Climate Dynamics Group
at the University of California, Santa Cruz

Since the 1970s, simulations of climate change forced by increased CO₂ concentrations have predicted warming that is greatest in polar regions. This polar-amplified warming 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, which we strive to disentangle through creative modeling experiments and novel statistical techniques.

This research is funded by the National Science Foundation under Award 1753034.

A random sample of the projects from this collective includes:

• Process drivers, inter-model spread, and the path forward: A review of amplified Arctic warming
• Sea ice loss, water vapor increases, and their interactions with atmospheric energy transport in driving seasonal polar amplification
• A semi-analytical model for water vapor, temperature, and surface-albedo feedbacks in comprehensive climate models
• Robust polar amplification in ice-free climates relies on ocean heat transport and cloud radiative effects
• Contributions to regional precipitation change and its polar-amplified pattern under warming

The energetic perspective on the changing large-scale atmospheric circulation focuses on interpreting changes in the equator-to-pole gradient of atmospheric energy. Feedbacks, by characterizing that anomalous gradient, enable a diagnostic decomposition of changes in poleward atmospheric energy transport into contributions from individual feedbacks, radiative forcing, and ocean heat uptake. These energy-transport changes in turn manifest in the changing atmospheric circulations, such as the magnitude and structure of the tropical Hadley circulation, the Intertropical Convergence Zone, and the midlatitude storm tracks, which are fundamental controls on regional climate and the hydrological cycle.

A random sample of the projects from this collective includes:

• Changes in poleward atmospheric energy transport over a wide range of climates: Energetic and diffusive perspectives and a priori theories
• Coupled high-latitude climate feedbacks and their impact on atmospheric heat transport
• Atmospheric eddies mediate lapse rate feedback and Arctic amplification
• Characterizing the Hadley circulation response through regional climate feedbacks

Uncertainty in the magnitude and geographic pattern of climate change is dominated by divergent predictions among climate models. Model differences are closely linked to their representation of climate feedbacks, that is, the amplifying or stabilizing radiative fluxes that are caused by changes in clouds, water vapor, surface albedo, and other factors, in response to an external climate forcing. Progress in constraining this uncertainty is therefore predicated on understanding how individual climate feedbacks aggregate into a regional and global climate response.

A random sample of the projects from this collective includes:

• Sources of uncertainty in the meridional pattern of climate change
• Climate sensitivity is sensitive to changes in ocean heat transport
• Four perspectives on climate feedbacks
• The nonlinear and nonlocal nature of climate feedbacks
• The remote impacts of climate feedbacks on regional climate predictability

Serious Games for Climate Change is a research cluster at the nexus of game design, climate science, and learning science. In collaboration with Elizabeth Swensen (Department of Performance, Play & Design), we create games that foster scientific thinking and promote the learning of complex topics through experimentation and narrative. Games additionally hold promise as tools for social empowerment, inspiring agency to advance climate solutions.

A random sample of the projects from this collective includes:

• Warmer