Ph.D., MIT, 1980
PhD. Honoris Causa Stockholms Universitet 2015
Chevalier de l'Ordre des Palmes Academiques
Fellow, American Geophysical Union
Fellow, American Academy of Arts and Sciences
King Karl XVI Gustaf Professorship in Environmental Science (Stockholm 2014/2015)
John Simon Guggenheim Fellow (1996/1997)
Note: On 1 July 2015 I took up the post of Halley Professor of Physics at the University of Oxford, and while I retain a number of collaborations with my colleagues at the University of Chicago, I am no longer an active faculty member there. At some point this site will be moved to Oxford. I am building a new group there covering a range of projects regarding planetary climate, including both exoplanets, Earth paleoclimate and global change problems. I can still be reached at the geosci email address on this page, or via the Oxford physics department.
At present, my central interest is in how climate works as a system.
I wish to develop idealized mathematical models that can be used
to address the big questions of climate science: How did the earth
keep from freezing over during the Faint Young sun period in its
history? Why did Earth keep its water while Venus got trapped
in a runaway greenhouse? What possible past climates could exist
on Mars? Why was the Eocene so warm on Earth? What was tropical
sea surface temperature doing during the Last Glacial Maximum?
This involves work at the interface of fluid dynamics and radiative
transfer. My philosophy is to approach this using simplified models
(albeit often ones involving some degree of computation) that
can be understood completely, rather than full-blown General Circulation
Models. Recently, I have been spending a great deal of my time thinking about the climates of the newly discovered extrasolar planets
Although I consider myself primarily a theoretician, modern network and computer facilities make data readily accessible, and I try to provide my students easy access to a variety of data sets and computational resources. We have links to the broader observational and modelling community through a number of collaborative efforts.
I have also maintained an interest in more traditional areas of geophysical fluid dynamics, particularly as related to baroclinic instability, storm track structure, and planetary wave propagation. I am also actively engaged in fluid mechanical research of a more abstract nature, particularly as related to two-dimensional turbulence and mixing in two-dimensional area-preserving flows. In this work there has proved to be good cross-fertilization with ideas generated in active nonlinear research groups in Physics and Astrophysics.