> Does this make sense to anyone here? > > - > http://environment.guardian.co.uk/climatechange/story/0,,1865081,00.html
Since he does not seem to be claiming he is a climate scientist, perhaps he was quoting James Hansen. See: http://www.cbsnews.com/stories/2006/03/17/60minutes/main1415985.shtml Hansen also wrote: "The CO2 amount of 440 ppm is a critical threshold. Other things being "normal", it is the peak CO2 amount in a scenario (1) that would keep additional global warming from exceeding 1°C (1.8°F). Based on the history of the Earth, it is estimated that warming greater than 1°C above today's level would weaken the ice sheets that cover Greenland and Antarctica, causing eventual rise of sea level by several meters. " See http://www.giss.nasa.gov/research/briefs/hansen_11/ Imagine you have an old set of scales, like the kind used to symbolise justice. If you put a pound weight in one pan the scales will tip over on that side, then add a weight of one gram to the other pan and nothing will happen. Add 2nd gram weight to the second pan and nothing will happen. Add 3rd gram weight to the second pan and nothing will happen. Add 4th gram weight to the second pan and nothing will happen. ... Add 100th gram weight to the second pan and nothing will happen. ... Add 200th gram weight to the second pan and nothing will happen. ... Add 300th gram weight to the second pan and nothing will happen. Add 400th gram weight to the second pan and nothing will happen. ... Add 450th gram weight to the second pan and nothing will happen. Add 451st gram weight to the second pan and nothing will happen. Add 452nd gram weight to the second pan and nothing will happen. Add 453rd gram weight to the second pan and nothing will happen. Add 454th gram weight to the second pan and the scales will tip over. The Greenland ice is like those scales. When global temperature rises above a certain level it will begin to melt, and if the temperature does not fall then the ice will eventually disappear completely. But if we stop pumping CO2 into the atmosphere the temperature will not fall. It will continue to rise because of 'commitment'. See http://www.ucar.edu/news/record/ ---------- Related Article: The Climate Change Commitment Wigley, T.M.L. (2005), "The Climate Change Commitment," Science, vol. 307, pp. 1766-69. Abstract Even if atmospheric composition were fixed today, global-mean temperature and sea level rise would continue due to oceanic thermal inertia. These constant-composition (CC) commitments and their uncertainties are quantified. Constant-emissions (CE) commitments are also considered. The CC warming commitment could exceed 1°C. The CE warming commitment is 2° to 6°C by the year 2400. For sea level rise, the CC commitment is 10 centimeters per century (extreme range approximately 1 to 30 centimeters per century) and the CE commitment is 25 centimeters per century (7 to 50 centimeters per century). Avoiding these changes requires, eventually, a reduction in emissions to substantially below present levels. For sea level rise, a substantial long-term commitment may be impossible to avoid. --------- James, what levels of CO2 do you think we should not exceed, bearing in mind that at 380 ppm the Greenland ice sheet is already starting to melt, hurricanes are starting to intensify, and forest fires are raging throughout the world? Coby, do you see now why geo-engineering is necessary. Even a complete ban on all fossil fuel burning would not prevent serious repercussions Cheers, Alastair. --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups Global Change ("globalchange") newsgroup. Global Change is a public, moderated venue for discussion of science, technology, economics and policy dimensions of global environmental change. Posts will be admitted to the list if and only if any moderator finds the submission to be constructive and/or interesting, on topic, and not gratuitously rude. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/globalchange -~----------~----~----~----~------~----~------~--~---
