Title: Global Warming Effects on Sea Level
Headings: Sea Level
Sea Level
Higher seas endanger coastal communities—where 40 percent of the world's population lives—and threaten groundwater supplies.

Content: High tides and storm surges riding on ever-higher seas are more dangerous to people and coastal infrastructure. Natural protections against damaging storm surges are increasingly threatened. Barrier islands, beaches, sand dunes, salt marshes, mangrove stands, and mud and sand flats retreat inland as sea level rises, unless there are obstructions along the retreat path. If they cannot move, these natural protections are washed over or drowned. Many shorelines have sea walls, jetties, and other artificial defenses to protect roads, buildings, and other vital coastal resources. In these areas, sea-level rise increases erosion of stranded beaches, wetlands, and engineered structures
Saltwater intrusion. Sea-level rise can mean that saltwater intrudes into groundwater drinking supplies, contaminates irrigation supplies, or overruns agricultural fields. Low-lying, gently sloping coastal areas are particularly vulnerable to contamination of freshwater supplies. See references.