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Coasts & Wetlands

Coasts will likely experience a loss of coral reefs and, in some places, a loss of wetlands. Coastal infrastructure is expected to be increasingly impacted due to accelerated sea level rise.


Loss of Wetlands

A 1.6 ft (0.5 m) rise in worldwide sea level could destroy approximately 100,000 sq mi (250,000 sq km) of wetlands through coastal erosion. Wetlands are crucial habitats that have also been negatively affected by human development.

Adaptation
Create physical barriers to prevent ocean water from entering estuaries and wetlands. Allow wetlands to migrate inland and reduce diversions from coastal rivers.

Locations
Global along coasts

 

Saltwater Intrusion of Freshwater Aquifers

Rising sea levels can cause salt water to intrude into freshwater aquifers, contaminating groundwater with salt. This reduces freshwater supplies in coastal areas.

Adaptation
Restore or create coastal wetlands, barrier islands, and other natural or artificial barriers.

Locations
Coastal areas

 

Loss of Nursery Habitats

Rising sea level could harm coastal wetlands and estuaries, coral reefs, and salt-marshes, which are important nursery habitats for larval and juvenile life-stages. These environments are already threatened by human actions.

Adaptation
Protect vital habitats with appropriate measures.

Locations
Global

 

Loss of Coastal Infrastructure

Rising sea levels could destroy homes, roads, and other infrastructure in coastal areas through flooding and coastal erosion.

Adaptation
Eliminate public subsidies for future development in high hazard areas along the coast. Build sea walls to protect existing infrastructure. Design future public works projects to take into account rising sea levels.

Locations
Global

 

Increased Dead Zones

As ocean water warms, ocean oxygen levels are likely to decline, exacerbating low-oxygen zones in coastal areas and deeper waters. These dead zones degrade habitat and can lead to extensive fish and invertebrate mortality.

Adaptation
Implement early warning and notification systems for events of coastal oxygen deprivation.

Locations
Brazil, India, Gulf Coast, Western Europe, China

 

Increased Coastal Flooding

A rise in sea level of 1.6 ft (0.5 m) would increase the number of people annually at risk from coastal flooding by 5–200 million. As many as 4 million people could be permanently displaced.

Adaptation
Relocate people living along vulnerable coasts.

Locations
New York, Miami, Nile Delta, Ganges Delta, Mekong Delta

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