Comments on: Dinosaur extinction a result of geo-sequestration?

By: Jennifer Marohasy

Jennifer Marohasy — Sat, 07 May 2005 09:20:54 +0000

PS Temperatures during the big ‘greenhouse’that corresponded with the about 165 million year reign of the dinasaurs are thought to have been comparable to temperatures during the previous ‘greenhouse’ (i.e. period that preceeded the Permian-Carboniferous Ice age). But Co2 levels where thought to be much much higher during the earlier ‘greenhouse’.

By: Jennifer Marohasy

Jennifer Marohasy — Sat, 07 May 2005 09:02:33 +0000

On being a skeptic there is worse – I was actually quoting from a piece by Ian Plimer, Prof of Geology at Melbourne Uni and acknowledged climate skeptic, wrt the “runaway greenhouse effect”!!! But note I opened with the words “thought to have occured”!
The point I was hoping to make though, is that sequestration can be offset by volcanic eruptions.

By: Graham Young

Graham Young — Fri, 06 May 2005 16:48:16 +0000

Tell me more. I thought you were fairly sceptical of the possibilities of a “runaway greenhouse effect”. But now you’re citing one from 90 million years ago.
As the source of my musings was really trying to understand what might happen with higher greenhouse gases using what has actually happened in the past as a better modelling guide than anything today’s climate scientists are likely to come up with, this sounds promising as a way of exploring the issue.
It doesn’t really answer the questions about dinosaur extinctions, because there were obviously a number of them over 165 million years. Perhaps the dimming from the eruptions did for them at the time of your eruption by cooling the earth and limiting plant growth, and then another hotter period helped other dinosaurs to thrive, with final extinctions occurring because 25 million years after your event the CO2 levels had dropped back again and the earth cooled for greenhouse reasons.

By: Jennifer

Jennifer — Fri, 06 May 2005 16:31:32 +0000

Hey Graham, Your hypothesis doesn’t correlate with the variations in Co2 levels. The carbon sequestration during this long period was offset by various volcanic eruptions. For example, a minor mass extinction is thought to have occured 90 million years ago when volcanos erupted enmass in the Indian and Pacific oceans and belched out lots of C02 resulting in a runaway greenhouse effect! Now give us the link to that website?