Counties where Sea Level Rise Could Threaten Economy in 2050

By Sam Stebbins  •  February 24, 2026
person holding surfboard near body of water
Photo by frank mckenna on Unsplash

Generating nearly $28.8 trillion in 2024, the U.S. economy is by far the largest in the world. In the coming decades, however, climate change will continually pose new challenges and risks to American prosperity, and major population centers across the country will be especially exposed.

According to the National Oceanic and Atmospheric Administration, the United States has over 95,400 miles of coastline. In the coming years, sea-level rise could threaten the lives and livelihoods of millions of Americans living in coastal areas. Predictive models from the U.S. Interagency Task Force on Sea Level Change suggest that the Pacific Ocean could rise as much as 8 inches in parts of the Western U.S. by 2050. Along the Atlantic, coastal communities could see water levels rise as much as 2 feet, and in the Gulf region, sea levels could rise as much as 18 inches by 2050. 

These trends are partly fueled by Earth’s warming atmosphere, which is causing glaciers to melt and ocean waters to expand. In the United States, this will likely result in a changing coast line and regular flooding in certain areas. Such an eventuality could have serious implications, not only for the 129 million Americans who live near the coast, but also for the American economy writ large, as coastal counties generate more than one-third of U.S. GDP. 

Using data from Climate Central, Climate Crisis 247 identified projected sea level rise in the coastal U.S. counties with the largest economies. We reviewed data on gross domestic product in 2024 for every county along the U.S. coast, and ranked the 10 with the largest economies. For each of these 10 counties, we listed predicted sea-level rise by the year 2050, 2100, and 2150, as well as the land area and number of people expected to be at high-risk of annual flooding by 2050. All projections in this story are based on models that assume pledged commitments to curbing climate change are met, and as a result, they may be underestimated. Supplemental data on population are five-year estimates from the U.S. Census Bureau’s 2023 American Community Survey, and GDP data is from the Bureau of Economic Analysis. Counties are listed in ascending order based on GDP. 

The 10 counties on this list span five states: California, Florida, New York, Texas, and Washington. Collectively, these places generate over $4.9 trillion in economic activity per year, and are home to over 31.1 million people. Coastal sea levels are projected to rise by as much as 1.4 feet in these areas by 2050, and by as much as 5.2 feet in 2150. 

10. San Mateo County, California

  • Projected sea level rise by year: +0.66 ft. by 2050, +1.7 ft. by 2100, +2.9 ft. by 2150
  • Est. land area at high-risk of annual flooding by 2050: 5,600 acres at minimum
  • Est. population at high-risk of annual flooding by 2050: 3,800 people at minimum
  • County GDP in 2024: $217.0 billion
  • Total county population: 745,100
  • Largest city in county: Daly City, California

9. Miami-Dade County, Florida

  • Projected sea level rise by year: +0.95 ft. by 2050, +2.3 ft. by 2100, +3.8 ft. by 2150
  • Est. land area at high-risk of annual flooding by 2050: 250,000 acres at minimum
  • Est. population at high-risk of annual flooding by 2050: 2,500 people at minimum
  • County GDP in 2024: $260.8 billion
  • Total county population: 2,685,296
  • Largest city in county: Miami, Florida
a city skyline with a river
Photo by Abhi Verma on Unsplash

8. San Francisco County, California

  • Projected sea level rise by year: +0.62 ft. by 2050, +1.7 ft. by 2100, +2.9 ft. by 2150
  • Est. land area at high-risk of annual flooding by 2050: 270 acres at minimum
  • Est. population at high-risk of annual flooding by 2050: 800 socially vulnerable people at minimum
  • County GDP in 2024: $268.3 billion
  • Total county population: 836,321
  • Largest city in county: San Francisco, California

7. San Diego County, California

  • Projected sea level rise by year: +0.62 ft. by 2050, +1.6 ft. by 2100, +2.7 ft. by 2150
  • Est. land area at high-risk of annual flooding by 2050: 2,200 acres at minimum
  • Est. population at high-risk of annual flooding by 2050: 1,500 people at minimum
  • County GDP in 2024: $331.9 billion
  • Total county population: 3,282,782
  • Largest city in county: San Diego, California

6. Orange County, California

  • Projected sea level rise by year: +0.59 ft. by 2050, +1.6 ft. by 2100, +2.7 ft. by 2150
  • Est. land area at high-risk of annual flooding by 2050: 4,400 acres at minimum
  • Est. population at high-risk of annual flooding by 2050: 18,000 people at minimum
  • County GDP in 2024: $351.8 billion
  • Total county population: 3,164,063
  • Largest city in county: Anaheim, California

5. Santa Clara County, California

  • Projected sea level rise by year: +0.59 ft. by 2050, +1.6 ft. by 2100, +2.6 ft. by 2150
  • Est. land area at high-risk of annual flooding by 2050: 6,500 acres at minimum
  • Est. population at high-risk of annual flooding by 2050: 4,800 people at minimum
  • County GDP in 2024: $438.5 billion
  • Total county population: 1,903,297
  • Largest city in county: San Jose, California

4. King County, Washington

  • Projected sea level rise by year: +0.49 ft. by 2050, +1.5 ft. by 2100, +2.4 ft. by 2150
  • Est. land area at high-risk of annual flooding by 2050: 1,100 acres at minimum
  • Est. population at high-risk of annual flooding by 2050: 260 people at minimum
  • County GDP in 2024: $477.2 billion
  • Total county population: 2,262,713
  • Largest city in county: Seattle, Washington

3. Harris County, Texas

  • Projected sea level rise by year: +1.4 ft. by 2050, +3.2 ft. by 2100, +5.2 ft. by 2150
  • Est. land area at high-risk of annual flooding by 2050: 5,600 acres at minimum
  • Est. population at high-risk of annual flooding by 2050: 420 people at minimum
  • County GDP in 2024: $592.8 billion
  • Total county population: 4,758,579
  • Largest city in county: Houston, Texas

2. Los Angeles County, California

  • Projected sea level rise by year: +0.56 ft. by 2050, +1.5 ft. by 2100, +2.6 ft. by 2150
  • Est. land area at high-risk of annual flooding by 2050: 1,900 acres at minimum
  • Est. population at high-risk of annual flooding by 2050: 2,000 people at minimum
  • County GDP in 2024: $1.0 trillion
  • Total county population: 9,848,406
  • Largest city in county: Los Angeles, California

1. New York County, New York

  • Projected sea level rise by year: +1.1 ft. by 2050, +2.7 ft. by 2100, +4.1 ft. by 2150
  • Est. land area at high-risk of annual flooding by 2050: 140 acres at minimum
  • Est. population at high-risk of annual flooding by 2050: 660 people at minimum
  • County GDP in 2024: $1.0 trillion
  • Total county population: 1,627,788
  • Largest city in county: Manhattan, New York

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