Mean atmospheric O2
Geologic Time Scale
North America with sea level +100m
This is how North America may appear with mean sea level about 100 meters (330 feet) above today's. Such a dramatic rise in sea level could occur if all of the Earth's glaciers were to melt.
In this image the Gulf of Mexico and Atlantic ocean have inundated nearly all of southeastern United State including the entire state of Florida, nearly all of Louisiana, and significant portions of the other southeastern states and the District of Columbia. Major US cities submerged include New York City, Boston and Houston, and on the west coast Los Angeles, San Francisco, and much of San Diego.
To the north the Hudson Bay has grown to claim much of the Canadian provinces of Ontario, Quebec, Manitoba and Nunavut. Further north Greenland's entire ice sheet, 110,000 years old and holding about 700,000 cubic miles of fresh water, has completely melted.
A likely cause of a catastrophic melting of the Earth ice stores would be a change in climate, a sudden rise in the global temperature accelerated by a runaway greenhouse effect. While the amount of water held by the Earth's glaciers can be calculated with some accuracy, the exact mechanism that would set those glaciers to melting, and how long it would take for them to melt, is poorly understood. Some models suggest that several millennia of higher temperatures would be required to melt all the world's glaciers, while others predict much faster processes on the scale of centuries, or even decades.
Copyright © Walter B. Myers. All rights reserved.
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