Key points adapted from the Fourth National Climate Assessment, Chapter 8
America’s coastal properties and infrastructure—and the economies they support—face increasing hazards from ongoing sea level rise.
Over time, chronic high tide flooding will result in substantial costs to property owners; if emissions continue increasing, this flooding could transform whole communities.
Preparing to respond to more frequent, widespread, and severe coastal flooding can decrease direct losses and cascading economic impacts.
Healthy coastal ecosystems support fisheries, tourism, human health, and public safety. Many of these ecosystems are being transformed, degraded, or lost due in part to climate change, particularly sea level rise and higher numbers of extreme weather events.
Restoring and conserving coastal ecosystems and adopting natural and nature-based infrastructure solutions can enhance community and ecosystem resilience to climate change.
As the pace and extent of coastal flooding and erosion accelerate, the impacts of climate change exacerbate existing social inequities. Many communities face difficult questions about determining who will pay for current impacts and future adaptation and mitigation strategies. Some communities must decide if, how, or when to relocate.
Rising seas, increasing impacts
U.S. coasts are dynamic environments and highly desirable places to live and work. Coasts support jobs in defense, fishing, transportation, and tourism and seaports serve as hubs of commerce that connect the country with its global trading partners. Coasts are also home to diverse ecosystems including beaches, estuaries, and deltas that provide opportunities for recreation, support fisheries, and protect land from coastal storms.
People and assets in the productive coastal region are routinely exposed to weather and climate-related hazards. Coastal floods occur at many locations each year, caused by events such as high tides, storm surges, strong waves, and heavy precipitation. Impacts from these events can range from mere inconvenience all the way to damaged property, bodily injury, or death. As global sea level rises, higher water levels exacerbate the impacts of these incidents, resulting in deeper floods that last longer and extend further inland. Additionally, as climate changes, some coastal hazards are projected to increase. For instance, coasts may see more severe or more frequent storms and heavier rainfall events.
Although storms, floods, and erosion have always been hazards, they now occur on top of higher sea levels. Combined with coastal development, these hazards now threaten approximately $1 trillion in real estate along U.S. coasts.
Recent Research: Sea Level Rise is Accelerating
The 2022 Sea Level Rise Technical Report provides the most up-to-date sea level rise projections available for U.S. states and territories. Average global sea level rose around 10-12 inches over the last 100 years (1920-2020). Now, the rate of global sea level rise is accelerating: the next 10-12 inches of sea level rise along U.S. coasts is projected to occur in just 30 years (from 2020-2050).