There is a paper here with free access which has several references to CO2 levels during the Tertiary (Cenozoic) http://www.pnas.org/content/105/2/407.full.pdf+html
It seems to me that you can push this maximum back 40 Ma if you discount the stomata evidence. However, that may not be valid. See http://geology.geoscienceworld.org/cgi/content/abstract/32/12/1017 Cheers, Alastair. On Jan 11, 5:43 pm, "William Connolley" <[email protected]> wrote: > 2009/1/11 Roger Coppock <[email protected]>: > > > On Jan 10, 3:52 pm, "William Connolley" <[email protected]> wrote: > >> 2009/1/10 Roger Coppock <[email protected]>: > >> > On Jan 10, 2:07 pm, "William Connolley" <[email protected]> wrote: > >> >> 2009/1/10 Roger Coppock <[email protected]>: > >> >> > 2008 CO2 Level at 650,000-Year High > >> > not to mention that the EPICA core goes back > >> >> futher. And anyway we know its on a 40Myr high. > > >> > Would you have a cite for these data? > >> > Are they reliable and robust results, > >> > as certain as the 650,000-year claim? > > Yes. > > >>http://doi.pangaea.de/10.1594/PANGAEA.710901?format=html > > > That's one study back to ~800,000 years. > > To be conservative with one's claims, > > one needs confirmation. > > Errm, there is only one source for the 650kyr data too. > > > How do "we" know it's 40,000,000 years > > as certain as the 650,000 year claim? > > We don't. And I made up 40 Myr. But its about right. The point is that > we know full well that CO2 hasn't been this high for ages. We don't > have good measurements from 1Myr ago, but we can be pretty sure its > was within the std preindustrial range then too. > > -William > > -- > William M. Connolley |www.wmconnolley.org.uk| 07... --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
