Future Sea Level Research Articles

A gradient-boosted tree framework to model the ice thickness of the world's glaciers (IceBoost v1.1)

Abstract. Knowledge of glacier ice volumes is crucial for constraining future sea level potential, evaluating freshwater resources, and assessing impacts on societies, from regional to global. Motivated by the disparity in existing ice volume estimates, we present IceBoost, a global machine learning framework trained to predict ice thickness at arbitrary coordinates, thereby enabling the generation of spatially distributed thickness maps for individual glaciers. IceBoost is an ensemble of two gradient-boosted trees trained with 3.7 million globally available ice thickness measurements and an array of 39 numerical features. The model error is similar to those of existing models outside polar regions and is up to 30 %–40 % lower at high latitudes. Providing supervision by exposing the model to available glacier thickness measurements reduces the error by a factor of up to 2 to 3. A feature-ranking analysis reveals that geodetic data are the most informative variables, while ice velocity can improve the model performance by 6 % at high latitudes. A major feature of IceBoost is a capability to generalize outside the training domain, i.e. producing meaningful ice thickness maps in all regions of the world, including on the ice sheet peripheries.

Sustainability of Fisheries in the Context of Climate Change and Variability in the Zanzibar Archipelago

Approximately 10 million people in Sub-Saharan Africa depend on fisheries as their primary source of livelihood. An additional 90 million participate in fishing as a supplementary source of income. Climate change is significantly impacting fish populations and their ecosystems. Key factors include rising sea temperatures and increasing sea levels. Furthermore, alterations in ocean currents, heightened salinity due to evaporation, and the occurrence of more frequent and intense cyclones also contribute to these disruptions. This study examines the impacts of climate change on the sustainability of fisheries in North Unguja, Zanzibar. Specifically, it seeks to address the following questions; How do fishers perceive the changing climate? To what extent is the fishery affected by the impacts of climate change? How do fishers adapt to the changing climate? This study collected both quantitative and qualitative data. Quantitative data were gathered through a questionnaire survey, while qualitative data were obtained from key informant interviews. Climate data from the Tanzania Meteorological Authority (TMA) on temperature and rainfall (1992-2023) were also used. Quantitative data were analysed descriptively using SPSS, and qualitative data were examined through content analysis, involving the coding of data and drawing conclusions from emerging themes. The findings revealed that the climate is changing, characterised by an increase in temperature, alterations in rainfall patterns, a rise in sea level, and an increase in the frequency and intensity of storms. The meteorological temperature and rainfall data from the Tanzania Meteorological Agency corroborated the perceptions of the fishers. The study also revealed a decrease in fish catch, partially attributed to the impacts of climate change, which could lead to increased poverty and malnutrition in North Unguja, Zanzibar. Additionally, the findings indicated that over 81 percent of respondents have not implemented any adaptation strategies, despite their awareness of climate change. This may be attributed to the low adaptive capacity of fishers in the study area. In general, climate change poses a significant threat to the sustainability of fisheries in North Unguja, Zanzibar, and jeopardises progress towards the Sustainable Development Goals, particularly in relation to poverty reduction (Goal 1) and food security (Goal 2). This study recommends that the Revolutionary Government of Zanzibar, along with relevant stakeholders, enhance the adaptive capacity of fishers by facilitating access to advanced fishing vessels for exploring new fishing grounds. Additionally, it advocates for fisheries research institutes to focus on the development of climate-resilient fish species. Furthermore, fishers in North Unguja and surrounding areas should explore alternative livelihoods and diversify their income sources to bolster resilience against both current and future climate-related impacts.

Small-scale spatial pattern of the trophic structure of polychaetes from coral reefs: Implications of future sea level rise

Small-scale spatial pattern of the trophic structure of polychaetes from coral reefs: Implications of future sea level rise

Evaluating equity and justice in Vancouver’s Sea2City Design Challenge

ABSTRACT Like many coastal cities, Vancouver, British Columbia faces risks from future sea level rise and has begun coastal adaptation planning in the last decade. In 2021, the City launched the Sea2City Design Challenge (Sea2City), a sea level rise design challenge in False Creek, a narrow inlet bordering downtown Vancouver on the unceded territories of the xʷməθkʷəy̓əm, Skwxwú7mesh, and səlilwətaɬ Nations. The challenge brought together city staff, international design teams, Indigenous cultural advisors, youth, community representatives, and technical advisors to develop design concepts for adapting to a rising False Creek. Now complete, Sea2City offers opportunities to innovate coastal adaptation and evaluative research practices. Using Sea2City as a case study, this research applies the JustAdapt framework to better understand how equity and justice were incorporated into its process and outcomes. Developed by the study’s researchers, the JustAdapt framework is a new evaluative framework for practitioners and academics alike to bring accountability to their equitable adaptation work. Findings suggest that equity, not justice, was actioned through Sea2City’s process and engagement. While the challenge shifted to emphasise Host Nations and local ecology, less focus was placed on different knowledges and lived experiences. With climate change already disproportionately impacting equity-denied populations, scholars and activists call for climate justice. Coastal adaptation planners have identified equity and justice as important principles guiding their work, yet evidence on implementation and evaluation is lacking. This research contributes a case study on evaluating equity and justice in Vancouver’s Sea2City Design Challenge and hopes to inspire future evaluative projects and research.

Medidas de adaptação e mitigação das alterações climáticas em uma metrópole sul-americana

The city of Rio de Janeiro, Brazil, has a rich history and its own. She went through several categories administrative. This has brought some benefits, but has been accompanied by several problems, which are getting worse with climate change. This study aimed to identify the main risk factors associated with climate change, as well as to analyze the public mitigation and adaptation policies developed by the city's public administrators. It was based on a bibliographic and documentary research. We concluded from the more significant findings of the study that the main climatic impacts that the city is subject to are the rains and strong winds, the waves and heat islands, the increase in sea level and the prolonged drought, and that its administrators neither adopted any effective measure in order to reduce such impacts, nor they are properly addressed, although there is strategic planning that contemplates them. In addition, it also emerged from the research that, although the city presented a reduction bias in its GHG emissions, this resulted from the change in the economic scenario that reduced its GDP, instead of the adoption of effective mitigation and adaptation measures.

Assessment of Saltwater Intrusion and Its Effects on Water Quality at Pantai Punggur, Johor

Coastal regions in Malaysia face significant risks from saltwater intrusion, influenced by multiple factors such as climate change, increasing sea levels, and human activities like agriculture, industry, and urban development. A study was carried out to investigate saltwater intrusion at Pantai Punggur, Batu Pahat. A series of tests are conducted to determine the characteristics of water using the Horiba Water Quality Monitor test. The parameters under consideration include salinity (ppt), dissolved oxygen (DO) (mg/L), turbidity (NTU), total dissolved solids (TDS) (g/L), and pH. Ten distinct sections were examined along the Pantai Punggur to assess the various parameters. The findings reveal that the highest salinity levels in Pantai Punggur are found at point sections 1 to 4, where saltwater intrusion is evident, exhibiting salinity values between 17.8 and 26.2 ppt. Consequently, saline water is observed at section points 5 to 10, where the measurement approaches 0 ppt. In terms of dissolved oxygen, the results indicate that the locations with the highest DO levels are points 8 and 9, with measurements ranging from 6.5 to 7.5 mg/L. The pH values at sampling points 1 to 6 are expected to be alkaline, falling within the range of 7.3 to 7.84. The red zone in turbidity indicates the peak turbidity values, which range from 60 to 80 NTU at point sections 8, 9, and 10. The maximum value for Total Dissolved Solids (TDS) ranges from 18 to 25 between sampling point 1 and point 2. These findings enhance our comprehension of the dynamics within coastal ecosystems. The study offers important findings for upcoming agricultural methods in salt-affected regions, with the goal of enhancing crop yield and informing stakeholders about the effects of saltwater intrusion on farming.

Prospects for the long‐term persistence of a severely endangered plant, Consolea corallicola (Cactaceae)

AbstractThe semaphore cactus, Consolea corallicola, is an endangered tree cactus endemic to just two sites in the Florida Keys. Since the 1980s, it has been threatened by the arrival of an invasive cactus‐eating moth, Cactoblastis cactorum, rot, and, more recently, by sea level rise. Between 1996 and 2017, we outplanted 641 propagated cacti at 10 different sites in the Lower Keys and 632 cacti at 19 sites in the Upper Keys in an effort to increase the population size. Some sites were actively managed, and others were not. Persistence of outplanted cacti was poor, with no long‐term survival at 17 sites and low survival at most others. Cactoblastis accounted for 9% of deaths, but crown rot, caused by a pathogenic fungus, Fusarium oxysporum, was the leading cause of death, accounting for 77% of mortality. Elevated soil moisture likely contributes to the high levels of crown rot. Cages to protect cacti from Cactoblastis and fertilization to alleviate the effects of crown rot did not increase survival rates. Observed saltwater intrusion and storms killed an additional 6% and 4% of cacti, respectively. Taken together as a whole, increased water levels and soil moisture are likely responsible for 87% of the mortality of our outplanted cacti. Cacti at actively managed sites did not survive better than those that were not actively managed. Given the likelihood of increasing sea levels, storm strength, and storm frequency, future strategies to save this iconic plant from extinction should include more outplantings at higher elevation sites, with as many individuals as possible, on higher ground with more consideration given to the ecology and genetics of its close relatives.

Wind driven ocean circulation changes can amplify future cooling of the North Atlantic warming hole

Abstract The North Atlantic warming hole is an area of relative cooling in the North Atlantic subpolar gyre. Observations and models have suggested numerous causes of the warming hole, including a role for wind driven ocean circulation changes. We investigate the role of wind driven ocean circulation changes on the development and projected future of the North Atlantic warming hole by comparing two ensembles within CESM2. One ensemble includes wind driven ocean circulation changes, while the other does not. The difference between the ensemble means isolates the role of wind driven ocean circulation changes on the externally forced North Atlantic warming hole. We find that wind driven ocean circulation changes do not alter the timing of the formation of an externally forced warming hole. However, anthropogenic changes to the near surface winds lead to enhanced upwelling near Greenland, and wind stress changes enable a positive feedback loop that relies on changes to mechanical stirring. These mechanisms amplify the cooling in the high latitude North Atlantic and lead to increased sea level pressure and reduced precipitation near the southern tip of Greenland. Thus, changes to wind driven ocean circulation are a crucial component of future changes in North Atlantic climate. Improved understanding of ocean-atmosphere coupling in this region will improve projections of SSTs and associated atmospheric impacts.

Exploring Storm Tides Projections and Their Return Levels Around the Baltic Sea Using a Machine Learning Approach

Extreme sea levels are a major global concern due to their potential to cause fatalities and significant economic losses in coastal areas. Consequently, accurate projections of these extremes for the coming century are crucial for effective coastal planning. While it is well established that relative sea level rise driven by ongoing climate change is a key factor influencing future extreme sea levels, changes in storm surges resulting from shifts in storm climatology may also play a critical role. In this study, we project future daily maximum storm tides (the combination of storm surge and tides) using a random forest machine learning approach for 59 stations around the Baltic Sea, based on atmospheric variables such as surface pressure, wind speed, and wind direction derived from climate datasets. The results suggest both positive and negative changes, with sub-regional variations, in 50-year storm tide return levels across the Baltic Sea when comparing the period of 2070–2099 to 1850–1879. Localized increases of up to 10 cm are projected along the west coast of Sweden and the northern Baltic Sea, while decreases of up to 6 cm are anticipated along the south coast of Sweden, the Gulf of Riga, and the mouth of the Gulf of Finland. Negligible levels of change are expected in other parts of the Baltic Sea. The variability in atmospheric drivers across the four climate models contributes to a high degree of uncertainty in future climate projections.

Long-term development of a perennial firn aquifer on the Lomonosovfonna ice cap, Svalbard

Abstract. An uncertain factor in assessing future sea level rise is the meltwater runoff buffering capacity of snow and firn on glaciers and ice caps. Field studies have resulted in observations of perennial firn aquifers (PFAs), which are bodies of water present deep in the firn layer and sheltered from cold surface conditions. PFAs can store surface melt, thereby acting as a buffer against sea level rise, and influence the thermodynamics of the firn layer. Furthermore, ice dynamics might be affected by the presence of liquid water through hydrofracturing and water transport to the bed, influencing bed properties and ice flow. In this study, we present results of applying the US Geological Survey (USGS) Modular Hydrological Model MODFLOW 6 to an observed perennial firn aquifer on the Lomonosovfonna ice cap in central Svalbard. The observations span a 3-year period, where a ground-penetrating radar (GPR) was used to measure the water table depth of the aquifer. We calibrate our model against these observations to infer a hydraulic conductivity of firn snow of 6.4×10-4 m s−1 and then use the model to project the aquifer evolution over the period 1957–2019. We find that the aquifer was present in 1957 and that it steadily grew over the modeled period with a relative increase of about 15 % in water table depth. On an annual basis, the aquifer exhibits sharp water table increases during the melt season, followed by slow seepage through the cold season.

Sediment and organic carbon discharges to the coastal oceans by badlands (English Channel, Normandy, France)

AbstractDetermining sedimentary and organic carbon fluxes and sources within the sedimentary continuum from land to sea is crucial for improving the understanding of Earth system dynamics, global carbon budgets and associated biogeochemical cycles, especially in the context of Global Change. Among continental sources, marly badlands, characterized by high erosion rates and significant Total Organic Carbon (TOC) contents, are potential contributors of material to the sea. However, data on sediment and TOC yields, fluxes and the contribution of badlands to the marine environment are still limited, particularly in NW Europe and oceanic regions. In this context, the instrumented sites of Vaches Noires cliffs on the western Normandy coast, France, were studied over three years. Suspended Particulate Matter (SPM) and source samples were collected along the eastern part of the cliff. Geochemical analyses, sediment fluxes and yields were obtained and compared with those from local rivers, European badlands and worldwide Small Mountain River systems (SMRs). These first results show that the cliffs exhibited high productivity in terms of sediment and organic carbon (OC) yields, like other studied badlands. Reaching the English Channel, material from badlands can enter and sediment within the Seine estuary, contributing to the Turbidity Maximal Zone and mixing with other OC sources (such as primary productivity and continental OC). Although the contribution of this material to the carbon (C) budget of this interface remains uncertain, it could be significant, especially with the increase in global sea level and major rainfall events.

Climate Adaptation for a Natural Atoll Island in the Maldives ‐ Predicting the Long‐Term Morphological Response of Coral Islands to Sea Level Rise and the Effect of Hazard Mitigation Strategies

AbstractCoral atoll islands, common in (sub)tropical oceans, consist of low‐lying accumulations of carbonate sediment produced by fringing coral reef systems and are of great socio‐economic and ecological importance. Previous studies have predicted that many atoll islands will become uninhabitable before the end of this century due to sea level rise exacerbating wave‐driven flooding. However, the assumption that such islands are morphologically static has been challenged by observations and modeling that show the potential for overwashing and sediment deposition to maintain island freeboard. Reliable long‐term predictions of island change and future flood risk, essential for adaptation planning, are, however, lacking. Here, we adopt a novel, efficient approach for modeling the long‐term island response and illustrate the morphological response of an atoll island to future sea level rise and the effect of various adaptation measures. We demonstrate that wave‐driven sediment deposition increases island (beach) crest freeboard. We find that the assumption of static island morphology leads to a significant increase in the predicted frequency of future island flooding compared to morphodynamically active islands. Reef adaptation measures were shown to modify the inshore wave energy, influencing the equilibrium island crest height and therefore the long‐term morphological response of the island, while beach restoration mainly delays the island's response. Accounting for long‐term natural island dynamics, including the morphodynamic feedback from adaptation measures, offers more realistic projections of future flood risk compared to current static island model predictions. These local projections of island response can serve as decision support tools for climate adaptation.

Black Sea As A New Maritime Tourism Destination

This study examined how the effects of climate change may shape coastal and maritime tourism in the Black Sea region through a systematic literature review method. The research findings show that climate change will significantly affect the Black Sea's essential environmental variables, such as sea level, temperature, humidity, precipitation, and wind. In particular, the annual average sea level increase of 2.5 mm and the expected total rise of 40-60 cm by the end of the century are expected to increase the risk of beach erosion on the Black Sea coast. It was evaluated that the increase in seawater temperature and air temperatures in the region may contribute to the extension of the tourism season; however, the decreasing precipitation and increasing humidity rates may negatively affect the comfort perception of tourists.

Estimating the sea level rise responsibility of industrial carbon producers

Abstract Global mean sea levels have risen at an accelerating rate over the past century in response, primarily to greenhouse gas emissions from the combustion of fossil fuels. We use MAGICC7, a reduced complexity climate-carbon cycle model, to quantify how emissions traced to the Carbon Majors, the world’s 122 largest fossil fuel and cement producers, from 1854–2020 contributed to present-day surface air temperature rise, and sea level rise both historically and projected through 2300. We find that emissions traced to these industrial actors have contributed 37%–58% to present day surface air temperature rise and 24%–37% to the observed global mean sea level rise to date. Critically, these emissions through 2020 are expected to contribute an additional 0.26–0.55 m of global sea level rise through 2300. We find that attribution of past emissions to projected future sea level rise is robust regardless of how emissions trajectories evolve in the coming centuries.

Crevasses on the Greenland Ice Sheet Are Growing

High-resolution 3D maps show crevasse volume is increasing across most of the Greenland Ice Sheet as it accelerates toward the ocean, which could affect future ice loss and sea level rise.

The Ecohydrology of Coastal Ghost Forests

ABSTRACTSea level rise and storm surges affect coastal forests along low‐lying shorelines. Salinization and flooding kill trees and favour the encroachment of salt‐tolerant marsh vegetation. The hydrology of this ecological transition is complex and requires a multidisciplinary approach. Sea level rise (press) and storms (pulses) act on different timescales, affecting the forest vegetation in different ways. Salinization can occur either by vertical infiltration during flooding or from the aquifer driven by tides and sea level rise. Here, we detail the ecohydrological processes acting in the critical zone of retreating coastal forests. An increase in sea level has a three‐pronged effect on flooding and salinization: It raises the maximum elevation of storm surges, shifts the freshwater‐saltwater interface inland, and elevates the water table, leading to surface flooding from below. Trees can modify their root systems and local soil hydrology to better withstand salinization. Hydrological stress from intermittent storm surges inhibits tree growth, as evidenced by tree ring analysis. Tree rings also reveal a lag between the time when tree growth significantly slows and when the tree ultimately dies. Tree dieback reduces transpiration, retaining more water in the soil and creating conditions more favourable for flooding. Sedimentation from storm waters combined to organic matter decomposition can change the landscape, affecting flooding and runoff. Our results indicate that only a multidisciplinary approach can fully capture the ecohydrology of retreating forests in a period of accelerated sea level rise.

Climate Change Trends and Vulnerabilities in Bangladesh’s Crop Sector: A Review of Crop Production Challenges and Resilience Strategies

Climate change has become one of the most important threats to worldwide agricultural production systems. This paper evaluates how Bangladesh, a prominent developing country in the low-lying Ganges-Brahmaputra-Meghna delta, is susceptible to climate change and assesses present agricultural practices that target sustaining production under these threats. The study synthesizes the ongoing research findings of climatic change tendency, involving the rising of temperature, alteration of precipitation pattern, along with the onward frequency of extreme weather incidence and their complication to crop production. It discusses the key susceptibilities of Bangladesh’s crop sector, such as a shortage of irrigation water, the impact of rising temperatures, increasing sea levels and the loss of biodiversity. Moreover, the study explores the resilience strategies and measures adopted by farmers, policymakers and researchers to alleviate the hostile effect of climate change on crop production. With all these considerations, the paper aimed to analyse the current climate change trend, adverse effects to agricultural sectors and existing resilience practices in Bangladesh as well as future strategies against climate change.

East Antarctic tectonic basin structure and its implications for ice-sheet modeling and sea-level projections

The volume of the East Antarctica Ice Sheet is equivalent to ~52 m of sea-level rise, but whether the ice sheet is a major contributor to global sea-level increase remains debated. How an ice sheet responds to climate-induced perturbations strongly depends on the physical conditions below the ice-bed interface; therefore, constraining the solid Earth structure beneath East Antarctica is critical. However, sparse seismic station coverage has limited our ability to image key characteristics. Here we employ full-waveform ambient noise tomography, an approach that better resolves Earth structure in sparsely sampled areas compared to traditional techniques, and our results reveal previously unrecognized, low-velocity anomalies under the Wilkes and Aurora Subglacial Basins. Our findings suggest thinner-than-expected lithosphere and thermally perturbed upper mantle, implying drastically different geothermal heat flux and mantle viscosity inputs compared to those from prior tomographic studies. This has notable implications for accurate ice-sheet modeling and future global sea-level projections.

Numerical modelling of the impact of coral reef degradation and sea level rise on coastal protection at The Buccoo Reef, Tobago: implications for reef restoration and management strategies

Coral reefs provide natural coastal protection through depth-induced wave breaking and frictional dissipation on the fore reef, the reef crest, and the back reef. The coral reef roughness is a significant factor in wave attenuation through frictional dissipation and is directly linked to the reef’s health. The influence of reef roughness on frictional dissipation under representative conditions, and the extent to which coral reef degradation and Sea Level Rise (SLR) reduces this coastal protection service remains underexplored, especially at coastal sites in Caribbean Small Island Developing States. A numerical modelling approach using a coupled depth-averaged (2DH) hydrodynamic and spectral wave model in Delft3D was used to evaluate the coastal protection effectiveness of a fringing reef under varying scenarios of coral reef degradation and SLR at The Buccoo Reef, Tobago. Using near present day conditions as the baseline scenario, assessed wave conditions showed 100% and 96.45% reductions at low and high tides respectively. Under modelled degraded reef conditions on the reef flat, wave heights increased by an average of 21.74% compared to baseline conditions, while for modelled healthier reefs, there was an 18.9% decrease in wave heights from the baseline scenario. Using various SLR scenarios, wave heights showed increases over baseline conditions between 160.5% and 388.4% for increases in sea level from 0.25 m to 1.00 m. The results highlight the importance of the frictional dissipation provided by healthy coral reefs, with degraded corals and rising sea levels leading to substantial increases in nearshore wave heights which could exacerbate issues such as coastal erosion and flooding. Management strategies such as Integrated Coastal Zone Management (ICZM) and innovative approaches such as the deployment of artificial reefs which are specifically designed to replicate the complex structure and roughness of natural reefs can contribute to wave attenuation by frictional dissipation.

ISMIP6-based Antarctic projections to 2100: simulations with the BISICLES ice sheet model

Abstract. The contribution of the Antarctic Ice Sheet is one of the most uncertain components of sea level rise to 2100. Ice sheet models are the primary tool for projecting future sea level contribution from continental ice sheets. The Ice Sheet Model Intercomparison for the Coupled Model Intercomparison Phase 6 (ISMIP6) provided projections of the ice sheet contribution to sea level over the 21st century, quantifying uncertainty due to ice sheet model, climate model, emission scenario, and uncertain parameters. We present simulations following the ISMIP6 framework with the BISICLES ice sheet model and new experiments extending the ISMIP6 protocol to more comprehensively sample uncertainties in future climate, ice shelf sensitivity to ocean melting, and their interactions. These results contributed to the land ice projections of Edwards et al. (2021), which formed the basis of sea level projections for the Sixth Assessment Report of the Intergovernmental Panel on Climate Change (AR6). Our experiments show the important interplay between surface mass balance processes and ocean-driven melt in determining Antarctic sea level contribution. Under higher-warming scenarios, high accumulation offsets more ocean-driven mass loss when sensitivity to ocean-driven melt is low. Conversely, we show that when sensitivity to ocean warming is high, ocean melting drives increased mass loss despite high accumulation. Overall, we simulate a sea level contribution range across our experiments from 2 to 178 mm. Finally, we show that collapse of ice shelves due to surface warming increases sea level contribution by 25 mm relative to the no-collapse experiments, for both moderate and high sensitivity of ice shelf melting to ocean forcing.