NSF Graduate Research Fellowship supports Roman’s research into Last Glacial Maximum – A. Putnam, G. Denton

What triggered the change in climate that caused the Last Glacial Maximum (LGM) — the largest expansion of ice cover across the planet in the last ice age — remains a mystery, one that Zander Roman of Belfast wants to help solve.

When he begins his paleoclimate Ph.D. program at the University of Maine, Roman hopes to identify how much the LGM climate state in the Northern Hemisphere, which occurred 26,000–19,000 years ago, was influenced by carbon dioxide levels, ice sheet feedback and the parameters of Earth’s orbit, which affects the extent of solar energy isolated in the planet. The endeavor earned Roman a National Science Foundation Graduate Research Fellowship.

The three-year fellowship supports graduate students in STEM fields. Roman, a UMaine senior majoring in Earth and climate sciences, is one of three fellowship recipients from UMaine this year, joining Ph.D. students Madeleine (Madi) Landrum and Morgan Stosic.

Roman’s research exploring what caused the change in climate that prompted the LGM, including the possible effects of carbon dioxide levels, ice sheet feedback and planetary orbital parameters, will focus on the Wind River Range in Wyoming. The ridge is located on the western periphery of the Laurentide Ice Sheet, which Roman says is ideal for assessing how much ice sheet feedback affects climate change in the Northern Hemisphere.

Aaron Putnam, an associate professor of Earth and climate sciences, and George Denton, UMaine Libra Professor of Geological Sciences, will collaborate with Roman on the project.

Roman will collect samples from granitic boulders on glacial moraines in the Wind River Range to examine the concentration of Beryllium-10 atoms in them, which will allow him to create a chronology identifying when a glacier deposited the boulders. Using the samples, lidar and drone imagery, Roman also will create a comprehensive geomorphological map of the range which, in combination with the chronology, will reconstruct a glacier and reveal where it expanded and retreated during the LGM.

The resulting reconstruction will be paired with a glaciological model Roman will create for the LGM Wind River Ice Cap, which should reveal the type of climate that caused glacial expansion. Roman will validate his reconstruction by comparing it to similar ones created by Putnam and other UMaine researchers for the Southern Alps in New Zealand.

Finally, Roman says he will work with climate scientist Joellen Russell, the Thomas R. Brown Distinguished Chair of Integrative Science and associate professor at the University of Arizona, to incorporate his reconstruction into Earth System Models (ESMs) for LGM climate to “evaluate the glacial climate state in North America, and globally, within an ESM framework.” The model created will allow them to evaluate how much glacial expansion in the Northern Hemisphere was influenced by carbon dioxide levels, ice sheet feedback and solar radiation insolation resulting from planetary orbital parameters.

Determining what causes ice ages and the various periods within them, such as the LGM, provides scientists a better understanding of how the climate has changed over time and the resulting effects. Knowing more about previous climate changes can help forecast future ones and their ramifications.

“The more we can learn about the climate and how it reacts and how it responds to stimuli — particularly CO2 — the more we can learn about,” how it changes, Roman says. “We’re contributing data to the understanding of glacial climates and the role of CO2 levels and orbital variables on glacial expansion and termination.”

Roman’s passion for paleoclimate science sparked while taking Putnam’s Earth’s Changing Climate course. It further blossomed when Roman joined a four-day expedition to New Zealand, supervised by Putnam and Denton, in spring 2020 prior to the COVID-19 pandemic, which resulted in the creation of glacial reconstructions Roman will use for his project.

After earning his Ph.D., Roman plans to either work in research or educate future scientists. He decided to continue studying at UMaine because of the working relationships he has with several faculty and staff, the quality of climate change research and scholarship at the institution, and its close proximity to family.

“It just seemed like the perfect fit,” he says.

Undergraduate seniors and first-year graduate students interested in a NSF’s Graduate Research Fellowship Program can learn more online. UMaine’s Graduate School and Office of Research Development hosts annual workshops about it. Learn more by contacting Danielle O’Neill at danielle.oneill@maine.edu.