Ice-sheet topography changes in North America affect teleconnection patterns on glacial time scales

The topography of the Laurentide Ice Sheet (LIS) during glacial periods, particularly the Last Glacial Maximum (LGM), played a pivotal role in shaping atmospheric circulation and teleconnection patterns. This study investigates the impact of LIS elevation changes on global atmospheric dynamics using fully coupled paleoclimate simulations with the isotope-enabled Community Earth System Model (CESM) version 1.2. Previous studies have shown that a higher LIS elevation significantly amplifies Arctic warming, reducing the equator-to-pole temperature gradient and influencing jet streams and stationary waves (Liakka & Lofverstrom, 2018 ; Beghin et al., 2014 ; Lofverstrom et al., 2014). This mechanism may also extend to the Southern Hemisphere, affecting teleconnection pathways.

By systematically modifying LIS elevation, we explore its role in altering large-scale atmospheric circulation features such as the Intertropical Convergence Zone (ITCZ), Southern Annular Mode (SAM), and Walker circulation, as well as modes of variability including El Niño–Southern Oscillation (ENSO). We show the critical influence of LIS topography on global teleconnections and how ice sheet dynamics shaped glacial climate variability and atmospheric feedbacks.