Department Seminar: Lyssa Freese

Title: Taking the Pulse of the Earth System

Abstract: Two of the most influential climate metrics– the social cost of carbon and the carbon budget– are grounded in pulse experiments, which measure how a system responds to a temporary perturbation. This impulse response approach has historically been used in the atmospheric, climate, and economic sciences to understand the global mean response to a perturbation.

Here, I expand this pulse response approach to the spatial level: does the carbon budget mean the same thing for every location? Can the social cost of carbon be estimated specifically for each country based on different climate and economic responses? And, now that we’ve developed this approach for spatially varying impacts, can we begin to use it for a much more heterogeneous problem– air pollution?

I will walk through the mathematical underpinnings of pulse experiments (Green’s functions), their global mean applications, and my recent work adapting them to show how local and regional variations shape pulse-responses for both human and earth systems. This spatial approach creates opportunities to design mitigation and adaptation strategies tailored to different locations and pollutants.