Icy, Moist, Seasonal: Polar Amplification Across the Model Hierarchy

Dr. Nicole Feldl

University of California, Santa Cruz

Monday September 28, 2026, 2 PM ET

Abstract:

Since the 1970s, simulations of climate change have predicted warming that is greatest in polar regions. This polar-amplified warming is ubiquitous, though uncertain in magnitude, in climate models subjected to increases in greenhouse gases and has been variously attributed to the ice-albedo feedback, associated with the retreat of reflective sea ice in summer; the lapse rate feedback, associated with vertically nonuniform atmospheric warming in winter; and changes in energy transport by atmospheric circulations. Uncertainty in projections of Arctic climate change arise in part from incomplete understanding of the interconnected nature of these processes. In this talk, I present a new implementation of an idealized model to isolate the role of sea ice loss in driving polar amplification and global climate consequences. I introduce a framework for uniting feedback analysis and feedback locking and with it highlight a midlatitude cloud contribution to Arctic warming. Lastly, I reconcile disparate answers to a fundamental question: is polar amplification an inherent feature of a moist circulating atmosphere or is it dependent on the presence of sea ice? The three parts of the talk illustrate a crucial coupling among high-latitude feedbacks that operates across the seasonal cycle, involves ocean-atmosphere interactions, and relies on the presence of ice thermodynamics to capture the seasonality of polar warming.

Biosketch:

Nicole Feldl is a professor of Earth and Planetary Sciences at the University of California, Santa Cruz. Her research investigates a range of topics within atmospheric and climate dynamics, including climate feedbacks and sensitivity, large-scale atmospheric circulation and moisture transport, and polar amplification of climate change. Through a combination of hierarchical numerical modeling, theory, and observational data analysis, she seeks to expose the physical mechanisms underlying changes in past, present, and future climates. She earned a PhD in Atmospheric Sciences from the University of Washington, an MS from the University of Colorado, and a BS from the University of North Carolina at Chapel Hill. She received the National Science Foundation CAREER award (2018) to support her research on polar climate dynamics.

Zoom Information

Event site: https://go.umd.edu/feldl

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Resources:

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Seminar recordings on Youtube: https://www.youtube.com/user/ESSICUMD

For IT assistance: Cazzy Medley: cazzy@umd.edu