The Web of Life (16-2) Volcanism


The intensity of mantle plumes occurs coincidentally with cyclic changes on the surface. As these plumes push up to form diapirs (intrusions) in the crust, water shifts toward continents, producing sea-level rise which precipitates volcanic activity which releases greenhouse gases that warm the climate.

Volcanism can also create massive dust veils that promote global cooling for 10–100 years. Countervailing tendencies play out their intensities for different durations.


Earth acts as an integrated gyre, with an interplay of intricate feedback loops among the biological, climatic, and geological realms. This planetary system has self-organized criticality: supporting or disfavoring life at times, depending upon a confluence of environmental conditions. Past mass extinction events most dramatically demonstrated biotic balance disrupted and restored over the course of millions of years.