Researchers from Dutch firm Data for Sustainability say their data shows that the land areas that would be inundated after the first one to two metres of sea level rise have been underestimated in the past.

The study used high-resolution measurements of land elevation from Nasa’s ICESat-2 lidar satellite, launched in 2018, to improve upon models of sea level rise and inundation. Previous assessments typically relied on radar-based data, which are less precise.

“Radar is unable to fully penetrate vegetation and therefore overestimates surface elevation,” said researcher Ronald Vernimmen. This had the impact of making many coastal areas appear to be higher than they actually were.

The underestimates of land elevation mean coastal communities have less time to prepare for sea level rise than expected, with the biggest impacts of rising seas occurring earlier than previously thought. After those first few metres of sea level rise, the rate at which land area...