Past changes in the Earth’s climate likely caused human migration

18 Feb 2023

Contributors: Lauriane CHARDOT, Timothy SHAW and LI Tanghua

Climate change could push millions of people in Southeast Asia to leave their homes and move to more tolerable environments. But is human migration due to environmental change something unique to present-day societies, or has it happened in the past?

A new study published in Communications Biology shows that periods of rapid sea-level rise coincided with the displacement of human populations that inhabited Southeast Asia thousands of years ago. 

The study was led by Assistant Professor Hie Lim Kim from the Asian School of Environment and the Singapore Centre for Environmental Life Sciences Engineering (SCELSE), in collaboration with other scientists including some from the Earth Observatory of Singapore (EOS).

The researchers used contemporary whole-genome sequencing, genetic modelling software and paleogeographic changes to examine the migration patterns of ancient populations during rising sea level between the Last Glacial Maximum about 26,000 to 20,000 years ago and mid-Holocene about 6,000 years ago. This is a period when the increase in global temperature led to widespread environmental change on Earth, including the melting of ice sheets and associated global sea-level rise.

This cross-disciplinary study involved EOS researchers from the SouthEast Asia Sea-Level (SEA2) Program, who modelled how the Earth surface deformed and sea levels changed due to the melting of the ice sheets, and mapped how the landscape changed in response to sea-level changes. 

Senior Research Fellows Tanghua Li and Timothy Shaw
Senior Research Fellows Tanghua Li and Timothy Shaw are co-authors on the study (Source: Lauriane Chardot/EOS) 

“Between 20,000 and 6,000 years ago, the global mean sea level rose 130 metres,” said Dr Tanghua Li, a Senior Research Fellow at EOS expert in sea-level modelling, and co-author on the study. “This sea-level rise submerged and flooded more than half of the Southeast Asian continent at the time, called Sundaland, and caused an indelible change to the genetic footprint of the population.”

Rising seas significantly reduced the land available for ancestral populations, which likely forced their migration across Southeast Asia. 

“As the rapid increases in sea level that forced populations to migrate are similar to what is projected under high-end scenarios for the 21st century, similar effects might occur in the future," said Dr Timothy Shaw, a Senior Research Fellow at EOS and co-author on the study, who helped collate sea-level data used in the study.

Watch some of the authors explain their findings in the video below. For more details about the study, read the news release by Nanyang Technological University Singapore. 

Blog Category

Sea-Level Rise

Geographic Area

Asia > Southeast Asia

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