Editing Volcanism (section)

===Earth===
On Earth, volcanoes are most often found where [[list of tectonic plates|tectonic plates]] are [[divergent boundary|diverging]] or [[convergent boundary|converging]], and because most of Earth's plate boundaries are underwater, most volcanoes are found underwater. For example, a [[mid-ocean ridge]], such as the [[Mid-Atlantic Ridge]], has volcanoes caused by divergent tectonic plates whereas the [[Pacific Ring of Fire]] has volcanoes caused by convergent tectonic plates. Volcanoes can also form where there is stretching and thinning of the crust's plates, such as in the [[East African Rift]] and the [[Wells Gray-Clearwater volcanic field]] and [[Rio Grande rift]] in North America. Volcanism away from plate boundaries has been postulated to arise from upwelling [[diapir]]s from the [[core–mantle boundary]], {{convert|3000|km|mi|sp=us}} deep within Earth. This results in [[hotspot (geology)|hotspot volcanism]], of which the [[Hawaiian hotspot]] is an example. Volcanoes are usually not created where two tectonic plates slide past one another. In 1912–1952, in the Northern Hemisphere, studies show that within this time, winters were warmer due to no massive eruptions that had taken place. These studies demonstrate how these eruptions can cause changes within the Earth's atmosphere.<ref>{{Cite book |last=Axelrod |first=Daniel I. |url=https://books.google.com/books?id=4N96OmWMYmQC&dq=volcanism&pg=PP1 |title=Role of Volcanism in Climate and Evolution |date=1981-01-01 |publisher=Geological Society of America |isbn=978-0-8137-2185-9 |language=en}}</ref>

Large eruptions can affect atmospheric temperature as ash and droplets of [[sulfuric acid]] obscure the Sun and cool Earth's [[troposphere]]. Historically, large volcanic eruptions have been followed by [[volcanic winter]]s which have caused catastrophic famines.<ref>{{cite journal |last1=Rampino |first1=M R |last2=Self |first2=S |last3=Stothers |first3=R B |title=Volcanic Winters |journal=Annual Review of Earth and Planetary Sciences |date=May 1988 |volume=16 |issue=1 |pages=73–99 |doi=10.1146/annurev.ea.16.050188.000445|bibcode=1988AREPS..16...73R }}</ref>