Extremes, Multi-model Ensembles and ScenarioMIP: Recent Work along Jerry’s Trailblazing Directions.

In this talk I will present some recent work that echoes themes to which I was introduced by Jerry over the years of our collaboration, when I was one of his mentees. In particular I would like to present some recent results exploring the behavior of a suite of extreme indices whose future behavior we analyzed for the first time, I believe, in a paper from 2006. That paper was inspired by Jerry's interest in impact relevant extreme metrics, soon after another seminal paper about heat waves (huthwaves!) changes in the future, inspired by the European heatwave of 2003, which remains highly cited. In this recent study, the robustness (or lack thereof) of the response of these extremes to changes in land use is analyzed in a multi-model context and the large variability of the results, depending on the model analyzed, leads us to conclude that the land use signal may emerge within a single model but is overwhelmed in a multi-model, CMIP-like, context.

The multi-model context, pre-eminently facilitated by the Coupled Model Intercomparison Project, CMIP, is another foundational framework for my research, a project and framework that Jerry was key in conceiving and organizing. In recognition of this important role, I will switch gears and briefly present the proposal for the next set of scenarios for CMIP7, which will characterize the next generation of future projections that will underpin myriads of studies across disciplines, and future assessments. The proposal, from the ScenarioMIP scientific steering committee of which Jerry was a founding member until last year, lays out a set of six scenarios and extensions that address scientific and policy questions reflecting the Paris Agreement goals, the current state of greenhouse gas emissions, and future plausible mitigation action, or inaction.