This thread was motivated by the following comment of kallog;
If these are the important issues (of global warming), then it would be helpful for those scientists and others who get in the media to actually mention them. The best I usually hear is "rising sea levels", "poor Bangladesh", and "poor cute polar bears" but those are relatively trivial problems.
Let's calculate the sea-level rise due to the Antarctic ice sheet melting.
From
http://en.wikipedia.org/wiki/Antarctica we gleam the following facts;
Area of ice-covered Antarctica = 13,720,000 sq km (5,300,000 sq mi)
Average depth of ice = 1.6 km (1.0 mi)
This implies a volume of ice = 13,720,000 * 1.6 = 21,952,000 km3
From
http://en.wikipedia.org/wiki/Ocean we have;
The area covered by the ocean = 361,000,000 km2
Thus if the Antarctic ice sheet were to melt the sea-level would rise by
21952000/361000000 = 0.06081 km = 60.81 meters.
To perform an accurate calculation one needs to take into account that the density of ice is less than that of water, that the land below the icecaps will rise (isostatic rebound), that sea water will replace some of the grounded ice, that the surface area of ocean will increase and that the ocean will expand as temperatures increase.
Since I don't know how to do these things, I defer to the following source,
http://pubs.usgs.gov/fs/fs2-00/ where the U.S. Geological Survey people claim that;
the Greenland ice sheet melting will raise sea-level 6.55 meters (21.5 feet),
the West Antarctica ice sheet melting will raise sea-level 8.06 meters (26.4 feet),
the East Antarctica ice sheet melting will raise sea-level 64.8 meters (212.6 feet),
and all other ice melting will raise sea-level 0.91 meters (3 feet).
For a grand total of 80.32 meters (263.5 feet).The U.S. Geological Survey people also claim that a 10-meter rise in sea level would flood approximately 25 percent of the United State's population. That is a 10-meter rise.
An 80 meter rise in sea-level will flood almost all of the world's coastal cities (you know, towns like London, Washington, New York, Los Angeles, Sydney and even places further from the coast like Paris and Bucharest) and it would flood a fair chunk of the best arable land on the planet.
But, don't worry,... be happy.The good news is that it will take a long time for the ice sheets to melt, but when they do, that land you have in London, or Manhattan, or Paris, isn't going to be worth a dime.
It will take many decades for an ice sheet the size of the Antarctic ice sheet, to melt. How long, will, of course, depend on the temperature rise. But remember, there was a much larger ice sheet over the US and Canada only some 10,000 years ago and it disappeared, in geological terms, very rapidly. Does anyone know any facts and figures for this?
Now, the melt of the Greenland ice-sheet is progressing nicely and will bring a 6.5 meter (21 feet) practise rise in sea-level. It is not yet clear whether the Antarctic ice sheet has begun an irreversible melt. It seems that it has not, but the jury is still out.
Maybe I should mention that, many years ago, after calculating the expansion of the oceans due to a one degree change in temperature, I claimed that sea-level rise would not be a problem. Hearing this, some kind person informed me that I was wrong and provided me with (something like) the above reply.
Maybe I should also mention, that I am quite impressed at the way the professional internet liars have kept such simple knowledge, as the above, from reaching the public.
Changing the topic a little, here is a graphic showing carbon dioxide concentration (ppm) versus temperature (centigrade) over the last 420,000 years.
Hmmm, there certainly seems to be a correlation. What do you think?
But, don't worry,... be happy.
