{"id":239692,"date":"2025-12-18T18:48:29","date_gmt":"2025-12-18T18:48:29","guid":{"rendered":"https:\/\/www.europesays.com\/ie\/239692\/"},"modified":"2025-12-18T18:48:29","modified_gmt":"2025-12-18T18:48:29","slug":"accelerating-sea-level-rise-in-africa-and-its-large-marine-ecosystems-since-the-1990s","status":"publish","type":"post","link":"https:\/\/www.europesays.com\/ie\/239692\/","title":{"rendered":"Accelerating sea level rise in Africa and its large marine ecosystems since the 1990s"},"content":{"rendered":"<p>Regional sea level rise and the exceptional 2023 event in AfricaLong-term acceleration in African sea level rise (1993\u20132023)<\/p>\n<p>Satellite altimetry shows Africa\u2019s regional mean geocentric sea level (RMSL) rose by 10.25\u2009cm from 1993 to 2023, driven by a linear trend of 3.31\u2009\u00b1\u20090.04\u2009mm\/yr and an acceleration of 0.11\u2009\u00b1\u20090.02\u2009mm\/yr\u00b2 (GIA-corrected; see Fig.\u00a0<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#Fig2\" rel=\"nofollow noopener\" target=\"_blank\">2a<\/a>). Vertical land motion, while influencing relative SLR, does not affect altimetry-derived geocentric trends. This acceleration is comparable to the global rate (0.12\u2009\u00b1\u20090.05\u2009mm\/yr\u00b2)<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 3\" title=\"WMO. State of the Global Climate 2023. (2024). &#010;                  https:\/\/doi.org\/10.18356\/9789263113474&#010;                  &#010;                 (2025).\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#ref-CR3\" id=\"ref-link-section-d190479614e738\" rel=\"nofollow noopener\" target=\"_blank\">3<\/a>,<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 44\" title=\"Leclercq, L. et al. Spatio-temporal changes in interannual sea level along the world coastlines. Glob. Planet. Change, 104972 &#010;                  https:\/\/doi.org\/10.1016\/j.gloplacha.2025.104972&#010;                  &#010;                 (2025).\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#ref-CR44\" id=\"ref-link-section-d190479614e741\" rel=\"nofollow noopener\" target=\"_blank\">44<\/a>. Notably, 2023 recorded the highest annual mean sea level to date. This increase is statistically significant, with a trend difference of 3.39\u2009mm\/yr between the first and last decades, and a notable 1.41\u2009mm\/yr difference between the last two decades (2003\u20132012 vs. 2013\u20132023). The rate of SLR<\/p>\n<p><b id=\"Fig2\" class=\"c-article-section__figure-caption\" data-test=\"figure-caption-text\">Fig. 2: Regional sea level variability and anomalies across Africa (1993\u20132023).<\/b><a class=\"c-article-section__figure-link\" data-test=\"img-link\" data-track=\"click\" data-track-label=\"image\" data-track-action=\"view figure\" href=\"https:\/\/www.nature.com\/articles\/s43247-025-02965-z\/figures\/2\" rel=\"nofollow noopener\" target=\"_blank\"><img decoding=\"async\" aria-describedby=\"Fig2\" src=\"https:\/\/www.europesays.com\/ie\/wp-content\/uploads\/2025\/12\/43247_2025_2965_Fig2_HTML.png\" alt=\"figure 2\" loading=\"lazy\" width=\"685\" height=\"632\"\/><\/a><\/p>\n<p><b>a<\/b> Time series of regional monthly mean sea level for Africa derived from satellite altimetry. Annual means are shown by red markers, with a purple curve representing a second-order polynomial trend. <b>b<\/b> Annual mean sea level for 2023 expressed as anomalies relative to the 1993\u20132022 baseline. <b>c<\/b> Difference between 2023 and 2022 annual means. <b>d<\/b> Spatial distribution of the year with the peak annual sea level recorded during the altimetry period. In 2023, sea levels across much of Africa continued to rise, primarily driven by global warming and modulated by large-scale climate variability such as El Ni\u00f1o. The seven African LMEs are labeled as in Fig.\u00a0<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#Fig1\" rel=\"nofollow noopener\" target=\"_blank\">1<\/a>.<\/p>\n<p>has sharply increased, with cumulative SLRs (i.e., total increases over each decade) of approximately 0.92\u2009cm (1993\u20132002), 2.82\u2009cm (2003\u20132012), and 4.60\u2009cm (2013\u20132023). The rate rose from 0.96\u2009\u00b1\u20090.26\u2009mm\/yr in the first decade to 4.34\u2009\u00b1\u20090.18\u2009mm\/yr in the last, a 4.54\u2009\u00b1\u20091.26-fold increase (Fig.\u00a0<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#Fig2\" rel=\"nofollow noopener\" target=\"_blank\">2a<\/a>). Over the past two decades, the average rate (3.67\u2009\u00b1\u20090.16\u2009mm\/yr) was 1.2 times the long-term trend, highlighting ongoing acceleration since the early 1990s (Supplementary Fig.\u00a0<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"supplementary material anchor\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#MOESM2\" rel=\"nofollow noopener\" target=\"_blank\">1<\/a>).<\/p>\n<p>This acceleration reflects intensified contributions from thermal expansion due to ocean warming and increased individual mass contributions, including glacier melt, Greenland and Antarctic ice sheets, changes in land water storage, freshwater fluxes, and atmospheric water vapor content<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 45\" title=\"Intergovernmental Panel on Climate, C. Climate Change 2022 &#x2013; Impacts, Adaptation and Vulnerability: Working Group II Contribution to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change (Cambridge University Press, 2023).\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#ref-CR45\" id=\"ref-link-section-d190479614e791\" rel=\"nofollow noopener\" target=\"_blank\">45<\/a>. These regional changes coincide with a globally coherent climate shift that began in the early 2010s, as evidenced by synchronized transitions in oceanic and atmospheric parameters worldwide, further underscoring the systemic nature of the observed SLR<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 44\" title=\"Leclercq, L. et al. Spatio-temporal changes in interannual sea level along the world coastlines. Glob. Planet. Change, 104972 &#010;                  https:\/\/doi.org\/10.1016\/j.gloplacha.2025.104972&#010;                  &#010;                 (2025).\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#ref-CR44\" id=\"ref-link-section-d190479614e795\" rel=\"nofollow noopener\" target=\"_blank\">44<\/a>. This rise is further amplified by mass contributions from melting glaciers, Greenland and Antarctic ice sheets, and changes in land water storage<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 46\" title=\"Rounce, D. R. et al. Downstream hydrology reduces glaciers&#x2019; direct contribution to sea-level rise. Geophys. Res. Lett. 52, e2025GL114866 &#010;                  https:\/\/doi.org\/10.1029\/2025GL114866&#010;                  &#010;                 (2025).\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#ref-CR46\" id=\"ref-link-section-d190479614e799\" rel=\"nofollow noopener\" target=\"_blank\">46<\/a>,<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 47\" title=\"Parkes, D. &amp; Marzeion, B. Twentieth-century contribution to sea-level rise from uncharted glaciers. Nature 563, 551&#x2013;554 (2018).\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#ref-CR47\" id=\"ref-link-section-d190479614e802\" rel=\"nofollow noopener\" target=\"_blank\">47<\/a>, as depicted in the trend curve of Fig.\u00a0<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#Fig2\" rel=\"nofollow noopener\" target=\"_blank\">2a<\/a>. While the long-term trend is generally upward, it includes minor fluctuations\u2014for example, a subtle 0.09\u2009cm decrease between 2021 to 2022 (ranking 22nd among 31 annual changes), likely influenced by regional ocean circulation anomalies. This was followed by a rise of 1.97\u2009cm from 2022 to 2023\u2014the second-highest annual increase on record, surpassed only by the 1997\u20131998 El Ni\u00f1o-driven rise. This increase drove 2023 to the highest annual domain-averaged SLA of 10\u2009cm, with peak monthly values in November (12.50\u2009cm) and December (12.73\u2009cm) ranking as the top two months over the 1993\u20132023 period (see Supplementary Fig.\u00a0<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"supplementary material anchor\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#MOESM2\" rel=\"nofollow noopener\" target=\"_blank\">2<\/a>). Notably, the 2022\u20132023 increase significantly outpaced the global mean rise of 0.59\u2009cm.<\/p>\n<p>Complementing the temporal evolution, the spatial patterns in 2023 reveal an alarming extent of regional SLAs. Spatially, more than 95% of the African ocean surface exhibited elevated sea levels in 2023 compared to the 1993\u20132022 climatology \u2014 here defined as the average sea level over that 30-year period (Fig.\u00a0<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#Fig2\" rel=\"nofollow noopener\" target=\"_blank\">2b<\/a>)\u2014with more than 75% showing an increase relative to 2022. In 2023, monthly SLAs across Africa and its seven LMEs significantly exceeded the 1993\u20132022 climatology, with differences of 4.22\u20138.53\u2009cm for Africa and up to 16.24\u2009cm for the Somali Coastal Current (December). Other LMEs, including the Guinea Current (up to 8.67\u2009cm, June), Benguela Current (up to 8.36\u2009cm, December), and Mediterranean Sea (up to 11.22\u2009cm, May), showed anomalies of 2.82\u201311.22\u2009cm (Supplementary Fig.\u00a0<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"supplementary material anchor\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#MOESM2\" rel=\"nofollow noopener\" target=\"_blank\">2<\/a>). Notably, 1.5% of the region experienced rises exceeding 10\u2009cm, particularly in dynamic ocean systems such as the Agulhas Current (Fig.\u00a0<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#Fig2\" rel=\"nofollow noopener\" target=\"_blank\">2c<\/a>). These localized hotspots of SLR are consistent with areas of strong mesoscale activity and boundary currents. By 2023, 38.6% of the regional ocean, especially in the Eastern Tropical Atlantic, reached its highest annual sea level on record, while 72.1% recorded peak levels during or after 2020 (Fig.\u00a0<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#Fig2\" rel=\"nofollow noopener\" target=\"_blank\">2d<\/a>). This clustering of record-high sea level years since 2020 confirms that recent intensification is not isolated but rather part of a sustained spatial trend affecting large portions of the basin. This widespread occurrence of record-high sea levels in recent years points to a sustained and intensifying trend. These patterns align with global sea level trends, which show a 10.5\u2009cm rise over the same period, but the accelerated rates and extreme annual increases in the African region amplify risks for coastal communities. The widespread elevation, affecting 95.8% of the region, underscores heightened coastal flooding risks, particularly in the Somali and Guinea Currents (Fig.\u00a0<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#Fig2\" rel=\"nofollow noopener\" target=\"_blank\">2b\u2013d<\/a>). These areas face heightened threats of inundation, salinization of freshwater resources, and loss of critical ecosystems.<\/p>\n<p>Peak SLA years and the exceptional 2023 event<\/p>\n<p>We assessed annual mean and peak monthly SLA, as well as their residuals, after removing the 1993\u20132023 GMSL trend (3.4\u2009\u00b1\u20090.3\u2009mm\/yr), as shown in the residuals time series in Fig.\u00a0<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#Fig3\" rel=\"nofollow noopener\" target=\"_blank\">3a<\/a>. The analysis focused on five peak years: 1995, 1997, 2010, 2019, and 2023. Residuals were calculated by subtracting a linear GMSL trend fitted to satellite altimetry data for the African region, isolating spatially variable anomalies driven by regional oceanographic or climate processes. Peak months were identified as the months with the highest SLA per year. Notably, the 2023 values were exceptional. The annual mean SLA reached 67.95\u2009mm, which was 19.24\u2009mm higher than in 2019, and the December peak month SLA reached 77.65\u2009mm, significantly exceeding 2019\u2019s 56.66\u2009mm, as illustrated in Fig.\u00a0<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#Fig3\" rel=\"nofollow noopener\" target=\"_blank\">3b<\/a>. After removing the GMSL trend, the 2023 residuals remained outstanding: annual mean residuals were 14.13\u2009mm, the highest of all years, and peak month residuals reached 22.32\u2009mm, surpassing 1997\u2019s value by 24.9%. Statistical tests, including Bonferroni-corrected t-tests<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 48\" title=\"Shi, Q., Pavey, E. S. &amp; Carter, R. E. Bonferroni-based correction factor for multiple, correlated endpoints. Pharm. Stat. 11, 300&#x2013;309 (2012).\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#ref-CR48\" id=\"ref-link-section-d190479614e844\" rel=\"nofollow noopener\" target=\"_blank\">48<\/a> (p\u20093b summarizes these metrics across peak years, underscoring 2023\u2019s exceptional ranking in all categories and highlighting 2023\u2019s dominance across all four metrics. Consequently, 2023 stands apart from years like 1997, which exhibited large residuals (16.64\u2009mm) linked to the 1997\u20131998 El Ni\u00f1o, and 2019 Atlantic Ni\u00f1o, which showed high SLA (56.66\u2009mm) but smaller residuals (14.53\u2009mm). Trend analysis further supports this conclusion: SLA trends accelerated over the three decades, providing context for the residuals in Fig.\u00a0<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#Fig3\" rel=\"nofollow noopener\" target=\"_blank\">3a<\/a>. This acceleration, combined with 2023\u2019s large residuals, suggests contributions from both global and regional drivers, potentially linked to basin-scale climate variability, such as the 2023\u20132024 El Ni\u00f1o\/Atlantic Ni\u00f1o or changes in coastal circulation. However, further analysis is needed to confirm these mechanisms. In conclusion, 2023 represents the most extreme regional SLA event in the satellite record for Africa, characterized by unprecedented magnitude, persistence after global signal removal, and strong regional forcing atop an accelerating background of global SLR.<\/p>\n<p><b id=\"Fig3\" class=\"c-article-section__figure-caption\" data-test=\"figure-caption-text\">Fig. 3: Residual sea level anomalies in Africa highlight the exceptional nature of 2023.<\/b><a class=\"c-article-section__figure-link\" data-test=\"img-link\" data-track=\"click\" data-track-label=\"image\" data-track-action=\"view figure\" href=\"https:\/\/www.nature.com\/articles\/s43247-025-02965-z\/figures\/3\" rel=\"nofollow noopener\" target=\"_blank\"><img decoding=\"async\" aria-describedby=\"Fig3\" src=\"https:\/\/www.europesays.com\/ie\/wp-content\/uploads\/2025\/12\/43247_2025_2965_Fig3_HTML.png\" alt=\"figure 3\" loading=\"lazy\" width=\"685\" height=\"720\"\/><\/a><\/p>\n<p><b>a<\/b> Time series of SLA residuals after removing the 1993\u20132023 GMSL trend, with pink dots marking peak maxima. <b>b<\/b> Comparison of SLA and residual magnitudes for selected peak years. The year 2023 exhibits the largest anomalies in both SLA and residuals across the satellite record, persisting even after global trend removal.<\/p>\n<p>Sea levels trends and its componentsRegional trends variability<\/p>\n<p>In this section, we analyze the spatial and long-term trend of the total SLA from 1993 to 2023, based on a reanalysis dataset that integrates altimetric, thermosteric, halosteric, and manometric components. This comprehensive approach captures the combined influence of these factors on sea level variability across the African region and its LMEs. We also quantify the relative contributions of the total steric effect and its individual components to overall sea level variability. As illustrated in Fig.\u00a0<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#Fig4\" rel=\"nofollow noopener\" target=\"_blank\">4a<\/a>, the SLA trend map reveals significant spatial patterns, with a statistically significant (p\u2009<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 44\" title=\"Leclercq, L. et al. Spatio-temporal changes in interannual sea level along the world coastlines. Glob. Planet. Change, 104972 &#010;                  https:\/\/doi.org\/10.1016\/j.gloplacha.2025.104972&#010;                  &#010;                 (2025).\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#ref-CR44\" id=\"ref-link-section-d190479614e902\" rel=\"nofollow noopener\" target=\"_blank\">44<\/a>,<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 49\" title=\"Hamlington, B. et al. The rate of global sea level rise doubled during the past three decades. Commun. Earth Environ. 5, 601 (2024).\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#ref-CR49\" id=\"ref-link-section-d190479614e905\" rel=\"nofollow noopener\" target=\"_blank\">49<\/a> to distinguish areas experiencing below- or above-average SLR compared to the global mean. Although the regional mean rate is similar to the GMSL, this average mask substantial spatial heterogeneity. Fig.\u00a0<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#Fig4\" rel=\"nofollow noopener\" target=\"_blank\">4a<\/a> shows that much of the African oceanic region experiences sea-level anomaly (SLA) trends above the GMSL, particularly across several LMEs. Notably, the Guinea Current (GCLME), Canary Current (CCLME), Red Sea (REDLME), Somali Coastal Current (SCCLME), and the northern parts of the Benguela Current (BCLME) and Agulhas Current (ACLME) exhibit SLR rates exceeding the GMSL. These elevated rates may be linked to intensified wind-driven circulation or enhanced tropical thermosteric expansion. In contrast, the Mediterranean LME (MEDLME) (see Fig.\u00a0<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#Fig1\" rel=\"nofollow noopener\" target=\"_blank\">1<\/a>) shows trends below the global mean.<\/p>\n<p><b id=\"Fig4\" class=\"c-article-section__figure-caption\" data-test=\"figure-caption-text\">Fig. 4: Spatial distribution of regional sea-level trends across Africa\u2019s coastal LMEs from 1993 to 2023.<\/b><a class=\"c-article-section__figure-link\" data-test=\"img-link\" data-track=\"click\" data-track-label=\"image\" data-track-action=\"view figure\" href=\"https:\/\/www.nature.com\/articles\/s43247-025-02965-z\/figures\/4\" rel=\"nofollow noopener\" target=\"_blank\"><img decoding=\"async\" aria-describedby=\"Fig4\" src=\"https:\/\/www.europesays.com\/ie\/wp-content\/uploads\/2025\/12\/43247_2025_2965_Fig4_HTML.png\" alt=\"figure 4\" loading=\"lazy\" width=\"685\" height=\"366\"\/><\/a><\/p>\n<p><b>a<\/b> Total sea-level trend; <b>b<\/b> total steric; <b>c<\/b> thermosteric; <b>d<\/b> halosteric; and <b>e<\/b> manometric (SLA minus steric) trends. GIA corrections were applied to both SLA and manometric trends. At each grid point, mean and seasonal cycles were removed prior to trend estimation. All trends are statistically significant at the 95% confidence level except in areas marked with gray dots. The seven African LMEs are labeled as in Fig.\u00a0<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#Fig1\" rel=\"nofollow noopener\" target=\"_blank\">1<\/a>.<\/p>\n<p>The trends in SLA across Africa\u2019s seven LMEs, as shown in Fig.\u00a0<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#Fig4\" rel=\"nofollow noopener\" target=\"_blank\">4a<\/a>, reflect a compound interplay between steric (thermosteric\u2009+\u2009halosteric) and manometric components, each contributing differently across regions. These components interact to create distinct spatial patterns in SLA, shaped by both local and large-scale oceanographic processes. In the equatorial and tropical LMEs-such as the GCLME, CCLME, SCCLME, and the REDLME-thermosteric expansion, driven by ocean warming, is the principal contributor to SLR. The steric component, which encompasses changes in seawater density due to temperature and salinity, accounts for 19.78% of the total SLA in the entire region, as depicted in Fig.\u00a0<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#Fig4\" rel=\"nofollow noopener\" target=\"_blank\">4b<\/a>. Notably, the thermosteric signal alone contributes 27.90% of SLA and exceeds the total steric trend by 41.10% (see Fig.\u00a0<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#Fig4\" rel=\"nofollow noopener\" target=\"_blank\">4c<\/a>), underscoring the dominant role of thermal expansion. This effect is especially pronounced along the equatorial Atlantic and Indian Ocean margins, where persistent high temperatures and seasonal upwelling fuel significant thermal expansion.<\/p>\n<p>In contrast, subtropical regions such as the MEDLME display different dynamics. In the CCLME, thermosteric trends closely mirror SLA patterns, indicating that temperature-driven expansion remains important, as shown in Fig.\u00a0<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#Fig4\" rel=\"nofollow noopener\" target=\"_blank\">4a<\/a> and Fig.\u00a0<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#Fig5\" rel=\"nofollow noopener\" target=\"_blank\">5<\/a> However, in the MEDLME, SLA variability aligns more closely with halosteric changes\u2014those driven by salinity-evident in Fig.\u00a0<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#Fig4\" rel=\"nofollow noopener\" target=\"_blank\">4d<\/a>. The halosteric signal strongly influences sea level trends in the MEDLME, where increased evaporation and reduced freshwater input elevate salinity, making it the dominant steric driver. The halosteric component, on average, exerts a modest but negative influence on SLA across most LMEs, contributing \u22128.13% (Fig.\u00a0<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#Fig4\" rel=\"nofollow noopener\" target=\"_blank\">4d<\/a>). Negative halosteric trends are most notable in the MEDLME and broader North BCLME at the Congo River runoffs, likely linked to regional climate and hydrological patterns. Positive halosteric trends are mostly observed in the CCLME and ACLME, with localized positive trends in the GCLME, particularly off the coasts of Cameroon and Liberia, where major rivers discharge freshwater into the ocean, as highlighted in Fig.\u00a0<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#Fig4\" rel=\"nofollow noopener\" target=\"_blank\">4d<\/a>. These regions, along with parts of the REDLME, Agulhas retroflection zone, and ACLME, experience enhanced steric SLR due to reduced water column density from riverine and estuarine runoff. Such freshwater inputs and regional circulation changes can locally offset the broader negative halosteric trend, highlighting the importance of hydrological variability in shaping regional sea level patterns. Dominating the SLA signal is the manometric component, which accounts for 80.23% of the total trend, as illustrated in Fig.\u00a0<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#Fig4\" rel=\"nofollow noopener\" target=\"_blank\">4e<\/a>. Manometric sea level changes refer to variations caused by the redistribution of ocean mass, primarily from land ice melt, changes in terrestrial water storage, and large-scale shifts in the global water cycle. These changes are measured as the difference between total sea level changes (from satellite altimetry) and steric changes (from in situ temperature and salinity observations). In Africa, manometric trends generally range between 1.8 and 2.9\u2009mm\/yr in most LMEs. The highest values are observed in the SCCLME and GCLME, while lower rates (0.5\u20132\u2009mm\/yr) occur in the southernmost ACLME, MEDLME, and REDLME (Fig.\u00a0<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#Fig4\" rel=\"nofollow noopener\" target=\"_blank\">4e<\/a>).<\/p>\n<p><b id=\"Fig5\" class=\"c-article-section__figure-caption\" data-test=\"figure-caption-text\">Fig. 5: Temporal evolution and decadal sea level components for Africa.<\/b><a class=\"c-article-section__figure-link\" data-test=\"img-link\" data-track=\"click\" data-track-label=\"image\" data-track-action=\"view figure\" href=\"https:\/\/www.nature.com\/articles\/s43247-025-02965-z\/figures\/5\" rel=\"nofollow noopener\" target=\"_blank\"><img decoding=\"async\" aria-describedby=\"Fig5\" src=\"https:\/\/www.europesays.com\/ie\/wp-content\/uploads\/2025\/12\/43247_2025_2965_Fig5_HTML.png\" alt=\"figure 5\" loading=\"lazy\" width=\"685\" height=\"896\"\/><\/a><\/p>\n<p><b>a<\/b> Time series and linear trends of de-seasoned monthly anomalies of total SLA (blue), steric (SSLA; green), thermosteric (TSLA; red), halosteric (HSLA; purple), and manometric (orange) components from 1993 to 2023. Trend values for each component are indicated. All time series are smoothed using a 13-month low-pass filter to highlight interannual-to-decadal variability. <b>b<\/b> Decadal sea-level trends and component contributions for the African region, with bars showing trends (mm\u2009yr\u207b\u00b9) and error bars indicating uncertainties.<\/p>\n<p>Figure\u00a0<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#Fig5\" rel=\"nofollow noopener\" target=\"_blank\">5a<\/a> provides a comprehensive view of SLR trends over Africa by illustrating the evolution of the total SLA and its contributing components. The SLA (depicted by the blue line) shows a steady and significant upward trend of 3.30\u2009\u00b1\u20090.04\u2009mm\/yr since the early 1990s, closely aligning with the GMSL trend of 3.4\u2009mm\/yr. As shown in Fig.\u00a0<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#Fig5\" rel=\"nofollow noopener\" target=\"_blank\">5b<\/a>, this regional trend masks a pronounced acceleration, increasing from 0.96\u2009\u00b1\u20090.26\u2009mm\/yr in 1993\u20132002 to 4.34\u2009\u00b1\u20090.18\u2009mm\/yr in 2013\u20132023, a more than fourfold increase, driven by two primary processes: steric changes, due to variations in seawater density (temperature and salinity), and manometric changes, linked to shifts in ocean mass from cryospheric and hydrological processes. The manometric contribution (orange line, Fig.\u00a0<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#Fig5\" rel=\"nofollow noopener\" target=\"_blank\">5a<\/a>), with a trend of 2.61\u2009\u00b1\u20090.04\u2009mm\/yr, accounts for 79% of the SLA rise, dominating the total SLR. This is in line with Bellas-Manley et al.<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 50\" title=\"Bellas-Manley, A., Nerem, R. S. &amp; Hamlington, B. D. Extrapolation of the Satellite Altimeter record to understand regional variations in future sea level change. J. Geophys. Res. Oceans 130, e2024JC022094 &#010;                  https:\/\/doi.org\/10.1029\/2024JC022094&#010;                  &#010;                 (2025).\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#ref-CR50\" id=\"ref-link-section-d190479614e1027\" rel=\"nofollow noopener\" target=\"_blank\">50<\/a>, who found that the rise is primarily driven by mass inputs from global ice melt, especially Antarctic ice loss, which contributes up to 1.2\u2009mm\/yr through gravitational fingerprints in southern LMEs and Greenland\u2019s more uniform effect, alongside changes in land water storage<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 51\" title=\"Mitrovica, J. X. et al. On the robustness of predictions of sea level fingerprints. Geophys. J. Int. 187, 729&#x2013;742 (2011).\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#ref-CR51\" id=\"ref-link-section-d190479614e1031\" rel=\"nofollow noopener\" target=\"_blank\">51<\/a>. Manometric contributions have accelerated significantly, rising by 3.28\u2009\u00b1\u20090.11\u2009mm\/yr above 1993\u20132002 (Fig.\u00a0<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#Fig5\" rel=\"nofollow noopener\" target=\"_blank\">5b<\/a>) levels, underscoring their pivotal role in shaping regional sea-level patterns. This acceleration closely tracks the intensified glacier melt reported by Dussaillant et al.<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 52\" title=\"Dussaillant, I. et al. Annual mass change of the world&#x2019;s glaciers from 1976 to 2024 by temporal downscaling of satellite data with in situ observations. Earth Syst. Sci. Data &#010;                  https:\/\/doi.org\/10.3929\/ethz-b-000735850&#010;                  &#010;                 (2025).\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#ref-CR52\" id=\"ref-link-section-d190479614e1039\" rel=\"nofollow noopener\" target=\"_blank\">52<\/a> with five of the last six years (2019, 2020, 2022, 2023, and 2024) exceeding 430 Gt\/yr, reinforcing the substantial contribution of glaciers to the SLR acceleration observed along African coasts. The post\u20112019 period of exceptional melt coincides with the smaller, but still positive, increment in manometric acceleration from the second to the third decade, indicating that while the largest step\u2011change occurred earlier (1993\u20132002 to 2003\u20132012), sustained high rates of glacier and ice\u2011sheet loss in recent years have maintained and reinforced elevated mass\u2011driven SLR trends across African LMEs. GIA has a negligible impact (5a) is minor, with a trend of 0.34\u2009\u00b1\u20090.02\u2009mm\/yr, reflecting changes in seawater density. This is subdivided into thermosteric (temperature-driven) and halosteric (salinity-driven) components. The thermosteric anomaly (red line) exhibits a positive trend of 0.49\u2009\u00b1\u20090.02\u2009mm\/yr, indicating that ocean warming and thermal expansion are significant within the steric component. Conversely, the halosteric anomaly (purple line) shows a negative trend of \u22120.15\u2009\u00b1\u20090.01\u2009mm\/yr, suggesting that increasing salinity slightly counteracts SLR by increasing seawater density. The higher thermosteric trend compared to the total steric trend indicates that the halosteric component modestly offsets warming effects. While steric changes drive interannual variability, the manometric component, significantly driven by glacier melt as quantified by Dussaillant et al.<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 52\" title=\"Dussaillant, I. et al. Annual mass change of the world&#x2019;s glaciers from 1976 to 2024 by temporal downscaling of satellite data with in situ observations. Earth Syst. Sci. Data &#010;                  https:\/\/doi.org\/10.3929\/ethz-b-000735850&#010;                  &#010;                 (2025).\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#ref-CR52\" id=\"ref-link-section-d190479614e1046\" rel=\"nofollow noopener\" target=\"_blank\">52<\/a> dominates the accelerated SLR affecting African coastal regions.<\/p>\n<p>Figure\u00a0<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#Fig5\" rel=\"nofollow noopener\" target=\"_blank\">5<\/a> clarify the relative contributions, highlighting the dominance of the manometric component, followed by the thermosteric contribution, with the halosteric effect remaining negative and minor. All components exhibit temporal variability, with short-term oscillations superimposed on long-term trends.<\/p>\n<p>As shown in Fig.\u00a0<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#Fig5\" rel=\"nofollow noopener\" target=\"_blank\">5b<\/a>, the African oceanic domains exhibit an increased trend over the observed last two decades, with the most recent decade marking an unprecedented increase in sea level, a signature of the strongest acceleration recorded to date. This regime shift aligns with the peak glacier mass loss documented by Dussaillant et al.<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 52\" title=\"Dussaillant, I. et al. Annual mass change of the world&#x2019;s glaciers from 1976 to 2024 by temporal downscaling of satellite data with in situ observations. Earth Syst. Sci. Data &#010;                  https:\/\/doi.org\/10.3929\/ethz-b-000735850&#010;                  &#010;                 (2025).\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#ref-CR52\" id=\"ref-link-section-d190479614e1063\" rel=\"nofollow noopener\" target=\"_blank\">52<\/a> particularly the 2023 record of 540\u2009\u00b1\u200969 Gt, contributing 1.5\u2009mm to GMSL rise, which exacerbates regional SLR impacts on African coasts through enhanced ocean mass inputs. The steric components, in particular, show notable interannual variability, likely linked to climate phenomena such as ENSO and shifts in the ITCZ, which influence temperature and salinity distributions in the tropical ocean. Africa LMEs Sea level trends.<\/p>\n<p>                    Atlantic Ocean LMEs<\/p>\n<p>The CCLME, a productive eastern boundary upwelling system situated along northwest Africa in the Atlantic Ocean, exhibits a SLA trend of 3.30\u2009\u00b1\u20090.05\u2009mm\/yr over the study period Fig.\u00a0<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#Fig6\" rel=\"nofollow noopener\" target=\"_blank\">6a<\/a>). This rise is primarily driven by mass (manometric) contributions of 2.63\u2009\u00b1\u20090.05\u2009mm\/yr, accounting for approximately 80% of the total and largely attributable to intensified land ice melt<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 39\" title=\"Cazenave, A. et al. Global sea-level budget 1993&#x2013;present. Earth Syst. Sci. Data 10, 1551&#x2013;1590 (2018).\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#ref-CR39\" id=\"ref-link-section-d190479614e1077\" rel=\"nofollow noopener\" target=\"_blank\">39<\/a>,<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 45\" title=\"Intergovernmental Panel on Climate, C. Climate Change 2022 &#x2013; Impacts, Adaptation and Vulnerability: Working Group II Contribution to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change (Cambridge University Press, 2023).\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#ref-CR45\" id=\"ref-link-section-d190479614e1080\" rel=\"nofollow noopener\" target=\"_blank\">45<\/a>. Steric contributions (0.66\u2009\u00b1\u20090.04\u2009mm\/yr), comprising about 20% of the SLA, include modest thermosteric expansion (0.47\u2009\u00b1\u20090.06\u2009mm\/yr) and a smaller positive halosteric signal (0.19\u2009\u00b1\u20090.03\u2009mm\/yr), the latter reflecting a salinity decrease primarily driven by increased continental runoff and possibly changes in precipitation, which overwhelms the salinizing effect of evaporation<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 53\" title=\"von Schuckmann, K. et al. Heat stored in the Earth system 1960&#x2013;2020: where does the energy go? Earth Syst. Sci. Data 15, 1675&#x2013;1709 (2023).\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#ref-CR53\" id=\"ref-link-section-d190479614e1084\" rel=\"nofollow noopener\" target=\"_blank\">53<\/a>,<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 54\" title=\"P&#xF6;rtner, H.-O. et al. The ocean and cryosphere in a changing climate. IPCC special report on the ocean and cryosphere in a changing climate. Cambridge University Press 1155 &#010;                  https:\/\/doi.org\/10.1017\/9781009157964&#010;                  &#010;                 (2019).\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#ref-CR54\" id=\"ref-link-section-d190479614e1087\" rel=\"nofollow noopener\" target=\"_blank\">54<\/a>. As a productive upwelling zone, the CCLME experiences moderated upper-ocean warming due to the persistent influx of cooler, nutrient-rich subsurface waters, which temper thermosteric expansion<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 25\" title=\"Bakun, A. et al. Anticipated effects of climate change on coastal upwelling ecosystems. Curr. Clim. Change Rep. 1, 85&#x2013;93 (2015).\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#ref-CR25\" id=\"ref-link-section-d190479614e1091\" rel=\"nofollow noopener\" target=\"_blank\">25<\/a>,<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 55\" title=\"Intergovernmental Panel on Climate Change (IPCC) (Ed.). Climate Change 2022&#x2014;Mitigation of Climate Change &#010;                  https:\/\/doi.org\/10.1017\/9781009157926&#010;                  &#010;                 (2023).\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#ref-CR55\" id=\"ref-link-section-d190479614e1094\" rel=\"nofollow noopener\" target=\"_blank\">55<\/a>. This upwelling-related cooling becomes more apparent in the decadal evolution of sea level trends. Between 1993\u20132002 (Fig.\u00a0<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#Fig9\" rel=\"nofollow noopener\" target=\"_blank\">9<\/a>, Supplementary Table\u00a0<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"supplementary material anchor\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#MOESM2\" rel=\"nofollow noopener\" target=\"_blank\">1<\/a>), SLA rose at 3.12\u2009\u00b1\u20090.30\u2009mm\/yr, driven largely by strong thermosteric expansion (2.07\u2009\u00b1\u20090.32\u2009mm\/yr). SLA peaked at 4.61\u2009\u00b1\u20090.31\u2009mm\/yr in 2003\u20132012, coinciding with an exceptional thermosteric contribution of 4.08\u2009\u00b1\u20090.23\u2009mm\/yr. However, in the most recent decade (2013\u20132023), although the SLA further increased to 4.69\u2009\u00b1\u20090.18\u2009mm\/yr, the thermosteric contribution dropped sharply to 0.45\u2009\u00b1\u20090.16\u2009mm\/yr\u2014a decline of 1.60\u2009mm\/yr from the 1993\u20132002 (Fig.\u00a0<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#Fig9\" rel=\"nofollow noopener\" target=\"_blank\">9a<\/a>) level-consistent with enhanced upwelling reducing heat retention in the upper ocean<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 55\" title=\"Intergovernmental Panel on Climate Change (IPCC) (Ed.). Climate Change 2022&#x2014;Mitigation of Climate Change &#010;                  https:\/\/doi.org\/10.1017\/9781009157926&#010;                  &#010;                 (2023).\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#ref-CR55\" id=\"ref-link-section-d190479614e1108\" rel=\"nofollow noopener\" target=\"_blank\">55<\/a>. In parallel, mass contributions nearly doubled from 1.39\u2009\u00b1\u20090.18\u2009mm\/yr in 1993\u20132002 (Figs.\u00a0<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#Fig9\" rel=\"nofollow noopener\" target=\"_blank\">9a<\/a>) to 3.12\u2009\u00b1\u20090.10\u2009mm\/yr in 2013\u20132023 (Fig.\u00a0<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#Fig9\" rel=\"nofollow noopener\" target=\"_blank\">9c<\/a>), underscoring the increasing influence of land ice melt. Halosteric trends also shifted markedly from negative (\u22120.35\u2009\u00b1\u20090.04\u2009mm\/yr) to positive values (1.12\u2009\u00b1\u20090.07\u2009mm\/yr), reflecting a transition from salinity increase (which raises density and contributes negatively to sea level) to salinity decrease (which lowers density and contributes positively). This shift likely reflects enhanced freshwater input<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 53\" title=\"von Schuckmann, K. et al. Heat stored in the Earth system 1960&#x2013;2020: where does the energy go? Earth Syst. Sci. Data 15, 1675&#x2013;1709 (2023).\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#ref-CR53\" id=\"ref-link-section-d190479614e1118\" rel=\"nofollow noopener\" target=\"_blank\">53<\/a>. This shift supported a steric contribution of approximately 33% in the latest decade, with halosteric effects playing a more prominent role.<\/p>\n<p><b id=\"Fig6\" class=\"c-article-section__figure-caption\" data-test=\"figure-caption-text\">Fig. 6: Regional sea level budget components for the Atlantic LMEs.<\/b><a class=\"c-article-section__figure-link\" data-test=\"img-link\" data-track=\"click\" data-track-label=\"image\" data-track-action=\"view figure\" href=\"https:\/\/www.nature.com\/articles\/s43247-025-02965-z\/figures\/6\" rel=\"nofollow noopener\" target=\"_blank\"><img decoding=\"async\" aria-describedby=\"Fig6\" src=\"https:\/\/www.europesays.com\/ie\/wp-content\/uploads\/2025\/12\/43247_2025_2965_Fig6_HTML.png\" alt=\"figure 6\" loading=\"lazy\" width=\"685\" height=\"1043\"\/><\/a><\/p>\n<p>Temporal evolution and linear trends of de-seasoned monthly anomalies for <b>a<\/b> the Canary Current LME (CCLME), <b>b<\/b> the Guinea Current LME (GCLME), and <b>c<\/b> the Benguela Current LME (BCLME) from 1993\u20132023. Contributions shown are total Sea-Level Anomaly (SLA; blue line), steric (SSLA; green line), thermosteric (TSLA; red line), halosteric (HSLA; purple line), and manometric (orange line). All time series are smoothed with a 13-month low-pass filter.<\/p>\n<p>Bordering the West African coast, the GCLME spans approximately 2 million km\u00b2 and is characterized by seasonal upwelling, high freshwater input, and low-salinity surface waters<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 25\" title=\"Bakun, A. et al. Anticipated effects of climate change on coastal upwelling ecosystems. Curr. Clim. Change Rep. 1, 85&#x2013;93 (2015).\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#ref-CR25\" id=\"ref-link-section-d190479614e1155\" rel=\"nofollow noopener\" target=\"_blank\">25<\/a>,<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 56\" title=\"Spalding, M. D. et al. Coastal ecosystems: a critical element of risk reduction. Conserv. Lett. 7, 293&#x2013;301 (2014).\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#ref-CR56\" id=\"ref-link-section-d190479614e1158\" rel=\"nofollow noopener\" target=\"_blank\">56<\/a>. Between 1993 and 2023, this region experienced a SLA trend of 3.41\u2009\u00b1\u20090.05\u2009mm\/yr, slightly above the global mean ranking it second among all LMEs (Fig.\u00a0<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#Fig6\" rel=\"nofollow noopener\" target=\"_blank\">6b<\/a>).<\/p>\n<p>This rise is predominantly driven by mass (manometric) contributions of 2.68\u2009\u00b1\u20090.03\u2009mm\/yr, representing about 79% of the total. Steric effects contribute 0.72\u2009\u00b1\u20090.04\u2009mm\/yr (21%) to the regional sea level trend in the GCLME. Of this, thermosteric expansion estimated at 1.07\u2009\u00b1\u20090.05\u2009mm\/yr reflects upper-ocean warming across the tropical Atlantic, amplified by seasonal upwelling that redistributes heat in the upper layers, while halosteric changes (\u22120.35\u2009\u00b1\u20090.02\u2009mm\/yr) indicate contraction driven by salinity increase (i.e., density increase causing volume reduction). These findings align with recent studies emphasizing the joint role of mass and steric components in driving SLR in river-dominated tropical LMEs<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 57\" title=\"Frederikse, T. et al. The causes of sea-level rise since 1900. Nature 584, 393&#x2013;397 (2020).\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#ref-CR57\" id=\"ref-link-section-d190479614e1168\" rel=\"nofollow noopener\" target=\"_blank\">57<\/a>. A decadal breakdown reveals a marked acceleration: SLA increased from 2.00\u2009\u00b1\u20090.27\u2009mm\/yr in 1993\u20132002 (Fig.\u00a0<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#Fig9\" rel=\"nofollow noopener\" target=\"_blank\">9a<\/a>) to 4.50\u2009\u00b1\u20090.19\u2009mm\/yr in 2013\u20132023 (Fig.\u00a0<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#Fig9\" rel=\"nofollow noopener\" target=\"_blank\">9c<\/a>), a 2.25-fold rise. Initially, this was supported by modest contributions from mass (0.54\u2009\u00b1\u20090.11\u2009mm\/yr) and thermosteric (1.55\u2009\u00b1\u20090.30\u2009mm\/yr) components. During 2003\u20132012 (Fig.\u00a0<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#Fig9\" rel=\"nofollow noopener\" target=\"_blank\">9b<\/a>), both peaked, with manometric input reaching 3.63\u2009\u00b1\u20090.11\u2009mm\/yr and thermosteric expansion at 1.41\u2009\u00b1\u20090.18\u2009mm\/yr. In the most recent decade, mass contributions stabilized at 2.88\u2009\u00b1\u20090.09\u2009mm\/yr, while thermosteric trends remained steady at 3.07\u2009\u00b1\u20090.18\u2009mm\/yr, reflecting sustained ocean warming. Concurrently, halosteric contributions became increasingly negative, reaching \u22121.45\u2009\u00b1\u20090.06\u2009mm\/yr in 2013\u20132023 (Fig.\u00a0<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#Fig9\" rel=\"nofollow noopener\" target=\"_blank\">9c<\/a>) consistent with increased salinity, which raises water density and reduces the height of the water column, thus lowering sea level. This intensification, as the GCLME transitions toward the Benguela system, underscores the growing dominance of mass-related SLR, compounded by thermal expansion and freshwater influxes, which are both projected to intensify under ongoing climate change<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 55\" title=\"Intergovernmental Panel on Climate Change (IPCC) (Ed.). Climate Change 2022&#x2014;Mitigation of Climate Change &#010;                  https:\/\/doi.org\/10.1017\/9781009157926&#010;                  &#010;                 (2023).\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#ref-CR55\" id=\"ref-link-section-d190479614e1185\" rel=\"nofollow noopener\" target=\"_blank\">55<\/a>,<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 58\" title=\"Syvitski, J. P. M. et al. Sinking deltas due to human activities. Nat. Geosci. 2, 681&#x2013;686 (2009).\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#ref-CR58\" id=\"ref-link-section-d190479614e1188\" rel=\"nofollow noopener\" target=\"_blank\">58<\/a>.<\/p>\n<p>The BCLME (Fig.\u00a0<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#Fig6\" rel=\"nofollow noopener\" target=\"_blank\">6c<\/a>), stretching along the coasts of Angola, Namibia, and South Africa, is a wind-driven upwelling system and one of the world\u2019s four major eastern boundary current upwelling regions<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 59\" title=\"Hutchings, L. et al. The Benguela current: an ecosystem of four components. Prog. Oceanogr. 83, 15&#x2013;32 (2009).\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#ref-CR59\" id=\"ref-link-section-d190479614e1198\" rel=\"nofollow noopener\" target=\"_blank\">59<\/a>. From 1993 to 2023, the region recorded SLA trend of 2.98\u2009\u00b1\u20090.05\u2009mm\/yr (Fig.\u00a0<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#Fig6\" rel=\"nofollow noopener\" target=\"_blank\">6c<\/a>), slightly below the GMSL. This rise is dominated by manometric (mass) contributions (2.52\u2009\u00b1\u20090.05\u2009mm\/yr), accounting for 85% of the total increase. A significant portion of the mass-driven rise is attributed to gravitational redistribution from Antarctic ice melt, which disproportionately affects the South Atlantic, and to regional upwelling dynamics that modulate local sea level<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 55\" title=\"Intergovernmental Panel on Climate Change (IPCC) (Ed.). Climate Change 2022&#x2014;Mitigation of Climate Change &#010;                  https:\/\/doi.org\/10.1017\/9781009157926&#010;                  &#010;                 (2023).\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#ref-CR55\" id=\"ref-link-section-d190479614e1205\" rel=\"nofollow noopener\" target=\"_blank\">55<\/a>,<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 57\" title=\"Frederikse, T. et al. The causes of sea-level rise since 1900. Nature 584, 393&#x2013;397 (2020).\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#ref-CR57\" id=\"ref-link-section-d190479614e1208\" rel=\"nofollow noopener\" target=\"_blank\">57<\/a>. Steric contributions remain modest (0.34\u2009\u00b1\u20090.03\u2009mm\/yr, 15%) due to the upwelling of cooler, nutrient-rich waters that suppress thermosteric expansion<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 55\" title=\"Intergovernmental Panel on Climate Change (IPCC) (Ed.). Climate Change 2022&#x2014;Mitigation of Climate Change &#010;                  https:\/\/doi.org\/10.1017\/9781009157926&#010;                  &#010;                 (2023).\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#ref-CR55\" id=\"ref-link-section-d190479614e1212\" rel=\"nofollow noopener\" target=\"_blank\">55<\/a>. Thermosteric expansion is measured at 0.46\u2009\u00b1\u20090.03\u2009mm\/yr, but this is further reduced by slight halosteric contraction (\u22120.12\u2009\u00b1\u20090.02\u2009mm\/yr), indicating a net reduction in sea level contribution, likely driven by increased salinity due to enhanced evaporation or reduced freshwater input<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 53\" title=\"von Schuckmann, K. et al. Heat stored in the Earth system 1960&#x2013;2020: where does the energy go? Earth Syst. Sci. Data 15, 1675&#x2013;1709 (2023).\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#ref-CR53\" id=\"ref-link-section-d190479614e1217\" rel=\"nofollow noopener\" target=\"_blank\">53<\/a>. This balance of forces reflects the region\u2019s sensitivity to both large-scale cryospheric changes (such as Antarctic meltwater) and local oceanographic processes (such as persistent upwelling)<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 55\" title=\"Intergovernmental Panel on Climate Change (IPCC) (Ed.). Climate Change 2022&#x2014;Mitigation of Climate Change &#010;                  https:\/\/doi.org\/10.1017\/9781009157926&#010;                  &#010;                 (2023).\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#ref-CR55\" id=\"ref-link-section-d190479614e1221\" rel=\"nofollow noopener\" target=\"_blank\">55<\/a>. Decadal variability reveals a strong acceleration in SLA, rising from 2.13\u2009\u00b1\u20090.22\u2009mm\/yr in 1993\u20132002 (Figs.\u00a0<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#Fig9\" rel=\"nofollow noopener\" target=\"_blank\">9a<\/a>) to 4.90\u2009\u00b1\u20090.17\u2009mm\/yr in 2013\u20132023 (Fig.\u00a0<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#Fig9\" rel=\"nofollow noopener\" target=\"_blank\">9c<\/a>) more than doubling over the period, with a 2.3-fold increase. Early in the record, SLA was mainly driven by thermosteric expansion (2.65\u2009\u00b1\u20090.20\u2009mm\/yr) amid negligible or even negative manometric input (-0.23\u2009\u00b1\u20090.13\u2009mm\/yr). By the most recent decade, mass contributions surged 13-fold to 3.19\u2009\u00b1\u20090.10\u2009mm\/yr, reflecting intensified Antarctic meltwater input and the increasing dominance of mass-driven SLR in the region. Thermosteric trends also rose to 2.98\u2009\u00b1\u20090.16\u2009mm\/yr but were offset by strong halosteric contraction (\u22121.27\u2009\u00b1\u20090.09\u2009mm\/yr), driven by increased salinity, thereby reducing the net steric contribution to 15% of total SLR.<\/p>\n<p>                    Indian Ocean LMEs<\/p>\n<p>The ACLME, a warm western boundary current along South Africa\u2019s east coast, presents a SLA trend of 3.00\u2009\u00b1\u20090.09\u2009mm\/yr (Fig.\u00a0<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#Fig7\" rel=\"nofollow noopener\" target=\"_blank\">7a<\/a>), ranking sixth among the seven African LMEs analyzed, slightly above the BCLME. This long-term SLA trend is primarily driven by manometric contributions, which account for 2.30\u2009\u00b1\u20090.05\u2009mm\/yr (~77%). These mass-driven changes are attributed to regional ocean mass redistribution, influenced by the intense eddy activity characteristic of the ACLME. Steric contributions account for the remaining ~23% (0.70\u2009\u00b1\u20090.07\u2009mm\/yr), but their influence is comparatively modest. Within the steric component, thermosteric expansion ranges from 0.45\u2009\u00b1\u20090.03 to 0.67\u2009\u00b1\u20090.08\u2009mm\/yr, reflecting upper-ocean warming. However, this warming effect is dampened by persistent eddy-induced cooling and vertical mixing, which reduce the net thermal expansion<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 60\" title=\"Durgadoo, J. V., R&#xFC;hs, S., Biastoch, A. &amp; B&#xF6;ning, C. W. B. Indian Ocean sources of Agulhas leakage. J. Geophys. Res. Oceans 122, 3481&#x2013;3499 (2017).\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#ref-CR60\" id=\"ref-link-section-d190479614e1242\" rel=\"nofollow noopener\" target=\"_blank\">60<\/a>. Halosteric effects are minimal to slightly negative, ranging from \u22120.10\u2009\u00b1\u20090.02 to 0.02\u2009\u00b1\u20090.02\u2009mm\/yr (Fig.\u00a0<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#Fig7\" rel=\"nofollow noopener\" target=\"_blank\">7a<\/a>), indicating weak salinity-driven contributions that marginally oppose thermal expansion. These effects further limit the overall steric contribution to the SLA trend. The region\u2019s dynamic oceanography is characterized by strong decadal variability, driven by shifts in eddy activity, mass inflow, and upper-ocean heat content. During the period 1993\u20132002 (Fig.\u00a0<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#Fig9\" rel=\"nofollow noopener\" target=\"_blank\">9a<\/a>), SLA exhibited a negative trend of \u22121.72\u2009\u00b1\u20090.65\u2009mm\/yr, driven primarily by strong cooling eddies and a large negative manometric contribution (\u22123.10\u2009\u00b1\u20090.20\u2009mm\/yr), while the thermosteric term was modestly positive (+1.45\u2009\u00b1\u20090.55\u2009mm\/yr) and the halosteric term slightly negative (\u22120.07\u2009\u00b1\u20090.06\u2009mm\/yr). These modest steric offsets were insufficient to counter the mass loss. This negative phase reflects reduced ocean mass input, linked to weakened current strength and shifts in regional atmospheric forcing, consistent with broader climate variability along the southeastern African coast.<\/p>\n<p><b id=\"Fig7\" class=\"c-article-section__figure-caption\" data-test=\"figure-caption-text\">Fig. 7: Regional sea level budget components for the Indian Ocean LMEs.<\/b><a class=\"c-article-section__figure-link\" data-test=\"img-link\" data-track=\"click\" data-track-label=\"image\" data-track-action=\"view figure\" href=\"https:\/\/www.nature.com\/articles\/s43247-025-02965-z\/figures\/7\" rel=\"nofollow noopener\" target=\"_blank\"><img decoding=\"async\" aria-describedby=\"Fig7\" src=\"https:\/\/www.europesays.com\/ie\/wp-content\/uploads\/2025\/12\/43247_2025_2965_Fig7_HTML.png\" alt=\"figure 7\" loading=\"lazy\" width=\"685\" height=\"704\"\/><\/a><\/p>\n<p>Temporal evolution of sea level budget components for <b>a<\/b> the Agulhas Current LME (ACLME) and <b>b<\/b> the Somali Coastal Current LME (SCCLME) from 1993 to 2023. Contributions shown are total Sea-Level Anomaly (SLA; blue line), steric (SSLA; green line), thermosteric (TSLA; red line), halosteric (HSLA; purple line), and manometric (orange line). All time series are smoothed with a 13-month low-pass filter.<\/p>\n<p>In contrast, the period 2003\u20132012 saw a sharp rise in SLA, with trends reaching 2.81\u2009\u00b1\u20090.35\u2009mm\/yr (Fig.\u00a0<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#Fig9\" rel=\"nofollow noopener\" target=\"_blank\">9b<\/a>). This increase was supported primarily by rising manometric contributions (2.81\u2009\u00b1\u20090.18\u2009mm\/yr), associated with intensified mass inflow into the region. This positive shift aligns with strengthened eddy activity and increased regional circulation, which enhanced ocean mass accumulation and contributed to upper-ocean warming despite persistent mixing. Between 2013 and 2023, SLA stabilized at 1.12\u2009\u00b1\u20090.39\u2009mm\/yr, with mass contributions (2.45\u2009\u00b1\u20090.13\u2009mm\/yr) continuing to dominate (Fig.\u00a0<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#Fig9\" rel=\"nofollow noopener\" target=\"_blank\">9c<\/a>). However, thermosteric trends remained negative (\u22122.02\u2009\u00b1\u20090.32\u2009mm\/yr), suppressing steric input to just 23% of the total rise. This underscores the ACLME\u2019s sensitivity to dynamic ocean processes, where local steric effects are frequently modulated by turbulent mixing and eddy variability.<\/p>\n<p>Along East Africa\u2019s Indian Ocean coast, the SCCLME unveils a SLA trend of 3.29\u2009\u00b1\u20090.13\u2009mm\/yr, ranking third among African LMEs (Fig.\u00a0<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#Fig7\" rel=\"nofollow noopener\" target=\"_blank\">7b<\/a>). This trend is primarily driven by manometric contributions, which dominate the signal at 2.87\u2009\u00b1\u20090.06\u2009mm\/yr, accounting for 87% of the total rise. These mass-driven changes are largely attributed to global ice mass loss and monsoon-enhanced circulation, underscoring the critical role of ocean mass in shaping regional sea-level dynamics<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 61\" title=\"Llovel, W. et al. Global ocean freshening, ocean mass increase and global mean sea level rise over 2005&#x2013;2015. Sci. Rep. 9, 17717 (2019).\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#ref-CR61\" id=\"ref-link-section-d190479614e1293\" rel=\"nofollow noopener\" target=\"_blank\">61<\/a>,<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 62\" title=\"Zemp, M. et al. Community estimate of global glacier mass changes from 2000 to 2023. Nature 639, 382&#x2013;388 (2025).\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#ref-CR62\" id=\"ref-link-section-d190479614e1296\" rel=\"nofollow noopener\" target=\"_blank\">62<\/a>. While smaller in magnitude, the steric contribution also plays a role in the SLA trend, with a net steric contribution of 0.42\u2009\u00b1\u20090.04\u2009mm\/yr. This is primarily driven by thermosteric expansion, which contributes 0.50\u2009\u00b1\u20090.04\u2009mm\/yr, reflecting modest ocean warming in the region. In contrast, halosteric effects are negligible, with a slight negative trend of \u20130.08\u2009\u00b1\u20090.02\u2009mm\/yr, indicating that increased salinity (density) slightly offsets the thermosteric expansion. This interplay between steric and manometric components highlights the dominance of mass-driven processes in the SCCLME, while steric contributions remain secondary. The sea-level budget also reveals pronounced decadal variability, reflecting the dynamic interplay of physical processes over time. During the period 1993\u20132002 (Fig.\u00a0<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#Fig9\" rel=\"nofollow noopener\" target=\"_blank\">9a<\/a>), SLA trends were negative at \u20131.90\u2009\u00b1\u20090.88\u2009mm\/yr, driven by declines in both manometric (\u20132.97\u2009\u00b1\u20090.24\u2009mm\/yr) and thermosteric (1.01\u2009\u00b1\u20090.79\u2009mm\/yr) contributions. This period of reduced SLR coincided with weak monsoonal forcing<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 63\" title=\"Swapna, P., Jyoti, J., Krishnan, R., Sandeep, N. &amp; Griffies, S. M. Multidecadal weakening of indian summer monsoon circulation induces an increasing Northern Indian Ocean Sea Level. Geophys. Res. Lett. 44, 10,560&#x2013;510,572 (2017).\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#ref-CR63\" id=\"ref-link-section-d190479614e1303\" rel=\"nofollow noopener\" target=\"_blank\">63<\/a>, which likely suppressed ocean circulation and upper-ocean heat content, reducing both mass and steric contributions. In contrast, the period 2003\u20132012 marked a sharp acceleration in SLA, with trends peaking at 5.92\u2009\u00b1\u20090.44\u2009mm\/yr (Fig.\u00a0<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#Fig9\" rel=\"nofollow noopener\" target=\"_blank\">9b<\/a>). This dramatic increase is likely to be driven by strengthened monsoonal winds<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 64\" title=\"Chatterjee, A., Kumar, B. P., Prakash, S. &amp; Singh, P. Annihilation of the Somali upwelling system during summer monsoon. Sci. Rep. 9, 7598&#x2013;7598 (2019).\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#ref-CR64\" id=\"ref-link-section-d190479614e1311\" rel=\"nofollow noopener\" target=\"_blank\">64<\/a> and enhanced ocean warming, as reflected in significant gains in both manometric (3.93\u2009\u00b1\u20090.12\u2009mm\/yr) and thermosteric (2.28\u2009\u00b1\u20090.43\u2009mm\/yr) contributions. The intensified monsoonal forcing during this decade likely enhanced upper-ocean heat content and circulation, amplifying both steric and mass-driven SLR. The most recent decade, 2013\u20132023, shows a sustained SLA trend of 4.72\u2009\u00b1\u20090.67\u2009mm\/yr (Fig.\u00a0<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#Fig9\" rel=\"nofollow noopener\" target=\"_blank\">9c<\/a>), slightly lower than the previous decade but still elevated. This trend remains primarily driven by manometric contributions (3.44\u2009\u00b1\u20090.15\u2009mm\/yr), which continue to dominate the sea-level budget with an 87% share.<\/p>\n<p>However, the thermosteric contribution decreased to 1.50\u2009\u00b1\u20090.25\u2009mm\/yr, reflecting a slight reduction in ocean warming compared to the previous decade. Despite this decline, the dominance of mass-driven processes persists, underscoring the critical role of global ice mass loss and monsoonal dynamics in shaping regional sea-level trends. Looking ahead, the anticipated succession of El Ni\u00f1o and La Ni\u00f1a phases is expected to intensify interannual variability in the SCCLME. These climate oscillations are likely to modulate monsoonal wind patterns, upwelling strength, and upper-ocean heat content, potentially amplifying both thermosteric and manometric contributions to regional SLR.<\/p>\n<p>                    Semi-Enclosed Basin LMEs<\/p>\n<p>The REDLME exhibits the highest SLA trend among African LMEs, measured at 3.91\u2009\u00b1\u20090.13\u2009mm\/yr (Fig.\u00a0<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#Fig8\" rel=\"nofollow noopener\" target=\"_blank\">8a<\/a>). This pronounced trend is primarily driven by the manometric contribution (2.06\u2009\u00b1\u20090.08\u2009mm\/yr), which accounts for 53% of the total rise, while thermosteric expansion (1.84\u2009\u00b1\u20090.09\u2009mm\/yr) accounts for 47%. The confined bathymetry and limited water exchange of the Red Sea enhance heat retention, amplifying upper-ocean warming and contributing significantly to the observed thermosteric trends. In contrast, halosteric effects (0.01\u2009\u00b1\u20090.02\u2009mm\/yr) are negligible, indicating minimal salinity-driven density changes and limited impact on steric sea level variations in this region. Together, the steric contribution totals 1.85\u2009\u00b1\u20090.09\u2009mm\/yr, underscoring the combined influence of temperature and salinity on SLR in this region. The decadal variability of SLA in the Red Sea LME highlights the dynamic interplay between regional temperature, salinity, and mass-driven processes. During the period 1993\u20132002 (Fig.\u00a0<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#Fig9\" rel=\"nofollow noopener\" target=\"_blank\">9a<\/a>), SLA exhibited a strongly negative trend of \u22127.14\u2009\u00b1\u20090.51\u2009mm\/yr, driven by significant declines in both thermosteric (\u22124.27\u2009\u00b1\u20090.27\u2009mm\/yr) and manometric (\u22123.25\u2009\u00b1\u20090.37\u2009mm\/yr) contributions. This period of negative trends reflects regional cooling and reduced mass inputs, likely linked to weakened trade winds<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 65\" title=\"St&#xFC;we, K., Robl, J., Turab, S. A., Sternai, P. &amp; Stuart, F. M. Feedbacks between sea-floor spreading, trade winds and precipitation in the Southern Red Sea. Nat. Commun. 13, 5405&#x2013;5405 (2022).\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#ref-CR65\" id=\"ref-link-section-d190479614e1335\" rel=\"nofollow noopener\" target=\"_blank\">65<\/a> and lower heat retention. In contrast, the period 2003\u20132012 (Fig.\u00a0<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#Fig9\" rel=\"nofollow noopener\" target=\"_blank\">9b<\/a>) marked a dramatic reversal, with SLA peaking at 6.18\u2009\u00b1\u20090.59\u2009mm\/yr. This sharp increase was driven by thermosteric contributions (2.89\u2009\u00b1\u20090.60\u2009mm\/yr), reflecting intensified upper-ocean warming, and manometric contributions (2.66\u2009\u00b1\u20090.27\u2009mm\/yr), associated with wind-driven mass inflow. The warming trends during this decade highlight the Red Sea\u2019s sensitivity to regional and global climate forcing, as its confined geography amplifies heat accumulation and limits heat dissipation. By the period 2013\u20132023 (Fig.\u00a0<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#Fig9\" rel=\"nofollow noopener\" target=\"_blank\">9c<\/a>), SLA trends stabilized at 3.55\u2009\u00b1\u20090.43\u2009mm\/yr, with thermosteric expansion (3.23\u2009\u00b1\u20090.40\u2009mm\/yr) emerging as the dominant driver. During this time, manometric contributions dropped to 0.01\u2009\u00b1\u20090.42\u2009mm\/yr, indicating a reduced influence of mass-driven processes, such as wind-driven inflow or regional mass redistribution. The sustained thermosteric trends, however, underscore the persistent warming of the Red Sea\u2019s water column, which continues to drive SLR in the absence of significant salinity-driven or mass-driven changes. The observed SLA trends in the Red Sea LME are closely tied to the region\u2019s unique oceanographic conditions, limited water exchange, and sensitivity to atmospheric forcing. The strong connection between SLA and temperature trends in the water column highlights the critical role of heat retention in driving thermosteric expansion. While salinity trends remain minimal, their slight variability contributes to the overall steric balance. The decadal shifts in SLA further emphasize the influence of regional climate variability, including trade wind patterns and heat fluxes, on the Red Sea\u2019s dynamic sea-level budget.<\/p>\n<p><b id=\"Fig8\" class=\"c-article-section__figure-caption\" data-test=\"figure-caption-text\">Fig. 8: Regional sea level budget components for the Red Sea and Mediterranean Sea LMEs.<\/b><a class=\"c-article-section__figure-link\" data-test=\"img-link\" data-track=\"click\" data-track-label=\"image\" data-track-action=\"view figure\" href=\"https:\/\/www.nature.com\/articles\/s43247-025-02965-z\/figures\/8\" rel=\"nofollow noopener\" target=\"_blank\"><img decoding=\"async\" aria-describedby=\"Fig8\" src=\"https:\/\/www.europesays.com\/ie\/wp-content\/uploads\/2025\/12\/43247_2025_2965_Fig8_HTML.png\" alt=\"figure 8\" loading=\"lazy\" width=\"685\" height=\"692\"\/><\/a><\/p>\n<p>Temporal evolution of sea level budget components for <b>a<\/b> the Red Sea LME (REDLME) and <b>b<\/b> the Mediterranean Sea LME (MEDLME) from 1993 to 2023. Contributions shown are total Sea-Level Anomaly (SLA; blue line), steric (SSLA; green line), thermosteric (TSLA; red line), halosteric (HSLA; purple line), and manometric (orange line). All time series are smoothed with a 13-month low-pass filter.<\/p>\n<p><b id=\"Fig9\" class=\"c-article-section__figure-caption\" data-test=\"figure-caption-text\">Fig. 9: Decadal sea level budgets across African LMEs.<\/b><a class=\"c-article-section__figure-link\" data-test=\"img-link\" data-track=\"click\" data-track-label=\"image\" data-track-action=\"view figure\" href=\"https:\/\/www.nature.com\/articles\/s43247-025-02965-z\/figures\/9\" rel=\"nofollow noopener\" target=\"_blank\"><img decoding=\"async\" aria-describedby=\"Fig9\" src=\"https:\/\/www.europesays.com\/ie\/wp-content\/uploads\/2025\/12\/43247_2025_2965_Fig9_HTML.png\" alt=\"figure 9\" loading=\"lazy\" width=\"685\" height=\"688\"\/><\/a><\/p>\n<p>Histograms of decadal sea-level budgets for <b>a<\/b> 1993\u20132002, <b>b<\/b> 2003\u20132012, and <b>c<\/b> 2013\u20132023 across Africa\u2019s LMEs.<\/p>\n<p>The MEDLME, the northernmost of the African LMEs, exhibits the lowest SLA trend among them, with an average rise of 2.70\u2009\u00b1\u20090.06\u2009mm\/yr from 1993 to 2023 (Fig.\u00a0<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#Fig8\" rel=\"nofollow noopener\" target=\"_blank\">8b<\/a>), representing the lowest trends across African LMEs during the analysis period (see Table\u00a0<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"table anchor\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#Tab1\" rel=\"nofollow noopener\" target=\"_blank\">1<\/a>). This reduced SLA trend is primarily attributed to strong negative halosteric effects (-1.03\u2009\u00b1\u20090.04\u2009mm\/yr) caused by reduced Nile River discharge and high evaporation rates, which increase salinity and density, thereby counteracting thermosteric expansion. In contrast, other African LMEs, such as the Red Sea (3.91\u2009\u00b1\u20090.13\u2009mm\/yr) and the Guinea Current (3.41\u2009\u00b1\u20090.05\u2009mm\/yr), exhibit higher SLA trends due to the dominance of mass-driven contributions and weaker salinity-driven suppression. The manometric contribution in the Mediterranean, which includes the effects of oceanic mass change and redistribution and changes in bottom pressure caused by ocean currents<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 55\" title=\"Intergovernmental Panel on Climate Change (IPCC) (Ed.). Climate Change 2022&#x2014;Mitigation of Climate Change &#010;                  https:\/\/doi.org\/10.1017\/9781009157926&#010;                  &#010;                 (2023).\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#ref-CR55\" id=\"ref-link-section-d190479614e1410\" rel=\"nofollow noopener\" target=\"_blank\">55<\/a>, accounts for 1.78\u2009\u00b1\u20090.07\u2009mm\/yr, representing 66% of the total SLA trend. Groundwater extraction and tectonic activity may also contribute to the residual trend. Meanwhile, thermosteric expansion contributes 1.95\u2009\u00b1\u20090.04\u2009mm\/yr, but this is significantly offset by salinity-driven contraction, resulting in a net steric contribution of 0.92\u2009\u00b1\u20090.05\u2009mm\/yr (34%). Decadal trends reveal substantial variability in SLAs, reflecting the dynamic interplay of physical oceanographic processes. Between 1993 and 2002 (Fig.\u00a0<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#Fig9\" rel=\"nofollow noopener\" target=\"_blank\">9a<\/a>), SLA rose at 3.94\u2009\u00b1\u20090.32\u2009mm\/yr, primarily driven by strong thermosteric expansion (4.50\u2009\u00b1\u20090.10\u2009mm\/yr) associated with upper-ocean warming<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 66\" title=\"Bonaduce, A., Pinardi, N., Oddo, P., Spada, G. &amp; Larnicol, G. Sea-level variability in the Mediterranean Sea from altimetry and tide gauges. Clim. Dyn. 47, 2851&#x2013;2866 (2016).\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#ref-CR66\" id=\"ref-link-section-d190479614e1417\" rel=\"nofollow noopener\" target=\"_blank\">66<\/a>,<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 67\" title=\"Legeais, J.-F. et al. An improved and homogeneous altimeter sea level record from the ESA Climate Change Initiative. Earth Syst. Sci. Data 10, 281&#x2013;301 (2018).\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#ref-CR67\" id=\"ref-link-section-d190479614e1420\" rel=\"nofollow noopener\" target=\"_blank\">67<\/a>, while manometric contributions were minimal (\u22120.35\u2009\u00b1\u20090.26\u2009mm\/yr), underscoring the dominance of temperature-induced changes during this period. From 2003 to 2012 (Fig.\u00a0<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#Fig9\" rel=\"nofollow noopener\" target=\"_blank\">9b<\/a>), SLA accelerated to 5.32\u2009\u00b1\u20090.42\u2009mm\/yr, coinciding with a significant rise in manometric contributions (3.18\u2009\u00b1\u20090.42\u2009mm\/yr) linked to ocean mass redistribution, bottom pressure changes, and wind-driven circulation<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 68\" title=\"Marcos, M. &amp; Tsimplis, M. N. Coastal sea level trends in Southern Europe. Geophys. J. Int. 175, 70&#x2013;82 (2008).\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#ref-CR68\" id=\"ref-link-section-d190479614e1428\" rel=\"nofollow noopener\" target=\"_blank\">68<\/a>,<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 69\" title=\"Borile, F. et al. The Eastern Mediterranean Sea mean sea level decadal slowdown: the effects of the water budget. Front. Clim. 7 &#010;                  https:\/\/doi.org\/10.3389\/fclim.2025.1472731&#010;                  &#010;                 (2025).\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#ref-CR69\" id=\"ref-link-section-d190479614e1431\" rel=\"nofollow noopener\" target=\"_blank\">69<\/a>. Meanwhile, steric contributions weakened to 2.13\u2009\u00b1\u20090.22\u2009mm\/yr as emerging negative halosteric trends (\u22121.88\u2009\u00b1\u20090.15\u2009mm\/yr) began to offset thermosteric expansion. In the Mediterranean Sea, SLA deceleration was primarily driven by intensified salinity effects: negative halosteric trends, indicating increased salinity, reduced SLA by 0.82\u2009mm\/yr, thereby diminishing both thermosteric and manometric contributions<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 66\" title=\"Bonaduce, A., Pinardi, N., Oddo, P., Spada, G. &amp; Larnicol, G. Sea-level variability in the Mediterranean Sea from altimetry and tide gauges. Clim. Dyn. 47, 2851&#x2013;2866 (2016).\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#ref-CR66\" id=\"ref-link-section-d190479614e1435\" rel=\"nofollow noopener\" target=\"_blank\">66<\/a>,<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 70\" title=\"Durack, P. J., Wijffels, S. E. &amp; Matear, R. J. Ocean salinities reveal strong global water cycle intensification during 1950 to 2000. Science 336, 455&#x2013;458 (2012).\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#ref-CR70\" id=\"ref-link-section-d190479614e1438\" rel=\"nofollow noopener\" target=\"_blank\">70<\/a>.<\/p>\n<p><b id=\"Tab1\" data-test=\"table-caption\">Table 1 SLA and contributing trends from 1993 to 2023 (mm\/yr)<\/b><\/p>\n<p>This highlights the Mediterranean as a key region for understanding salinity-driven suppression of SLR. During the most recent decade (2013\u20132023, Fig.\u00a0<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#Fig9\" rel=\"nofollow noopener\" target=\"_blank\">9c<\/a>), SLA growth slowed to 2.71\u2009\u00b1\u20090.30\u2009mm\/yr, representing a 31% decrease from the 2003\u20132012 peak and 1.24\u2009mm\/yr below the early period\u2019s rate. This decline reflects a shift in ocean dynamics, with steric contributions accounting for only 34% of the total SLA during this period. Negative steric trends (\u22120.93\u2009\u00b1\u20090.20\u2009mm\/yr), dominated by halosteric suppression (\u22122.86\u2009\u00b1\u20090.07\u2009mm\/yr), played a key role in this slowdown. While unusually large for a halosteric contribution, this value is supported by the data and may reflect intense regional salinification. Although manometric contributions increased to 3.64\u2009\u00b1\u20090.34\u2009mm\/yr, their effect was largely offset by the persistent influence of salinity. The Mediterranean\u2019s low SLA trend is justified by its unique salinity-driven suppression of SLR, which distinguishes it from other African LMEs where mass-driven SLR typically dominates. For example, the Red Sea exhibits the highest SLA trend (3.91\u2009\u00b1\u20090.13\u2009mm\/yr, Fig.\u00a0<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#Fig8\" rel=\"nofollow noopener\" target=\"_blank\">8a<\/a>) due to strong manometric contributions from ice melt and water mass redistribution, while the Guinea Current (3.41\u2009\u00b1\u20090.05\u2009mm\/yr, Fig.\u00a0<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#Fig6\" rel=\"nofollow noopener\" target=\"_blank\">6b<\/a>) and Canary Current (3.30\u2009\u00b1\u20090.05\u2009mm\/yr, Fig.\u00a0<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#Fig6\" rel=\"nofollow noopener\" target=\"_blank\">6a<\/a>) are similarly influenced by mass-driven processes. In contrast, the Mediterranean\u2019s sensitivity to hydrological changes, including reduced riverine input, high evaporation, and regional climate variability, results in a distinct response characterized by salinity-driven contraction. The inclusion of manometric contributions, which encompass oceanic mass redistribution, bottom pressure changes, and local vertical land movements, helps disentangle the competing drivers of SLA in this region and reinforces the central role of salinity changes in modulating sea-level trends.<\/p>\n<p>                  Ocean-atmosphere interactions and sea level variability in African LMEs<\/p>\n<p>Climate modes drive large-scale patterns of sea level variability across ocean basins, as noted by Han et al.<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 71\" title=\"Han, W. et al. Spatial patterns of sea level variability associated with natural internal climate modes. Surv. Geophys. 38, 217&#x2013;250 (2017).\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#ref-CR71\" id=\"ref-link-section-d190479614e1858\" rel=\"nofollow noopener\" target=\"_blank\">71<\/a>. In the context of Africa\u2019s seven LMEs, the influence of these modes varies between the open ocean and coastal regions, particularly along the EBUS of the Canary and Benguela Currents. SLAs along these eastern boundaries are predominantly influenced by remote and local wind forcing, which propagates through equatorial and coastal waveguides<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 14\" title=\"Ghomsi, F. E. K. et al. Exploring steric sea level variability in the Eastern Tropical Atlantic Ocean: a three-decade study (1993&#x2013;2022). Sci. Rep. 14, 20458 (2024).\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#ref-CR14\" id=\"ref-link-section-d190479614e1862\" rel=\"nofollow noopener\" target=\"_blank\">14<\/a>,<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 34\" title=\"Ghomsi, F. E. K. et al. Sea level variability in Gulf of Guinea from satellite altimetry. Sci. Rep. 14, 4759 (2024).\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#ref-CR34\" id=\"ref-link-section-d190479614e1865\" rel=\"nofollow noopener\" target=\"_blank\">34<\/a>. In contrast, SLAs in the interior of these LMEs are driven by open-ocean forcing that propagates westward from the eastern boundaries. Consequently, coastal sea level variability in African LMEs is expected to correlate strongly with climate modes that are prominent in the tropics and with atmospheric centers of action that modulate longshore winds and sea level pressure.<\/p>\n<p>The regression of SLA with respect to climate indices is shown in Fig.\u00a0<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#Fig10\" rel=\"nofollow noopener\" target=\"_blank\">10<\/a> (the corresponding correlation map is provided in Supplementary Fig.\u00a0<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"supplementary material anchor\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#MOESM2\" rel=\"nofollow noopener\" target=\"_blank\">3<\/a>). Starting with the Atlantic Ni\u00f1o (ATL3) in Fig.\u00a0<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#Fig10\" rel=\"nofollow noopener\" target=\"_blank\">10a<\/a>, a strong positive regression emerges along both Atlantic and equatorial domains, especially along the Gulf of Guinea and extending westward. This pattern reflects the role of ATL3 in modulating SLA through SST anomalies, which drive thermal expansion and mass redistribution in the ocean. The influence of ATL3 is most pronounced in the GCLME, BCLME, and SCCLME, but it diminishes both northward toward the Canary and southward toward the Benguela Current, indicating a more localized impact of ATL3 on SLA variability, largely confined to the tropics. Transitioning to the Tropical North Atlantic (TNA) index in Fig.\u00a0<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#Fig10\" rel=\"nofollow noopener\" target=\"_blank\">10b<\/a>, the regression map reveals pronounced positive anomalies along the northern tropical Atlantic, with significant effects extending into the Canary Current LME and the Mediterranean Sea. This underscores the importance of SST anomalies in the Tropical North Atlantic, which drive SLA variability through atmospheric teleconnections and oceanic processes such as wind-driven circulation and heat fluxes. However, the influence of TNA fades in the southern LMEs, including GCLME, BCLME, ACLMEs, and SCCLME, highlighting the regional specificity of this index and its primary relevance to the northern Atlantic margin with no impact on the REDLME. The Tropical Atlantic SST Gradient Index (TASI), shown in Fig.\u00a0<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#Fig10\" rel=\"nofollow noopener\" target=\"_blank\">10c<\/a>, captures the meridional SST gradient in the Atlantic and exhibits a dipolar pattern, with positive regression coefficients in the northern Atlantic while not significant as the TNA and negative coefficients in the southern Atlantic. This spatial structure emphasizes the role of TASI in modulating SLA through changes in the interhemispheric SST gradient, which in turn affects wind patterns and ocean circulation. The Canary and Benguela Current LMEs are particularly sensitive to TASI, as these regions are directly influenced by shifts in the Atlantic dipole mode, while the Mediterranean LME and other LMEs remain less affected. Moving eastward, Fig.\u00a0<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#Fig10\" rel=\"nofollow noopener\" target=\"_blank\">10d<\/a> presents the regression of SLA on the Indian Ocean Dipole (DMI). Here, strong positive coefficients dominate the western Indian Ocean, especially along the Somali Current LME and extending into the Agulhas Current LME. This dipolar pattern reflects the DMI\u2019s capacity to drive SLA variability through SST changes and associated atmospheric circulation, with the Somali Current LME being especially responsive to the western Indian Ocean\u2019s warming and mass redistribution. The Atlantic LMEs, by contrast, show minimal response to DMI, underscoring the basin-specific nature of this influence. The Western Tropical Indian Ocean (WTIO) index, depicted in Fig.\u00a0<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#Fig10\" rel=\"nofollow noopener\" target=\"_blank\">10e<\/a>, further reinforces the dominance of the western Indian Ocean, with a pronounced positive regression along the Somali and Agulhas Current LMEs. The influence of WTIO even extends into the Red Sea Current outlets through the Gulf of Aden, highlighting the significant role of SST anomalies in this region in driving SLA variability through thermal expansion and changes in ocean circulation. However, the impact of WTIO diminishes toward the northern LMEs, such as the Mediterranean and Canary Currents, again reflecting the regional specificity of this index. A similar spatial pattern is observed for the Southwest Indian Ocean (SWIO) index in Fig.\u00a0<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#Fig10\" rel=\"nofollow noopener\" target=\"_blank\">10f<\/a>, where sporadic positive regression coefficients are concentrated in the southwestern Indian Ocean. The Agulhas Current LME is particularly affected by SWIO, as this region is directly influenced by warming and mass redistribution in the southwestern Indian Ocean, mostly along the Madagascar coastal domain. In contrast, the Atlantic LMEs remain largely unaffected by SWIO, further emphasizing the spatial selectivity of Indian Ocean climate drivers. The influence of the central Pacific is captured by the Ni\u00f1o3.4 index in Fig.\u00a0<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#Fig10\" rel=\"nofollow noopener\" target=\"_blank\">10g<\/a>, which shows a widespread impact across both the Indian Ocean and less impact on the Atlantic Ocean. Positive regression coefficients are evident in the western Indian Ocean close to the DMI patterns. This pattern reflects the teleconnections between the Pacific and other ocean basins, where changes in atmospheric circulation and oceanic processes driven by Pacific SST variability propagate their effects. The Somali and Red Sea Current LMEs are particularly sensitive to Ni\u00f1o3.4, while the Mediterranean and Agulhas LMEs remain less affected, indicating the reach but also the limits of Pacific influence. The Pacific Decadal Oscillation (PDO) (Fig.\u00a0<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#Fig10\" rel=\"nofollow noopener\" target=\"_blank\">10h<\/a>) exhibits a notable large-scale influence on sea level variability, primarily across the Indian Ocean sector of the African LMEs. Positive regression coefficients are particularly evident in the Somali, Red Sea, and Agulhas Current LMEs, indicating that positive phases of the PDO typically associated with cooler SSTs in the western Pacific and warmer conditions in the eastern Pacific coincide with SLR in these regions. This response reflects enhanced Indian Ocean warming during positive PDO phases, which promotes upper-ocean thermal expansion and SLAs<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 71\" title=\"Han, W. et al. Spatial patterns of sea level variability associated with natural internal climate modes. Surv. Geophys. 38, 217&#x2013;250 (2017).\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#ref-CR71\" id=\"ref-link-section-d190479614e1903\" rel=\"nofollow noopener\" target=\"_blank\">71<\/a>,<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 72\" title=\"Zhang, X. &amp; Church, J. A. Sea level trends, interannual and decadal variability in the Pacific Ocean. Geophys. Res. Lett. 39, L21701 (2012).\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#ref-CR72\" id=\"ref-link-section-d190479614e1906\" rel=\"nofollow noopener\" target=\"_blank\">72<\/a>. The Agulhas Current LME\u2019s sensitivity may be linked to PDO-induced modulation of the Indian Ocean Walker circulation and subtropical gyre dynamics, influencing the transport and convergence of water masses along southeast Africa. In contrast, Atlantic LMEs, including the Guinea Current and Canary Current systems, show limited correlation with PDO, likely due to weaker atmospheric teleconnections between the Pacific and Atlantic basins in decadal timescales<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 73\" title=\"Meehl, G. A. et al. Atlantic and Pacific tropics connected by mutually interactive decadal-timescale processes. Nat. Geosci. 14, 36&#x2013;42 (2021).\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#ref-CR73\" id=\"ref-link-section-d190479614e1911\" rel=\"nofollow noopener\" target=\"_blank\">73<\/a>. The Southern Annular Mode (SAM) (Fig.\u00a0<a data-track=\"click\" data-track-label=\"link\" data-track-action=\"figure anchor\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#Fig10\" rel=\"nofollow noopener\" target=\"_blank\">10i<\/a>), which reflects the north\u2013south displacement of the westerly wind belt encircling Antarctica, shows no statistically significant impact on sea level trends across any African LMEs. This limited influence is consistent with previous findings that SAM-driven sea level variability is largely confined to southern extratropical latitudes, particularly the Southern Ocean and the high-latitude South Atlantic and Indian sectors<a data-track=\"click\" data-track-action=\"reference anchor\" data-track-label=\"link\" data-test=\"citation-ref\" aria-label=\"Reference 74\" title=\"Boening, C., Willis, J. K., Landerer, F. W., Nerem, R. S. &amp; Fasullo, J. The 2011 La Ni&#xF1;a: so strong, the oceans fell. Geophys. Res. Lett. 39, L19602 (2012).\" href=\"http:\/\/www.nature.com\/articles\/s43247-025-02965-z#ref-CR74\" id=\"ref-link-section-d190479614e1918\" rel=\"nofollow noopener\" target=\"_blank\">74<\/a>. As a result, the absence of significant regression patterns in African LMEs suggests that SAM\u2019s dynamical effects on wind stress, Ekman transport, and associated mass redistribution do not strongly project onto the sea level variability of equatorial or subtropical African coastal systems.<\/p>\n<p><b id=\"Fig10\" class=\"c-article-section__figure-caption\" data-test=\"figure-caption-text\">Fig. 10: Relationship between African sea level and major climate indices.<\/b><a class=\"c-article-section__figure-link\" data-test=\"img-link\" data-track=\"click\" data-track-label=\"image\" data-track-action=\"view figure\" href=\"https:\/\/www.nature.com\/articles\/s43247-025-02965-z\/figures\/10\" rel=\"nofollow noopener\" target=\"_blank\"><img decoding=\"async\" aria-describedby=\"Fig10\" src=\"https:\/\/www.europesays.com\/ie\/wp-content\/uploads\/2025\/12\/43247_2025_2965_Fig10_HTML.png\" alt=\"figure 10\" loading=\"lazy\" width=\"685\" height=\"686\"\/><\/a><\/p>\n<p>Linear regression coefficients (mm) of sea level over Africa and its LMEs with respect to <b>a<\/b> ATL3, <b>b<\/b> TNA, <b>c<\/b> TASI, <b>d<\/b> DMI, <b>e<\/b> WTIO, <b>f<\/b> SWIO, <b>g<\/b> NINO 3.4, <b>h<\/b> PDO, and <b>i<\/b> SAM. White areas (white dots) indicate regions where regression coefficients are not statistically significant at the 95% confidence level.<\/p>\n","protected":false},"excerpt":{"rendered":"Regional sea level rise and the exceptional 2023 event in AfricaLong-term acceleration in African sea level rise (1993\u20132023)&hellip;\n","protected":false},"author":2,"featured_media":239693,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[269],"tags":[126509,14697,18,440,6129,910,7753,19,17,6234,133,37277],"class_list":{"0":"post-239692","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-environment","8":"tag-developing-world","9":"tag-earth-sciences","10":"tag-eire","11":"tag-environment","12":"tag-environmental-impact","13":"tag-general","14":"tag-governance","15":"tag-ie","16":"tag-ireland","17":"tag-physical-oceanography","18":"tag-science","19":"tag-water-resources"},"share_on_mastodon":{"url":"https:\/\/pubeurope.com\/@ie\/115742069274754085","error":""},"_links":{"self":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/posts\/239692","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/comments?post=239692"}],"version-history":[{"count":0,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/posts\/239692\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/media\/239693"}],"wp:attachment":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/media?parent=239692"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/categories?post=239692"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/tags?post=239692"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}