USA - How sea levels in 40 cities will change by 2050
By 2050, global sea levels could increase by 1 foot from where they were at the start of the millennium. Iconic beaches, large city centers, and quaint coastal towns will all have to be adapted for higher water levels.
Sea level rise means more than just coastal land eaten up by the ocean. It will cause more inland neighborhoods to be at risk of storm surges during hurricanes and high tides, more regular flooding, and saltwater intrusion into freshwater resources.
For communities facing the brunt of shifting waters, planning for resilience has become paramount. Charleston, South Carolina’s climate resilience office has a multipronged plan, including seawall construction and shoreline restoration. Still, Charleston Harbor experienced 70 flooding events in 2022, the second highest in recorded history dating back to 1922.
Continued flooding and extreme weather events highlight the urgency of infrastructure fixes to mitigate sea level rise, but such plans are often expensive.
In California, the San Francisco Bay Conservation and Development Commission has identified projects to enhance and build seawalls, levees, and marshes across the region’s coastline. The cost of all the projects is estimated to be $110 billion by 2050. So far $5 billion has been allocated.
In western Oregon, the state’s Department of Transportation estimates it would cost over $40 million to make a section of U.S. Highway 101 resilient to cliff erosion that will become more pronounced with sea level rise.
Planning for the future is also challenging for smaller communities. Solutions like paying to move and demolish waterfront houses are often unpopular with homeowners, and beach nourishment, or adding more sand to the coastline from the ocean floor, is an expensive and temporary solution.
The impact of sea level rise will be far-reaching on both the Atlantic and Pacific sides of the U.S., but sea level rise will not affect the world equally. Some of the countries impacted will be those who have contributed the least to global greenhouse gas emissions such as Vietnam, Bangladesh, and small South Pacific islands.
An analysis from Carbon Brief found the U.S. was responsible for releasing over 500 gigatons of carbon dioxide equivalent since 1850, or 20% of the world’s historical total. Other major emitters include China (11%) and Russia (7%). As human activity releases greenhouse gases into the atmosphere, their heat-trapping characteristics fuel the warmer weather that causes sea level rise.
Ocean water naturally expands with warmer temperatures. Along with meltwater from shrinking Arctic sea ice and glaciers pouring into the world’s oceans, global mean sea levels increase.Emissions currently in the atmosphere mean sea level rise can’t be stopped, but lower emissions scenarios can slow its pace.
Using data from the National Oceanic and Atmospheric Administration’s sea level rise technical report, released in 2022, Stacker identified projected sea level rise by 2050 for 40 cities in the U.S. The report identifies five sea level rise scenarios based on changes by 2100 from 2000 levels. They are low (an average of 1 foot globally), intermediate-low (1.6 feet), intermediate (3.3 feet), intermediate-high (4.9 feet), and high (6.6 feet). For each, projections under low, medium, and high emissions scenarios are included. Stacker focused on each emissions scenario for low, intermediate, and high sea level rise.
Unlike most places on this list, cities in Alaska are seeing falling sea levels, as its land is actually rising with shifting tectonic plates. Read on to see where major coastal cities in the U.S. stand.
Anchorage, Alaska
– NOAA Region: National
– Low sea level rise scenarios:
— With low emissions: -1.0 feet
— Medium emissions: -0.7 feet
— High emissions: -0.5 feet
– Intermediate sea level rise scenarios:
— With low emissions: -0.9 feet
— Medium emissions: -0.6 feet
— High emissions: -0.3 feet
