Advisors: Dr. Seth Campbell, Dr. Brenda Hall
I study past and current ice-volume changes in Antarctica, Patagonia and Alaska with the aid of ground-penetrating radar, other geophysical methods and a range of paleoclimate proxies. Currently, I am part of the on-going International Thwaites Glacier Collaboration and our team will use geologic evidence to put the rapid loss of ice volume in this region into an historical context. During the summers, I work with the Juneau Icefield Research Program in Alaska to teach undergraduate and high school students about the cryosphere and how changes in the Arctic relate to changes they are seeing back home.
Additionally, I have worked several years as a conservationist in Patagonia and Costa Rica with Round River Conservation Studies. My interests also include the connections between the cryosphere and biosphere as they are intricately linked around the world. Especially so in fast-changing ecosystems such as around the Southern Patagonian Icefield.
Braddock, S., Hall, B.L., Johnson, J.S. et al. Relative sea-level data preclude major late Holocene ice-mass change in Pine Island Bay. Nat. Geosci. 15, 568–572 (2022). https://doi.org/10.1038/s41561-022-00961-y (https://www.nature.com/articles/s41561-022-00961-y)
Johnson, J. S., Venturelli, R. A., Balco, G., Allen, C. S., Braddock, S., Campbell, S., Goehring, B. M., Hall, B. L., Neff, P. D., Nichols, K. A., Rood, D. H., Thomas, E. R., and Woodward, J.: Review article: Existing and potential evidence for Holocene grounding line retreat and readvance in Antarctica, The Cryosphere, 16, 1543–1562, https://doi.org/10.5194/tc-16-1543-2022, 2022.
Upcoming and Recent Projects:
2022/23, Pine Island Glacier, West Antarctica. A team of scientists and drillers with the International Thwaites Glacier Collaboration will aim to uncover the Holocene ice history around Pine Island Glacier. Did glaciers in this region retreat and readvance to their current extent in the recent past? If so, what does that mean for model projections that suggest the current retreat of Thwaites and Pine Island glaciers may be irreversible? These are questions we aim to address by drilling 30 -50 m beneath the current ice surface to retrieve rock samples from beneath the ice. We can then measure for levels of certain cosmogenic isotopes such as C14 to reveal if the rock surface was exposed to cosmogenic rays during the Holocene – therefore revealing if the surface of the ice was at least 30-50 m lower in the recent past. Stay tuned for results!
Kahiltna Glacier, Denali National Park, Alaska. We will use ground-penetrating radar to determine the water content within snow and firn layers on the Kahiltna Glacier over an elevation transect to act as an analog for other mountain glaciers in the region.
JIRP-Upward Bound field camp, Juneau, Alaska. Working with Upward Bound high school students from around the U.S., we will facilitate a field season in Juneau, Alaska that aims to introduce students to a range of opportunities and experiences in the Earth Sciences through hands-on projects, field trips, and activities. The goal of this collaboration between Upward Bound and the Juneau Icefield Research Program is to introduce and promote Polar STEM to students who are underrepresented in the geoscience community.
Summer, 2021: Juneau Icefield, Alaska. As part of the Juneau Icefield Research Program, I participated on the program as teaching and research faculty member. Our goal is to work with students on a range of cryopshere-related projects that serve to teach new skills and to better quantify the rapid rate of change being experienced by the Juneau Icefield.
Coring to get an estimate of the annual snow depth
Fall, 2019: Southern Patagonian Icefield, Chile: A small team will join the Chilean park service (CONAF) on a trip to Bernardo Fjord on the western flank of the Southern Patagonian Icefield to better understand ice/ocean interactions on rapidly-retreating tidewater glaciers. Check out the trip report.
Installing time-lapse cameras to monitor Tempanos Glacier
Spring, 2019: Thwaites Glacier, Antarctica: Cruise to Pine Island and Thwaites glacier aboard the NB Palmer. This was the first field season for research around the Thwaites glacier system as a small piece of the larger five-year International Thwaites Glacier Collaboration between the UK and US. Check out the trip report and recent publication.
Office: contact me via email! email@example.com