How much have sea levels risen since 1850?

Since 1850, global sea levels have risen by approximately 20 to 25 centimeters (about 8 to 10 inches). This increase is primarily due to thermal expansion of seawater as it warms and the melting of glaciers and polar ice sheets. The rate of sea-level rise has accelerated in recent decades, with current estimates suggesting an increase of about 3.3 millimeters per year. This trend poses significant risks to coastal communities and ecosystems.