1816 summer temperature anomaly with respect to 1971-2000 climatology
The April 1815 eruption of Mount Tambora was the most powerful volcano eruption in recorded history. Mount Tambora is situated on the island of Sumbawa in Indonesia. At least 6 months and probably about 3 years of increased steaming and small phreatic eruptions preceded the 1815 eruption. A moderately large explosive eruption occurred on 5 April 1815, from which ash fell in east Java and thunderlike sounds were heard up to 1,400 kilometers away. A still larger eruption occurred on 10-11 April 1815, beginning as "three columns of fire rising to a great height" and ultimately ejecting about 50 cubic kilometers of magma. The eruption had a Volcanic Explosivity Index ranking of 7, a super-colossal event that ejected immense amounts of volcanic dust into the upper atmosphere. It was the world's largest eruption since the Hatepe eruption over 1,630 years earlier in AD 180.
The Tambora eruption column lowered global temperatures, and some experts believe this led to global cooling and worldwide harvest failures, sometimes known as the Year Without a Summer.
The Year Without a Summer (also known as the Poverty Year, Year There Was No Summer and Eighteen Hundred and Froze to Death) was 1816, in which severe summer climate abnormalities caused average global temperatures to decrease by about 0.4–0.7 °C, resulting in major food shortages across the Northern Hemisphere and leading to the worst famine of the 19th century.