Christian Schoof was awarded the 2011 James B. Macelwane Medal at the AGU Fall Meeting Honors Ceremony, held on 7 December 2011 in San Francisco, Calif. The medal is for “significant contributions to the geophysical sciences by an outstanding young scientist.”
Citation
Christian Schoof is a glaciologist with an impressive foundation in applied mathematics who has solved one of the most important and challenging problems of ice sheet dynamics. Words like “elegant” get debased by overuse, but Schoof’s astonishing work on ice sheet grounding line dynamics is both elegant and profoundly significant. The central issue is how the internal boundary between grounded ice sheets and floating ice shelves moves around and whether this motion is subject to instability. This important question has been dodged in most large-scale ice dynamics models, which, in essence, paste together a model of ice sheet mechanics and a model of ice shelf mechanics. Schoof is the first to describe, correctly and for all time, the smooth physics that connects these two entities. In doing so, he has demonstrated that grounding line dynamics need not be stable and that the belief that they are neutrally stable (hence unable to deliver surprising responses) is simply wrong. As a measure of the relevance of this contribution, the Summary for Policymakers in the 2007 Fourth Assessment Report of the Intergovernmental Panel on Climate Change concluded with the much quoted statement, “Dynamical processes related to ice flow not included in current models but suggested by recent observations could increase the vulnerability of ice sheets to warming, increasing future sea level rise. Understanding of these processes is limited and there is no consensus on their magnitude.” Schoof’s work is targeted at removing these uncertainties by closely scrutinizing and, where necessary, correcting the physical basis of numerical ice dynamics models.
Schoof’s most recent contribution on the subglacial hydrology of ice sheets strikes out in a new direction. Alarming images of surface meltwater plunging into the depths of the Greenland Ice Sheet and evidence that this water input can accelerate the rate of ice flow have helped to inspire an apocalyptic literature on the dangers of Greenland meltdown and rapid sea level rise. Schoof shows that part of this concern is based on misconceptions about how subglacial water affects ice sheet flow. By putting together what is known about the contrasting physics of subglacial channels and of spatially distributed subglacial cavities, Schoof has captured the physics of both drainage elements in a single equation that respects the physics yet can switch from one limit to the other. By doing so he shows that high rates of water supply can actually decelerate ice flow: It is the rate of increase rather than the magnitude of the water supply that gives rise to accelerated flow.
Christian Schoof is a gifted physical scientist who can see far into the heart of challenging fundamental problems and then, with great skill, apply mathematics to crystallize new truths. He is making singular and enduring contributions to glaciology by leading the science in directions in which others cannot go. By concentrating on problems that are both important and mathematically challenging, he is setting a path uniquely his own yet fundamentally rewarding to the rest of us.
—Garry Clarke, Department of Earth and Ocean Sciences, University of British Columbia, Vancouver, Canada
Response
Thank you, Garry. In response, I can only say that I have simply been very lucky. Glaciology has grown enormously in the past decade, and I would not be here were it not for the many people who have made it such a rich and rewarding field of study. Nor would I be here but for the people who have guided me personally along the way.
Like many beginning graduate students, I went into glaciology primarily because I loved the mountains. Felix Ng showed me how it was possible to combine that with a passion for physics and mathematics. He introduced me to Andrew Fowler, who would become my doctoral supervisor at Oxford and teach me almost everything I know about modeling and who remains one of the biggest influences on my work. Andrew in turn later suggested I work with Garry Clarke at the University of British Columbia (UBC), who continues to be a source of inspiration even long after my postdoc with him has ended.
Along the way, I have benefited enormously from the help of many colleagues. Too many, in fact, to name, mostly because I worry I would leave someone out. I do want to single out Richard Hindmarsh, however, who has always been generous with his support and ideas. In 2005 we found ourselves exploring similar approaches to coupling ice sheets and ice shelves, and had it not been for Richard’s imminent departure to Antarctica, I would have hoped we might publish our work together. This was not to be, as Richard submitted his own manuscript before heading south. In the end, my own paper went just a little further than his. It became the work I am best known for, and it owes a great deal to Richard.
After a somewhat turbulent search for employment, I ended up staying at UBC, where I have been privileged to work in an exceptionally collegial environment. I am especially grateful to Mark Jellinek and Neil Balmforth for their support, as well as to Gwenn Flowers at Simon Fraser University, without whom I would not have been able to start a field program, and to all my undergraduate and graduate students.
Garry characterized my work as unique. I would disagree; I simply found myself in a rapidly expanding field with a background that was, at the time, still somewhat unusual. The enormous growth that glaciology has experienced has also brought with it a new generation that uses the same methods that I do, only they do it better. Perhaps receiving a young scientist award is a sign that it is time to make way for that younger generation, and I am grateful to several postdocs, in particular, for a number of wonderful collaborations: Faron Anslow, Tim Creyts, Dan Goldberg, Ian Hewitt, Alex Jarosch, Sam Pimentel, and Mauro Werder.
My biggest thanks go to my parents, who have supported me throughout, and to my partner, Valentina, and son, Oliver. Research can be a somewhat obsessive and selfish pursuit, and without their long-suffering patience much of my work would never have been possible.
—Christian Schoof, University of British Columbia, Vancouver, Canada