New Study Reveals Sea Level Rise Slower Than Expected
A recent study challenges prevailing views on global sea level rise, asserting that the increase is significantly lower than many scientists have predicted. Researchers Hessel Voortman, a Dutch engineering consultant, and independent researcher Rob de Vos analyzed historical data and concluded that the average sea level rise in 2020 was approximately 1.5 mm per year, or 6 inches per century. This figure contrasts sharply with the 3 to 4 mm per year often cited in scientific literature and media reports.
Voortman expressed surprise that such an analysis had not been conducted before. “It is crazy that it had not been done,” he stated in an interview with independent journalist Michael Shellenberger. He began this research in 2021 by reviewing existing literature, and noted, “Who has done the comparison of the projections with the observations? There were none.”
Findings and Methodology
This groundbreaking study stands out not only for its findings but also for its lack of external funding. Voortman, who has spent three decades working on flood protection and coastal infrastructure projects, was motivated by his previous observations. In 2023, he published a paper indicating that sea level rise along the low-lying Dutch coast had not accelerated as projected.
To substantiate his claims, Voortman analyzed data from 200 tide-gauge stations with at least 60 years of records. He discovered that for the majority of these stations, the differences between projected and observed sea levels were not statistically significant. “This indicated no detectable acceleration in sea level rises,” he explained.
Most existing scientific studies, particularly those utilizing satellite imagery, have reported a marked acceleration in sea level rise over the past three decades. According to Voortman, the sea levels were at a “trough” in 1993 and at a “peak” in 2020. He argues that once these fluctuations are considered, there is no substantial rise in global sea levels.
Local Factors and Implications
Voortman also examined stations that reported notable increases in sea level. He found that most were situated near other stations showing negligible changes, suggesting that phenomena such as CO2-driven global warming are unlikely culprits. Instead, he attributed these local increases to factors such as earthquakes, extensive construction, or post-glacial adjustments.
The study criticized models from the Intergovernmental Panel on Climate Change (IPCC), claiming they “significantly overestimate local sea level rise in 2020.” Voortman emphasized the importance of both measurements and projections in coastal infrastructure design, stating, “Understanding the differences between them is crucial for practical applications.”
Despite his findings, Voortman maintains that he does not deny the existence of climate change or the value of climate models. He stated, “It is important to stress that there are good reasons to have models. If we as engineers design something in the coastal zone, then we try to achieve a technical lifetime of 50 to 100 years, and that means we need to look into the future.”
This study invites a reevaluation of how sea level rise is projected and the implications for infrastructure planning in vulnerable coastal areas. It raises important questions about how communities prepare for future changes in sea levels and the role of climate science in shaping public policy.
