Sea level trends along the South African coast from 1993 to 2022 using XTRACK altimetry, tide gauges, and GNSS measurements

Abstract This study presents a comprehensive investigation of the complex dynamics of sea-level rise (SLR) and its multiple impacts on coastal regions in southern Africa. We meticulously analyse trends and patterns in SLR and subsidence rates using a wealth of data from 1993 to 2022, including obser...

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Main Authors: Franck Eitel Kemgang Ghomsi, Muharrem Hilmi Erkoç, Roshin P. Raj, Atinç Pirti, Antonio Bonaduce, Babatunde J. Abiodun, Julienne Stroeve
Format: Article
Language:English
Published: Nature Portfolio 2025-02-01
Series:Scientific Reports
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Online Access:https://doi.org/10.1038/s41598-025-89258-9
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author Franck Eitel Kemgang Ghomsi
Muharrem Hilmi Erkoç
Roshin P. Raj
Atinç Pirti
Antonio Bonaduce
Babatunde J. Abiodun
Julienne Stroeve
author_facet Franck Eitel Kemgang Ghomsi
Muharrem Hilmi Erkoç
Roshin P. Raj
Atinç Pirti
Antonio Bonaduce
Babatunde J. Abiodun
Julienne Stroeve
author_sort Franck Eitel Kemgang Ghomsi
collection DOAJ
description Abstract This study presents a comprehensive investigation of the complex dynamics of sea-level rise (SLR) and its multiple impacts on coastal regions in southern Africa. We meticulously analyse trends and patterns in SLR and subsidence rates using a wealth of data from 1993 to 2022, including observations from a network of 10 reliable tide gauges and XTRACK data processed using the Coastal Altimetry Approach to minimise the shortcomings of conventional coastal altimetry data. Our results show that sea level rise in coastal areas of South Africa, such as Cape Town (6.3 mm/yr), is almost double the global average (3.3 mm/yr). This alarming rate of SLR, coupled with a subsidence rate of more than 2.2 mm/yr, poses a significant and immediate threat to coastal communities, infrastructure and ecosystems. Our research also highlights the impact of seismic activity on coastal dynamics, further exacerbating the challenges posed by SLR. By incorporating the influence of earthquakes on subsidence, we provide a more nuanced understanding of the complex interplay of natural and anthropogenic factors contributing to SLR in the region. In addition, our research sheds light on the wider implications of SLR for some of Africa’s most iconic and culturally significant heritage sites, highlighting the urgent need for proactive coastal management and adaptation strategies.
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spelling doaj-art-9e2f596641e643ef8f4b610fb12ab7d32025-08-20T02:12:58ZengNature PortfolioScientific Reports2045-23222025-02-0115111510.1038/s41598-025-89258-9Sea level trends along the South African coast from 1993 to 2022 using XTRACK altimetry, tide gauges, and GNSS measurementsFranck Eitel Kemgang Ghomsi0Muharrem Hilmi Erkoç1Roshin P. Raj2Atinç Pirti3Antonio Bonaduce4Babatunde J. Abiodun5Julienne Stroeve6Centre for Earth Observation Science, University of ManitobaDepartment of Geomatic Engineering, Yildiz Technical UniversityNansen Environmental and Remote Sensing Center and Bjerknes Center for Climate ResearchDepartment of Geomatic Engineering, Yildiz Technical UniversityNansen Environmental and Remote Sensing Center and Bjerknes Center for Climate ResearchDepartment of Oceanography, Nansen-Tutu Center for Marine Environmental Research, University of Cape TownCentre for Earth Observation Science, University of ManitobaAbstract This study presents a comprehensive investigation of the complex dynamics of sea-level rise (SLR) and its multiple impacts on coastal regions in southern Africa. We meticulously analyse trends and patterns in SLR and subsidence rates using a wealth of data from 1993 to 2022, including observations from a network of 10 reliable tide gauges and XTRACK data processed using the Coastal Altimetry Approach to minimise the shortcomings of conventional coastal altimetry data. Our results show that sea level rise in coastal areas of South Africa, such as Cape Town (6.3 mm/yr), is almost double the global average (3.3 mm/yr). This alarming rate of SLR, coupled with a subsidence rate of more than 2.2 mm/yr, poses a significant and immediate threat to coastal communities, infrastructure and ecosystems. Our research also highlights the impact of seismic activity on coastal dynamics, further exacerbating the challenges posed by SLR. By incorporating the influence of earthquakes on subsidence, we provide a more nuanced understanding of the complex interplay of natural and anthropogenic factors contributing to SLR in the region. In addition, our research sheds light on the wider implications of SLR for some of Africa’s most iconic and culturally significant heritage sites, highlighting the urgent need for proactive coastal management and adaptation strategies.https://doi.org/10.1038/s41598-025-89258-9Sea level riseSubsidence ratesSouthern AfricaTide gaugesCoastal altimetry
spellingShingle Franck Eitel Kemgang Ghomsi
Muharrem Hilmi Erkoç
Roshin P. Raj
Atinç Pirti
Antonio Bonaduce
Babatunde J. Abiodun
Julienne Stroeve
Sea level trends along the South African coast from 1993 to 2022 using XTRACK altimetry, tide gauges, and GNSS measurements
Scientific Reports
Sea level rise
Subsidence rates
Southern Africa
Tide gauges
Coastal altimetry
title Sea level trends along the South African coast from 1993 to 2022 using XTRACK altimetry, tide gauges, and GNSS measurements
title_full Sea level trends along the South African coast from 1993 to 2022 using XTRACK altimetry, tide gauges, and GNSS measurements
title_fullStr Sea level trends along the South African coast from 1993 to 2022 using XTRACK altimetry, tide gauges, and GNSS measurements
title_full_unstemmed Sea level trends along the South African coast from 1993 to 2022 using XTRACK altimetry, tide gauges, and GNSS measurements
title_short Sea level trends along the South African coast from 1993 to 2022 using XTRACK altimetry, tide gauges, and GNSS measurements
title_sort sea level trends along the south african coast from 1993 to 2022 using xtrack altimetry tide gauges and gnss measurements
topic Sea level rise
Subsidence rates
Southern Africa
Tide gauges
Coastal altimetry
url https://doi.org/10.1038/s41598-025-89258-9
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