US sea levels could rise half a metre by end of century

Report by National Oceanic and Atmospheric Administration shows sea levels rising at ‘alarming rate’

Part of the sidewalk near the Jefferson Memorial is covered in water during high tide at the Tidal Basin in Washington. AP

Sea levels along the US coast could rise by an “alarming” 30 centimetres by 2050 and up to half a metre by the end of the century, said a report released on Tuesday by the National Oceanic and Atmospheric Administration (NOAA).

To put this into perspective, sea levels have risen by about 30cm over the past 100 years, with scientists attributing the sharp recent increase to global warming.

“Climate change is causing sea levels to rise, ocean surface temperatures to warm, moisture to build in the atmosphere and all of these factors are leading to more intense and destructive storms,” said Nasa Administrator Bill Nelson.

The inter-agency report led by the NOAA pointed to a host of data gathered from tide gauges and satellites since 2017 that indicated a sustained rapid rise in sea levels.

“If emissions continue at their current pace, it's likely that we will see at least two feet [0.6 metres] of sea level rise by the end of this century along the US coastline,” said NOAA Administrator Richard Spinrad.

The report estimates that flooding in several areas in the US will increase in both frequency and severity.

“Today's report finds that by 2050, moderate flooding, flooding that typically damages property in commerce is expected to occur 10 times as often as it does today,” said Nicole LeBoeuf, director of NOAA’s National Ocean Service.

“What that means is that communities now dealing with nuisance flooding will be facing more damaging floods in just 30 years time.”

Projections for sea level rise in Louisiana and parts of Texas are particularly discouraging.

“In Louisiana, land is disappearing in front of people's eyes,” said William Sweet of the NOAA’s National Ocean Service.

“That's being projected forward into the future.”

The goal of the report is to help local and federal agencies plan for the future and to have a better sense of what to expect.