Throughout Earth’s history, large explosive volcanic eruptions and asteroid impacts have episodically perturbed the Earth system, driving major climate disruptions with profound consequences for the biosphere. These events can modify atmospheric composition, perturb Earth’s radiative balance, trigger abrupt surface cooling, weaken the hydrological cycle, alter ocean circulation and biogeochemistry, suppress terrestrial and marine productivity, and generate cascading effects across ecosystems and food webs. Such environmental changes may further shape the evolutionary trajectories of species, including humans.

One notable example is the Chicxulub impact about 66 million years ago, which generated a global impact winter and almost certainly triggered the Cretaceous–Paleogene mass extinction. Another example is the Toba supereruption about 74,000 years ago, which likely caused substantial climatic effects and may have affected human populations. However, the magnitudes, timescales, spatial patterns, and underlying mechanisms of climate and biosphere responses to major perturbations remain incompletely understood and actively debated.

This session invites contributions that investigate how major perturbations—including volcanic eruptions, asteroid impacts, and other abrupt climatic events of varying magnitudes—affect the climate system, terrestrial and marine ecosystems, and the evolution of mammals and humans across a wide range of timescales and regions. We welcome theoretical, observational, proxy-based, and modeling studies from multidisciplinary perspectives spanning volcanology, planetary science, climate science, paleoclimatology, ecology, archaeology, and paleoanthropology.