You have these conversations. Been a quiet evening, tinkering. Daughter lounging on the couch, exhausted after over tiring school day, heightened by ever-increasing examination pressure.
I walked into the room and a hackneyed film of a flock of Tyrannosaurus rex stampeding but with the commentator observing that actually seventy per cent of dinosaurs had been herbivores. But we all know this and Mia says how dumb the teachers were in handling the subject. It gave me the chance to bring out one of my pet theories – maybe all those ginormous herbivores ate all the vegetation. “Yeah, and then there were all those beasts breathing out loads and loads of CO2 and using up all the oxygen” she put in, taking the idea on board “Dinosaur induced climate change” she added, triumphantly, laughing.
I agreed and we talked over the details and the irony of the event maybe having been caused before only totally naturally. There are ecological models where total extinction arises in closed systems. For example foxes and rabbits when if the normal balance between carnivore and predator is disturbed it can quickly result in both populations being lost. On a larger scale though effects are global and can be dramatic. Take “Arctic plant diversity in the Early Eocene greenhouse” – http://rspb.royalsocietypublishing.org/content/early/2011/11/08/rspb.2011.1704 – by Guy J. Harrington1, Jaelyn Eberle, Ben A. Le-Page, Mary Dawson and J. Howard Hutchison.
Some take this to suggest that our present day climate change is not a problem. I answered one such with the following note:
“Yes the world was warmer, CO2 levels were higher and so were sea levels all those years ago. With today’s frozen North Pole then a large, brackish lake, profoundly full of Azolla – http://www.uu.nl/faculty/science/en/organisation/depts/biology/research/chairs/biomarinesciences/people/judithbarke/Pages/default.aspx – you would expect Northern Canadian mainland to be forested.
“Noone can now determine how fast we might return to such conditions from our current starting point. I’m not sold on the idea of climate catastrophe, feeling that nature buffers change if at all possible. The Gaiea principle, I guess, aka Lovelock thinking. However we have undoubtedly tipped the balance in the direction of all the above most of which are great. Except the dramatic sea level rise which has to happen now. Only question is, as I say, how long the flooding will take.
“Doggerland, the huge land mass which joined the UK to mainland Europe for 30000 years or so up until around 8000 years ago – linking Yorkshire, East Anglia and Kent to Denmark, Germany, Holland, Belgium and France – was finally submerged, it seems, when an enormous ice sheet plunged into the sea from the Scandanavian mainland, creating a cataclysmic tsunami.
“At present the Greenland Ice Sheets are being underwashed by ever increasing amounts of meltwater…………………..”
What seems to have happened then, though, echoes the proposed Dinosaur Induced Climate Change. Simply, the Azolla kept on growing, with each annual life cycle precipitating more carbon into a seabed sump, as moss do today into the permafrosted peats of the Arctic circle. This reduced atmospheric carbon dioxide allowed atmospheric cooling and, it is suggested, this led to the eventual demise of the Azolla population as the Polar water froze.
It seems more than plausible, then, that species other than humans could have enacted, albeit without any understanding of the resultant calamities, the processes leading to climate change. I can put up similar arguments for the causation and eventual regression of the later, cyclical glaciations together with a reasonable catalogue of evidence.
Now, however, we do not have the excuse of ignorance that the dinosaurs had, or that they were plants, which the Azolla can justly cry. We are perceptive beings with a detailed understanding of the impacts our actions are having. I feel that we have no excuse to ignore the present situation and, further, if we don’t watch out, the joke’s most certainly going to be on us.