Future Sea Level Research Articles

Evolution of Coastal Environments under Inundation Scenarios Using an Oceanographic Model and Remote Sensing Data

A new methodology to map Italian coastal areas at risk of flooding is presented. This approach relies on detailed projections of the future sea level from a high-resolution, three-dimensional model of the Mediterranean Sea circulation, on the best available digital terrain model of the Italian coasts, and on the most advanced satellite-derived data of ground motion, provided by the European Ground Motion Service of Copernicus. To obtain a reliable understanding of coastal evolution, future sea level projections and estimates of the future vertical ground motion based on the currently available data were combined and spread over the digital terrain model, using a GIS-based approach specifically developed for this work. The coastal plains of Piombino-Follonica and Marina di Campo (Tuscany Region), Alghero-Fertilia (Sardinia), and Rome and Latina-Sabaudia (Lazio Region) were selected as test cases for the new approach. These coastal stretches are important for the ecosystems and the economic activities they host and are relatively stable areas from a geological point of view. Flood maps were constructed for these areas, for the reference periods 2010–2040, 2040–2070, and 2040–2099. Where possible, the new maps were compared with previous results, highlighting differences that are mainly due to the more refined and resolved sea-level projection and to the detailed Copernicus ground motion data. Coastal flooding was simulated by using the “bathtub” approach without considering the morphodynamic processes induced by waves and currents during the inundation process. The inundation zone was represented by the water level raised on a coastal DTM, selecting all vulnerable areas that were below the predicted new water level. Consequent risk was related to the exposed asset.

Subglacial Discharge Accelerates Dynamic Retreat of Aurora Subglacial Basin Outlet Glaciers, East Antarctica, Over the 21st Century

AbstractRecent studies have revealed the presence of a complex freshwater system underlying the Aurora Subglacial Basin (ASB), a region of East Antarctica that contains ∼7 m of global sea level potential in ice mainly grounded below sea level. However, the impact that subglacial freshwater has on driving the evolution of the dynamic outlet glaciers that drain this basin has yet to be tested in a coupled ice sheet‐subglacial hydrology numerical modeling framework. Here, we project the evolution of the primary outlet glaciers draining the ASB (Moscow University Ice Shelf, Totten, Vanderford, and Adams Glaciers) in response to an evolving subglacial hydrology system and to ocean forcing through 2100, following low and high CMIP6 emission scenarios. By 2100, ice‐hydrology feedbacks enhance the ASB's 2100 sea level contribution by ∼30% (7.50–9.80 mm) in high emission scenarios and accelerate the retreat of Totten Glacier's main ice stream by 25 years. Ice‐hydrology feedbacks are particularly influential in the retreat of the Vanderford and Adams Glaciers, driving an additional 10 km of retreat in fully coupled simulations relative to uncoupled simulations. Hydrology‐driven ice shelf melt enhancements are the primary cause of domain‐wide mass loss in low emission scenarios, but are secondary to ice sheet frictional feedbacks under high emission scenarios. The results presented here demonstrate that ice‐subglacial hydrology interactions can significantly accelerate retreat of dynamic Antarctic glaciers and that future Antarctic sea level assessments that do not take these interactions into account might be severely underestimating Antarctic Ice Sheet mass loss.

A framework for physically consistent storylines of UK future mean sea level rise

We present a framework for developing storylines of UK sea level rise to aid risk communication and coastal adaptation planning. Our approach builds on the UK national climate projections (UKCP18) and maintains the same physically consistent methods that preserve component correlations and traceability between global mean sea level (GMSL) and local relative sea level (RSL). Five example storylines are presented that represent singular trajectories of future sea level rise drawn from the underlying large Monte Carlo simulations. The first three storylines span the total range of the Intergovernmental Panel on Climate Change (IPCC) Sixth Assessment Report (AR6) likely range GMSL projections across the SSP1-2.6 and SSP5-8.5 scenarios. The final two storylines are based upon recent high-end storylines of GMSL presented in AR6 and the recent literature. Our results suggest that even the most optimistic sea level rise outcomes for the UK will require adaptation of up to 1 m of sea level rise for large sections of coastline by 2300. For the storyline most consistent with current international greenhouse gas emissions pledges and a moderate sea level rise response, UK capital cities will experience between about 1 and 2 m of sea level rise by 2300, with continued rise beyond 2300. The storyline based on the upper end of the AR6 likely range sea level projections yields much larger values for UK capital cities that range between about 3 and 4 m at 2300. The two high-end scenarios, which are based on a recent study that showed accelerated sea level rise associated with ice sheet instability feedbacks, lead to sea level rise for UK capital cities at 2300 that range between about 8 m and 17 m. These magnitudes of rise would pose enormous challenges for UK coastal communities and are likely to be beyond the limits of adaptation at some locations.

Seawater oxygen isotopes as a tool for monitoring future meltwater from the Antarctic ice-sheet

To reduce uncertainties in future sea level projections, it is necessary to closely monitor the evolution of the Antarctic ice-sheet. Here, we show that seawater oxygen isotopes are an effective tool to monitor ice-sheet freshwater discharge and its contributions to sea level rise. Using the isotope-enabled Community Earth System Model with imposed estimates of future meltwater fluxes, we find that the anthropogenic ice-sheet signal in water isotopes emerges above natural variability decades earlier than salinity-based estimates. The superiority of seawater isotopes over salinity in detecting the ice-sheet melting can be attributed to the higher signal-to-noise ratio of the former and the fact that future sea ice changes only contribute little to seawater isotopes but a lot to salinity. We conclude that in particular in the Ross Sea sector, continuous seawater oxygen isotope measurements could serve as an early warning system for rapid anthropogenic Antarctic ice-sheet mass loss.

Non-market value losses to coastal ecosystem services and wetlands from sea-level rise and storm surge, 2050 to 2100: The Kimberley Region, Western Australia

Accelerating climate change from the thermal expansion of oceans and losses from terrestrial glaciers and ice sheets causes sea level rise (SLR), damaging coastal ecosystems and generating non-market value losses. Using an innovative Artificial Intelligence (AI) projection method and 18 existing geographical SLR projections, we project future sea level rise and storm surge (SLR/S) for the 1600 km coastline of the Kimberley Region, Western Australia, a region with a larger surface area than Great Britain, Ireland, and Portugal combined and with a permanent population of 40,000 people of which more than 16,000 identify as Indigenous. Using our projected coastal area inundation from future SLR, we estimated the non-market value losses of the Kimberley's coastal ecosystem and wetlands with projected SLR/S to 2050 and 2100 for Representative Concentration Pathway (RCPs) 4.5 and 8.5. Average annual non-market losses from SLR/S in 2050 and 2100 in the Kimberley are large relative to the size of the regional economy and are estimated to range from A$2.7 to A$4.3 billion (2050) and A$8.1 to A$15.8 billion (2100), depending on the RCP and temperature pathway. Our findings highlight the need for adequately resourced community-based approaches to climate adaptation.

A distinct manganese deposit on a Middle Permian carbonate platform in South China

During the Middle Permian, Earth experienced a period of profound environmental changes, including the final stages of the Late Paleozoic Ice Age (LPIA), global seawater regression, the Guadalupian mass extinction event, and the eruption of the Emeishan Large Igneous Province (ELIP) in South China. These events collectively induced significant shifts in both the environment and biosphere, yielding several geochemical anomalies, including deposition of manganese (Mn) deposits. The link between Middle Permian Mn deposits and the prevailing environmental conditions, however, remains unclear. Here, four sections spanning the Middle Permian Maokou Formation to the Late Permian Longtan Formation in the Zunyi area of northern Guizhou, South China are investigated. Through sedimentological and geochemical analyses, this work aims to elucidate the evolution of sedimentary environments over the Middle to Late Permian. During this period, a transition from a shallow-water carbonate platform in the 1st Member of the Maokou Formation to a deeper, siliceous deposit in its 2nd Member was recorded. This shift results in a pronounced paleogeographic differentiation in the 3rd Member, juxtaposing the shallow-water carbonate platform against a deeper Mn-enriched basin. A number of geochemical proxies indicate a strong hydrothermal signal in the Mn deposits. Combined with positive Eu anomalies and low Sr isotopes, the data underscore the profound influence of hydrothermal input linked with early subaqueous eruptions from the ELIP on the nearby marine environment. A detailed examination of carbon isotope profiles from the Maokou Formation indicates that volcanic influences, shifts in marine ecosystems, and changes in primary production caused the fluctuations of δ13Ccarb and δ13Corg. Moreover, the formation of Mn carbonate in deeper waters effectively sequestered organic C. Collectively, our new data demonstrate that the essential conditions for the development of the carbonate-hosted Mn deposits include drowning of the carbonate platform through an increase in sea level, the availability of a sufficient Mn source, and the presence of a redox-stratified water column.

Coupled ice–ocean interactions during future retreat of West Antarctic ice streams in the Amundsen Sea sector

Abstract. The Amundsen Sea sector has some of the fastest-thinning ice shelves in Antarctica, caused by high, ocean-driven basal melt rates, which can lead to increased ice streamflow, causing increased sea level rise (SLR) contributions. In this study, we present the results of a new synchronously coupled ice-sheet–ocean model of the Amundsen Sea sector. We use the Wavelet-based, Adaptive-grid, Vertically Integrated ice sheet model (WAVI) to solve for ice velocities and the Massachusetts Institute of Technology general circulation model (MITgcm) to solve for ice thickness and three-dimensional ocean properties, allowing for full mass conservation in the coupled ice–ocean system. The coupled model is initialised in the present day and run forward under idealised warm and cold ocean conditions with a fixed ice front. We find that Thwaites Glacier dominates the future SLR from the Amundsen Sea sector, with a SLR that evolves approximately quadratically over time. The future evolution of Thwaites Glacier depends on the lifespan of small pinning points that form during the retreat. The rate of melting around these pinning points provides the link between future ocean conditions and the SLR from this sector and will be difficult to capture without a coupled ice–ocean model. Grounding-line retreat leads to a progressively larger Thwaites Ice Shelf cavity, leading to a positive trend in total melting, resulting from the increased ice basal surface area. Despite these important sensitivities, Thwaites Glacier retreats even in a scenario with zero ocean-driven melting. This demonstrates that a tipping point may have been passed in these simulations and some SLR from this sector is now committed.

Coastal vulnerability considering combined effect of tropical cyclones and future sea level rise

Coastal vulnerability considering combined effect of tropical cyclones and future sea level rise

Future sediment transport to the Dutch Wadden Sea under severe sea level rise and tidal range change

Future sediment transport from the North Sea coasts to the Dutch Wadden Sea for various future sea level scenarios has been studied because it influences the future sand nourishment demand for the maintenance of the coastline and because it determines bio-geomorphological development of the Wadden Sea. The present study focuses on two questions which have not yet been considered in the previous modelling studies using ASMITA: How will the transport develop around drowning of the intertidal flats in the Wadden Sea? How will tidal range change influence the future sediment exchange? By using SLR scenarios with faster acceleration and running the simulations for longer periods of time some inlets exhibited drowning, i.e., where the tidal flat volume vanishes. When drowning occurs, the sediment import rate approaches a maximum or a minimum, depending on the initial morphological state of the tidal inlet system. This maximum or minimum rate for a certain tidal inlet system depends on the SLR scenario. Theoretical analysis as well as modelling results show that tidal range change will influence the sediment import to the Wadden Sea. A tidal range increase will cause a decrease of the sediment demand in the Wadden Sea resulting into less sediment import to the Wadden Sea. It is thus important to study the tidal range development in the Wadden Sea by considering the interaction between SLR, tidal range change and morphological development in the system. It is further concluded that the empirical relation used in the previous studies is not representative of conditions in a tidal basin with fixed basin area, even though this relation has been derived from field observations in many tidal inlet systems worldwide. The equilibrium channel volume should be proportional to the tidal prism instead of to its 1.5th power.

Simulating Future Exposure to Coastal Urban Flooding Using a Neural Network–Markov Model

Urbanization and climate change are two major challenges of the 21st century, and the effects of climate change, combined with the urbanization of coastal areas, increase the frequency of coastal flooding and the area exposed to it, resulting in increased risk of flooding and larger numbers of people and properties being vulnerable. An urban growth modeling system was used to simulate future growth scenarios along the coast of the Vendée region in western France, and the potential exposure to flooding with each scenario was evaluated. The model used was an Artificial Neural Network combined with a Markov Chain, using data obtained by the remote sensing and geographic information system techniques to predict three future urban growth scenarios: business as usual, environmental protection, and strategic urban planning. High-risk flood areas and future sea level projections from the Sixth Assessment Report of the Intergovernmental Panel on Climate Change were then used to assess future flood risk under each growth scenario in the study area. According to the results, the different growth scenarios are associated with different development patterns, and the strategic urban planning scenario significantly reduces the risk of flooding compared to the other two scenarios. However, the rise in sea level considerably expands the areas vulnerable to flooding. Finally, the methodology adopted can be used to prepare for the impact of climate change and develop strategies to mitigate the risk of flooding in the future.

Experimental study on wave damping potential of seaweed aquaculture systems on the Portuguese coast

The sea-level rise and intensification of extreme weather events pose a significant threat to coastal regions and their communities worldwide. With significant wave heights reaching over 5 m, and wave periods over 10 s (Mendes & Oliveira, 2021), the Portuguese coastline is exposed to major coastal erosion, due to the marine harsh conditions of the North Atlantic. In the last decades the preferred strategy to protect the coastline from coastal hazards has been the construction of hard-engineering structures such as seawalls and breakwater, which tend to be expensive and unsustainable, often becoming obsolete and were not designed to account for the increasing sea level. As such, there has been a growing trend over the adoption of soft, adaptative, and nature-based coastal protection measures (Pranzini et al., 2015). Longline seaweed aquaculture systems have long been identified as a nature-based, soft structure with wave damping potential by several studies performed by Mork (1996), Liu et al. (2015) among others. The AquaBreak Project aims at exploring the synergetic applications of seaweed aquaculture systems on food production, coastal protection, and sea decarbonization on the Portuguese coast with the creation of the AOS - the AquaBreak Offshore System (Miranda et al., 2023; Proença et al., 2023). However, in order to create a strategic and effective implementation plan for the AOS, it is important to assess the wave damping potential of such structure exposed to the common maritime conditions of the Portuguese Coast.

20th‐Century Antarctic Sea Level Mitigation Driven by Uncertain East Antarctic Accumulation History

AbstractIncreasing snow accumulation over the Antarctic Ice Sheet may mitigate future sea level rise. However, current estimates of mitigation potential are poorly constrained due to limited records of past variability. We present an annually resolved reconstruction of Antarctic snow accumulation from 1801 to 2000 CE, employing a paleoclimate data assimilation methodology to integrate ice core records with a multi‐model ensemble of climate simulations. Our reconstruction correlates well with instrumental reanalysis, and we find that Antarctic accumulation rates increased over the 20th‐century, resulting in a modest amount (∼1 mm) of sea level mitigation. Mitigation is primarily driven by an accelerating trend since around 1970. Our results contrast with previous mitigation estimates of ∼10–12 mm; this discrepancy is due to poorly constrained baseline estimates of 19th‐century accumulation in East Antarctica. Our reconstruction suggests that the uncertainty of future sea level mitigation from increasing Antarctic accumulation has been underestimated.

Intrinsically Episodic Antarctic Shelf Intrusions of Circumpolar Deep Water via Canyons

Abstract The structure of the Antarctic Slope Current at the continental shelf is crucial in governing the poleward transport of warm water. Canyons on the continental slope may provide a pathway for warm water to cross the slope current and intrude onto the continental shelf underneath ice shelves, which can increase rates of ice shelf melting, leading to reduced buttressing of ice shelves, accelerating glacial flow and hence increased sea level rise. Observations and modeling studies of the Antarctic Slope Current and cross-shelf warm water intrusions are limited, particularly in the East Antarctica region. To explore this topic, an idealized configuration of the Antarctic Slope Current is developed, using an eddy-resolving isopycnal model that emulates the dynamics and topography of the East Antarctic sector. Warm water intrusions via canyons are found to occur in discrete episodes of large onshore flow induced by eddies, even in the absence of any temporal variability in external forcings, demonstrating the intrinsic nature of these intrusions to the slope current system. Canyon width is found to play a key role in modulating cross-shelf exchanges; warm water transport through narrower canyons is more irregular than transport through wider canyons. The intrinsically episodic cross-shelf transport is found to be driven by feedbacks between wind energy input and eddy generation in the Antarctic Slope Current. Improved understanding of the intrinsic variability of warm water intrusions can help guide future observational and modeling studies in the analysis of eddy impacts on Antarctic shelf circulation.

Identification of climate change and its impact on maize (Zea mays L.) production in Majalengka Regency

Maize is one of the multipurpose crop whose yields can be affected by climate change. Climate change includes increasing air temperature, increasing sea levels, and changes in rainfall can be a threat and cause a decrease in maize yields. This could be caused by climate change factors. This research aims to identify climate change and analyze the correlation between climate change and maize production in the Majalengka Regency. Maize plantations in the 26 sub-districts are still fluctuative. The method used in this research is quantitative descriptive using trend analysis and correlation. The data used include temperature, rainfall, harvested area, production, and productivity of maize obtained from (i) the Meteorological, Climatological, and Geophysical Agency of Majalengka Regency, (ii) Statistics Indonesia, (iii) Food Security, Agriculture, and Fisheries Office of Majalengka Regency, and other related sources. The results of this research showed that climate change in Majalengka Regency was marked by an increase in temperature trend and a decrease in rainfall trend. The correlation between temperature and changes in maize production in Majalengka Regency was significant, while rainfall was not significant.

Advances in monitoring glaciological processes in Kalallit Nunaat (Greenland) over the past decades

Greenland’s glaciers have been retreating, thinning and accelerating since the mid-1990s, with the mass loss from the Greenland Ice Sheet (GrIS) now being the largest contributor to global sea level rise. Monitoring changes in glacier dynamics using in-situ or remote sensing methods has been and remains therefore crucial to improve our understanding of glaciological processes and the response of glaciers to changes in climate. Over the past two decades, significant advances in technology have provided improvements in the way we observe glacier behavior and have helped to reduce uncertainties in future projections. This review focuses on advances in in-situ monitoring of glaciological processes, but also discusses novel methods in satellite remote sensing. We further highlight gaps in observing, measuring and monitoring glaciers in Greenland, which should be addressed in order to improve our understanding of glacier dynamics and to reduce in uncertainties in future sea level rise projections. In addition, we review coordination and inclusivity of science conducted in Greenland and provide suggestion that could foster increased collaboration and co-production.

Evaluation of Urban Land Suitability under Multiple Sea Level Rise Scenarios

Anticipated sea level rises from global climate change pose a significant flood risk to urban land. Evaluating urban land suitability under sea level rise scenarios is crucial for promoting sustainable development. Recent research has advanced the application of artificial intelligence and the integration of GIS with models, yet the impact of climate change on land suitability has often been overlooked. This study focuses on Xihu District in Hangzhou, utilizing the entropy weight and matter-element model to evaluate land suitability for urban development. The evaluation results were cross-verified with land use plans. A comprehensive analysis of potential flood risk to urban land in 2100 was conducted, considering varying degrees of sea level rise under Sustainable Development Scenario SSP1-2.6 and High-end Emission Scenario SSP5-8.5, as well as the scenario reflecting the most severe sea level rise during extreme climate events. The results indicate that more than half of the land in the study area is suitable for construction, aligning spatially with the current planned urban land. The analysis process of the matter-element model reflects the impact level of each indicator on urban land suitability, conveying information both spatially and numerically, thus enhancing accuracy. Scenario analysis reveals that approximately 10% to 20% of urban land in the study area could face flooding threats due to future sea level rises, primarily in the northern and southeastern regions. Recommendations for future land development and spatial planning strategies to address flood risk are discussed, aiming to alleviate the pressure on urban land in response to future climate change.

Saltwater intrusion increases phosphorus abundance and alters availability in coastal soils with implications for future sea level rise

Sea level rise (SLR) promotes saltwater intrusion (SWI) into coastal soils globally at an increasing rate, impacting phosphorus (P) dynamics and adjacent water quality. However, how SWI influences P molecular speciation and availability in coastal soils remains poorly understood. By using a space-for-time substitution strategy, we evaluated the SWI impacts on P transformation along a SWI gradient at the Rehoboth Inland Bay, which consists of five sampling locations along a transect representing different SWI degrees. Soils were analyzed at the macro- and micro-scale using X-ray absorption near edge spectroscopy (XANES) and the modified Hedley fractionation. With increasing distance from the Bay, soil salinity (29.3–0.07 mmhos cm−1), the proportion of Fe3+ to total Fe, and P concentrations decreased. The fractionation showed that recalcitrant P was dominant (86.9–89.5% of total P). With increasing SWI, labile P increased gradually, reached a plateau, and then decreased sharply. Bulk XANES spectroscopy showed that soil P was likely dominated by iron and aluminum-associated P (Fe/Al-P), regardless of the SWI degree. Hence, with increasing SWI, P increasingly accumulated in a recalcitrant pool, mainly as Fe/Al-P. μ-XANES spectroscopy revealed that calcium-associated P (Ca-P) existed in P-rich spots of the greatest SWI soil while Al-P occurred in P-rich spots of the low SWI soil, consistent with the greater HCl-P (presumably Ca-P) in the former soil. Overall, results demonstrate that SWI impacts P availability and environmental risk in coastal soils depending on the degree of SWI. These findings have important implications for understanding soil P cycling and availability in SLR-impacted coastal areas.

Recent increase in the surface mass balance in central East Antarctica is unprecedented for the last 2000 years

AbstractThe Antarctic Ice Sheet’s reaction on the continuing global warming is crucial to project the future sea level rise. The increasing air temperature causes both accelerating mass loss on the Antarctica’s margins and increased surface mass balance in its interior. Here, we use data from firn cores drilled near Vostok station (central East Antarctica) to analyze the surface mass balance variability over the past 2200 years. We show a 24% increase of snow accumulation rate since early 19 century confirmed by the instrumental data for the last 52 years. The mean surface mass balance value in 1970–2021 (2.25 ± 0.064 g cm−2 yr−1) is very likely unprecedented in the pre-industrial era. The surface mass balance growth is accompanied by the air temperature increase with the sensitivity of 11 ± 2% per 1 °C. These results will help to constrain the potential magnitude of Antarctic snowfall mitigation of future sea level rise.

Tropical or extratropical cyclones: what drives the compound flood hazard, impact, and risk for the United States Southeast Atlantic coast?

Subtropical coastlines are impacted by both tropical and extratropical cyclones. While both may lead to substantial damage to coastal communities, it is difficult to determine the contribution of tropical cyclones to coastal flooding relative to that of extratropical cyclones. We conduct a large-scale flood hazard and impact assessment across the subtropical Southeast Atlantic Coast of the United States, from Virginia to Florida, including different flood hazards. The physics-based hydrodynamic modeling skillfully reproduces coastal water levels based on a comprehensive validation of tides, almost two hundred historical storms, and an in-depth hindcast of Hurricane Florence. We show that yearly flood impacts are two times as likely to be driven by extratropical than tropical cyclones. On the other hand, tropical cyclones are 30 times more likely to affect people during rarer 100-year events than extratropical cyclones and contribute to more than half of the regional flood risk. With increasing sea levels, more areas will be flooded, regardless of whether flooding is driven by tropical or extratropical cyclones. Most of the absolute flood risk is contained in the greater Miami metropolitan area. However, several less populous counties have the highest relative risks. The results of this study provide critical information for understanding the source and frequency of compound flooding across the Southeast Atlantic Coast of the United States.

Late Pleistocene-Holocene sea level and climate changes in the Gulf of Saros: Evidence from seismostratigraphic record and sediment core data

A detailed record of sea level changes and climate oscillations in the Gulf of Saros during the late Pleistocene to the Holocene is provided by high-resolution seismic reflection profiles and analysis of a sediment core. The seismic stratigraphy reveals the formation of four main depositional units bounded by prominent reflection surfaces, reflecting high sea level variations. The Last Glacial Maximum period in the gulf is associated with the lowstand sea level, forming the deepest marine terrace at −148 m. The increasing sea level due to post-glacial warming was accompanied by the deposition of transgressive units characterized by coastal onlaps together with local channel-fills. This transgressive phase was modulated by three brief still-stands sea levels at 17 cal ka BP, 14.6 cal ka BP and 13.6 cal ka BP, producing the younger marine terraces in the gulf at −135 m, −112 m and −90 m, respectively. A comparison of their depths with the global sea level curve reveals elevation differences with decreasing subsidence rates from the older to younger ages, implying tectonic subsidence along the gulf floor.The close correlation of multi-proxy data from core SAG-22 in the gulf with the northern Aegean and Anatolia data strongly indicates that the timings of the past climate events generally agree with the global and regional climate patterns. The warm climate around the gulf during the late phase of Bølling/Allerød (13.3–12.6 cal ka BP) is represented by high marine biological productivity and improved ventilation in the deeper water due to subsequent transgression. Permafrost formation in the catchment area during the following cold and dry Younger Dryas period (12.6–11.7 cal ka BP) resulted in reduced soil erosion and sediment input to the gulf. Noticeable warming during the Early Holocene between 11.2 cal ka BP and 9.4 cal ka BP is recorded by the multi-proxy data of the core when the enhanced marine biological productivity occurred above the poorly oxygenated deep water column. The climatic deterioration to a cooler and drier phase during the Early to Middle Holocene transition (9.4–7.8 cal ka BP) resulted in intense physical weathering and erosion, causing the highest sedimentation in the gulf. The later period of the Holocene is associated with the formation of two discrete sapropels at 7.8 cal ka BP and 5.4 cal ka BP that were accompanied by warm and wet climates around the gulf.