Rethinking sea-level baseline widens coastal risk estimates

A Nature study finds that hundreds of sea-level assessments underestimate baseline coastal water heights by about 1 foot, which could mean up to 37% more land could flood and 77–132 million more people could be at risk if sea levels rise ~3 feet by the end of the century, with the Pacific and Southeast Asia most affected; the discrepancy stems from how land and water elevations are measured and may require planners to account for waves and tides rather than assuming a zero baseline.