According to a report prepared by the National Oceanic and Atmospheric Administration (NOAA), sea levels are expected to rise by 30 centimeters by 2050. The interagency report says that while volumes vary by region, this will lead to more coastal flooding and exacerbate tidal and storm surges.
"Sea levels continue to rise at a very alarming rate," National Aeronautics and Space Administration administrator Bill Nelson told reporters on a conference call Tuesday. “And it endangers communities around the world.”
Rising water threatens coastal cities including New York, Boston and Miami, which are already flooded frequently during full and new moon tides. Homes, businesses, highways and other infrastructure along the coast are vulnerable to flood damage and rising sea levels. Nearly 8 million homes with a $1.9 trillion renovation cost are at risk from storm surge, according to a 2021 CoreLogic report.
According to NOAA estimates, sea levels in Manhattan could rise by 2 feet as early as 2055 or even 2078, depending on the effects of climate change. Approximately 7,895 people in Manhattan live in low-lying areas that could be inundated with less than 2 feet of sea level rise.
The report says flooding in New York City has more than doubled since 2000 and now occurs 10 to 15 times a year. The annual frequency of flooding in Miami and Charleston, South Carolina has risen from zero to two days in 2000 to about five to ten days last year.
“This increase will continue, accelerate and spread to more locations over the next few decades,” says the report, which updates the 2017 sea level forecast. The US uses satellites to measure ice thickness and the rise in ocean levels. . “These new data on sea level rise are the latest confirmation that our climate crisis is — as the president said — flashing ‘code red’,” White House national climate adviser Gina McCarthy said in a statement. “We must redouble our efforts to reduce climate change-causing greenhouse gas emissions while helping our coastal communities become more resilient in the face of rising sea levels.”
By trapping the heat that melts the ice sheets, greenhouse gas emissions are likely to raise global sea levels by about 2 feet by 2100, according to the report. Failure to curb future emissions could see sea levels rise another 18 inches by the end of the century to as high as 5 feet. The US coastline from North Carolina to Maine is a hotspot for global sea level rise.
Global warming above 5.5 degrees Fahrenheit (3 degrees Celsius) will cause the Greenland and Antarctic ice sheets to melt rapidly, releasing this water into the oceans. Precise damage is difficult to model due to "ice sheet instability," the report says.
In addition to NOAA, the 111-page report included researchers from NASA, the Environmental Protection Agency, the US Geological Survey, the Department of Defense, the Army Corps of Engineers, and the Federal Emergency Management Agency.