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RE: Only nuclear power can now halt global warming
Brian Riely wrote:
-----Original Message-----
From: Riely, Brian P. [mailto:brian.riely@ngc.com]
Sent: Tue 5/25/2004 7:30 AM
To: radsafe@list.vanderbilt.edu
Cc:
Subject: RE: Only nuclear power can now halt global warming
I want to thank everyone who responded to my question. I know it took some time. My question was meant to address several issues. 1.) Some people claim that the melting of the south pole will cause the ocean to rise by a significant amount, yet Antarctica is floating. 2.) I realize that Greenland is a chunk of land, and as such the ice is not displacing the water. The question then becomes, "how did the ice get there?" If there were a change in the earth surface (land mass) that caused the water to flow to Greenland, stay in the vicinity, and subsequently freeze; and if the earth's surface is roughly the same now as it was then, as the ice melts it should stay in that vicinity. If the accumulation of ice on Greenland is due to water being transported from the ocean, via processes such as evaporation and currents, then we should have a steady decrease in the ocean's level. Of
course, if we get a steady decrease over 10,000 years and a reversal in a 100 years, that could be a major problem. So, it seems to me that before one can say that ice melting in Greenland is going to add water to New Orleans, one has to address how the water got to Greenland. 3.) Sometimes, ostensibly obvious and simple statements are not true. For example, I believe if you ask a typical physicist what would a sphere moving at a velocity close to the speed of light look like to an observer, he would say, " a prolate spheroid." The correct answer is, "a sphere." (to be pedantic: a rotated sphere). It took around 50 years before people realized that the correct answer is a sphere. The scientific literature is replete with errors because the author assumed an "obvious" statement to be true.
Anyway, if someone knows how the water initially accumulated on Greenland, I would be interested.
My apologies for the lengthy e-mail, but I was misunderstood by being too brief.
================
Responses to questions:
1) Antarctica is NOT floating. Portions of the up to two-mile thick ice cap are grounded on land that is below sea level, but since it is grounded, it can accumulate to a much thicker cap than the sort of floating ice shelf. Floating shelf comprises something on the order of 10-20% of Antactic ice. Melting of Antarctic ice would produce a 50-100 meter increase in sea level, submerging much of today's coastal dry land. Melting of Greenland would have a smaller, but still significant impact.
2) The ice in Greenland and Antarctica and the former ice caps in the northern high latitudes and mountain regions around the world accumulated and disappeared because of an imbalance between winter precipitation and summer melting. The relationship between melting of the giant continental ice caps and sea level is pretty complex, combining both an increase in the volume of the ocean and localized rebound of the earth's crust as the ice caps disappear. If memory serves, in parts of the world (Scandinavia?) sea levels are currently decreasing rather than increasing because the rebound of the land is faster than the increase in global mean sea level. The precipitation/melting imbalances have produced sea level swings on the order of 300 meters up and down between glacial and interglacial periods.
Best regards.
Jim Dukelow
Pacific Northwest National Laboratory
Richland, WA
jim.dukelow@pnl.gov
These comments are mine and have not been reviewed and/or approved by my management or the U.S. Department of Energy.
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