Study Suggests Ocean Levels Underestimated Due to Inaccurate Modeling. The research was conducted by Dr. Philip Minderhoud of Wageningen University in the Netherlands and PhD researcher Katharina Seeger. Their analysis found that more than 90 percent of the studies examined did not rely on local, direct measurements of sea levels.
Global sea levels may be significantly higher than scientists previously believed, according to new research indicating that widely used modeling methods have underestimated ocean heights around the world.
The findings suggest that average global sea levels are about 30 centimeters higher than earlier estimates. In parts of the Global South — particularly Southeast Asia and the Indo-Pacific — levels could be 100 to 150 centimeters higherthan previously thought.
The research raises new questions about how coastal risks are calculated and could reshape projections about the long-term effects of global heating on coastal communities.
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New Analysis Combines Hundreds of Scientific Studies
The study, published in the journal Nature, analyzed 385 peer-reviewed scientific papers published between 2009 and 2025.
Researchers compared commonly assumed sea-level values with actual measured coastal sea levels, revealing a consistent gap between modeled estimates and real-world conditions.
The research was conducted by Dr. Philip Minderhoud of Wageningen University in the Netherlands and PhD researcher Katharina Seeger.
Their analysis found that more than 90 percent of the studies examined did not rely on local, direct measurements of sea levels. Instead, most relied on land elevation measurements referenced to global geoid models.
Why Sea Levels May Have Been Miscalculated
Geoid models are mathematical representations used to estimate global sea levels based on the Earth’s gravity and rotation.
While widely used in climate and coastal studies, the models do not fully capture the complexity of local ocean conditions.
Because of this reliance, the research found that sea levels were undervalued by an average of 24 to 27 centimeters, depending on which geoid model was applied.
In some locations, the discrepancies were far larger — ranging from 550 to 760 centimeters.
“In reality, sea level is influenced by additional factors such as winds, ocean currents, seawater temperature and salinity,” Minderhoud said.
Southeast Asia and Indo-Pacific Face Larger Differences
The study suggests the largest differences between estimated and actual sea levels may occur in Southeast Asia and the Indo-Pacific, regions already considered among the most vulnerable to rising oceans.
In these areas, sea levels could be 100 to 150 centimeters higher than earlier estimates suggested.
Such findings could have major implications for coastal risk planning, especially in regions with large populations living near shorelines.
Implications for Future Climate Projections
Sea-level rise remains one of the most widely studied impacts of climate change.
The United Nations Intergovernmental Panel on Climate Change (IPCC) estimates that global sea levels could rise between 28 and 100 centimeters by 2100.
If baseline sea levels are already higher than previously assumed, projections about flooding risks, coastal infrastructure and long-term adaptation strategies may need to be reassessed.
The research does not change the fundamental trend of rising oceans driven by global heating. But it highlights how measurement methods and modeling assumptions can influence how risks are understood.
The study underscores the importance of local measurement systems for accurately assessing sea levels.
Direct coastal measurements can capture regional influences — such as ocean currents and temperature differences — that global models may overlook.
For policymakers and coastal planners, the findings suggest that refining measurement methods could play a crucial role in understanding future sea-level risks.
As global temperatures continue to influence the world’s oceans, improving how sea levels are measured may be just as important as predicting how fast they will rise.
