Modeling as a Way of Learning About Complexity of Earth Systems

Dave Bice, Professor of Geoscience, Penn State University

For the last two decades, I've been fascinated by the complexity of Earth systems and have made teaching about these systems one of the main foci of my career. I have found that my own personal understanding as well as student learning has been greatly enhanced through the use of models. To my mind, the beauty of models is multifaceted: 1) they allow for experimentation as a way of learning; 2) they force us to think about quantifying things; 3) they provide a unifying framework for discussing processes; and 4) they force us to look for and describe relationships and feedbacks. Models alone are not enough for understanding all of the complexity of Earth systems, but I think they are essential tools.

How did I get to this point? I went to graduate school at Berkeley in the mid-eighties thinking that I was going to become an all-purpose, field-based stratigrapher/structural geologist/tectonicist, like my mentor Walter Alvarez. To a certain extent, this is what I still do, but I also spend a great deal of time working with and teaching with numerical models of all kinds of Earth systems. This evolution was a natural outgrowth of my environment – Walter filled our office with computers, my classmate Lung Chang taught me how to program, and Walter had this unique way of looking at geology as the result of a vast array of processes with complex causes and effects. Before long, we began to realize the potential power of the computers to help us explore numerically the ideas we were always talking about. This, my slide into modeling began.

As I was about to leave graduate school for my first faculty position at Carleton College, Walter excitedly called me into his office to show me this new program he had learned about that made numerical experimentation with systems so easy – this was my introduction to STELLA. When I got to Carleton, I bought a bunch of computers and started to find ways of including STELLA modeling into class and lab exercises in many of my classes. I found it to be an effective and stimulating vehicle for getting students to think about how earth systems work and how complex the dynamics of these systems can be. Fr the most part, I was tinkering with modeling these systems because I was busy with the task of teaching a crowd of wonderfully curious and fantastically talented students.

I finally got serious about developing a more comprehensive set of earth systems models during a sabbatical leave, which gave me the time to learn about the how to represent some of the key features of the climate system in the form of simple models. I created a web page presenting these materials in the hopes that they would be useful to like-minded educators (Exploring the Dynamics of Earth Systems (more info) ), and have been pleased to see that many people have made use of these resources. My interest in these models is now in a sort of renaissance period due to interactions with my colleagues at Penn State, many of whom are catching the STELLA bug.

I include along with this essay some examples of teaching exercises using STELLA, exploring Daisyworld and the thermohaline circulation of the north Atlantic.