Here's an idea you've probably heard before: volcanic eruptions--the big, explosive Pinatubo kind--spew millions of tons of sulfur dioxide into the stratosphere, and the sulfur dioxide stays there for a few years, reflecting sunlight and cooling down the planet for a few years. In other words, eruptions can affect climate.
But new evidence suggests that the volcano-climate relationship can go the other way, too: Periods of warming after ice ages can lead to volcanic eruptions.
In a recent study, a team of geologists examined samples of sea-floor mud from around the Ring of Fire for evidence of past eruptions. Preserved within the million-year mud record were tell-tale layers of ash from 91 volcanic eruptions. Since mud accumulates at a regular rate, the researchers could use the position of the ash layers to date each of the volcanic events.