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Fact check: What is the sea rising level for the last 10 years
Executive Summary
Global mean sea level has risen noticeably over recent decades and accelerated during the last ten years, with satellite records and major studies reporting an increased rate from about 2.1 mm/year in the 1990s to roughly 4.5 mm/year by 2023 and a 2024 increment of about 0.59 cm in one review; cumulatively this translates to roughly 10–11 cm of rise since 1993 and continued faster year‑to‑year increases in the early 2020s [1] [2] [3]. Different analyses emphasize improved coastal data, unexpected faster annual rises in 2024, and the implications for future coastal adaptation [4] [5] [6].
1. Why the last decade looks different and why scientists warn of acceleration
Satellite altimetry and coastal-specific datasets show that the rate of sea level rise has increased over the past decade, shifting from multi-decade averages near 2 mm/year toward values above 4 mm/year by 2023; this doubling is a central finding in recent syntheses and underlies projections of further rapid increases [1] [3]. Independent examinations highlight that 2024 exhibited a notably higher-than-expected annual rise—about 0.23 inches (≈5.8 mm) reported in NASA-led analyses—driven mainly by thermal expansion as oceans warm and interannual climate variability, making the most recent decade stand out compared with earlier satellite eras [6] [2].
2. How much did sea level actually rise over the last ten years — the numbers that matter
Reviewing the provided analyses yields consistent magnitudes: the long satellite record since 1993 shows a 111 mm increase through the early 2020s, with one review putting the 31‑year satellite total at 10.5 cm through 2024; extrapolating the accelerated rate implies the last ten years contributed a substantial fraction of that increase as year‑to‑year rises climbed [3] [2] [1]. Exact decadal totals vary by dataset and baseline years, but the robust conclusion is measurable, accelerating rise during the last decade rather than a steady linear trend.
3. Data improvements change the picture: better coastal observations matter
New datasets focused on coastal altimetry, like the IAS2024 evaluation, report improved data availability and precision relative to older retrackers—availability gains of 12.6%–53.2% and precision gains of 4.8%–10.1% depending on coastal strip—allowing clearer detection of local and short‑term changes and reducing uncertainty about recent annual spikes [4]. These methodological advances mean that some of the apparent acceleration reflects both real physical change and better detection capability, which strengthens confidence in recent higher annual values while also refining regional patterns for adaptation planning [4].
4. The 2024 anomaly: faster-than-expected annual rise and its drivers
Multiple sources flagged an unexpectedly fast rise in 2024, with one NASA analysis quantifying 0.23 inches (~5.8 mm) versus an expected 0.17 inches (~4.3 mm), and a Nature Reviews summary reporting a 0.59 cm global rise that year; thermal expansion of warming oceans and short‑term climate variability were highlighted as main contributors [6] [2] [5]. This single‑year spike illustrates how interannual factors can temporarily boost sea level; when such spikes occur on top of an accelerating baseline, decadal averages rise faster, increasing near‑term coastal risk and complicating short‑term projections [6] [2].
5. What the different studies agree on and where they diverge
All cited analyses agree on an accelerating trend and a substantial multi‑decadal rise since 1993, with consistent language about doubling of rates over roughly three decades and a 111 mm aggregate rise in the satellite era; divergence appears in emphasis—some focus on coastal dataset improvements and precision gains, others on single‑year anomalies like 2024 or on projections to 2050 of additional rises [1] [3] [4] [5]. The primary area of methodological difference lies in coastal versus open‑ocean retrievals and how newly available coastal altimetry modifies local assessments [4].
6. Projections and implications if recent rates continue
Studies warning that the current trajectory could add roughly 169 mm over the next three decades if the recent accelerated rate continues frame a high‑impact scenario for coastal systems and adaptation needs; this projection arises directly from extending the observed higher rates and underscores the importance of planning for substantially larger near‑term rises than earlier linear models suggested [1] [3]. The combination of improved measurement, a 2024 spike, and accelerating baseline implies that policymakers should prioritize updated risk assessments and local adaptation, since regional variations will modulate impacts despite a clear global upward trend [5] [4].
7. What remains uncertain and what to watch next
Key uncertainties include how much of recent acceleration reflects short‑term variability versus sustained trend, regional differences driven by ocean dynamics and land motion, and how continuing improvements in coastal retrievals will refine the record; resolving these depends on continued satellite monitoring, improved coastal datasets, and synthesis across methods [4] [6] [1]. Upcoming annual updates and multi‑sensor integrations will be crucial to distinguish persistent acceleration from episodic spikes and to translate global averages into actionable local sea‑level rise projections for communities.