Warming Near 1.5°C Commits Coastal Louisiana to Substantial Sea-Level Rise

Nature Sustainability, 4 May 2026

Sediment records from the Last Inter-Glacial (LIG) period suggest that when global temperatures were approximately 0.5-1.5°C warmer than pre-industrial levels in Earth’s past, coastal Louisiana experienced 7.5 meters of sea-level rise. These findings raise a clear warning signal for low-lying regions today. Coastal Louisiana is a ‘canary in the coal mine’ with respect to climate impacts, with IPCC AR6 identifying it as the single most exposed low-elevation coastal zone to relative sea-level rise this century. Low-elevation coastal zones are regions subject to 1-in-a-100-year coastal floods and are among the most physically vulnerable environments to climate change. Since today’s warming is occurring much more rapidly than during Earth’s past, the authors warn that ice sheet instability and sea-level rise could occur much faster than occurred during that past period. The study estimates 110 million people currently live below the high-tide line, and this number will increase sixfold by 2100 under high emissions and bring greater flooding, infrastructure damage, and displacement.

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