Jiang Zhu, University of Michigan Ann Arbor, Ann Arbor, MI, United States, Christopher J Poulsen, University of Michigan, Earth and Environmental Sciences, Ann Arbor, MI, United States, Jessica E Tierney, University of Arizona, Geosciences, Tucson, AZ, United States and Bette L Otto-Bliesner, National Center for Atmospheric Research, Climate and Global Dynamics Laboratory, Boulder, CO, United States