Rutgers scientists have produced new research that reaffirms that modern sea-level rises are linked to human activities and not to changes in Earth's orbit.
"Our team showed that the Earth's history of glaciation was more complex than previously thought," said in a statement lead author Kenneth G. Miller, a Distinguished Professor in the Department of Earth and Planetary Sciences in the School of Arts and Sciences at Rutgers University-New Brunswick.
"Although carbon dioxide levels had an important influence on ice-free periods, minor variations in the Earth's orbit were the dominant factor in terms of ice volume and sea-level changes -- until modern times."
The study took into account the history of sea levels and glaciation since the age of the dinosaurs. The researchers compared global average sea levels with continental margin records.
Worrisomely, the study found that periods of nearly ice-free conditions took place when the concentration of atmospheric carbon dioxide was not much higher than today.
"We demonstrate that although atmospheric carbon dioxide had an important influence on ice-free periods on Earth, ice volume and sea-level changes prior to human influences were linked primarily to minor variations in the Earth's orbit and distance from the sun," Miller said.
The paper also found that the largest sea-level decline took place during the last glacial period about 20,000 years ago. After that, sea levels rose a foot per decade and then slowed from 10,000 to 2,000 years ago. They then remained at a standstill until around 1900, when human activities began affecting the climate.
The study is a worrisome reminder that it is up to us to save our planet before it is too late. Today, sea-level rises threaten to inundate densely populated coastal cities and other low-lying lands by 2100.