According to a new paper (Oliver and Terry, 2019) published in Palaeogeography, Palaeoclimatology, Palaeoecology, oyster remains have been found encrusted in rock 2.5 to 3.8 meters above the present mean sea level. This fossilized evidence dates to ~6000 to years ago, a period when the Earth’s surface temperatures were 4-6°C warmer than they are today.
Image(s) Source: Oliver and Terry, 2019
The evidence provided by Oliver and Terry (2019) will be added the to growing list of more than 80 scientific papers indicating sea levels from locations throughout the world were meters higher than they are today just a few thousand years ago.
Relative sea-level highstands in Thailand since the
Mid-Holocene based on 14C rock oyster chronology
• “~6000 cal yr B.P. old oysters can be found from between 3.8 ± 0.1 m to 2.5 ± 0.1 m above present day mean sea level. … Dead (fossil) oysters were collected from between 1 and 3 m above the centre of the live oyster band in a more sheltered cleft inside the notch. The oldest sample with an age of 5270–4950 cal yr B.P. was collected at an elevation of 3.01 ± 0.1 m above the apex of the notch. The ages decrease with elevation down to 920–710 cal yr B.P. at 1.03 m.”
• “In all the sites, the 14C age of the dead oysters inside the notches increases with increasing elevation above present day MSL. Clearly, relative sea level was 2 to 3 m higher than present between 6000 and 3000 B.P. and has steadily fallen since.”
• “There was a progressive warming from ~13,500 years ago to a peak at 6500 ± 200 years ago followed by a cooling of −2.6 °C to the present day.”
• “Generally, there is a ~1 m wide live oyster band (with modern 14C ages) in the apex of the sea notch that corresponds to the present day MSL. 14C ages of dead oysters are systematically older higher up the sea notch and reach a maximum 14C cal yr B.P. age of 6513–6390 cal yr B.P. at an elevation of 2.5 ± 0.1 m above present day MSL in an exposed site at West Railay Beach. Consequently, relative sea levels must have been higher in the mid Holocene than they are now.”
• “[A]t a more sheltered site inside a bay on Ko Pha Nak, the highest preserved oyster shell is at 3.2 ± 0.1 m above MSL and has a younger 14C calibrated age of 5845–5605 cal yr B.P. Furthermore, oysters from 3.8 ± 0.1 m above present day MSL, encrusted on a stalactite in a cave at West Railay Beach has a 14C calibrated age of 6176–6041 cal yr B.P.”