Which volcano’s 1815 eruption helped cause the global “Year Without a Summer”?

Mount Tambora’s 1815 eruption helped cause the global “Year Without a Summer.” Located on Sumbawa island in Indonesia, Tambora produced one of the most powerful explosive eruptions in recorded history.

The eruption reached its climax in April 1815, collapsing the summit and forming a large caldera. Vast quantities of sulfur dioxide entered the stratosphere, where sulfate aerosols reflected sunlight and disrupted climate patterns. The following year, 1816, became known in parts of the Northern Hemisphere as the Year Without a Summer.

The eruption caused crop failures, unusual frosts and food shortages in several regions, though local effects varied. Tambora is sometimes confused with Krakatoa because both are Indonesian volcanoes associated with global atmospheric effects. Tambora’s 1815 event, however, was substantially larger and remains the largest eruption in the historical record by many measures.