63-Year Ocean Dataset Closes the Sea Level Budget Gap, Confirming Oceans Rose Nearly 10 Centimeters Since 1960 at a Doubling Pace
A Science Advances study reconciles six decades of sea level data, resolving a long-standing measurement discrepancy and pinpointing ocean warming and ice melt as drivers of an accelerating rise.
Overview
A new study published in Science Advances has resolved a decades-long gap between observed sea level measurements and what scientists could account for from known physical causes. Drawing on 63 years of ocean observations from 1960 to 2023, the research finds that global mean sea level has risen at 2.06 millimeters per year over the full period — and that the pace has nearly doubled, reaching 3.94 millimeters per year between 2005 and 2023. The total cumulative rise since 1960 amounts to nearly 10 centimeters.
What We Know
The paper, titled “Improved closure of the global mean sea level budget from observational advances since 1960,” was led by Huayi Zheng at the Institute of Atmospheric Physics, Chinese Academy of Sciences, with co-authors at Tulane University, the NSF National Center for Atmospheric Research, the University of St. Thomas, and scientific collaborators in France. The full author list includes Lijing Cheng, Sönke Dangendorf, Benoit Meyssignac, Anne Barnoud, Kevin E. Trenberth, John T. Fasullo, and John Abraham, according to SciTechDaily.
The study breaks down the contributions to cumulative sea level rise since 1960 as follows, per ScienceDaily:
- Thermal expansion of seawater: 43%
- Mountain glaciers: 27%
- Greenland Ice Sheet: 15%
- Antarctic Ice Sheet: 12%
- Changes in land water storage: 3%
The acceleration itself is driven by a different mix of factors. According to Eos, ocean warming accounts for 41% of the rate increase, while reduced land water storage explains 21% — reflecting a shift toward more rapid ice-sheet loss in recent decades.
In absolute terms, as reported by Above the Norm News, the Greenland Ice Sheet’s contribution grew from 0.29 mm/year to 0.70 mm/year between the full study period and the 2005–2023 window. Antarctica’s contribution grew from 0.23 mm/year to 0.51 mm/year over the same interval, and mountain glaciers from 0.51 mm/year to 0.73 mm/year. The rate during the satellite era from 1993 to 2023 was 3.41 mm/year, intermediate between the long-period average and the most recent acceleration.
Closing the Budget Gap
The study’s central contribution is resolving what oceanographers call the “sea level budget gap” — a persistent discrepancy between the total observed rise and the sum of known individual contributors. The IPCC’s 2021 Sixth Assessment Report put the unexplained residual at 0.33 mm/year; the new analysis narrows it to 0.17 mm/year, according to Above the Norm News.
The improvements came from three methodological advances described by SciTechDaily: correcting satellite observation data that had drifted after 2015; developing better techniques to measure land movement near coastal tide gauges; and refining ice loss estimates from Greenland and Antarctica.
Professor John Abraham of the School of Engineering at the University of St. Thomas, one of the co-authors, described the significance in a statement published by SciTechDaily: “For years, there has been a frustrating gap between how much the oceans were observed to be rising and how much we could explain from the individual causes. This work shows that, with better instruments, processes, and smarter analysis, this knowledge gap can be closed. We can explain sea level rise with greater confidence.”
What We Don’t Know
The study does not resolve how fast sea levels will rise in coming decades. While the improved budget closure confirms the physical processes at work, the magnitude of future ice sheet loss — particularly from the West Antarctic Ice Sheet — remains uncertain. Scientists note that sea levels will continue rising for centuries due to ocean thermal inertia and the slow response times of large ice sheets, even under reduced emissions scenarios, according to SciTechDaily.
The residual gap of 0.17 mm/year has not been fully explained. The authors acknowledge it as a remaining margin of uncertainty rather than evidence of a missing source.
Analysis
The stakes are substantial. As reported by Above the Norm News, approximately 1 billion people live within 10 meters of current sea level, concentrated in Bangladesh, Vietnam, China, Egypt, the Netherlands, and coastal areas of the United States.
Eos noted that the study’s improved accounting means policymakers and local communities can now create more informed mitigation strategies that account for future rise. With the acceleration parameter quantified at 0.71 millimeters per year per decade, the research provides a concrete basis for updating coastal infrastructure planning assumptions across the world’s most vulnerable shorelines.