threaten several Portuguese urban areas, calling for the implementation of adequate coastal management and adaptation plans, to reduce the impacts of climate change on population, infrastructures, livelihood, and ecosystems. • An innovative methodology for a coastal vulnerability assessment is proposed. • Impact of SLR and wave climate changes on future shoreline evolution are assessed. • Robust shoreline retreat up to 300 m is projected along the Portuguese coastlines. • Shoreline evolution is responsible for loss of up to 0.786 km2 of dry land by 2100. [ABSTRACT FROM AUTHOR]

• Decrease of suspended sediment transport in the Mediterranean over the last century. • Time series reconstruction using artificial intelligence. • Crucial role of climate change in the regulation of suspended sediment transport. • Secondary influences of the anthropic impact. The analysis of suspended sediment transport and of its variations over time is crucial for understanding environmental evolution and it is the key to future challenges caused by current global warming. The Mediterranean area is a hot spot for global changes, and the variation of precipitation amount and intensity will modify the environment of this region. In this work, we analyse the time series of suspended sediment transport of two rivers located in central Italy by using statistical and artificial intelligence techniques. Our study aims to re-analyze time series of suspended sediment transport, in order to demonstrate that climate change is responsible for the substantial decrease in the amount of sediment over the past century, in relation to the atmospheric teleconnections of the North Atlantic. Anthropic pressures like reforestation, land use change, and dam building have influenced the sediment transport capacity of rivers, causing a reduction of sediment concentration in water. These results are key factors to determine the future management of the Mediterranean areas, where the future scenarios predict a greater drop in yearly precipitation, and therefore a possible further decrease in the sediment transport capacity of the rivers, with major consequences for coastal and fluvial environments. [ABSTRACT FROM AUTHOR]

Triassic strata in the Greater Barents Sea Basin are important records of geodynamic activity in the surrounding catchments and sediment transport in the Arctic basins. This study is the first attempt to investigate the evolution of these source areas through time. Our analysis of sediment budgets from subsurface data in the Greater Barents Sea Basin and application of the BQART approach to estimate catchment properties shows that (1) during the Lower Triassic, sediment supply was at its peak in the basin and comparable to that of the biggest modern-day river systems, which are supplied by tectonically active orogens; (2) the Middle Triassic sediment load was significantly lower but still comparable to that of the top 10 largest modern rivers; (3) during the Upper Triassic, sediment load increased again in the Carnian; and (4) there is a large mismatch (70%) between the modeled and estimated sediment load of the Carnian. These results are consistent with the Triassic Greater Barents Sea Basin succession being deposited under the influence of the largest volcanic event ever at the Permian- Triassic boundary (Siberian Traps) and concurrent with the climatic changes of the Carnian Pluvial Event and the final stages of the Northern Ural orogeny. They also provide a better understanding of geodynamic impacts on sedimentary systems and improve our knowledge of continental-scale sediment transport. Finally, the study demonstrates bypass of sediment from the Ural Mountains and West Siberia into the adjacent Arctic Sverdrup, Chukotka, and Alaska Basins in Late Carnian and Late Norian time. [ABSTRACT FROM AUTHOR]

With the ongoing climate change and the prolongation of the summer melting season and increasing air temperature that this entails, fluvial transport is likely to become a more important process shaping the deglaciated areas of Antarctica. Quantification of suspended sediment transport in the deglaciated catchment of the Bohemian Stream is presented in this study. It was shown that a large amount of fine-grained material is being transported even in the relatively small catchment during the short period of the Antarctic summer. The average calculated suspended sediment concentration during the 2018 austral summer reached 274.6 mg l−1, which corresponded to an average suspended sediment load of 3662 kg day−1 and suspended sediment yield of 68 t km−2 year−1 when considering the flow season to be approximately 4 months per year. Such values are considerably higher than those reported from continental Antarctica; however, they are lower compared to most of the Arctic catchments. [ABSTRACT FROM AUTHOR]

• A strong signal of reduced winter conditions i.e. duration, snow accumulation and frost days. • Hydroclimatic regime shift alters the sediment flux seasonality in near future. • Thaw-seasons have important role controlling the annual sediment flux. Climate change alters high latitude hydrological cycle by diminishing the snow accumulation and spring flood magnitude, and by altering temperature and rainfall finally leading to hydroclimatic regime shift from snow-dominated to rain-dominated. These changes in temperature, precipitation patterns, and discharge strongly influence geomorphological processes in fluvial environments, leading to alterations in sediment transport, erosion, accumulation, and landscape changes. We conducted comprehensive analysis of hydroclimatic trends and shifts on boreal Oulanka River system, spanning over the past five decades. A strong signal of warming temperatures (+0.61 Celsius/decade), reduced winter conditions and warmer summers (+0.41 Celsius/decade) was detected. The spring flood magnitude diminished 7 %, but high discharge peaks (Q > annual p90m3/s) during other seasons increased 22 % together with 28 % increase of annual minimum discharge. Simultaneously, precipitation intensity increased during summer. The meander migration rate (mean 0.89 or 2.55 m/year) and bank erosion volume were interconnected to ground frost, high snow sum, high discharge, and high-water level during spring flood, but no significant long-term trends were observed. Our findings underscore that climate is the first-order control on fluvial geomorphology and emphasizes the complex interplay between various hydrological and climatic factors that shape the dynamics of river systems. Based on the results, we expect to see changes in the spatial–temporal distribution of high latitude rivers sediment flux in future. In addition, more attention should be addressed to the thaw seasons controlling the sediment transport, as majority of the observed shifts took place in these months. [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]

Central Argentina from the Pampean flat‐slab segment to northern Patagonia (27°–41°S) represents a classic example of a broken retroarc basin with strong tectonic and climatic control on fluvial sediment transport. Combined with previous research focused on coastal sediments, this actualistic provenance study uses framework petrography and heavy‐mineral data to trace multistep dispersal of volcaniclastic detritus first eastwards across central Argentina for up to ca. 1,500 km and next northwards for another 760 km along the Atlantic coast. Although detritus generated in the Andes is largely derived from mesosilicic volcanic rocks of the cordillera, its compositional signatures reflect different tectono‐stratigraphic levels of the orogen uplifted along strike in response to varying subduction geometry as well as different character and crystallization condition of arc magmas through time and space. River sand, thus, changes from feldspatho‐litho‐quartzose or litho‐feldspatho‐quartzose in the north, where sedimentary detritus is more common, to mostly quartzo‐feldspatho‐lithic in the centre and to feldspatho‐lithic in the south, where volcanic detritus is dominant. The transparent‐heavy‐mineral suite changes markedly from amphibole ≫ clinopyroxene > orthopyroxene in the north, to amphibole ≈ clinopyroxene ≈ orthopyroxene in the centre and to orthopyroxene ≥ clinopyroxene ≫ amphibole in the south. In the presently dry climate, fluvial discharge is drastically reduced to the point that even the Desaguadero trunk river has become endorheic and orogenic detritus is dumped in the retroarc basin, reworked by winds and temporarily accumulated in dune fields. During the Quaternary, instead, much larger amounts of water were released by melting of the Cordilleran ice sheet or during pluvial events. The sediment‐laden waters of the Desaguadero and Colorado rivers then rushed from the tract of the Andes with greatest topographic and structural elevation, fostering alluvial fans inland and flowing in much larger valleys than today towards the Atlantic Ocean. Sand and gravel supply to the coast was high enough not only to promote rapid progradation of large deltaic lobes but also to feed a cell of littoral sediment transport extending as far north as the Río de la Plata estuary. [ABSTRACT FROM AUTHOR]

Black, K.P.; Baba, M.; Mathew, J.; Kurian, N.P., and Ilic, A., 2021. Guidelines to prepare India's coast for climate change. Journal of Coastal Research, 37(6), 1117–1129. Coconut Creek (Florida), ISSN 0749-0208. India's first coastal protection guidelines for climate-change adaptation are described. The guidelines are holistic, recognizing the links between engineering, economic, physical, legal, social, environmental, and governmental intricacies. Robust protection solutions under climate change for millions of coastal residents may occur only when all these facets are improved within the complex regulatory, budgetary, and practical circumstances in India. Fifty-seven specific guidelines are presented in nine categories ranging from administrative to best-practice coastal protection. An "environmental softness ladder" that ranks coastal protection methods was developed as a scientific tool to guide policy development and project implementation. "Minimum floor level" for safe building was defined for each Indian coastal state using climate-change data produced for the study by Indian and international institutes. Beaches are more stable when the net sediment transport fluxes are close to neutral. "Grand schemes," which make large-scale changes to the coast rather than continuing with piecemeal localised works, are recommended. With diverse dynamics over a long coastline in India, the 4-year study engaged an exceptionally large number of experts, agencies, government bodies, development partners, and other stakeholders. [ABSTRACT FROM AUTHOR]

Grassed waterways are used to mitigate the offsite transport of sediment generated by soil erosion. This study used a novel trait‐based ranking approach as a method to screen potential candidate grass monocultures and mixes based on their theoretical performance in reducing (a) detachment via rainsplash, (b) detachment via scouring due to concentrated flow and (c) sediment transport and deposition processes. Selected grass species were grown under simulated UK summer and autumn establishment conditions under three different replicated rainfall scenarios: drought, normal rainfall and excess rainfall. The grass species used were the novel hybrid species Festulolium cv Prior (Fest_1) and Festulolium Bx511 (Fest_2) and a conventional mixture of Lolium perenne and Festuca rubra (Conv). Monocultures and mixtures of these species were studied. Plant traits pertinent to control of soil erosion by water were measured. Aboveground traits included plant height, percentage ground cover, aboveground biomass, stem diameter, stem area density and number of tillers. Belowground traits included total root length, root total surface area, belowground biomass, root diameter and % fine roots ≤0.25 mm. For summer conditions, the species treatments that had the highest overall soil erosion mitigation potential were Conv, Fest_1 + 2 + Conv and Fest_2. For autumn conditions, the best treatments were Fest_1 + 2, Fest_1 + 2 + Conv and Conv. The Fest 1 + 2 + Conv had more desirable traits for erosion control than mono Festulolium treatments for the autumn conditions. The conventional mixture had more desirable traits for erosion control than mono Festulolium treatments in both climate scenarios. The results indicate that the trait‐based ranking approach utilized in this study can be used to inform rapid screening of candidate grass species for soil erosion control. Highlights: How to select the most suitable grass species for soil erosion control under changing climate conditions?A novel scoring system based on plant traits associated with soil erosion mitigation was developed.Fest_1 + 2 and Conv treatments expressed traits strongly associated with maximum soil erosion mitigation.Species selection for grassed waterways should consider the establishment growing season and expected rainfall. [ABSTRACT FROM AUTHOR]

Rivers originating in High Mountain Asia are crucial lifelines for one-third of the world’s population. These fragile headwaters are now experiencing amplified climate change, glacier melt, and permafrost thaw. Observational data from 28 headwater basins demonstrate substantial increases in both annual runoff and annual sediment fluxes across the past six decades. The increases are accelerating from the mid-1990s in response to a warmer and wetter climate. The total sediment flux from High Mountain Asia is projected to more than double by 2050 under an extreme climate change scenario. These findings have far-reaching implications for the region’s hydropower, food, and environmental security. [ABSTRACT FROM AUTHOR]

Assessing rivers' and hillslopes' sensitivity to external forcing is paramount to understand landscape evolution, in particular as a response to Quaternary climate changes. River networks are usually considered to be the main conveyors of environmental signals, such as changes in precipitation, temperature, or baselevel. Yet because hillslopes provide the source of sediment for river networks, their response to environmental change also modulates landscape dynamics. In order to characterize such behavior, we analyze the response times of a transport‐limited hillslope. We use simple numerical models of denudation to study hillslope responses to oscillatory forcing and understand their filtering effects on environmental signals. Modifications in the frequency of climate oscillation, such as the change that occurred at the Mid‐Pleistocene Transition, can significantly modulate hillslope sediment‐flux response. We infer a wide range of hillslope responses, ranging from negligible change over the full range of climate‐forcing frequencies, to a significant filtering of long‐period signals. Plain Language Summary: Landscapes are constituted of hillslopes and rivers where different types of erosion and sediment transport processes take place. Due to their large extent, river networks are an important driver of global landscape response to climatic or tectonic changes. Hillslopes have smaller dimensions but are also where most sediment production occurs and for that reason it is important to have a good understanding of how they respond to perturbations. We use simple numerical models of hillslope evolution to study the influence of oscillating changes of either the efficiency of sediment transport across the hillslope or the rate of channel downcutting at its base. Our results indicates that the period of oscillations for these perturbations controls the amplitude of the sediment flux response out of the hillslope, and provide a framework to understand how this landscape component reacts to climatic cycles such as the glacial/inter‐glacial oscillations of the Quaternary. For example, a major change occurred 800 ka ago with a shift in climate oscillation from 40 to 100 ka period. Our models suggest that in some landscapes this change in period alone could have induced a significant decrease in the amplitude of hillslope sediment flux response. Key Points: A complex hillslope dynamics is associated with the linear to nonlinear sediment flux transitionHillslopes filtering potential of external signals is highly contrasted depending on the type of forcingChanges in the climatic signal frequency at the Mid‐Pleistocene Transition could induce a significant shift in hillslope erosional response [ABSTRACT FROM AUTHOR]

A rich assemblage of various marine taxa from the lower Carnian Polzberg Konservat-Lagerstätte near Lunz am See (Northern Calcareous Alps, Lower Austria) is described for the first time in detail. The fossiliferous layers were deposited during the Julian 2 Ib (Austrotrachyceras austriacum Zone, Austrotrachyceras minor biohorizon). The fine-laminated Reingraben Shales comprise abundant and well-preserved members of the marine Carnian food chain. Invertebrates with the bivalve Halobia, the ammonite Austrotrachyceras and the coleoid Phragmoteuthis dominate over vertebrate actinopterygian fishes. Fragile groups such as polychaetes and isopods are entirely preserved as soft body fossils. The diverse assemblage comprises ammonites (Austrotrachyceras, Carnites, Sageceras, Simonyceras), coleoids (Phragmoteuthis, Lunzoteuthis), bivalves (Halobia), gastropods (caenogastropods/heterobranchs), one echinoid, thylacocephalan arthropods (Austriocaris), crustaceans (the decapod Platychela and isopods such as Obtusotelson, Discosalaputium), polychaetes (Palaeoaphrodite sp., eunicid polychaete), acytinopterygians (Saurichthys, Polzbergia, Peltopleurus, Habroichthys), cartilaginous fishes (Acrodus), coelacanth fish ("Coelacanthus"), a lungfish (Tellerodus), and a conodont cluster (Mosherella). Regurgitalites produced by large durophagous fish and coprolites produced by piscivorous actinopterygians accompany the Polzberg palaeobiota along with rare plant remains (Voltzia). The entire fauna of Polzberg and the excellent preservation of the specimens present a window into the Upper Triassic assemblage and palaeoenvironment during the so-called Carnian Pluvial Episode (CPE) in the early Mesozoic. The occurrence of the freshwater lungfish Tellerodus and the branchiopod Eustheria, a member of brackish to freshwater environments, points to the influence of occasional freshwater pulses or sediment transport events on the marine environment. The Polzberg palaeobiota was deposited during the global CPE, triggering the environmental conditions of the Polzberg Basin and resulting in the formation of the Reingraben Shales with the Polzberg Konservat-Lagerstätte. [ABSTRACT FROM AUTHOR]

Late Cenozoic changes in the intensity of the East Asian Summer Monsoon (EASM) are reconstructed using both terrestrial and marine proxy records; however, proxies from terrestrial (e.g., loess, pollen, and pedogenic isotopes) and marine environments (e.g., foraminifer assemblages and geochemistry) commonly display large discrepancies both in the direction and timing of changes in the EASM. In part, these discrepancies reflect long-term changes in paleogeography that are independent of climate variations. We assess the influence of a rapidly uplifting orogen on EASM records by comparing temporally constrained gamma-ray, δ13C org , hematite/goethite, and magnetic susceptibility records from Late Miocene–Early Pleistocene strata of the Taiwan Western Foreland Basin to time-equivalent EASM proxy records in the South China Sea (SCS). Prior to the emergence of modern Taiwan (∼6.3–5.4 Ma), sediment in the SCS was largely derived from Eurasia and transported into the Pacific Ocean. Following its emergence and southwest migration of the collision zone ∼5.4 Ma, proto-Taiwan became a major sediment source to the SCS. The uplift and southwest migration of Taiwan and northwest migration of the Luzon volcanic arc resulted in the formation of southwest-flowing deep- (1500–2500 m water depth) and bottom-water (>2500 m water depth) currents and the SCS Branch of the Kuroshio Current. Together these currents transported sediment from Taiwan towards the SCS. Increased sediment input from Taiwan is recorded as a decline in hematite/goethite values in sediment records from the northern and central SCS. By ∼3.2 Ma, continued southwest migration and growth of the Taiwan orogen resulted in the formation of the Taiwan Warm Current, which remobilized some sediment from Taiwan towards the East China Sea. Despite strengthening of deep-water currents during the Late Pliocene–Early Pleistocene, relative sediment input from Taiwan to the wider SCS decreased. Consequently, relative contributions from Eurasia and Luzon increased. In the southern SCS, where the Mekong River has dominated sedimentation since the Late Miocene, proxy records show no influence from the Taiwan orogen and instead reflect environmental changes in Mainland Southeast Asia driven mainly by monsoon variability. Our results show that a rapidly uplifting orogen has the potential to significantly impact paleoclimate records >1000 km away from the collision zone. This highlights the influence of shifting sediment sources on paleoclimate proxy records, which must be considered in interpreting past climate change from the sedimentary record. • Taiwan orogenesis is linked to South China Sea climate proxies. • Rapid orogenesis can drive shifts in sediment source and ocean currents. • Tectonic activity is the dominant control on proxies prior to ∼3 Ma. • After ∼3 Ma, proxies reflect enhanced monsoon strength related to glaciation. [ABSTRACT FROM AUTHOR]

The Thar Desert is a major sediment depocenter located in southwestern Asia and bordering the Indus drainage system to its east. It is unclear where the sediment that built the desert is coming from, and when the desert experienced phases of construction. In particular, we seek to establish the role of the South Asian monsoon in the initial formation and subsequent expansion of the desert. Here we integrate bulk-petrography and heavy-mineral data with U-Pb ages of detrital zircon grains to understand how the Thar Desert relates to the major potential sediment sources in the Himalayan orogen and to the large rivers that adjoin it to the west and north. Bulk petrography and heavy-mineral data from eolian sand in Cholistan (NE Pakistan) show closer similarity with that of Himalayan tributaries than eolian sand in Sindh (S Pakistan), which contains heavy-mineral suites close to those of mainstream Indus sand largely supplied by erosion of the Karakorum and Kohistan ranges. Kohistan is a particularly rich source of heavy minerals and is thus over-represented in provenance budgets based on that proxy alone. U Pb ages of detrital-zircon fail to show a sharp difference between dune sands in Sindh and Cholistan but confirms a somewhat greater supply from the Himalaya in Cholistan and from the Karakorum, Kohistan, and Nanga Parbat in Sindh. Zircon ages are similar in Sindh desert sand and in the Indus Delta, and are most similar to deltaic sand dated as 7 ka or older in the deglacial period. In parallel, the age signature of Cholistan sand resembles more that of older river channels found along the northwestern edge of the desert (e.g., paleo-Ghaggar-Hakra) than that of modern Himalayan tributaries (e.g., Sutlej). Both Cholistan and Sindh sands suggest that sediment supply to the desert was greater during the early Holocene when the summer monsoon was stronger. The southwesterly summer monsoon was the most effective agent of eolian transport and recycling of Indus delta sediments entrained towards the central and northern parts of the Thar Desert. [ABSTRACT FROM AUTHOR]

• (234U/238U) were analyzed for the Changjiang estuary sediments. • Catchment erosion was revealed by sediment comminution age. • Climate changes play a leading role in catchment erosion. • Human activities changed the natural erosion processes since the late Holocene. Catchment erosion not only plays an important role on landscape evolution, but also determines the exposure of rock debris in the regolith profile, and therefore impacts the chemical weathering and associated CO 2 absorption and ultimately global climate. But climate also modulates erosion and complex interaction loops, especially at large scale can hamper a clear understanding of these processes. Here we mainly use Uranium-series Comminution Age (t com) of core sediments from Changjiang estuary to reconstruct the catchment erosion, and the relationship with climate changes and human activities during the last 14 kyrs. Since 14 ka, the sea level has been rising continuously until current highstand system tract in the East China Sea where the Changjiang estuary is located. The sediments in the Changjiang estuary mainly come from the upper reaches erosion zone during this period, but the sediment supply from the middle and lower reaches has gradually increased since the Late Holocene. The period can be divided into two modes. The first mode happens from the Bølling-Allerød period to the Mid-Holocene when the sea level rose rapidly, and the t com of sediment recorded the residence time in the upper reaches erosion zone, with a periodic pattern of t com in a good agreement with climate changes. During the cold and dry periods, the longer t com (average 460 kyrs) is consistent with less precipitation resulting in shallower erosion with transported material mainly coming from the soil with longer residence time. In contrast, during the warm and wet periods, the t com is shorter (average 290 kyrs), with the more abundant precipitations that contribute to deeper erosion in the upper catchment, and more fresh material transported to the estuary through stronger hydrodynamic forces. The second mode is more chaotic and corresponds to 0 to 4 ka, when climate was warm and humid and stable sea level, but t com fluctuated from 200 kyrs to 650 kyrs. The increasing river flooding caused by abundant precipitation leads to lateral migration of the river channel in the middle and lower reaches, and the sediments deposited in the floodplain were eroded and mobilized again. In addition, the rapid development of human activities since 2 ka has accelerated deforestation and agricultural cultivation, leading to localized erosion of the floodplain. These remobilized sediments were transported to the estuary and deposited, resulting in a larger t com value. This study overall indicates that, in the millennial scale, the t com of fine detrital fraction shows a sensitive and quick response to catchment erosion, and provides new insights into quantifying the time scale of sediment source to sink processes and inferring the paleoenvironment accurately climate changes. [ABSTRACT FROM AUTHOR]

[Display omitted] • Continued erosion is expected to occur in the sandy shores. • Equilibrium relationship between sediment supply and hydrodynamic forces has been severely disrupted. • Global climate change-induced sea level rise has a small effect on erosion in the short term. • Human activities are the critical effect on the erosion. • Reduced seaward sediment transport by coastal surface runoffs is a new factor. Most sandy shores (SSs) are currently experiencing erosion to various degrees due to the combined impact of increasing climate change and human activities. In order to reveal the evolution of the SSs in the Shandong Peninsula (SP), shoreline and elevation changing data are obtained from 29 SSs and results show that most (27 of 29) of the SSs exhibited erosion. The length of the SSs has decreased by 241.4 km from 2010 to 2020, and the average shoreline recession rate was found to be 1.0 m/a and the downward erosion rate was in the range of 0.05 to 0.10 m/a. Climate change-induced sea level rise has a smaller effect on the erosion in the short term and the construction of massive coastal engineering structures has become a major cause of local coastal erosion. The coastal erosion rate caused by river damming and sand mining in the early years has abated and reduced seaward sediment transport induced by the expansion of the built-up area has become a new factor of coastal erosion. In the past decade, the 672 km2 net increase in land area mainly originated from human activities, has occupied the original space for hydrodynamic energy dissipation, which has severely disrupted the balance between sediment supply and the hydrodynamic environment and the system then rebalance itself by eroding unprotected SSs. Therefore, with the increase in hydrodynamic forces caused by climate change and the scarcity of sediment supply caused by human activities, continued erosion is expected to occur in the SSs. [ABSTRACT FROM AUTHOR]

• The streamflow, sediment and heat flux input to the delta substantially increased. • The changes in the sediment and carbon pathways across delta is the result of thermal erosional processes. • Lena Delta is the World's hot spot in hydrological consequences of climate change. Water and sediment supply are essential to the health of deltaic ecosystems. Diverse datasets were integrated to better understand how climate change is shifting the supply of water and sediment to the largest polar distributary channel pattern – the Lena River Delta. Here the increase in warming rate from an average air temperature is from 4.1 °C for the period 1950–99 to 6.1 °C during 2000–21, which is higher than in the adjacent polar regions. Streamflow and sediment yield entering the Lena Delta have increased since 1988 by 56.3 km3 and 6.1×106 t, respectively; meanwhile, the Lena River's increases in water temperature in June, July–August and September were found to be as much as 1.1, 0.6 and 0.05 °C. These changes have a pronounced effect on sediment regimes in particular parts of the delta. Based on analyses of correlations between various hydroclimatic drivers and sediment concentration changes across particular distributaries of the Lena Delta extracted from Landsat datasets, bank degradation driven by thermal erosional processes (which are in turn related to air and soil temperature increases) is proved to be the primary factor of the sediment regime in the delta. The study also highlights that sediment load changes are sensitive to wind speed due to remobilization of bottom sediment. Sums of daily air temperature and wind speed over 3 days are correlated with sediment concentration changes in the delta. The results also indicate that carbon transport across the delta (both POC and DOC) depends on sediment transport conditions and water discharge and might increase by up to 10 %. We conclude that the Lena Delta can be recognized as the global hot spot in terms of the hydrological consequences of climate change, which is altering sediment regimes, stream hydromorphology and carbon transport. [ABSTRACT FROM AUTHOR]

[Display omitted] • Climate and human contributions to NPP were 62% and 38% in Loess Plateau. • Precipitation contributed to NPP much than temperature in 2000–2020. • The feedback of GTGP to NPP and climate was higher in second decade. • GTGP brings environmental benefits (river sediment, PM 2.5 , dust weather). Net primary productivity (NPP) has been the subject of numerous studies, but the qualitative and comparative study on NPP that considers human activities, climate change, and their interactions is still insufficient. The Grain for Green Program (GTGP) was established in the Loess Plateau since 1999, could be used as a reference study. The temporal and spatial patterns, change trend, and driving factors of vegetation NPP were analysed in Loess Plateau using data derived from GLASS NPP (the Global Land Surface Satellite Product), meteorology, atmospheric quality, hydrology and land use by correlation and improved residual trend analysis from 2000 to 2020. After GTGP implementation, the climate and human contributions to vegetation NPP were 62 % and 38 %. NPP increased at a rate of 6.3 g C m−2 a−1 from 2000 to 2020, which was higher in 2010–2020 (6.9 g C m−2 a−1) than it was in 2000–2010 (5.7 g C m−2 a−1). The same trend was followed by the contribution of climate change to NPP between 2010 and 2020 (70.6 %) and 2000–2010 (65 %). The GTGP core area was mostly where the vegetation NPP rising zone was located. From the original bare land in the desert area, 4442 km2 of vegetation grew and increased the NPP (68.7 g C m−2). Under the warm–humid climatic trend, the climate factors contributed to NPP more in grasslands (40 %) compared to woodlands (29 %) and precipitation (33 %) was more sensitive than temperature (12.7 %). Consequently, sediment transport, PM 2.5 and dusty weather decreased significantly. In conclusion, although climate change has a greater impact on vegetation, human activities have enhanced the impact faster in the first decade, which benefit and profit from the environment finally. [ABSTRACT FROM AUTHOR]

• Compared dynamics of discharge and sediment loads in four large basins. • Explored the impact of climate, and human activities on water and sediment. • Sediment transport showed significant decreasing trends with abrupt changes. • Human activities played a predominant role in reducing sediment transport (>80%). • Impacts of land cover change on sediment loads were basin-independent. Human activities and climate are two key factors affecting hydrological and soil erosion processes. Understanding their impacts on water discharge and sediment transport is very important for sustainable development of watersheds, particularly in subtropical regions with high precipitation and high sediment loads. We here compared the long-term dynamics of water discharge and sediment transport in four large contiguous watersheds in subtropical China and explored the importance of the main influencing factors including climate, nature endowment such as geology, and human activities. Significant differences have been observed between watersheds in terms of sediment and water discharge (p < 0.001). Pairwise comparison among the four basins demonstrated significant differences in sediment modulus among 5 of the 6 pairs (p < 0.05). The sediment modulus in the Lishui Basin was significantly higher than those in other basins, mainly due to the substantial presence of steep slopes in the mountainous region, which is prone to soil erosion. Temporally, sediment transport in the four basins was well synchronized showing significant decreasing trends with abrupt change points (p < 0.001). In contrast, no trends and abrupt change points were detected in water discharge, mainly influenced by precipitation. Human activities played a predominant role to the reduction of sediment transport (80% to 102%) compared with those of climate (-2% to 19%) across the four basins. Additionally, our study also showed land cover had various basin-independent impacts on the change of sediment transport. Through cross-basin comparisons of the long-term changes in water discharge and sediment transport, our study revealed the similarities and differences in their driving mechanisms, providing valuable information for land use planning and water resource management in large subtropical basins. [ABSTRACT FROM AUTHOR]

• Ridge slope erosion included inter-rill erosion, headward erosion, and rill erosion process. • Erosion rate reached the maximum during headward erosion process. • The dominated erosion process was detachment-limited after headward erosion occurring. • Re-detachment, transport, and deposition simultaneously occurred with the appearance of headward erosion. Extreme rainfall is becoming more frequent and intense, which no doubt increases the risks and uncertainty of water erosion in widely-used contour ridge systems. Ridge slope erosion can increase the probability of contour failure occurrence and then induce contour ridge losing anti-erosion properties. However, there is little understanding of ridge slope erosive process controlled by contour ridge system responding to extreme rainfall. In this study, five rare earth elements were applied in different ridge segments and soil layers to monitor the successive development of ridge slope erosion process under extreme rainfall in contour ridge system. Simulated rainfall experiments at high rainfall intensity (100 mm h−1) lasting for 60 min were conducted in runoff plots with ridge tillage practices characterized by microtopography indices and ridge geometry indices. Results showed that three sub-processes were observed for ridge slope erosion, including inter-rill erosion, headward erosion, and rill erosion. Headward erosion mainly resulted from the break-point at ridge surface and sidewall collapse at ridge toe, and the pouring of ponding water in furrow greatly promoted rill development. Erosion rate was the largest during headward erosion process, and rill erosion contributed the most to eroded source. The dominated erosion process was transport-limited during inter-rill erosion process, and detachment-limited during headward and rill erosion processes. Sediment transport and deposition processes as well as their transformation occurred simultaneously after the development of headward erosion. Eroded sediment was mainly from the low part of ridge, which was transported by raindrop-impacted sheet flow or overflow. These findings provide better responding of agricultural tillage to global climate change and references for the development of physically-based erosion models. [ABSTRACT FROM AUTHOR]

• Climate change effects on ice regime and water and sediment processes examined. • The ice flood reaches of the Yellow River in Inner Mongolia are taken as the case study. • Mann–Kendall test applied to define the years of temperature mutations and trends. • Meteorological condition and breakup type affect sediment transport in the channel. • Complex relationship exists among channel, hydrodynamic, sediment, and ice factors. The presence of winter ice in cold regions changes the water level, flow rate, velocity distribution, and other parameters of the river, which in turn affects the sediment concentration and channel evolution. Based on data obtained from Toudaoguai Hydrological Station from 1959 to 2021, this study examines the characteristics of the ice regime during cold and warm winters and the water and sediment transport processes along the Yellow River in Inner Mongolia in the context of climate change. The Mann–Kendall test and trend analysis were applied to define the years of temperature mutations and their trends, and the temperature mutation point was determined to be the 1987/1988 season. The study considers the effect of climate change on the combination of hydrological and hydraulic conditions. Therefore, trends in suspended sediment transport, ice type formation, water discharge, and storage in different ice flood seasons (November 1 to March 31, from 1998 to 2021) were attained. Based on the cumulative negative air temperature, winters were categorized into three types, warm, normal, and cold (52.2%, 17.4%, and 30.4%, respectively). Strong and weak grades further divide cold and warm winters, and statistical analyses were used to examine the characteristics of ice, water discharge, channel storage, and sediment transport. The duration of open water, freeze-up, ice cover, and breakup periods were calculated, and the relationship between the suspended sediment transport rate and discharge rate in these various ice periods was defined. The obtained relations show that the suspended sediment rate during the ice cover and first drift was smaller than that during the open water and post-breakup conditions. For the ice cover period, the sediment transport rate was on average approximately four times smaller than the freeze-up condition and six times smaller than the open water condition. The reduced sediment transport rate in the freeze-up period can be attributed to the weakened vertical turbulent mixing and increased flow resistance. [ABSTRACT FROM AUTHOR]

The late Paleozoic glacial-to-postglacial turnover evolved complexly across Gondwana. Successions bearing volcaniclastic material that can be radiometrically dated provide crucial information about the timing of those climate events. The southernmost part of the Paraná Basin, for instance, has a high-precision geochronological framework. The eastern sector of this basin (Paraná State and north of Santa Catarina State), however, lacks radiometric ages, but conversely, has a more complete stratigraphic record, and paleontological information still poorly explored for the purpose of biostratigraphic correlation. This work examines the glacial-to-postglacial interval in the Paraná State, represented by the upper Itararé Group (Taciba Formation; glacial) and lower–middle Rio Bonito Formation (postglacial). Sedimentological, paleontological and geochemical data from outcrops, cores and well logs were used to decipher the timing, paleoclimatic and paleogeographic scenarios of this transition. The examined succession comprises four stacked units (U1 to U4, from older to younger). Diamictite-dominated units (U1 and U3), here interpreted as consecutive glaciation–deglaciation events, are separated by non-glacial, continental to shallow marine deposits, commonly bearing fossil plants and coal seams (U2). An important transgression followed the first deglaciation, which is equivalent to the " Eurydesma transgression", based on the presence of marine invertebrates of the homonymous fauna in the Passinho Shale. U2 holds elements of two different floras, i.e., Phyllotheca – Gangamopteris (P–G), predating the " Eurydesma transgression", and Glossopteris – Brasilodendron (G–B), above the transgression. Therefore, U2 is interpreted as an interglacial interval, once it records a climate improving before the last glacial episode of U3, which is further supported by relatively high values of the Chemical Index of Alteration (CIA). Deposits of U3, associated with a decrease in the value of the CIA, are unconformably overlain by U4. The occurrence of coal-bearing postglacial facies (U4) associated with the G–B Flora, coincides with an increase in the CIA values. Sediment transport was toward the SW in all units and in the same direction it is observed an overall thinning of U1 and U3 and thickening of U2. The interglacial P–G Flora of the study area correlates with postglacial southernmost floras, based on U–Pb CA-TIMS Asselian ages of tonsteins. Correlation of the Eurydesma fauna-containing Passinho Shale with equivalent successions with high-precision age control in southern Africa, allowed us to position both deglaciations of the Taciba Formation (U1 and U3) in the Asselian. These findings suggest that U1 and U3 record two early Permian glacial episodes, with the younger one (U3) disappearing southward. Accordingly, our results indicate that the glacial-to-postglacial turnover was diachronous along the eastern belt of the Paraná Basin, being progressively older southward, considering that interglacial fossil plant assemblages in the eastern margin correspond in time to postglacial assemblages farther south. • The examined succession includes two glaciation-deglaciation stages insterspersed by interglacial deposits and an uppermost postglacial interval. • The interglacial stage is time equivalent to postglacial deposits farther south, suggesting that the last glaciation was limited to NE Paraná Basin • Biostratigraphy based on floral and faunal assemblages indicates an early Permian age. • The glacial–postglacial transition is diachronous along the eastern margin of the basin. [ABSTRACT FROM AUTHOR]

Beach accretion is the natural mechanism that allows dry beaches to recover. Human response to climate change produces hardening of the coasts and the incident marine climate, which increases beach erosion produced during winter and prevents a full recovery during summer. Beach nourishments are performed all around the world to fight coastal erosion with a nature-friendly philosophy. Softer techniques as beach scraping are also widely applied. A kind of beach scraping is proposed here as an innovative nature-assisted beach enhancement technique, that aims to accelerate naturally produced sand accretion on the beach profile. It consists of mechanically ploughing the intertidal area of a beach to create ridges and furrows. Prototype-scale laboratory experiments were performed to analyse its effectiveness under controlled conditions. Seven 1 h tests having different water levels and the same initial bottom geometry and sea state conditions (H s = 0.3 m, T p = 7 s) were performed. Sea state, sand, and initial slope characteristics assured accretive conditions. Ploughed and flatbed initial slope geometries were simultaneously tested into two sub-channels of the wave flume. The results indicate that the bottom roughness is 3.57 times larger for the ploughed geometry. Consequently, wave energy dissipation is larger for the ploughed geometry, and therefore, the significant wave height at the shoreward end of the study area is 11% smaller for the ploughed geometry. This smaller wave height under the ploughed morphology leads to more accretive conditions, as observed from the measured onshore sediment transport, which is 2.9 times larger than the natural transport, and the larger accreted sediment volume in all seven test cases. These results demonstrate the effectiveness of ploughing to enhance natural beach accretion under highly probable accretion conditions. Further research is required to define the thresholds of marine conditions in which the potential of beach ploughing can be exploded. • Working with nature. • Ploughing the intertidal area of a beach enhances natural accretion. • Real scale laboratory experiments measuring sediment transport. • Mechanically ploughing increases bed roughness. • Extra wave energy dissipation is produced by ploughing. [ABSTRACT FROM AUTHOR]

• Proglacial areas show complex dynamics of sediment transport. • Today proglacial areas act as both sediment storage and sediment source areas. • Positive temperature anomalies lead to changes in sediment connectivity. • Extreme precipitation and snow-melt events enhance functional connectivity. Proglacial areas in high-mountain environments are among the most dynamic landscape zones in terms of morphological, sedimentological, and hydrological changes. In fact, in such areas both glacial and paraglacial dynamics exert a strong control on water fluxes (and thus on bedload transport capacity) and on sediment supply. Because of the rapid changes undergoing in these environments, the understanding of the dynamics of sediment transfer and the prediction of how this will change in future still remain a challenge. In this study, we used four different high-resolution topographic surveys to quantitatively analyse the spatio-temporal patterns of sediment transport that occurred in the proglacial area of the Sulden glacier (South Tirol, Italy). The topographic surveys covered the period 2013–2019 and – by building DEMs of difference (DoDs) – we calculated the volumes of erosion and deposition occurring at the glacier terminus and along its outflow channels. Our results indicate that, within the analysed time-period and for different areas, erosion and deposition generally show similar values, suggesting that the analysed proglacial areas has been acting both as a sediment trap and as a sediment source for the downstream river reaches. In addition, the results indicate a complex morphological dynamics, which have strongly impacted coarse sediment connectivity in the upper catchment. In particular, high temperatures and the recent and rapid glacier melt, have promoted a direct control on the structural connectivity within the proglacial area. Morphological changes have increased or decreased sediment connectivity depending on pre-existing morphological features. In contrast, extreme precipitation events, both in term of rainfall and snowfall, have locally and temporally increased the functional connectivity, sometimes leading to long-term modifications in the proglacial area. Overall, in the analysed time-period sediment transfer has been extremely dynamic, suggesting that sediment in the downstream river channel may have been supplied with irregular pulses associated with the morphological changes taking place in the proglacial area. [ABSTRACT FROM AUTHOR]

This study investigated the spatiotemporal variation of arsenic (As) distribution, species and its behaviour in the aquatic environment changed by extended dry and heavy rainfall periods in the area adjacent an abandoned gold mine, South Korea. As appears to be transported from the mine wastes to Guryong stream through groundwater baseflow and leachate. The oxidation-reduction potential (ORP) conditions changed spatially and temporally following dry and heavy rainfall periods, and rainfalls caused decrease in the stream pH. As mainly existed as arsenates (AsO 4 3-) bound with H, Ca, and Fe in water. In groundwater, the lower the pH and the ORP, the higher the proportions of acid species of arsenate (HAsO 4 2-, H 2 AsO 4 -) and arsenite (H 3 AsO 3), resulting in increased As mobility and toxicity, respectively. In stream, the primary influencing factor of As variation is the ORP. Under oxidizing conditions, As in stream could precipitate as amorphous FeAsO 4 ·2H 2 O and FeOOH in the streambed. Then, the ORP decrease could remobilize As by redissolution and desorption of As bound to bed sediments. Thus, streambed sediments acted as a temporary sink-and-source for As, and extension of source areas accompanied with physical transport after heavy rainfalls. [Display omitted] • Total As concentration and pH-Eh conditions controlled As behavior in water. • Dryness and rainfalls change the pH and ORP conditions in the aquatic environment. • Streambed sediments acted as a sink-and-source in groundwater-stream interface. • Physical transport of bed sediments could extend the areas of As-pollution potential. [ABSTRACT FROM AUTHOR]

The present and paleo-drainage networks, depositional surfaces, fault throw, slope of the downthrown fault blocks, soil properties, sediment characteristics and published optically stimulated luminescence (OSL) ages are used to define the role of tectonics and climate in the growth of forty-five terminal fans (TFs) in the Indo-Gangetic foreland basin. Twenty-three TFs show a single exposed surface throughout, suggesting no or imperceptible breaks in sedimentation during their formation. In contrast, twenty-two TFs show multiple growth surfaces, separated by soil profiles and erosional surfaces. The available optically stimulated luminescence (OSL) dates of these depositional surfaces suggest different phases of TF growth. Tectonically triggered surface faulting altered accommodation space, slope of the substrate, and sediment supply and initiated new TF depositional cycles. The tectonically stable periods, in contrast, did not form TFs, despite the favourable humid climate conditions. Instead, the dry and humid climatic regimes, when combined with frequent surface faulting, produced and remobilized sediments more quickly, promoting TF growth. The humid climate TFs are spatially extensive (average area = 2000 km2), with clay horizons interspersed between sand facies. The dry climates TFs are smaller (average area = 1370 km2), with intervening calcrete horizons and surface salt-efflorescence. Low precipitation and inadequate sediment supply hampered the growth of these dry climate TFs. Despite a considerable period of surface exposure, the surfaces of dry climate TFs lack a well-developed soil profile. The upper Ganga Plain provides more accommodation space across the faults than the middle Ganga Plain. Accommodation space and substrate slope have little effect on TF area unless climatically triggered sediment remobilization occurs. For a given accommodation space and substrate slope, steeper sloping TFs occupy less area than lower sloping ones. Faults with throws of <5 m and substrate slopes of <2° do not form TFs; instead sediment wedges are formed across fault slope breaks. The TFs in the upper Ganga Plain show more growth surfaces than the middle Ganga Plain. The older growth surfaces are either progressively arranged across the direction of channel shift or occur as inliers in between the younger alluvium. Well-developed distributaries on the older TFs disperse sediment more readily, rather than accumulating it in proximal fan regions. However, the younger TFs, with relatively less-developed distributary channel networks, vertically stack sediments in their proximal part and occasionally transport sediment as sheet floods to their distal end regions. The combined geomorphic response of TFs to tectonic events and climatic fluctuations is, therefore, simultaneous for TF growth and stabilization. • Ganga Plain terminal fans (TF) form at topographic slope breaks away from mountains. • TF growth mechanism investigated using remote sensing and field investigations. • Ganga Plain TFs develop as a result of tectonic-climatic interactions. • Tectonics provides overall accommodation space for TF building. • Climate then controls TF growth (humid periods) and inactivity (drier periods). [ABSTRACT FROM AUTHOR]

• Review of hydro-morphological responses to LULC and climate changes. • The first review paper of this type focused on tropical regions. • A comprehensive review of 60 case studies. • Meta-analysis of the findings of all case studies. • Significant correlations are revealed between LULCC and hydrological processes. Tropical regions have experienced the fastest Land Use Land Cover Change (LULCC) in the last decades, coupled with climate change (CC) this has affected the hydrological and geomorphological processes of river systems. With the increased demand for land, the general trend has been the loss of forest land to agriculture and settlements. These changes have altered the water balance components through enhanced or reduced evaporation, peak flow, flooding, and river morphology. The aim of this review paper is to provide a meta -analysis on the effects of spatiotemporal changes in climate and LULC on river hydro-morphology in the tropics. Following a systematic search, 60 case studies were identified, of which the majority (68%) experienced forest loss due to agricultural and urban expansion, resulting in increased streamflow, surface flow, and total water yield and decreased ET and groundwater recharge. 12% of the case studies showed the impacts of LULCC on channel morphology features through sediment transport and riverbank erosion. Results from this study show limited correlation between LULCC and hydrological variables, indicating that there are likely other factors controlling hydrological processes. Catchment heterogeneity including soil and topography play an important role. Based on studies that project these changes into the future, similar trends are expected over the next decades, with differences based on LU and climate scenarios. There are still limited studies on river hydro-morphology responses to LULCC and CC in the tropics despite the major changes taking place there. In light of future changes, more studies are needed to improve our understanding. [ABSTRACT FROM AUTHOR]

The formation process for Martian gullies is a critical unknown for understanding recent climate conditions. Leading hypotheses include formation by snowmelt in a past climate, or formation via currently active CO 2 frost processes. This paper presents an expanded catalog of >300 recent flows in gullies. The results indicate that sediment transport in current gully flows moves the full range of materials needed for gully formation. New flows are more likely to transport boulders in gullies that have pre-existing boulder-covered aprons, indicating that current flows are transporting the same materials required for gully formation overall. The distribution of gully activity frequencies can be described by a power law and indicates that the recurrence intervals for flows in individual gullies are commonly tens to hundreds of Mars years. Over the last ~300 kyr, climate variations have been modest but individual gullies have had tens to thousands of flow events. This could be sufficient to account for the entirety of gully formation in some cases, although the same processes are likely to have occurred further in the past. For any gullies that may have initiated under higher-obliquity conditions, this level of recent activity indicates that the observable morphology has been shaped by CO 2 -driven flows. These observations of sediment transport and the tempo of gully activity are consistent with gully formation entirely by CO 2 frost processes, likely with spatial and temporal variability, but with no role required for liquid water. • Sediment transport in current gully flows is consistent with present-day gully formation. • Gully sites have a range of activity frequencies that can be described by a power law. • Contemporary activity due to CO 2 frost processes is a significant part of gully evolution and could form gullies. [ABSTRACT FROM AUTHOR]

[Display omitted] • The Brazilian semiarid is the most densely populated dry region in the world. • Sediment source apportionment was quantified in a semiarid ephemeral catchment. • The combination of conventional and alternative tracers improved source discrimination. • Our results may gain high visibility given the climate change projections for the semiarid regions. The Brazilian semiarid is the most densely populated dry region in the world. Although climate change projections underline the need for the creation of integrated strategies to protect water resources in the semiarid, sediment source apportionment data remain scant for this environment. Accordingly, we evaluated sediment source contributions in one of the most relevant Brazilian semiarid catchments by combining geochemical and colour tracer properties. In doing so, we explored the applicability of colour tracers as a low-cost alternative to the use of time-consuming and costly properties, such as geochemical tracers. Two source classification schemes were used based on environmentally contrasting regions within the catchment (upper, middle and lower catchment parts) and land use (Caatinga biome - natural vegetation, unpaved roads, and channel banks). Suspended sediments (SS) and bed sediments (BS) were used as target sediment. A total of 660 individual source material samples were collected and composited. Geochemical and colour tracers were measured on the source and target sediment samples and used as potential fingerprints to discriminate and quantify the sediment source contributions. The geochemical tracers provided weak source discrimination based on land use. However, combining geochemical and colour tracers improved the final outputs. Using the MixSIAR model, the lower catchment contributed more sediment than the other regional sources. The Caatinga (SS = 49 %; BS = 47 %) contributed more sediment than channel banks (SS = 35 %; BS = 39 %). Overall, our results suggest that the recovery and conservation of the Caatinga vegetation and the stabilization of channel banks, especially in the lower catchment part, are critical for improving sediment supply control in the semiarid study basin. More studies are needed to evaluate the conservative behaviour of colour tracers in ephemeral rivers. [ABSTRACT FROM AUTHOR]

The Himalayan foreland basin, manifested as the Indo-Gangetic Plain (IGP) on the surface, has been filling up with sediment, carried by the Himalayan river network. Since 1960, several sediment budget records have been established for this region, estimated by different approaches, and averaged over different time scales. Here, we have compiled 196 records of sediment load, sediment yield, and erosion rate published between 1960 and 2022 for different catchments across the IGP. We categorised the data as long-term (multi-centennial to multi-millennial) and short-term (annual to multi-decadal) records, based on the timescale they are averaged upon. We find that there is a clear gradient of sediment yield across the IGP where long-term sediment yield decreases from ∼5800 t/yr/km2 (Sutlej basin) in the west to ∼1200 t/yr/km2 (Ganges basin) in the east and the short-term yield decreases from ∼1800 t/yr/km2 (Sutlej basin) in the west to ∼100 t/yr/km2 (Ganges basin) in the east. Our analysis shows that the driving factors of sediment generation and dispersion vary throughout the region and among the integration timescales. The region south of the Main Frontal Thrust, specifically the IGP, is highly populated and the short-term records suggest an anthropogenic bias. However, we show that only a low but measurable percentage of the annual sediment load is trapped by anthropogenic interventions, such as dams and barrages, when we compare the short- and long-term sediment loads. Among 172 sampled catchments, both short (n = 87) and long-term (n = 60) loads from basins with area >100 km2, show nearly log-linear correlation with their respective basin sizes. However, in case of the Ganga-Brahmaputra basin, the slope of the best fit line for the short-term loads is 30% lower compared to long-term loads. The short-term load estimations for the same basin size are consistently lower than the long-term loads. We attribute this discrepancy on the lag in response time of the vast IGP dispersal system. We note that the variability of long-term erosion rates from west to east correspond well (R2 = 0.77, n = 6) with the variability of mean normalized channel steepness indices for all major catchments to the south of the Main Frontal Thrust region. To the north of the Main Frontal Thrust, the variation of long-term erosion rates correlates well with channel steepness within a single catchment, but not in a similar fashion across different catchments from west to east. We observe that the linear relationship between long-term erosion rate and channel steepness index for individual basins to the north of the MFT is influenced by the presence of high vegetation density; however, any correlation between long-term erosion rates with mean annual rainfall and vegetation cover is absent. Our analyses suggest that short-term records are more susceptible to vegetation cover changes in steep terrains, but landscape erosion rates at these timescales are also driven by various degrees of landscape steepness. We show that short-term records are influenced by transient sediment storages on the IGP that respond to past tectonic and climatic forcing. This underlines the importance of understanding transient sediment storages when interpreting short-term records in the context of recent climatic changes and anthropogenic impacts. [ABSTRACT FROM AUTHOR]

• Landslide contribution to basin sediment budget was determined. • Individual landslide tracing and routing was conducted. • Coupling between landslide and climate change impact was analysed. Mass movements such as landslides are prominent sources of sediment in post-seismic mountain belts. Earthquake triggered landslides can generate substantial volumes of fresh sediment and this may have significant long-term (decade to millennium) geomorphic effects on landscape evolution. Downslope and downstream transport of sediment into the channel network is sensitive to meteorological perturbations especially for extreme rainfall events. However, no established techniques can explicitly fingerprint/track landslide-derived sediment under climate change. In this study, we use a new tracing function incorporated into CAESAR-Lisflood (CL) to track the landslide-derived sediment dynamics in response to climate change. The hourly future rainfall sequences under two climate scenarios (RCP4.5, RCP8.5) were firstly generated using 'NASA Earth Exchange Global Daily Downscaled Projections (NEX-GDDP)' dataset and then used as hydrological input to drive CL simulations. The landscape evolution at the Hongxi basin, which suffered great damage from the Wenchuan earthquake (Ms 8.0), was then simulated for 93 years (2008–2100) using CL under two climate scenarios. The results show that the landslides can greatly increase the sediment yield and climatic perturbations can lead to variation of sediment dynamics, the coupling of these two factors perform a combined impact on sediment budget, while the interplay and relevant importance between landslides and climate impact is dependent on the landslide density of specific basin. The landslide-channel connectivity (location of landslides with respect to river channels) plays an important role in post-earthquake sediment evacuation. The yearly sediment yield generated by the landslides can be stable after 20 years under both RCP 4.5 and RCP 8.5 scenarios in the study basin. These findings are of great importance to understand the interplay between landslide and climatic perturbations and support the risk management and mitigation after the 2008 Wenchuan earthquake. [ABSTRACT FROM AUTHOR]

The Eocene was a critical period of global plate reorganization and it also saw the Earth's climate transition from the warmhouse state to the coolhouse state. Reconstructing the Eocene sedimentary history in the climate-sensitive Southern Ocean is important for understanding paleoenvironmental changes in response to the accelerated Australia/Antarctica separation and global cooling throughout the middle and late Eocene. Here, we present the first detailed multiproxy record of a continuous sequence from International Ocean Discovery Program (IODP) Site U1514 in the Mentelle Basin off southwestern Australia. Our aim is to reconstruct the sediment provenances and paleoenvironmental evolution in response to the abovementioned climatic and tectonic changes in the mid-high southern latitudes during the Eocene. Provenance analyses based on Sr-Nd isotopes, trace elements, and clay mineral assemblages suggest that Eocene sediments at Site U1514 predominantly originated from the southwestern Australian continent and the Naturaliste Plateau. Sediment provenance variations during the middle Eocene indicate that the onset of fast separation between Australia and Antarctica at 43 Ma caused an increased supply of volcanic materials from the Naturaliste Plateau between 43 and 38 Ma. Terrigenous inputs to the Mentelle Basin during the middle Eocene were primarily controlled by paleoclimate changes rather than tectonic processes because coeval clay mineralogical changes (higher kaolinite/smectite ratio and MAR kaolinite) indicate a period of stronger physical erosion and chemical weathering on the western Australian continent that resulted in increased terrigenous materials delivered to the Mentelle Basin. Our results reveal a 5 Myr-long (43–38 Ma) warming reversal in the southern mid-high latitudes, providing an exception to the generally short-lived (10–100 kyr-long) hyperthermals that interrupted the long-term global cooling throughout the middle to late Eocene. As for the late Eocene (38–37 Ma), tectonic processes related to the sudden acceleration in seafloor spreading in the Tasman Sea led to the exposure of shallower areas, resulting in rapid detritus accumulation at the study site. During the late Eocene (37–34 Ma), major sediment provenance shifted from distal source areas (e.g., the Yilgarn Craton) to relatively proximal sources (e.g., the Leeuwin Block and Perth Basin). We interpret that the regional uplift in southwestern Australia and coeval climate cooling resulted in the diversion and inactivation of large drainage systems, thus blocking the transportation of sediment from distant regions. • First detailed record of the Eocene source-to-sink process in the Mentelle Basin. • The onset of fast Australia/Antarctica separation caused increased volcanic input. • Regional warming led to enhanced chemical weathering in Australia during 43–38 Ma. • Regional uplift and global cooling induced sediment source change during 37–34 Ma. [ABSTRACT FROM AUTHOR]

• Daily sampling of aquatic chemistry after megafires in a large catchment. • Significant increases in major parameters and highly distorted CQ relationships. • Extreme dynamism and transient behaviour with monotonic recovery in ∼3–12 months. • Greatest sensitivity to erosion during initial flow events following fire. • Initial dominance of NH 4 and rapid biogeochemical cycling of N species. Increased frequency and intensity of drought, wildfires and flooding due to climate change has major implications for river water quality, yet there are limited high-temporal resolution data capturing the combined transient impacts of these extreme events at large catchment scales. We present flow-stratified water quality data from a large coastal catchment (Macleay River, Australia) spanning severe drought and extensive fires followed by flooding. We examine concentrations (C), discharge (Q) and flux of suspended sediment, major ions, dissolved organic carbon (DOC) and key nutrients (NO 3 and PO 4), with a focus on the critical first-flush period after the fires. Highly elevated suspended sediment (∼5500 mg L−1; >100x median pre-fire levels) during the initial post-fire period reflected enhanced erosion from fire-impacted, high-relief landscapes, with peak monthly suspended sediment loads of ∼1.1–3.7 t ha−1. The greatest sensitivity to erosion was during initial flow events following fire, highlighting the compounding effect of sequential extreme events on sediment transport. Maximum solute concentrations typically occurred during the first hydrograph peak post-fire with significantly (P = 0.01) elevated major ions following the order of K>Ca>SO 4 >HCO 3 ≈Mg>Cl>Na, broadly reflecting the composition of ash materials. Distorted CQ relationships for major ions, DOC and nutrients indicated mobilisation behaviour and enhanced surface runoff during initial hydrograph peaks post-fire, with mean concentrations and CQ relationships progressively shifting to those approximating pre-fire within ∼3–12 months. Elevated DOC (∼7x; P = 0.01) displays distinct changes in fluorescence excitation-emission matrix spectral characteristics, attributable to both fire and drought. Both NO 3 N (160 μM) and PO 4 (7.5 μM) were significantly elevated after the fires (∼15–22x; P = 0.01), with maximum monthly loads of 0.82 and 0.14 kg ha−1 respectively. Fast biogeochemical cycling of dissolved inorganic nitrogen (DIN) species occurred during initial flow events following fire, with NH 4 N initially dominant (>80% of DIN) and exceeding ecosystem guideline threshold values (>100 μM NH 4 N), followed by rapid (∼1 week) nitrification. The extreme dynamism and transience of water quality parameters highlights the critical importance of high-frequency sampling to adequately capture the compound impacts drought, fires and floods on aquatic systems. [Display omitted] [ABSTRACT FROM AUTHOR]

The Jinsha River, the upper reaches of the Yangtze River, winds and incises through the eastern margin of the Tibetan Plateau, where Asian monsoon climate prevails. Along the Jinsha River, extensive and thick Quaternary valley fillings and multiple river terraces have been developed. However, their specific relations to climate change and tectonics remain elusive. In this study, we conducted field investigation, chronological studies and numerical modeling in its lower reaches. Our study indicates that the extensive valley fillings in the Wudongde-Menggu segment were formed in cold-arid climate with Optically Stimulated Luminescence (OSL) ages of ~23–19 ka B.P., coinciding with the timing of the Last Glacial Maximum (LGM). We suggest that the post-LGM warming and humidifying, by restrained sediment supply while enhanced discharge, switched the valley from prevailing aggradation into incision. Multiple subsequent fill-cut terraces, postdating the LGM, were formed and nested in the valley fillings. OSL data indicate that sediments of three terraces (T1–T3) were formed at ~10 ka B.P., ~11.5–12.5 ka B.P. and ~13.5 ka B.P., respectively. Our study suggests that these terraces are sensitive records of millennial and sub-millennial cold-arid climate perturbations superimposed over the post-LGM deglaciation. Our modeling highlights a high sensitivity of valley aggradation and incision to cold-arid and warm-wet climate change, as well as a fast valley landscape response in the Jinsha River characterized by high sediment transport influx. We propose that valley landscape and terraces serve as a timely record for climate change in certain rivers with short response time threshold characterized by high sediment transport influx. • Valley filling was driven by the cold-arid climate in the LGM. • Fill-cut terraces record sub-millennial cold-arid climate perturbations. • Modeling supports a sensitive and fast response of Jinsha River to climate change. • The present valley landscape remains in a transient adjustment since the LGM. [ABSTRACT FROM AUTHOR]