A volcanic winter is a reduction in global temperatures caused by droplets of sulfuric acid obscuring the Sun and raising Earth's albedo (increasing the reflection of solar radiation) after a large, sulfur-rich, particularly explosive volcanic eruption. Climate effects are primarily dependent upon the amount of injection of SO2 and H2S into the stratosphere where they react with OH and H2O to form H2SO4 on a timescale of a week, and the resulting H2SO4 aerosols produce the dominant radiative effect. Volcanic stratospheric aerosols cool the surface by reflecting solar radiation and warm the stratosphere by absorbing terrestrial radiation for several years. Moreover, the cooling trend can be further extended by atmosphere–ice–ocean feedback mechanisms. These feedbacks can continue to maintain the cool climate long after the volcanic aerosols have dissipated.
The conversion of sulfur dioxide to sulfuric acid, which condenses rapidly in the stratosphere to form fine sulfate aerosols.
It is speculated that Munch's famous painting was inspired by the red volcanic aerosol cloud over Oslo produced by the 1892 Awu eruption
The supervolcano caldera Lake Toba
A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface.
Sabancaya volcano erupting, Peru in 2017
Lakagigar fissure vent in Iceland, the source of the major world climate alteration of 1783–84, has a chain of volcanic cones along its length.
Skjaldbreiður, a shield volcano whose name means "broad shield"
Izalco volcano, the youngest volcano in El Salvador. Izalco erupted almost continuously from 1770 (when it formed) to 1958, earning it the nickname of "Lighthouse of the Pacific".