Professor of Geophysics
Co-Director of the Lorenz Center
I am a theoretical scientist. My current interests focus on understanding how the organization of the natural world emerges from the interactions of life and the physical environment. This work uses mathematics in addition to statistical and nonlinear physics.
The carbon cycle and its coupling to climate are central to the effort. Despite the huge societal interest in such problems, fundamental mysteries remain unsolved. For example, how do global biogeochemical cycles arise and evolve? Are they stable? How do they impact the stability of climate? To address such questions, I typically construct simple mathematical models that predict or explain observational data. One recent result identifies characteristic climate-carbon cycle disruptions and their relation to mass extinction. Another shows how simple physical mechanisms lead to temporal scale-invariance in microbial respiration.
I've contributed to research in each of my department's sub-disciplines, and statistical and nonlinear physics more generally. A unifying theme is the dynamics of complex systems.
I majored in applied mathematics as an undergraduate at Brown, and obtained my Ph.D. in geophysics from Stanford. When MIT hired me as an assistant professor, they thought they were strengthening their program in seismology.
I instead pursued other interests. Over the next decade or so, I worked on cellular automata models of fluid dynamics, focusing on the dynamics of interfaces in two-phase flow. After co-authoring a book on the subject, it was time to move on. The work on fluid interfaces led to research in pattern formation and the branching of river networks. My current interests began when I became fascinated with the causes of mass extinction. I started by viewing major past environmental fluctuations in terms of nonlinear dynamical systems. Further progress required that I learn more about how the carbon cycle works.
Attention in the press and elsewhere resulting from my group's work is collected here.
Interdisciplinary, curiosity-based research in climate science needs an environment to foster it. To meet that need, Kerry Emanuel and I founded the Lorenz Center, named after our former colleague Ed Lorenz, the founder of chaos theory. Raffaele Ferrari and I now co-direct the Center.
Lecture courses (course materials are available at the links)
Recent seminar courses
A list of current and past students and postdocs is here. Please contact me if you're interested in working in my group.