By Kenneth Richard on 9. March 2023
Two new studies indicate centennial-scale sea level rise rates ranged up to 29-45 mm/yr during the period between 14,500 and 8000 years ago, when CO2 levels were 250 to 265 ppm.
Modern global sea level rise rates have been reported to be 1.56 mm/yr for 1900-2018, decreasing slightly to 1.3 to 1.5 mm/yr during 1958-2014 (Frederikse et al. (2020) and Frederikse et al., 2018).
But from 9000 to 8000 years ago sea levels in the East Vietnam Sea rose 29 meters – from -35 m to -6 m relative to present levels (Thanh et al., 2023). That’s 2.9 m per century, or 29 mm/yr. Sea levels then rose another 7.5 m from 8000 to 6700 years ago. At that time (6700 to 5500 years ago), sea levels were 1.5 m higher than present.
Image Source: Thanh et al., 2023
Another new study (a thesis) indicates global sea levels rose 13.5 m in 300 years (45 mm/yr), even 6.5 m in 140 years (>46 mm/yr), during the centuries centered around 14,500 years ago. Sea levels ultimately rose to 3 m higher than present throughout the Holocene’s sea level highstand.
At sites along the coasts of New Zealand sea levels were 1.2 to 2.5 m higher than today for much of the last 7000 years, or before sea levels fell to present levels in the last millennium.