The elephant in the global warming room

One predicted effect of global warming is rising sea level. Predictions are of course predictions, and people may choose to be unpersuaded. But here's an observable fact they cannot deny—the sea level has risen 8 inches in the last 100 years, according to this Los Angeles Times article, which describes the inexorable effects in Malibu. This NASA report confirms that and reviews sea level rise events over the last 20,000 years, based on geological evidence. NASA reports an acceleration in the rise starting a century or century and a half ago.

Twentieth century sea level trends, however, are substantially higher that those of the last few thousand years. The current phase of accelerated sea level rise appears to have begun in the mid/late 19th century to early 20th century, based on coastal sediments from a number of localities. Twentieth century global sea level, as determined from tide gauges in coastal harbors, has been increasing by 1.7-1.8 mm/yr, apparently related to the recent climatic warming trend. Most of this rise comes from warming of the world's oceans and melting of mountain glaciers, which have receded dramatically in many places especially during the last few decades. Since 1993, an even higher sea level trend of about 2.8 mm/yr has been measured from the TOPEX/POSEIDON satellite altimeter. Analysis of longer tide-gauge records (1870-2004) also suggests a possible late 20th century acceleration in global sea level.