Volcanism and climate

Abstract

Incontrovertible evidence for causal connections between volcanism and climate extends far back in Earth history. In particular, the link is well established for Holocene time. On the other hand, climate change or major transient climate events may also initiate episodic and protracted volcanism, commonly associated with lithospheric loading and unloading. Both mechanisms document an intimate interplay among the geosphere, hydrosphere, cryosphere, and atmosphere. Cause-and-effect relations incorporate complex feedback loops, not yet fully understood, but which may become increasingly efficient during an environmental threshold situation because active volcanoes are unstable systems quite sensitive to small changes in their external environment. The volcano-climate link may also initiate secondary events, some catastrophic. Depending on the state of societal development, volcanism may at times have inflicted severe climatic strain on human societies affecting food supply, living conditions, and, in cases, migration patterns.