2 to 3 feet of sea level rise expected this century
By Summit Voice
SUMMIT COUNTY — Scientists continue to grapple with the question of how global warming will affect sea levels, looking at evidence of past climate change to try and determine how the future will play out.
In one of the latest studies, researchers from Rutgers University looked at rock and soil cores in Virginia, Eniwetok Atoll in the Pacific and New Zealand, dating back to the Pliocene epoch, 2.7 million to 3.2 million years ago — the last time concentrations of carbon dioxide in the atmosphere were as high as they are now, and atmospheric temperatures were 2 degrees C higher than they are now.
“The natural state of the earth with present carbon dioxide levels is one with sea levels about 20 meters higher than at present,” said Kenneth G. Miller, professor of earth and planetary sciences in the School of Arts and Sciences at Rutgers University. “The current trajectory for the 21st century global rise of sea level is 2 to 3 feet (0.8 to1 meter) due to warming of the oceans, partial melting of mountain glaciers, and partial melting of Greenland and Antarctica.”
The findings suggest that sea levels were so high during that Pliocence that the volume of extra water equaled the amount frozen in the entire Greenland and West Antarctic Ice Sheets, as well as some of the marine margin of the East Antarctic Ice Sheet, according to H. Richard Lane, program director of the National Science Foundation’s Division of Earth Sciences, which funded the work.
“Such a rise of the modern oceans would swamp the world’s coasts and affect as much as 70 percent of the world’s population,” Lane said.
“You don’t need to sell your beach real estate yet, because melting of these large ice sheets will take from centuries to a few thousand years,”Miller said.
Miller said the research highlights the sensitivity of the earth’s great ice sheets to temperature change, suggesting that even a modest rise in temperature results in a large sea-level rise.
There is plenty of evidence that the West Antarctic ice sheet has melted a previously, including during the Pliocene. Some studies suggest that a 5 degree increase in ocean temps could trigger a collapse. The ice sheet melted and refroze several times, with each phase taking only a few thousand years.