What are two physical consequences of a global rise in sea level on coastlines?

• A. Shoreline erosion and coastal flooding
• B. Longer coastlines and more beaches
• C. More tidal flats
• D. Decreased coastal erosion

Answer: (A)

Global sea level rise raises the baseline water level at the shore, allowing waves and tides to reach further inland and to push on the coast more often. This increased energy at the shoreline drives erosion of beaches, dunes, and cliffs, causing the shoreline to retreat and thinning protective features. At the same time, higher water levels mean that during high tides and storms, water can inundate areas that were dry, raising flood risk and leading more land to be submerged for longer periods.

Areas that might gain beaches or have longer coasts are not guaranteed outcomes of sea level rise, and the idea of decreased erosion runs opposite to how higher water levels interact with shoreline materials.