Sea levels are not rising at a steady, gradual pace, but can accelerate significantly within a short period of time. This is the conclusion of a recent study conducted by an international research team as part of the Sea Level Climate Change Initiative (SLCCI) of the European Space Agency (ESA). Researchers from the Technical University of Munich (TUM) played an important role in the methodological analyses.
The research consortium evaluated satellite data from the early 1990s to the present day. Researchers found that the oceans were rising by about 2.9 millimeters per year until 2011. After that, the rate abruptly increased to about 4.1 millimeters per year, a sharp acceleration occurring over just a year or two. Between 2010 and 2012, the rate of global sea level rise suddenly increased by around 40 percent. This was mainly due to changes in natural climate patterns, including the Pacific Decadal Oscillation (PDO) and the North Atlantic Oscillation (NAO). These processes caused additional water to flow from land into the world's oceans.
TUM scientists Dr. Julius Oelsmann and Dr. Marcello Passaro used the open-source software DiscoTimes, developed jointly at the Deutsches Geodätisches Forschungsinstitut (DGFI-TUM), for their research. In the ESA study, DiscoTimes was used in conjunction with the Bayesian Estimator of Abrupt Change, Seasonal and Trend (BEAST) software platform. These programs detect deviations from linear trends in time series and thus the point in time when sea level rise suddenly changed. Both independent methods provided consistent results in identifying the trend change between 2010 and 2012—a crucial factor for scientific robustness. “I find it particularly significant that we used different sources and independent methods to confirm the same trend change. Both our DiscoTimes software and the BEAST package show the same abrupt change. This greatly strengthens the significance of the result,” said Dr. Marcello Passaro, research associate at DGFI-TUM at the TUM School of Engineering and Design.
Break point in both thermosteric and mass-related components
The study identifies a clear “break point”: a point in time when sea level development suddenly diverges from the trends of previous decades. The abrupt change can be found in both the thermosteric component of sea level (expansion of water due to warming) and the mass component (water inflow due to melting glaciers and changes in land water reservoirs). This consistency across different data sources underscores how strongly our Earth system responds to natural climate variability—and how closely these processes are intertwined with human-induced climate change. "Our study impressively demonstrates the importance of international cooperation and open, reproducible analysis methods. Only by continuously observing the different components of sea level can we understand the rapid changes in the Earth system and distinguish the influence of natural variability from human-induced climate change," said Dr. Julius Oelsmann, TUM researcher and currently a Marie Skłodowska-Curie Fellow at Tulane University in New Orleans.
Long-term satellite records, combined with modern open analysis tools, can reveal abrupt changes in sea level. Sea level responds more strongly and dynamically to climate variations than long assumed—a finding that is crucial for assessing future risks in coastal regions.
Read the full paper (Nature Communications Earth & Environment):
Leclercq L., Oelsmann J., Cazenave A., Passaro M., Jevrejeva S. Connors S., Legeais J.-F., Birol F., Abarca-del-Rio R.: Abrupt trend change in global mean sea level and its components in the early 2010s. Communications Earth & Environment, 10.1038/s43247-025-03149-5, 2026 (Open Access)https://www.nature.com/articles/s43247-025-03149-5