PhD MIT, 1980
PhD. Honoris Causa Stockholms Universitet 2015
Jean Dominique Cassini Medal 2025, EGU
Chevalier de l'Ordre des Palmes Academiques
Fellow, Royal Society
Royal Society Rumford Medal 2022
Fellow, American Geophysical Union
Fellow, American Academy of Arts and Sciences
Kung Karl XVI Gustaf Chair (Stockholm 2014/2015)
John Simon Guggenheim Fellow (1996/1997)
The Planetary Climate Dynamics group, led by Prof. Raymond T. Pierrehumbert, conducts research on planetary atmospheres, their associated climates, their origins and evolutions. This includes work on Earth climate (including Early Earth, more recent paleoclimate, and anthropogenic climate change), Solar System bodies and exoplanets.
The same fundamental physics (thermodynamics, radiative transfer and fluid mechanics) can be hooked together in a variety of ways to study a diverse range of planetary climate problems (recalling that Earth, too is a planet, and the Early Earth is practically a different planet than the Earth we now live on). Currently my chief interest relates to the climate dynamics of exoplanets, and of the ancient Earth, but there are many general phenomena, such as generalizations of water vapor feedback, that are as important to global change problems on Earth as they are to the climate of exoplanets with permanent magma oceans. My general philosophy is that big ideas come from small models, but three dimensional global circulation models are also included in our toolkit. Even when we use 3D climate models, the emphasis is on using the tool to illuminate fundamental physical phenomena, rather than to provide the greatest realism (at the cost of being understandable). The problems emerging at the leading edge of the subject often blur the boundaries between geology, geochemistry and atmospheric science as atmospheres are dynamic entities which exchange with crustal material, the deep planetary interior and outer space. Besides this class of problems, I am leading research in a number of global change problems that are motivated primarily by their significance for policy. This includes such things as the effect of beef production on climate, and the proper way to assess the relative importance of mitigation of carbon dioxide vs. short-lived greenhouse gases such as methane.
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. Besides that, I am 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 (a subject which has a close affinity with Hamiltonian chaos). Many of these more abstract mathematically motivated lines of research have cross-fertilized with climate dynamic problems of central physical importance, as in the case of dynamical systems analysis of fluid mixing and the problem of water vapor feedback.
We have close collaborations with Astrophysics and Earth Sciences, as well as with climate change research in the Geography department. I am always interested in inquiries from anybody interested in joining in this effort, as undergraduates, DPhil students or at the postdoctoral level.