Sea-level Rise Has Quadrupled the Frequency of Coastal Flooding Extremes Since 1900

Nature Climate Change, 10 June 2026

Human-driven sea-level rise is transforming once-rare “extreme sea-level events” into more frequent coastal hazards, increasing the risk of flooding, infrastructure damage, and coastal erosion worldwide. This study combined more than a century of global tide measurements with climate models to determine how much human-driven sea-level rise has increased the frequency of these events. They found that sea-level rise is now the primary driver of extreme sea-level events at most locations. Globally, historical 1-in-100-year coastal sea-level events are now occurring about 12 times more often than they did in 1900, with human-driven climate change alone increasing their likelihood fourfold. Under high emissions, 1-in-100 year extreme sea-level events, once only expected to happen once a century, are projected to occur annually by 2100. Directly linking more frequent coastal flooding to human-caused climate change provides evidence that helps strengthen coastal adaptation planning, risk management, climate litigation, and loss and damage claims.

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