Hi Brian,
To my knowledge, the ozone depletion cause is nowhere near as clear-cut as 
you ake it sound.
But back to 'global warming potential-GWP.'
Earth has gone through quite a number of climatic cycles, alternating between 
cool  periods and warmer [Climatic Optima] periods. Since the end of the last 
glacial period, the Wisconsin or Würm Stage, about 6 to 7,000 years ago, 
there have been a number of warm and even hot periods. The hot Holocene 
Optimum occurred between 6 to 5,000 and 3,000 B.C., and the Little Climatiic 
Optimum (LCO) or Medieval Warming Period from 750 to 1215; cold periods 
occurred from 900 to 300 B.C., moderating to cool from 300 B.C. to 750 A.D.
During the LCO, ice and severe weather vanished from the Northern seas, 
allowing the Vikings to expand to Iceland, Greenland [it was green, fertile, 
and supported a population of 3,000 with nearly 400 farms at its height], and 
Markland ["Wooded Land"--today's Labrador], and Vinland [today's 
Newfoundland--where then grapes, currents, and gooseberries grew]. The LCO 
also brought about the European Agricultural Revolution, with vineyards 300 
miles farther north than today, and England producing high-quality wines.
The end of the LCO spelled doom to the Viking settlements, other than 
Iceland, and crop yields fell by a third throughout Europe, leading to some 
of the worst famines in 1315 to 1317 and 1347, driggering the medieval 
depression which lasted a century and a half and bringing the return of the 
plague.
So, in history, it was the cooling, not the warming, that brought about human 
disasters on a wide scale.
Those interested, may consult: Crowley, J. J., and G.R. North, 
"Paleoclimatology," (Oxford, 1991), or Gimpel, J., "The Medieval Machine. The 
Industrial Revolution of the Middle Ages," (N.Y., 1976), or Jones, G., "A 
History of the Vikings,"(Oxford, 1984).

Werner Engelmaier

---------------------------------------------------------------------------------
Technet Mail List provided as a free service by IPC using LISTSERV 1.8d
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Technet
To temporarily halt delivery of Technet send the following message: SET Technet NOMAIL
Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives
Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional
information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315
---------------------------------------------------------------------------------