Sea levels around the world’s coasts are higher than previously thought, potentially putting millions more people at risk from rising oceans, scientists have warned. A study conducted by researchers from Wageningen University and Research in the Netherlands has revealed a concerning “blind spot” in many studies that assess the impacts of rising seas and other coastal hazards.
The study, published in the prestigious journal Nature, points out that 90% of coastal hazard studies rely on land elevation measurements and geoid models to estimate sea levels. However, these models fail to take into account various factors that influence actual sea height, such as ocean currents, circulation patterns, winds, tides, water temperature, and saltiness. According to Dr. Philip Minderhoud, one of the study authors, it is crucial to use actual sea-level measurements rather than relying on assumptions that geoid height equals present mean sea level.
The research findings indicate that coastal sea-level height has been underestimated by an average of 30cm (1ft) globally, with some regions like south-east Asia and the Indo Pacific experiencing sea levels up to one meter (3ft) higher than previously believed. This discrepancy has significant implications for climate change adaptation strategies, particularly in dealing with the impacts of rising sea levels as a result of global warming and melting ice caps.
The latest UN science review projects a sea-level rise of 0.28m to 1.01m by the end of the century, compared to levels recorded between 1995 and 2014. Study co-author Katharina Seeger emphasized that ignoring actual sea level measurements leads to an underestimation of coastal area exposure and population vulnerability worldwide. The researchers also noted the challenges in combining land elevation and sea level data from different satellites, which have varying baselines.
Calculations from the study suggest that 37% more land could be inundated in the event of a 1m relative sea-level rise, affecting up to 132 million people compared to previous estimates of 50 million. This highlights the urgent need for improved accuracy in sea-level measurements and a reassessment of coastal vulnerability to mitigate the impacts of climate change on coastal communities.
In conclusion, the study underscores the importance of incorporating actual sea level data into coastal hazard assessments to accurately predict and prepare for the increasing risks posed by rising sea levels. By addressing this blind spot in current research practices, we can better protect coastal populations and ecosystems from the adverse effects of climate change.
