Impacts of Basin-Scale Climate Modes on Coastal Sea Level: a Review

Exploring steric sea level variability in the Eastern Tropical Atlantic Ocean: a three-decade study (1993-2022)

Sea level rise (SLR) poses a significant threat to coastal regions worldwide, particularly affecting over 60 million people living below 10 m above sea level along the African coast. This study analyzes the spatio-temporal trends of sea level anomaly (SLA) and its components (thermosteric, halosteric and ocean mass) in the Eastern Tropical Atlantic Ocean (ETAO) from 1993 to 2022. The SLA trend for the ETAO, derived from satellite altimetry, is 3.52 ± 0.47 mm/year, similar to the global average of 3.56 ± 0.67 mm/year. Of the three upwelling regions, the Gulf of Guinea (GoG) shows the highest regional trend of 3.42 ± 0.12 mm/year. Using the ARMORD3D dataset, a positive thermosteric sea level trend of 0.88 ± 0.04 mm/year is observed, particularly in the equatorial and southern Atlantic regions. The steric component drives the interannual SLA variability, while the ocean mass component dominates the long-term trends, as confirmed by the GRACE and GRACE-FO missions for 2002-2022. For those two decades, the total SLR from altimetry amounts to 3.80 ± 0.8 mm/year, whilst the steric component is reduced to only 0.19 ± 0.05 mm/year, leaving a residual increase in the ETAO of 3.69 ± 0.5 mm/year. The independent mass change from GRACE amounts to 2.78 ± 0.6 mm/year for this region, which just closes the sea level budget within present uncertainty levels. Spatial analysis of the steric components indicates a warming along the equatorial African coast including the GoG and a freshening near Angola. Strong correlations with regional climate factors, particularly the Tropical South Atlantic Index, highlight the influence of persistent climate modes. These findings underscore the urgent need for mitigation and adaptation strategies to SLR in the ETAO, especially for densely populated coastal communities.

A Short Review on Causes of Sea Level Rise for Climate Monitoring

Sea level rise has currently become a major issue for climate change. It has globally drawn attention because as time passes, global sea levels will continue to rise at an accelerating rate in the 21st century. It will cause a serious impact on environmental problems such as coastal inundation, salt intrusion, coastal erosion, and other phenomena. These scenarios lead to earth problems in which land and oceans continue shifting due to climate change, posing a threat to the very existence of all living beings in the coming years. As a result, climate monitoring is critical for tracking the change. Therefore, this paper reviews the physical factors that contribute to sea level rise. The main contributors for sea level rises, such as ice melting from land into the ocean, thermal expansion, a slowing of the Gulf Stream, and land sinkage, are being discussed. This paper also emphasises the studies of regional sea level, and sea level rate changes. Finally, this review will be discussed in order to clarify the causes of sea level rise issues for human society.

Contemporary sea-level changes from global to local scales: a review

Sea-level variations spread over a very broad spectrum of spatial and temporal scales as a result of complex processes occurring in the Earth System in response to natural variability of the climate system, as well as to external forcing due to natural phenomena and anthropogenic factors. Here, we address contemporary sea-level changes, focusing on the satellite altimetry era (since the early 1990s), for which various observing systems from space and in situ allow precise monitoring of sea-level variations from global to local scales, as well as improved understanding of the components responsible for the observed variations. This overview presents the most recent results on observed global and regional sea-level changes and on associated causes, focusing on the interannual to decadal time scale. Recent progress in measuring sea level at the coast are presented. Finally, a summary of the most recent sea-level projections from the Intergovernmental Panel on Climate Change is also provided.

An Integrated Approach for Evaluating Climate Change Risks: A Case Study in Suriname

This paper combines long-term state-of-the-art climate projections and indices to provide detailed insights into the future climate of Suriname to facilitate comprehensive information of areas and sectors at high climate risk for political decision-making. The study analyses Suriname’s historical climate (1990–2014) and provides climate projections for three time horizons (2020–2044, 2045–2069, 2070–2094) and two emissions scenarios (intermediate/SSP2-4.5 and severe/SSP5-8.5). Coupled Model Intercomparison Project (CMIP6) modeling is used to analyze changes in sea level, temperature, precipitation, relative humidity, and winds. In addition, risk impact chains were produced for the country’s four most important socio-economic sectors: agriculture and fisheries, forestry, water, and infrastructure. Results show the temperature is expected to increase for all regions and timeframes, reaching warming up to 6 °C in the southern region in the long-term future (2070–2094). Projections point towards a reduction in precipitation in the southwest and coastal regions and a rise in mean sea level. Regarding risk, Paramaribo and Wanica face the highest climate risk. Coronie and Nickerie face the least climate risk. These regions remain the most and least vulnerable in both the SSP2-4.5 and SSP5-8.5 scenarios, but overall values of their risk indices increase substantially over time.

Sea-Level Variability in the Gulf of Naples and the “Acqua Alta” Episodes in Ischia from Tide-Gauge Observations in the Period 2002–2019

This work presents an 18-year-long (2002–2019) tide-gauge dataset collected on the Island of Ischia (Gulf of Naples, Southern Tyrrhenian Sea) that can contribute to the analysis of the basic features of sea-level variability in this region. Analysis of tidal constituents shows that the Gulf of Naples is characterized by the absence of any amphidromic system. In this area, sea-level changes due to the astronomical component of the tide are generally limited to ±20 cm with respect to the mean sea level, but the impact of this variability is enhanced by global sea-level increase and the effect of regional atmospheric perturbations that might also triple sea-level variations. The effects of these events, whose frequency has increased in recent decades, has been dramatic in coastal areas where intense social and economic activity occurs, e.g., in Ischia. On interannual time scales, the results indicate that the relative sea-level rise in Ischia has a magnitude of 3.9 mm/year. Special attention is dedicated to the “acqua alta” episodes and to their linkage with long-term sea-level trends and atmospheric forcing.