> The CO2 drop was due to either the evolution of grasses, which can > function at lower CO2 levels, or the erosion of the new Himalayas > mountain range which can drawdown atmospheric CO2. > There would have been evidence for the asteroid: a crated or iridium > layer, and the same with volcanic activity, but neither would have had > a permanent effect. > > Cheers, Alastair.
Ok I did a little research on the Ecocene and Oligocene epochs and now I'm buying it even less. It sounds to me like they just jumped to the conclusion based on their computer model. We're talking 35 million years ago, I mean we can't even get all the factors and variables right in the present. Garbage in garbage out, don't know if you ever read Hitchhikers Guide to the Galaxy but that computer answering the Purpose Of Life question is a perfect example :o). Before I get into it, I think your attributing the CO2 drop to the evolution of grasses is wrong, its the other way around forests and trees absorb more CO2, grasslands would absorb less and so keep more CO2 in the air. The Ecocene era which began 55 - 100 Million years ago was marked by volcanic activity in Europe and tectonic activity. India collided into Asia. South America broke with North America and Australia with Antarctica. Oh by the way there was a famous asteroid hit 65 Million years ago. The beginning of the Ecocene was marked by "an extraordinary burst of global warming" At the end of that period ocean temperatures were around 75 degrees F. Whats a more plausible and reasonable scenario is that which I've seen on two sites. When Australia and Antarctica were connected the ocean currents would mix warm and cold waters to allow for homogenous temperate climate. When Australia and Antarctica broke apart that allowed the formation of what we now call the Circum-Antarctic current. And there is your cause for the Global Cooling and your drop in CO2 levels because all the forests gave way to grasslands. http://www.enotes.com/earth-science/eocene-epoch http://www.associatedcontent.com/article/164599/earths_eocene_epoch.html?cat=58 --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
