Understanding future sea-level rise

July 30, 2025

Projecting future sea-level rise is a complex task. It involves understanding how different global and regional factors interact—ranging from melting glaciers and thermal expansion to greenhouse gas emissions and ocean dynamics.

Scientists group these influencing factors into four main categories to help communicate the range of possibilities and uncertainties. Projections vary depending on how much greenhouse gas is emitted in future decades and how Earth’s systems respond.

Despite the uncertainties, sea-level projections are crucial for planning and adaptation. This explainer outlines what goes into creating sea-level projections and how they inform decision-making for coastal communities, infrastructure, and ecosystems.