Josh, I don't think the runaway global warming is a valid model mostly because of the buffering capacity of the oceans with respect to CO2. If you look at the Cretaceous Period it was 10 to 12 degrees warmer than today. A number of models had dramatically higher levels of CO2 in the atmosphere at the time. One model for the final dinosaur extinction suggests that a rapid drop of the CO2 levels resulted in a drastic drop in atmospheric O2 pressure that dealt the last death blow to the dinosaurs. It was suggested in the model that a turn over of the ocean waters - cause unknown - was responsible for bringing the vast amounts of bottom water understaurated with CO2 to the surface. The linkage idea is that the pressure of CO2 is related to the O2 production by plants. This model has some strong support. The pattern of extinctions was one in which a wide variety of different classes of species went extinct, while others were virtually unaffected. This is not what would be expected from a catastrophic model. Essentially the argument is that animals with a poor Oxygen uptake structures dies of severe asthma attacks. The dinosaurs could not survive with their passive lung structures, while all of the existing mammal and modern bird species survived. A primitive bird family with dinosaur-like breathing all died. There was virtually no change in plant and insect species. All consistent with the change in atmospheric composition.
Anyway with regard to the future of the Earth with much higher CO2, modern birds and mammals developed under similar conditions. The CO2 would not reach toxic levels. Mollusks have survived since the beginning of the Cambrian period, with even higher CO2 levels than that and so have diatoms, and corals. The corals may die out because the temperature change and water level changes may be such that they can't adapt, but I doubt if ocean acidity is problem. There would be some areas uninhabitable - like Death Valley - uninhabitable for practical purposes - even though people did live there for awhile - , but these would be isolated areas and not wide band of uninhabitable land. Arctic ice and Antarctic ice would be lost, These areas would still get snow, but the glaciers would be gone. Some mountain glaciers would survive, but most would be gone Places like Mt. McKinley would still have glaciers, but likely much smaller. This level of CO2 returning is very unlikely but remotely possible. I don't believe the runaway greenhouse warming scenarios are even remote possibilities. Catastrophic scenarios always get more attention than reasonable ones. Ed Frank Check out my new Blog: http://nature-web-network.blogspot.com/ (and click on some of the ads) --~--~---------~--~----~------------~-------~--~----~ Eastern Native Tree Society http://www.nativetreesociety.org Send email to [email protected] Visit this group at http://groups.google.com/group/entstrees?hl=en To unsubscribe send email to [email protected] -~----------~----~----~----~------~----~------~--~---
