Sea-Level Rise Projections Under Various Warming Scenarios

Global mean sea level will continue rising throughout the 21st century, but the magnitude and pace depend strongly on the warming trajectory the world follows. Using multi‑model ensembles from recent climate assessments, this study evaluates sea‑level outcomes under low‑emissions stabilization, intermediate mitigation, and high‑warming scenarios. Results show that thermal expansion and glacier melt dominate near‑term increases, while ice‑sheet dynamics drive long‑term uncertainty. Under a 1.5 °C pathway, projected rise by 2100 ranges from 0.28–0.55 m; under 2 °C, 0.32–0.65 m; and under >3 °C, 0.45–1.0 m, with extreme ice‑sheet responses potentially exceeding 1.5 m. Regional impacts vary due to ocean circulation, gravitational effects, and land subsidence, producing hotspots of amplified risk across low‑lying deltas, small island states, and coastal megacities. The findings underscore the importance of rapid emissions reductions and adaptive coastal planning to limit irreversible long‑term impacts.