Monday, July 6, 2009

Sea Level Rise; A Major Non-existent Threat Exploited by Alarmists

Shoreline change, Eustasy, Isostasy

Global warming alarmists often exploit the determination of what is happening along a shoreline or on ocean islands. Shorelines change over time due to the water rising or falling, scientifically called eustasy, or the land rising or falling called isostasy. It is difficult to separate one from the other in some locations, but in most it is clear. A classic example exploited by alarmists is along the Gulf of Mexico. Here the land is sinking as the continent adjusts to the removal of massive ice sheets but it appears the sea is rising. At the other end of the continent the land is rising as evidenced by the hundreds of shorelines around Hudson Bay.

History

Sea level has risen as the vast continental glaciers formed during the last ice age melted. It was some150 meters (490 feet) lower 18,000 years ago and has risen since that time. The massive glaciers were built up by water evaporating from the oceans and accumulating as snow on the land that changed to ice. Melt began 18,000 years ago but most occurred from 15,000 to 8000 years ago and sea level rose at an average rate of 14 mm a year. From 3000 to 100 years ago the rise was approximately 0.2 mm. Now sea level rise is directly and simplistically linked to melting glaciers and in turn linked to global warming.

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