Washington: Sea levels could rise up to 22 metres in the future due to global warming, says a new study.
An international team, led by Prof Ken Miller of Rutgers University in the US and Prof Tim Naish from Victoria University of Wellington in New Zealand, has published its findings in the latest edition of the `Geology` journal.
For their study, researchers analysed sediment cores in Virginia in the United States, Enewetak Atoll in the Pacific and the Whanganui region of New Zealand.
They investigated the late Pliocene epoch -- 2.7 million to 3.2 million years ago -- which is the last time the carbon dioxide level in the atmosphere was at its current level, and atmospheric temperatures were two degrees higher than are now.
"We know that global sea levels at this time were higher than present, but estimates have varied from five to over 40 metres higher," Prof Naish said.
The team analysed the position of the sea level three million years ago and concluded that it was extremely likely -- with 95 per cent confidence -- that sea level peaked 10 to 30 metres above present, with a best estimate of 22 metres.
"Whanganui holds one of the world`s best geological archives of global sea level during the warm climate of the Pliocene and is a key data set in this new study," Prof Naish said in a release.
Prof Naish also led an international team to Antarctica as part of the ANDRILL Project to drill beneath the floor of the Ross Sea in 2006 and discovered that the Antarctic ice sheets retreated significantly during the Pliocene epoch.
"What we`re seeing is that the evidence of Antarctic ice sheet collapse is consistent with evidence for sea level rise in this new study.
"If the present levels of carbon dioxide in the atmosphere are not abated, and humans were to disappear from the planet and return in 2,000 years, they would find a world where the oceans have risen 20 metres," he added.
However, Prof Miller said that sea level rise would take time. "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.
"The current trajectory for the 21st century global rise of sea level is 2 to 3 feet (0.8 to 1 metre) due to warming of the oceans, partial melting of mountain glaciers, and partial melting of Greenland and Antarctica."