The Capital Weather Gang has posted a great story about the eruption of Mount Tambora in Indonesia in 1816, 200 years ago this summer.  The sulfuric acid emissions from this eruption helped contribute to some of the coldest temperatures we have seen in the Northern Hemisphere in modern times, due to the reflection of sunlight back to space by the tiny sulfuric acid droplets.  You can read all about it here.  Only a few eruptions, mostly in the tropics, have had that much effect on the earth’s climate, usually lasting for a few years.  The last major eruption that had noticeable effects: Mount Pinatubo, which erupted in the Philippines in 1991.

Source: Jialiang Gao, Commons Wikimedia
Source: Jialiang Gao, Commons Wikimedia