Enhanced Orbital‐Forcing Sensitivity of Northern High Latitude Temperatures in the Late Cretaceous Relative to Modern Geography

Abstract Orbital forcing is a primary driver of paleoclimate change, but its influence on deep time climates, particularly in the polar regions of the Late Cretaceous, is poorly understood. Here, we conduct climate simulations with an atmosphere‐ocean‐vegetation coupled model, MIROC4mV, to investigate the response of northern high latitude temperature using Maastrichtian geography. By accounting for the full range of orbital parameters, the model successfully reproduces proxy‐based estimates of polar temperatures. Our experiments show that the sensitivity of northern high latitude surface temperature to orbital forcing is higher with Maastrichtian geography than with Modern. In particular, Maastrichtian geography greatly amplifies obliquity‐driven fluctuations due to the large continental landmass at northern high latitudes and the absence of ice sheets. These findings highlight the importance of considering the full range of orbital sensitivity when interpreting geological records from deep‐time periods.