Global Sea Levels Rose More Than 5 Meters Per Century After Ice Ages

Global sea level rise isn't just something we're dealing with in the present day. Scientists have now found at the end of the last five ice-ages, global sea-levels rose at rates of up to 5.5 meters per century. These findings may shed some light on current sea-level rise and may show researchers what we can expect in the future.

In order to better understand how sea-levels fluctuated in the past, the researchers used data from sediment cores from the Red Sea, an area that's especially sensitive to sea-level changes. The sediment samples recorded wind-blown dust variations, which the scientists then linked to well-dated climate record from Chinese stalagmites. But the dust and stalagmite records showed a pronounced change at the end of each ice age, which allowed the scientists to examine the sea-levels in detail.

"The really fast rates of sea-level rise typically seem to have happened at the end of periods with exceptionally large ice sheets, when there was two or more times more ice on the Earth than today," said Katharine Grant, lead researcher, in a news release. "Time periods with less than twice the modern global ice volume show almost no indications of sea-level rise faster than about 2 meters per century. Those with close to the modern amount of ice on Earth show rates of up to 1 to 1.5 meters per century."

While the findings show that sea-level rise did occur, what's more interesting is that they also show the timescale of this rise. This gives scientists data to study the timescale over which ice-sheet responses developed.

"This happened within 400 years for 68 percent of all 120 cases considered, and within 1100 years for 95 percent," said Eelco Rohling, co-author of the new study. "In other words, once triggered, ice-sheet reduction (and therefore sea-level rise) kept accelerating relentlessly over periods of many centuries."

The findings reveal a bit more about sea-level rise, which could help scientists understand what might happen in the future due to climate change.

"Manmade warming spans 150 years already and studies have documented clear increase in mass-loss from the Antarctic and Greenland ice sheets," said Rohling. "Once underway, this response may be irreversible for many centuries to come."