James T. Randerson

2005 James B. Macelwane Medal Winner

James T. Randerson received the James B. Macelwane Medal at the AGU Fall Meeting Honors Ceremony, which was held on 7 December 2005 in San Francisco, Calif. The medal is given for significant contributions to the geophysical sciences by a young scientist of outstanding ability.


It is indeed an honor and a privilege to present the citation for James T. Randerson’s James B. Macelwane Medal.

Jim Randerson’s scientific contributions focus on the very difficult problem of determining the fate of CO2 put into the atmosphere by fossil fuel burning. Currently, just under half of the carbon humans emit to the atmosphere accumulates there; a portion of the rest dissolves in the oceans. The remainder, which varies in magnitude from year to year and over decades, is thought to be taken up on land, though the mechanisms responsible for this uptake have remained an enigma. Jim uses observations and models to test hypotheses about what factors control the uptake and loss of carbon by land ecosystems, which put his research at the heart of one of today’s most debated issues in global environmental change.

Jim began work in biogeochemistry as an undergraduate at Stanford University [Calif.] in 1991, when he became a research assistant to Chris Field at the Carnegie Institution of Washington [Stanford, Calif.]. During this period, Randerson helped develop the Car-negie Ames Stanford Approach (CASA) model, one of the first global biogeochemistry models. In subsequent Ph.D. thesis work with Chris Field and in a postdoc with Inez Fung at the University of California, Berkeley, Randerson applied CASA in innovative ways to better understand the global carbon cycle.

Among the insights this work has produced are a demonstration that observed variations in CO2 and carbon isotopes are inconsistent with the hypothesis that the global biosphere is growing faster due solely to CO2 ‘fertilization,’ a deeper understanding of the processes that shape the seasonal cycle of atmospheric CO2, and a demonstration of the importance of fire in the rapid rate of rise of CO2 during the 1998 El Niño event. What is truly innovative and unique in Jim’s approach to these problems is his ability to understand disparate data sets, and combine them with modeling to provide answers to well-posed and timely questions.

But there is more. As a new assistant professor at Caltech, Randerson made the relatively radical move from being mostly a modeler to starting his own measurement program involving stable isotopes and eddy covariance measurements of energy, carbon, and water exchange between boreal forests at the atmosphere. His goal was to constrain some of the sensitivities in the models of ecosystem carbon balance in high-latitude systems, in particular the role of fire, which was not well incorporated in biogeochemical models. Jim’s measurements in boreal forests of Alaska and Siberia are providing much needed measurements of the physical and biogeochemical feedbacks between land surface and atmosphere.

Jim Randerson is a caring and thoughtful mentor to his students. He is a delightful colleague who is generous with his time and ideas, and his enthusiasm for a problem is infectious. He is conscientious in his service to the scientific community, as attested to by two Editor’s Citations for Excellence in Refereeing for Global Biogeochemical Cycles. In summary, Jim is a very special person, a valued colleague, and a brilliant scientist, and is truly deserving of the honor bestowed by the James B. Macelwane Medal.

—SUSAN TRUMBORE, University of California, Irvine


Thank you, Sue, for that very generous citation and also for your enthusiasm and commitment to strengthening the biogeosciences within AGU. Your research has inspired me, and it is wonderful to now work closely with you. I also thank Michael Prather for nominating me and other faculty within the Department of Earth System Science at the University of California, Irvine for their collegiality and support.

I am deeply honored to receive the Macelwane Medal. I share this medal with extremely talented collaborators, postdocs, and students I’ve had the privilege of working with over the last decade. The Macelwane Medal represents an affirmation of our work together. This is especially true for my first group of Ph.D. students, including Nicole, Lisa, Nir, and Zhonghua. I also share this with my collaborators, including the GFED fire team, scientists working on the Delta chronosequence and at the Northeast Science station in Cherskii [Republic of Sakha, Russia], and colleagues at Caltech and the National Center for Atmospheric Research.

I thank my mentors who have helped me develop as a scholar and scientist. These include Chris Dickerson and Margaret Maple for teaching me how to think creatively and independently in high school, Scott Jenkins and Dave Skelly for introducing me to oceanography and for letting me hang out at SIO [Scripps Institution of Oceanography, San Diego, Calif.] during summers, and Jim Simpson [SIO] for building my analytical skills. I am indebted to Chris Field for his generosity with his time and advice as a graduate advisor and for, among other things, rescuing me from a snowfield behind Mount Conness, [Calif.], on a field trip in 1994. I also thank my postdoc advisors, Inez Fung and Terry Chapin-Inez for providing me with much needed perspective on how to navigate as an assistant professor and Terry [University of Alaska, Fairbanks] for serving as a role model of how to conduct oneself while doing fieldwork. The Fung/Mooney/Sellers NASA IDS [Interdisciplinary Science] team on biosphere-atmosphere interactions created a unique and truly remarkable context for learning about the Earth system and one that had a profound influence on my development as a young scientist.

Continuing a thread from Sue’s citation, it is interesting to consider that some fields within the geosciences, including my own, are rapidly transitioning from a state of being data-poor to being data-rich. On good days this makes it incredibly exciting to study global change, given the large and diverse data streams now available from satellites, the sequencing of genomes, and expanding air, land, ice, and ocean sampling programs. On other days I find the possibility of such a trend a little daunting, with respect to how I spend my time and to how best to train the next generation of students. In this regard I’m grateful to my advisors for providing me with a sense of how difficult and valuable it is to take the time to identify important questions.

It means everything to me to be able to share this with Kathleen-my spouse and soul mate. I’m grateful for the tremendous support I’ve received from my family, including Kathleen, my sister, Maria, and my mom, Laurie, all of whom are here tonight. Finally, I thank my father, Tremper, who was unable to join us, but whose love and support made it possible for me to become a scientist.

—JAMES T. RANDERSON, University of California, Irvine