Eleni’s “Icehouse” class at Bowdoin College

A few days ago I had the opportunity to lead a discussion on the Descent into the Icehouse in Dr. Michéle LaVigne’s upper level undergraduate course, ‘Earth climate history’ at Bowdoin College (Brunswick, ME, USA). During the class, which was arranged as a video conference, the students discussed a selection of literature related to the Descent into the Icehouse project (Pearson et al. 2009, Bijl et al. 2009, Beerlingand Royer 2011).

We had a lively discussion and several issues have been raised, some of the most interesting ones were:

1.  The timescales of global climate change are very different between early Cenozoic and future predictions; how does understanding the Cenozoic help us predict the future?
2. Ice caps seem to show a nonlinear response to climate forcing during melting due to a hysteresis effect, but will this hold true on current time scales? Could this response eventually manifest itself into hastened melting as opposed to persistence of ice caps?
3. On early Cenozoic time scales, how much does the distance of the Earth’s orbit from the sun implicate atmospheric CO2 levels and how much of that theory is guesswork?

 The most intriguing point to me was the question if the change in sea surface temperature was due to decline carbon dioxide concentrations, why/how did the tropics remain fairly stable during the Eocene? What are the possible mechanisms such as different ocean circulation, different atmospheric circulation, or something having to do with the uneven radiation from the sun based on latitude?

 Well…. the answer to this question will have to wait until we have generated more data…

Overall, it was a great experience that I would certainly do again.

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