By Kenneth Richard on 17. June 2026
Higher sea levels were due to a warmer climate, or the consequence of more water in ocean basins rather than locked up on land as ice.
In a new study, scientists assess they can now clearly separate “tectonic and climate signals in Holocene sea-level records” by precisely identifying patterns of long-term vertical land motion near coastal regions.
Meters-higher relative sea levels during the Middle Holocene have often been attributed to land uplift, or glacio-isostatic rebound – the gradual rising of the Earth’s crust as the weight of glaciers and ice sheets melted away.
This tectonic attribution precluded explanations that the sea level highstands could have been connected to a warmer climate and consequent smaller ice sheets and glaciers.
In the study we learn tectonic signals along 500 km of Chilean coast have been largely constant over the last 125,000 years. In other words, there has been negligible vertical land motion in this region.
As reliable indicators embedded in marine terraces clearly show Holocene relative sea levels were 3.2 m higher than today along this Chilean coast from about 7000 to 5500 years ago, it can be determined these highstands were a consequence of water-loading, or a warmer climate.
Image Source: Melnick et al., 2026
Another new study calls attention to the 1.76 m higher sea levels along the coasts of southeastern Australia 6000 years ago, falling to 0.59 m higher than today by 2000 years ago.
Australia is another region that would not be heavily impacted by glacio isostatic rebound, which again affirms these higher sea levels were linked to eustatic (climate-related) processes.
