PAOC Spotlights

Climate's Dusty Clues

Thu January 12th, 2012
Helen Hill

David McGee's general interest is paleoclimatology. More specifically, he focusses on reconstructing past changes in extratropical atmospheric circulation and hydrology. He explores this area through studies of dust blown out of the world's drylands and deposited in the ocean; changes in dryland water balance as reflected in closed-basin lakes; and studies of precipitation source and amount recorded in stalagmites. These studies involve a variety of types of data, but at the center of all of them are uranium-series isotopes, which he uses for dating in terrestrial deposits and determination of accumulation rates in marine sediments.

Following an extended visit to MIT last term he now joins the PAOC faculty as an Assistant Professor of Paleoclimate.

In this interview, recorded in November 2011, David shares his excitement about paleoclimatology, dust and his move to MIT.


One of the reasons David cites for his interest in paleoclimate is that for lots of key parts of the Earth’s climate system we only have direct measurements that go back little more than 150 years and for many others only about 30 years: the satellite era. This gives us a very limited range of conditions under which to explore the basic physics of climate. Paleoclimate, literally the study of changes in climate taken on the scale of the entire history of Earth, allows us to see how the climate has behaved under a much broader range of, for example, CO2 levels, orbital configurations, and amounts of ice. It also allows us to better understand the conditions under which life evolved as well as providing a context for understanding other parts of the Earth system, prompting exploration of the interaction between, for example, climate and ocean biogeochemistry or climate and tectonics.

"I’ve always been interested in how we figure out things we can’t directly observe. It's what brought me into geology in the first place. How do we know what’s deep in the Earth? How do we know what the Earth was like in times when we couldn’t observe it?Trying to reconstruct things like winds and precipitation and ocean currents, which we simply have no direct records of, with a degree of precision and accuracy presents an enormous challenge."

“I’m particularly drawn to paleoclimate because of the way in which it integrates so many branches of Earth science. We use geochemical tools. We use archives that are fundamentally geological and so require some understanding of field geology. Finally we have to interpret our geochemical data in the light of how climate physics works in the model world [...] As a paleoclimatologist you find yourself going back and forth between all these different branches of science. It keeps you on your toes and is a lot of fun.”

"Over the next few months and years getting started at MIT, I’m really excited about building a research group and the autonomy that being an investigator affords. After years of being a graduate student and postdoc I’m looking forward to being really part of a department. I look forward to helping make decisions from curriculum to student admissions to everything else that matters and makes the department what it is. As someone who especially enjoys teaching I’m excited about having students, as well as getting back into the classroom. As a graduate student and a postdoc you come into labs that are already functioning where routines and equipment were calibrated and developed before you got there. I am thrilled to be building a lab of my own!"

You can read more about David's Lake Bonneville work in this November's feature article in High Country News.