Climate Wire | A new study finds sea levels have soared along the southeastern United States coastline to the highest level in more than a century.
With an increase of more than one centimeter per year over the past decade, reaching about three times the global average, impacts on communities near the Gulf of Mexico and Atlantic Ocean are already being observed in the form of increased flooding, more severe hurricanes and erosion. It has been. coastline.
Sönke Dangendorf, a coastal engineering expert at Tulane University and lead author of the new study, said:
A study published in the journal on Monday Nature Communications, is the latest to point out the trend.Another study published earlier this month journal of climatehighlighted a similar pattern – sea level rise of more than 1 cm per year along the Gulf and Southeast coasts since 2010.
Surveys show the affected area extends from the western Gulf of Mexico to Cape Hatteras in North Carolina.
According to Dangendorf, this growing interest dates back to the 2022 NOAA report on sea level rise. The report presents projections for the U.S. coastline over the next few decades, predicting an average sea level rise of about 1 foot around the U.S. by mid-century. Higher-than-average sea level rise was also projected along the East Coast and Gulf Coast.
Still, the amount of sea level rise observed in the Southeast and Gulf has exceeded model projections over the next 30 years, and scientists wanted to know why.
The latest study, led by Dangendorf, analyzed 66 tide gauge records above and below the East Coast and Gulf Coast, with satellite observations and model simulations for further investigation. Researchers have isolated the extra impact of sinking land, a notable problem in parts of Texas and Louisiana.
They found that sea levels were rising rapidly across the region, even without the effects of surface subsidence. For example, in Pensacola, Florida, velocities of over 11 millimeters per year have been found.
Researchers began analyzing possible causes of the sharp increase. Meltwater from the world’s shrinking glaciers and ice sheets is contributing to the global acceleration of sea level rise, but it doesn’t fully explain the pattern occurring along the US coastlines.
The researchers suggest that rising ocean temperatures and changes in wind patterns have altered ocean circulation in parts of the North Atlantic and Caribbean, changing the way large amounts of water flow to the U.S. coastline. I’m here. These changes may be partly due to human-induced global warming and partly to natural climate change, they say.
They also add that if the changes are partly natural cycles, the accelerating sea level rise should eventually slow down, though it’s unclear how long.
There is still some scientific debate about the exact cause behind the acceleration, and other research groups have put forward alternative theories. journal of climate A study suggested that the increase could be caused by changes in the flow of warm water through the Gulf of Mexico. And these changes are likely to be further accelerated by the recent slowdown in major Atlantic currents, caused by human-induced climate change.
Dungendorf said that while theories about the mechanism differ, scientists generally agree that the acceleration is caused by changes in physical ocean dynamics.
“I wouldn’t necessarily say they disagree,” he said. “They all agree it’s a dynamic factor, almost certainly.”
But more research is needed to determine the exact cause and what it means for future rates of sea level rise along the Gulf and Southeast coasts.
Meanwhile, research shows the impact sea level rise has had on both regions.
of journal of climate The rate of increase is consistent with record-breaking hurricane seasons in recent years, the study said, likely resulting in increased coastal flooding and damage. Rising sea levels can exacerbate the consequences of hurricanes, as they can increase storm surges and cause devastating coastal flooding.
Storm surge flooding is also accelerating along most of the Gulf and East Coast, according to NOAA. Also, compared to 2000, the total number of days of storm surge flooding has increased by 400% in the Southeast and by 1,100% in the Gulf.
At the same time, flood damage is increasing and insurance premiums are soaring. And coastal communities watch the coastline slide down into the gradually rising waves.
“We have to prepare for it. We have to adapt,” said Dangendorf. “It affects us all.”
Reprinted from E&E News with permission of POLITICO, LLC. Copyright 2023. E&E News provides essential news for energy and environmental professionals.
