What does an ancient 3-foot sea level shift mean for us?

A three-foot shift in sea level might not sound like that much to most of us. To those who actually live within three feet of sea level, however, it sounds like a lot.

That’s why news of a sea level change that occurred in Southeast Asia 6,000 years ago is attracting major attention. Adding to the concern is the discovery that this fluctuation happened without humans influencing a change in climate.

A group of oceans scientists and statisticians reported that starting 6,850 years ago, the relative sea level around Belitung Island in Indonesia rose approximately two feet in 350 years. This shift happened without any human-assisted climate change, which suggests that any future sea level rises could be a significant: a combination of a natural rise in sea level plus that caused by climate change that’s been set in motion by humans.

“This research is a very important piece of work that illustrates the potential rates of sea-level rise that can happen from natural variability alone,” says Benjamin Horton of Rutgers University. “If a similar oscillation were to occur in East and Southeast Asia in the next two centuries, it could impact tens of millions of people and associated ecosystems.”

Lead author Aron Meltzner from Nanyang Technological University and the rest of the team studied coral microatolls to learn about the rise and fall of sea levels in the area around Belitung. A microatoll is a coral colony with dead layers on top and living layers beneath. Scientists can study the layers of coral much the way archaeologists study layers of rock. The microatolls helped the team determine general dates when sea levels rose and fell.  

The findings, published in Nature Communications, are of particular concern to those who live extremely close to the sea. Researcher hope that by understanding what happened in the past, they will be better able to predict what kind of changes to expect in the future.

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By Dawn Henderson, Earth.com Staff Writer

Source: Benjamin Horton, Rutgers University

Aron Meltzner, Nanyang Technological University