Julius Oelsmann

We have developed a probabilistic reconstruction of vertical land motion (VLM) from 1995 to 2020, which reveals the effects of spatially and temporally varying vertical land motion on relative sea level on a global scale (nature.com/articles/s4156…).

Scientists created the first #globalatlas showing how tides affect #coastalrivers. These regions are especially prone to flooding, which is increasing with #climatechange. The free world map presents the impacts at a glance: go.tum.de/851202 📷T. Pavelsky

@rahmstorf Passt auch gut zu dem trend change im globalen mittleren Meerespiegel, Leclercq et al. 2026; doi.org/10.1038/s43247…

Unsere neue Studie: die Erderwärmung hat sich ab 2015 erheblich beschleunigt. Die rote Kurve zeigt 10-Jahres-Trends, um je 1 Jahr versetzt; der letzte ist 2015-2024. Die blaue Kurve zeigt den Trend vor und nach dem objektiv bestimmten change point. 👉 agupubs.onlinelibrary.wiley.com/doi/10.1029/20…

*** New Publication Alert *** 🌍 Coastal cities aren’t just facing sea-level rise — many are sinking. Our new global, interdisciplinary review brings together #EarthScience, #engineering, #social science, and #policy to show how vertical land motion is silently amplifying #flood risk, #infrastructure failure, and #inequality worldwide. This is a call to rethink coastal resilience — with data, justice, and decision-ready science at the core. 📖 Annual Review of Earth & Planetary Sciences annualreviews.org/content/journa… #SinkingCities #ClimateRisk #CoastalResilience #InSAR #SeaLevelRise #Infrastructure #EnvironmentalJustice @VT_Science @UNUINWEH Why this work matters 👇 • Human-driven subsidence often exceeds climate-driven sea-level rise — in some cities by an order of magnitude • Groundwater extraction, urban loading, and resource use are major — and actionable — drivers • Flood risk, infrastructure damage, and displacement are being systematically underestimated What’s new and different • Global synthesis of 204 coastal cities using satellite geodesy (InSAR + GNSS) • Connects physics → infrastructure → people → policy in one framework • Moves beyond maps to decision-ready intelligence for planners and governments Equity & justice lens • Subsidence disproportionately impacts low-income and marginalized communities • Creates spatial and intergenerational injustice — from housing loss to cultural heritage erosion • Current adaptation plans often miss these hidden vulnerabilities Where we need to go next • Integrate VLM into flood models, zoning, insurance, and infrastructure design • Expand open, global monitoring, especially in the Global South • Deploy digital twins & decision theaters to test adaptation pathways before failure happens

*** NEW PAPER ALERT *** Led by our rockstar, Leonard (Assistant Prof. @UCIrvine), in collaboration with an international team, just published in @Nature. The first #global assessment of #Land Subsidence in #Deltas, #drivers, and #socioeconomic impacts. Congratulations to Leonard and team for this groundbreaking work! @vtgeosciences @UNUINWEH @EOI_lab @HIRSlab Pub Link: nature.com/articles/s4158… 🌍 Major Takeaways: Global Subsidence of River Deltas • River deltas are sinking worldwide. Over half of global delta land areais already subsiding—many at rates faster than sea-level rise. • Subsidence is often the dominant driver of flooding risk. In 18 of 40 major deltas, land is sinking faster than oceans are rising. • This is happening now—not in the distant future. Some deltas are sinking 2–10× faster than projected climate-driven sea-level rise this century. • Groundwater pumping is the biggest culprit. Among all human activities, groundwater extraction is the strongest driverof delta subsidence globally. • Urban growth and sediment starvation make it worse. Dams, levees, and rapid urbanization reduce sediment supply and increase land loading—accelerating sinking. • Hundreds of millions are already affected. About 236 million peoplelive in deltas where subsidence outpaces sea-level rise. • The most vulnerable people live the lowest. Of the 76 million people living below 1 m elevation, 84% are in rapidly sinking areas. • Subsidence is highly uneven—even within the same delta. Cities and infrastructure can sink much faster than surrounding rural areas, creating localized disaster hotspots. • Climate adaptation plans are missing a key variable. Most global risk assessments focus on sea-level rise—but ignore vertical land motion, underestimating real risk. • The good news: subsidence is actionable. Unlike sea-level rise, human-driven subsidence can be slowedthrough groundwater regulation, managed aquifer recharge, and sediment management. • Failing to act now locks in irreversible risk. Ignoring subsidence undermines flood defenses, adaptation investments, and long-term delta habitability.

*** Media Coverage *** I have the opportunity to contribute to this @BBCWorld article on #coastal #sinking cities, along with several other experts. Very informative with eye-opening illustrations! @EOI_lab @HIRSlab @VT_Science @UNUINWEH link: bbc.com/news/resources…

In Savannah, Georgia, small businesses and city streets are washed in floods even on bright, sunny days. That’s because sea levels in the U.S. South have risen twice as fast as the global average over the last 14 years. wapo.st/402rxGd

Therefore, future community-based approaches are needed to improve the observational database, to enhance process understanding, and to facilitate robust projections of relative sea-level change at regional to local scales (e.g., @IPLSubsidence).

These results are based on the assumption that the present-day variability is representative for future changes. However, our results reinforce that it is not clear that VLM will continue to be linear and that the observed variability is a robust predictor of future behaviour.

We use a Bayesian principal component analysis to estimate linear trends, common modes of variability and station-dependent noise, based on data from 11,000 GNSS stations, tide gauges and satellite altimetry.

We have developed a probabilistic reconstruction of vertical land motion (VLM) from 1995 to 2020, which reveals the effects of spatially and temporally varying vertical land motion on relative sea level on a global scale (nature.com/articles/s4156…).

Have you considered submitting your work to the sea-level session at EGU24? CL4.9 - Understanding sea level changes: global to local, from past to future meetingorganizer.copernicus.org/EGU24/session/… with @AimeeSlangen, @CaroMLCamargo, Svetlana Jevrejeva and @mpclimate

Will the #AMOC collapse by 2025? Here’s what we know from direct observations (since 2004). Image from Srokosz & Bryden (2015) shorturl.at/ryB34 A 🧵

DiscoTimeS: Novel Bayesian approach detects discontinuities & trend changes in geophysical time series. A study applying DiscoTimeS to #GNSS and #altimetry data is published in J. #Geodesy (doi.org/10.1007/s00190…). DiscoTimeS is available on GitHub (github.com/oelsmann/disco…).

Here's the link to our session: meetingorganizer.copernicus.org/EGU21/session/…

What are the rates of contemporary absolute sea level change in the Baltic Sea? Join us tomorrow at 15h30 at #vEGU21 CL2.12 to discuss our investigations on the impact of atmospheric forcing on regional sea level variability using data from @Baltic_SEAL, lead by @m_passaro.

Super proud of this publication with @backeb. The result of several years of hard work.

Check out our use case!

Doing research opens doors to many new opportunities and discoveries. Check out the doors the #BalticRegionalInitiative #EO4society Baltic SEAL team opened, in our (just released) scientific roadmap. Available at balticseal.eu/outputs/