How many inches/cm have the world's oceans and seas risen so far?

Question

I know the predictions for the future are pretty dire but what's the story so far?

Answer 1

Sea levels have risen about 20 cm in the last century. Apparently, it's not an easy matter to measure sea level change, as the long-term trends are small compared to the tides, effects caused by currents and wind, etc.

Answer 2

Sea levels have been rising at a constant rate ever since the last ice age ended.

You would assume that if we are contributing to this constant steady rise that the rate of sea level rise should have accelerated during the 20th century, but tide gauge data for the 20th century show no significant acceleration.

Answer 3

Remeber that in the beginning there WAS no sea, so it has raised 10,924 metres - that's the depth of the Mariana Trench, the lowest known point in the ocean. There is no fixed level of the sea 'before global warming' to compare the oceans' depth against now.

Extra credit fact: Ice melting, eg., in the Antartic, does not contribute to the sea levels raising, because ice is less dense than water, so it takes up more space. Because of this, the ice melting in the water actually lowers the sea levels. Higher temperatures give the water molecules greater energy, so they 'spread out' more, because they move across a greater amount of space.

Hope this helps you understand this better! (C'mon, best answer please! =] )

Answer 4

Try one of these sights...they may help answer the question for you.

http://www.nrdc.org/globalWarming/default.asp

http://www.floridaenvironment.com/programs/fe00501.htm

http://www.whoi.edu/page.do?pid=7135


As far as the whole ice melting NOT raising water idea, these particular links should help answer any questions in regards to this. As some people may think this is a little different than a few ice cubes in a glass of water.

http://illconsidered.blogspot.com/2006/03/ice-caps-will-melt-into-aquifers.html

http://www.physorg.com/news5619.html

http://www.livescience.com/environment/070404_GW_ice.html

http://www.livescience.com/environment/060323_ice_melt.html

http://www.giss.nasa.gov/research/briefs/gornitz_09/

http://illconsidered.blogspot.com/2006/03/ice-caps-will-melt-into-aquifers.html

Answer 5

well the thing is at this point in time land/see levels are fluctuating in different places.