Earths sea level was more than 70 feet higher 400,000 years agoFebruary 10th, 2009 - 1:55 pm ICT by ANI
Washington, Feb 10 (ANI): Scientists have found evidence in Bermuda that Earths sea level was once more than 70 feet higher about 400,000 years ago than it is now, which may be critical for anticipating the possible effects of future climate change.
The clues for this ancient rise in sea level was found by Storrs Olson, research zoologist at the Smithsonians National Museum of Natural History, and geologist Paul Hearty of the Bald Head Island Conservancy.
They discovered sedimentary and fossil evidence in the walls of a limestone quarry in Bermuda that documents a rise in sea level during an interglacial period of the Middle Pleistocene in excess of 21 meters above its current level.
The nature of the sediments and fossil accumulation found by Olson and Hearty was not compatible with the deposits left by a tsunami but rather with the gradual, yet relatively rapid, increase in the volume of the planets ocean caused by melting ice sheets.
A rise in sea level to such a height would have ramifications well beyond geology and climate modeling.
For the organisms of coastal areas, and particularly for low islands and archipelagos, such a rise would have been catastrophic.
We have only to look at Bermuda to begin to assess the impact for terrestrial organisms or seabirds dependant on dry land for nesting sites, said Olson.
This group of islands in the Atlantic was so compromised as a nesting site for seabirds that at least one species of shearwater became extinct as well as the short-tailed albatross, marking the end of all resident albatrosses in the North Atlantic, he added.
Determining the timing and extent of this global rise in sea level is not only important for interpreting the influence that it may have had on biogeographical patterns and extinctions of organisms on islands and low-lying continental coastal areas, it is also critical for anticipating the possible effects of future climate change.
This particular interglacial period is considered by some scientists to be a suitable comparison to our current interglacial period.
With future carbon dioxide levels possibly rising higher than any time in the past million years, it is important to consider the potential effects on polar ice sheets.
According to Olson, These findings are incredibly important and have major relevance because of their potential predictive value since this sea-level rise took place during the interglacial period most similar to the present one now in progress.
It thus becomes essential that the full extent and duration of this event be more widely recognized and acknowledged, he added. (ANI)
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Tags: albatrosses, bald head island, climate change, coastal areas, extinctions, fossil evidence, global rise, interglacial period, island conservancy, limestone quarry, low islands, melting ice, museum of natural history, national museum of natural history, olson research, pleistocene, rapid increase, research zoologist, short tailed albatross, terrestrial organisms