Tracing the space-time causal origins of Earth system extremes

Identifying the causes of Earth's extremes is challenging because counterfactual experiments are not possible in the observed world, while numerical experiments are computationally expensive and subject to biases. Data-driven causal discovery offers a complementary path, but existing approaches can fail in undersampled, high-dimensional regimes, and may not recover multi-timestep, multivariate pathways leading to particular events. We introduce Tracer of Causal Evolutions in Space and Time (TraCE-ST), a probabilistic Lagrangian approach that produces event-conditioned causal trajectories in multivariate gridded data. In synthetic experiments and real-world extreme events, TraCE-ST recovers known causal drivers and estimates their relative contributions, while also highlighting less-studied drivers, including orography-driven vorticity for Tropical Storm Debby (2006) and anomalous ocean-surface fluxes for the 2021 Pacific Northwest heatwave. Here, we propose causal tracking as an efficient data-driven framework for synthesizing causal evidence and generating testable hypotheses, complementing association analyses and numerical modeling while accelerating the study of high-impact events.