John T. Andrews

Arctic Workshop

2021 Workshop

The 50th Arctic Workshop will recognize John's many contributions at special Saturday event as well as with talks by some of his former students. John is still an active researcher, he may give a synopsis of his current research during the Workshop.

Workshop history

The workshop grew out of a series of informal annual meetings started in 1970 by John. The purpose of the early meetings was to give graduate students an opportunity to present their ongoing research, gain experience in public speaking, and obtain feedback from more senior researchers. Subsequent meetings retained this emphasis while simultaneously expanding the contributions of professional researchers.

See more Workshop history, including a list of 50 Workshop locations.

Early career

John began his career at the University of Nottingham after making the crucial decision to change his undergraduate focus (and likely career path) from rugby to geosciences. He then moved to McGill University for his Master’s degree, where he was first introduced to the Canadian Arctic. After completing his M.Sc. thesis in 1961, he was hired by the Department of Energy, Mines, and Resources in Ottawa, and started fieldwork on Baffin Island. He was able to use his research for the Canadian government as the basis for a Ph.D. at the University of Nottingham, which he completed in 1965. In 1968, he accepted a position at the University of Colorado, where he initiated the successful and influential Baffin Island research program that has been running continuously since.

Relative sea level and ice thickness

John's benchmark work in the 1960s and 1970s on developing records of relative sea level change clearly revealed the isostatic response to loading by the Laurentide Ice Sheet. At the same time, John developed the first history of changes in the area and thickness of the ice sheet during the last deglaciation. This work formed the geological underpinning for research done in collaboration with Richard Peltier to derive the rheology of the solid Earth as well as to develop a forward model to predict relative sea level histories around the globe. Such models have now become central in evaluating our understanding of Earth’s rheology as well as in understanding past, present, and future regional sea-level variability.

Deglaciation and energy budget

His 1973 analysis of the energy budget required to deglaciate the Laurentide Ice Sheet demonstrated that there was a substantial energy deficit from insolation forcing alone, identifying, for the first time, the importance of ice-sheet instabilities and feedbacks in causing the rapid deglaciation. This was the first demonstration of the 100-kyr problem that continues to challenge the paleoclimate community, and has implications that continue to resonate today over our understanding about the future of Earth’s present ice sheets.

Ice sheet modeling

His work with graduate student Molly Mahaffy in the 1970s led to the first three-dimensional numerical ice-sheet model, the basic components of which remain the standard for many ice-sheet models today. At the same time, John and colleagues addressed the question of the last glacial inception, including using the ice-sheet model to first demonstrate that Milankovitch forcing alone was insufficient to initiate ice-sheet growth at the rate inferred from the geological record, implying the need for additional feedbacks on that forcing.

Importance of ice sheets

Why is John's work of such significance? Ice sheets, past and present, represent a key component of the global climate system, and variations in their size have been the dominant control on global sea level for much of Earth history. Understanding how ice sheets (present and past) respond to and amplify climate change thus represents one of the grand challenges in the geological sciences.

Much of the content in this page is based on John's 2016 Penrose Medal (Geological Society of America)

• Peter Clark's citation
• John's response

Photo at left and in website banner: John Andrews on board the C.S.S. Hudson, Kangerlugsuaq Fjord, East Greenland, Oct. 1993. Photographer: Jaia Syvitski.