1 digit calculations just for orders of magnitude: If we assume a doubling of CO2 is 4 W / m2 and the earth is 5 x 10^14 m2, a doubling of CO2 traps about 2 x 10^15 W.
If we assume 2 GtC / ppm, and think it takes say 300 ppm to double CO2, that is 600 GtC, 600 x 10^12 kgC = 6 * 10^14 GC, so each kgC in the atmosphere traps around 3 W. Oil is about 4.5 x 10^7 J / kg. If we pretend oil is CH2, then we can assume that most of this mass is carbon, but a lot of the energy comes for the hydrogen. So by this reckoning it would take ( 4.5 x 10^7 J / kg ) / (3 W / kgC) = 1.5 * 10^7 s or less than half a year for the greenhouse gas to heat up as much as the thermal heating from the oil. Of course, this CO2 is accumulating in the atmosphere. If you think the airborne fraction on the margin, is around 0.5 over the first thousand years, giving you about the radiative heating each year equivalent to the chemical heating from burning. Then you get a few hundred thousand years with several fold less heating, with a cumulative radiative heating on the order of 100,000 times the direct chemical heating. (I am not going to quibble about small integer multipliers one way or the other.) Of course, all of this heat will not go into melting ice. (I think that 75 was the ratio of current atmospheric CO2 radiative forcing to direct heating from fossil fuel burning, but I would need to go back to check.) ___________________________________________________ Ken Caldeira Carnegie Institution Dept of Global Ecology 260 Panama Street, Stanford, CA 94305 USA [email protected]; [email protected] http://dge.stanford.edu/DGE/CIWDGE/labs/caldeiralab +1 650 704 7212; fax: +1 650 462 5968 On Thu, Nov 19, 2009 at 3:08 PM, Ron Larson <[email protected]>wrote: > Dave (cc Ken and list): > > Thanks to Dave. > > 1. Since I doubt very much that the computation shown included anything > on CO2 effects, I hope Ken can weigh in on this, per the discussion last > week re: > http://climateprogress.org/wp-content/uploads/2009/11/Warming-burning-091018.pdf > > 2. The answer might be 100,000 times larger - but that might exhaust the > supply of glaciers. > > 3. Would Exxon today say that one day's worth of melting was > calculated properly. That we are only talking of an insignificant addition > of only about 75/365 (only about another 20%, assuming we don't worry > about whether today's energy consumption is impacting any glacier tomorrow.) > (Ken had a factor of 75 for 1 year). > > 4. I haven't had any luck logging on to to leave a comment at the > Grist site, so hope someone will. One chap has shown a multiplicative > factor of 65 - which looks like he has calculated for a year. > > Ron > > Hawkins, Dave wrote: > >> Ad in Life magazine 1962. >> http://www.grist.org/article/2009-11-18-oil-enough-energy-to-melt-glaciers/ >> >> -- >> >> You received this message because you are subscribed to the Google Groups >> "geoengineering" group. >> To post to this group, send email to [email protected]. >> To unsubscribe from this group, send email to >> [email protected]<geoengineering%[email protected]> >> . >> For more options, visit this group at >> http://groups.google.com/group/geoengineering?hl=. >> ------------------------------------------------------------------------ >> >> >> No virus found in this incoming message. >> Checked by AVG - www.avg.com Version: 9.0.707 / Virus Database: >> 270.14.73/2513 - Release Date: 11/19/09 00:51:00 >> >> >> > > -- You received this message because you are subscribed to the Google Groups "geoengineering" group. 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/geoengineering?hl=.
