Amelia E. Shevenell is an American marine geologist who specializes in high-latitude paleoclimatology and paleoceanography. She is currently a Professor in the College of Marine Science at the University of South Florida. She has made notable contributions to understanding the history of the Antarctic ice sheets and published in high-impact journals and, as a result, was awarded full membership of Sigma Xi. She has a long record of participation in international ocean drilling programs and has served in leadership positions of these organizations. Shevenell served as the elected Geological Oceanography Council Member for The Oceanography Society (2019-2021).
Early life and education
Shevenell earned a bachelor's degree in Geology and Studio Art at Hamilton College in New York State. Shevenell worked as a laboratory technician and environmental scientist in Juneau, Alaska, before attending the University of California, Santa Barbara, where she studied Antarctic ice sheet evolution and paleoceanography and earned her Ph.D. in Marine Science (2004). Shevenell was a postdoctoral fellow at the Program on Climate Change at the University of Washington School of Oceanography. From 2007–2011, Shevenell was a lecturer in Earth Sciences and Geography at University College London. In 2011, Shevenell joined the faculty of the University of South Florida College of Marine Science, earning tenure in 2017.
Career and impact
Amelia Shevenell's research is aimed at the evolution of Antarctica's ice sheets over the last 65 million years. Shevenell uses the sedimentological, geochemical, and micropaleontological properties of marine sediments from the deep-sea and Antarctica's continental margins to reconstruct relationships between Antarctica's ice sheets and Earth's oceans, carbon cycle, and climate on million - to decadal timescales. Shevenell's research is relevant to Intergovernmental Panel on Climate Change (IPCC) concerns that ongoing oceanic and atmospheric warming is accelerating polar ice cap melting and global sea level rise. She has participated in eight oceanographic expeditions to the Southern Ocean, several of which are featured in her scientific blogs.
Antarctic ice sheet development during the Cenozoic. Shevenell's research has focused on Antarctic ice sheet development in the Miocene when a spurt of expansion occurred. Her work discovered that Southern Ocean cooling during the Middle Miocene Climate Transition occurred before the expansion of Antarctica's ice sheets at ~14 million years ago. Shevenell has since shown that progressive ice sheet expansion on Antarctica began around 16 million years ago, during the Miocene Climatic Optimum, when average global temperatures were warmer than present. Ice growth was paced by changes the eccentricity of Earth's orbit around the sun. Another study established that glaciers reached the Sabrina Coast of East Antarctica by at least the late Paleocene to early Eocene. This finding was counter to earlier studies that placed the beginning of ice expansion in Antarctica at the start of the Oligocene roughly 34 million years ago.
Carbon cycling in high-latitude oceans. In a study of Holocene marine sediments in the western Pacific Shevenell found evidence for increased upwelling in the North Pacific. The increased upwelling was caused by stronger winds, which in turn released more CO2 into the atmosphere enhancing global warming during the Holocene and the shrinkage of ice sheets. Thus, demonstrating that a possible cause of the warming was a change in ocean circulation.
Holocene ocean temperature and climate evolution of the western Antarctic Peninsula. TEX86 proxy analysis of sediments from the western Antarctic Peninsula continental shelf documented the changing influence of warm Circumpolar Deep Water on regional glacier and sea ice extent since the last deglaciation, ~13,000 years ago. Cooling rather than warming occurred, driven by changes in local solar irradiance associated with changes in Earth's orbit. At present, atmospheric connections to the tropical Pacific allow warm ocean waters to move onto Antarctica's continental shelves, melting regional glaciers. Shevenell's research indicates this process has occurred in past warm climate intervals, and will likely continue as Earth's climate continues to warm.