Underestimated Sea Levels Pose Greater Threat to Coastal Communities

Recent research published in *Nature* indicates that global sea levels have been significantly underestimated due to flawed modelling practices. The study, conducted by Dr. Philip Minderhoud from Wageningen University and PhD researcher Katharina Seeger, reveals that ocean levels are, on average, 30 centimeters higher than previously believed. In certain regions of the global south, particularly in Southeast Asia and the Indo-Pacific, sea levels may be as much as 100 to 150 centimeters higher than earlier estimates.

The Guardian

The research analyzed 385 peer-reviewed scientific studies released between 2009 and 2025. The authors found that over 90% of these studies relied on land elevation measurements instead of local, direct sea level measurements. These land elevation figures were referenced against global geoid models, which estimate sea levels based on the Earth's gravity and rotation. The reliance on these models has led to an average undervaluation of sea levels by 24 to 27 centimeters, with some discrepancies reaching as high as 550 to 760 centimeters.

The Guardian

The implications of these findings are profound. According to the UN Intergovernmental Panel on Climate Change (IPCC), sea levels are projected to rise between 28 to 100 centimeters by 2100. However, the new research suggests that a relative sea level rise of one meter could result in 37% more coastal areas falling below sea level, potentially affecting up to 132 million people. Dr. Minderhoud emphasized that if sea levels are higher than previously assumed, the impacts of rising waters will occur sooner than anticipated.

The Guardian

The authors of the study have described the discrepancies in sea level measurements as an “interdisciplinary blind spot.” They express concern that many of the studies they analyzed, which they consider inaccurate, are cited in recent IPCC climate change reports. The researchers advocate for a reevaluation of existing coastal hazard study methodologies to ensure that climate change policies are based on accurate data.

The Guardian

While the findings present a compelling case for reevaluating sea level assessments, some experts caution against over-reliance on new data without considering the broader context of climate modelling. Critics argue that while local measurements are essential, they must be integrated with global models to provide a comprehensive understanding of sea level rise.

The Guardian

• “In reality, sea level is influenced by additional factors such as winds, ocean currents, seawater temperature and salinity.” — Dr. Philip Minderhoud, Wageningen University

The Guardian

• “If sea level is higher for your particular island or coastal city than was previously assumed, the impacts from sea level rise will happen sooner than projected before,” — Dr. Philip Minderhoud, Wageningen University

The Guardian

This new research underscores the urgency of addressing the inaccuracies in sea level modelling to better prepare coastal communities for the impending challenges posed by climate change.

The Guardian