funky question regarding sea rise...

[Javaman]

okay, it's been long known that the earths shape is roughly oval. Due to centrifugal force there is more water around the equator than at the poles.

So with that said, as the seas rise, and these various islands that are disappearing near india, isn't there a chance that the effects of the sea rise be lessened somewhat near the poles?

[DRoseDARs]

1. Simple answer: No. Detailed answer: More math than I care to do.

Sea level will rise everywhere regardless, but yes there will be an ever-so-slightly higher amount of rise along the equator than at higher latitudes.

[Salviati]

2. And it will be very "ever so slight"

The Earths north-south diameter is 12,714 km while the diameter in the plane of the equator is 12,756 km. The difference is only about 0.33%.

So, assuming that the sea level rise doesn't change this ratio (which it will, but even ever more slightly), then for every 1 meter rise at the equator, at the poles, the water will rise 3.3 milimeters less, so only .9967m

[Javaman]

3. I thought as much. thanks :) nt

[sbyte]

4. NASA GISS: Science Briefs: Sea Level Rise, After the Ice Melted and Today

NASA GISS: Science Briefs: Sea Level Rise, After the Ice Melted and Today
http://www.giss.nasa.gov/research/briefs/gornitz_09/

NASA released reports on global sea rise.:

It stood 4-6 meters above the present during the last interglacial period, 125,000 years ago, but was 120 m lower at the peak of the last ice age, around 20,000 years ago.

-snip-

By the mid-Holocene period, 6000-5000 years ago, glacial melting had essentially ceased, while ongoing adjustments of Earth's lithosphere due to removal of the ice sheets gradually decreased over time. Thus, sea level continued to drop in formerly glaciated regions and rise in areas peripheral to the former ice sheets. At many low-latitude ocean islands and coastal sites distant from the effects of glaciation, sea level stood several meters higher than present during the mid-Holocene and has been falling ever since. This phenomenon is due to lithospheric responses to changes in ice and water loading. Water is "siphoned" away from the central equatorial ocean basins into depressed areas peripheral to long-gone ice sheets. Loading by meltwater that has been added to the oceans also depresses far-field continental shelves, tilting the shoreline upward and thus lowering local sea level. Over the past few thousand years, the rate of sea level rise remained fairly low, probably not exceeding a few tenths of a millimeter per year.

-snip-

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.

Recent observations of Greenland and the West Antarctic Ice Sheet raise concerns for the future. Satellites detect a thinning of parts of the Greenland Ice Sheet at lower elevations, and glaciers are disgorging ice into the ocean more rapidly, adding 0.23 to 0.57 mm/yr to the sea within the last decade. The West Antarctic Ice Sheet is also showing some signs of thinning. Either ice sheet, if melted completely, contains enough ice to raise sea level by 5-7 m. A global temperature rise of 2-5°C might destabilize Greenland irreversibly. Such a temperature rise lies within the range of several future climate projections for the 21st century. However, any significant meltdown would take many centuries. Furthermore, even with possible future accelerated discharge from the West Antarctic Ice Sheet,it highly unlikely that annual rates of sea level rise would exceed those of the major post-glacial meltwater pulses.

[Dogmudgeon]

5. We're forgetting isostasis

It's not just about ocean levels.

Isostasis (or isostasy) is the term for the balance of mass on the Earth. When you change the way the mass is distributed -- by melting polar ice, for instance -- it causes significant seismic activity.

Not exactly on a par with the mythical sinking of Atlantis, but it could be pretty bad in some areas.

In addition, the slight deformation of the shape of the globe will produce locally devastating effects to places near and below sea level. I think a few islands have already disappeared as a result of the combination of different terrestrial changes.

This won't happen in a scenario that can be captured in a disaster movie, but a series of "small" disasters over the course of a century would be bad enough.

--p!