{"id":37380,"date":"2025-08-23T21:39:05","date_gmt":"2025-08-23T19:39:05","guid":{"rendered":"https:\/\/www.co2news.sk\/?p=37380"},"modified":"2025-08-23T21:40:18","modified_gmt":"2025-08-23T19:40:18","slug":"a-decade-of-proven-accuracy-in-relation-to-sea-level-change","status":"publish","type":"post","link":"https:\/\/www.co2news.sk\/en\/2025\/08\/23\/a-decade-of-proven-accuracy-in-relation-to-sea-level-change\/","title":{"rendered":"Decades of proven accuracy in sea level change"},"content":{"rendered":"<p>Climate projections that predicted future climate trends are now being put to the ultimate test: comparison with observed data. Three decades of satellite measurements of global sea level change are now available <!--more-->since 1993, provide an exceptional opportunity to assess the validity of these early predictions. These assessments are <strong>essential for demonstrating the impact of human activity on the Earth&#039;s climate<\/strong> and to strengthen confidence in model-based future climate projections.<\/p>\n<p><strong>Remarkable accuracy of overall projections<\/strong><\/p>\n<p><a href=\"https:\/\/agupubs.onlinelibrary.wiley.com\/doi\/10.1029\/2025EF006533\" target=\"_blank\" rel=\"noopener\"><span style=\"color: #0000ff;\">Study<\/span><\/a> focused on the IPCC Second Assessment Report (IPCC-SAR) from 1995\/1996, specifically on <strong>IS92a scenario<\/strong>This scenario was chosen because its projections of atmospheric CO2 concentrations match observed values extremely well (427 ppmv vs. 423 ppmv in 2024). The findings show that <strong>The IPCC-SAR median projection for sea level rise was remarkably close to the actual development over the next 30 years.<\/strong>, with the extent of the rise being underestimated by only about 1 cm by 2023. The observed acceleration of sea level rise, which doubled between 1993 and 2023, closely follows the median projection of the IS92a scenario. This <strong>confirms the robustness of early IPCC projections from the mid-1990s<\/strong>.<\/p>\n<p><strong>Variability in projections of individual components<\/strong><\/p>\n<p>Although the overall projection was accurate, analysis of the contributions of individual components to sea level rise showed variability.<\/p>\n<ul>\n<li><strong>Thermal expansion of seawater<\/strong> (steric component) and <strong>loss of mass of glaciers and ice caps<\/strong> were predicted fairly well, although the steric rise in sea level was slightly overestimated.<\/li>\n<li><strong>The contributions of the ice sheets (Greenland and Antarctica) have been significantly underestimated or even neglected<\/strong> in early reports; Antarctica was even projected to see a slight increase in mass.<\/li>\n<li><strong>Land water storage<\/strong> (e.g., groundwater transfer to the ocean) was considered too uncertain and small to model explicitly at the time, but it turned out to be a more significant factor than anticipated.<\/li>\n<\/ul>\n<p><strong>Key differences and their implications<\/strong><\/p>\n<p>The main reason for the underestimation was that early IPCC reports treated ice sheets only using mass balance models. For example, the IPCC-SAR report stated that \u201cthe dynamic response can be ignored on timescales of decades to centuries.\u201d This weakness led to <strong>dynamic mass loss from ice sheets was not sufficiently taken into account<\/strong>. Mass losses from Greenland and Antarctica accounted for approximately 25 % of global sea level rise from 1992\u20132018\/2017. Interestingly, <strong>reassessment of thermal expansion partially compensated for low projections of ice sheet contributions<\/strong>, which led to a relatively accurate overall result that could be considered partially fortunate.<\/p>\n<p><strong>Modeling development and confidence in the future<\/strong><\/p>\n<p>Deficiencies in ice sheet modelling have been evident in later IPCC reports. For example, IPCC-AR4 largely excluded this component, leading to the lowest sea level projections. Subsequently, IPCC-AR5 explicitly included dynamic ice sheet change, increasing the projections. The most recent assessments even acknowledge the \u201cdeep uncertainty\u201d associated with ice sheet break-up processes and the possibility of \u201clow probability but high impact scenarios\u201d where sea levels rise much faster. Despite these limitations, particularly with regard to ice sheets and terrestrial water supplies, <strong>The early success of the IPCC-SAR projections builds considerable confidence in future climate projections.<\/strong>This historical test confirms the importance of continued and rigorous monitoring of all relevant components of the climate system. <em><strong>JRi<\/strong><\/em><\/p>\n<hr \/>\n<p><span dir=\"auto\">The study is published in the journal\u00a0<\/span><em><span style=\"color: #0000ff;\"><a style=\"color: #0000ff;\" href=\"https:\/\/agupubs.onlinelibrary.wiley.com\/doi\/10.1029\/2025EF006533\" target=\"_blank\" rel=\"noreferrer noopener\"><span dir=\"auto\">Earth&#039;s Future<\/span><\/a><\/span><span dir=\"auto\">\u00a0.<\/span><\/em><\/p>","protected":false},"excerpt":{"rendered":"<p>Climate projections that predicted future climate trends are now being put to the ultimate test: comparison with observed data. Three decades of satellite measurements of global sea level change are now available<\/p>","protected":false},"author":7,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[4],"tags":[],"class_list":["post-37380","post","type-post","status-publish","format-standard","hentry","category-klimaticka-zmena"],"acf":[],"_links":{"self":[{"href":"https:\/\/www.co2news.sk\/en\/wp-json\/wp\/v2\/posts\/37380","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.co2news.sk\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.co2news.sk\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.co2news.sk\/en\/wp-json\/wp\/v2\/users\/7"}],"replies":[{"embeddable":true,"href":"https:\/\/www.co2news.sk\/en\/wp-json\/wp\/v2\/comments?post=37380"}],"version-history":[{"count":0,"href":"https:\/\/www.co2news.sk\/en\/wp-json\/wp\/v2\/posts\/37380\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.co2news.sk\/en\/wp-json\/wp\/v2\/media?parent=37380"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.co2news.sk\/en\/wp-json\/wp\/v2\/categories?post=37380"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.co2news.sk\/en\/wp-json\/wp\/v2\/tags?post=37380"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}