Editing Mount Tambora (section)

===== Global effects =====
[[File:Greenland sulfate.png|thumb|right|[[Sulfate]] concentration in [[ice core]] from Central [[Greenland]], dated by counting [[oxygen isotope]] seasonal variations. There is an unknown eruption around the 1810s.<ref name="Dai1991">{{cite journal |last1=Dai |first1=J. |first2=E. |last2=Mosley-Thompson |first3=L.G. |last3=Thompson |date=1991 |title=Ice core evidence for an explosive tropical volcanic eruption six years preceding Tambora |url=https://pdfs.semanticscholar.org/4574/f163f9c8321c258cf88710e69e0fd0a3de13.pdf |archive-url=https://web.archive.org/web/20180802194725/https://pdfs.semanticscholar.org/4574/f163f9c8321c258cf88710e69e0fd0a3de13.pdf |url-status=dead |archive-date=2018-08-02 |journal=Journal of Geophysical Research: Atmospheres |volume=96 |issue=D9 |pages=17361–17366 |doi=10.1029/91JD01634 |access-date=2 August 2018 |bibcode=1991JGR....9617361D |s2cid=8384563}}</ref>]]
{{see also|Year Without a Summer}}

The 1815 eruption released 10 to 120 million tons of [[sulfur]]<ref name="Oppenheimer2003"/> into the [[stratosphere]], causing a global climate anomaly. Different methods have been used to estimate the ejected sulfur mass: the [[petrological]] method, an optical depth measurement based on [[anatomy|anatomical]] observations, and the [[polar region|polar]] [[ice core]] sulfate concentration method, which calibrated against cores from [[Greenland]] and [[Antarctica]].

In the spring and summer of 1816, a persistent stratospheric sulfate [[aerosol]] veil, described then as a "dry fog", was observed in the northeastern United States. It was not dispersed by wind or rainfall, and it reddened and dimmed sunlight to an extent that sunspots were visible to the naked eye.<ref name="Oppenheimer2003"/> Areas of the [[northern hemisphere]] suffered extreme weather conditions and 1816 became known as the "[[Year Without a Summer|year without a summer]]". Average global temperatures decreased about {{convert|0.4|to|0.7|C-change|1}},<ref name="Stothers1984"/> enough to cause significant agricultural problems around the globe. After 4 June 1816, when there were frosts in [[Connecticut]], cold weather expanded over most of [[New England]]. On 6 June 1816, it snowed in [[Albany, New York]] and [[Dennysville, Maine]]. Similar conditions persisted for at least three months, ruining most crops across North America while Canada experienced extreme cold. Snow fell until 10 June near [[Quebec City]], accumulating to {{convert|30|cm|in}}.<ref name="Oppenheimer2003"/>

That year became the second-coldest year in the northern hemisphere since 1400,<ref name="Briffa1998"/> while the 1810s were the coldest decade on record, a result of Tambora's eruption and other suspected volcanic events between 1809 and 1810.<ref>{{cite journal |last1=Cole-Dai |first1=Jihong |last2=Ferris |first2=David |last3=Lanciki |first3=Alyson |last4=Savarino |first4=Joël |last5=Baroni |first5=Mélanie |last6=Thiemens |first6=Mark H. |title=Cold decade (AD 1810–1819) caused by Tambora (1815) and another (1809) stratospheric volcanic eruption |journal=Geophysical Research Letters |date=1 November 2009 |volume=36 |issue=22 |pages=L22703 |doi=10.1029/2009GL040882 |url=https://hal.archives-ouvertes.fr/hal-01757253/file/cole_dai_grl_09.pdf |bibcode=2009GeoRL..3622703C |s2cid=10579910 |access-date=30 June 2019 |archive-date=6 December 2019 |archive-url=https://web.archive.org/web/20191206085906/https://hal.archives-ouvertes.fr/hal-01757253/file/cole_dai_grl_09.pdf |url-status=live }}</ref> (See sulfate concentration chart.) Surface-temperature anomalies during the summers of 1816, 1817 and 1818 were −0.51, −0.44 and −0.29&nbsp;°C, respectively.<ref name="Briffa1998"/> Along with a cooler summer, parts of Europe experienced a stormier winter,<ref name="Oppenheimer2003"/> and the [[Elbe River|Elbe]] and [[Ohře River]]s froze over for twelve days in February 1816. As a result, prices of [[wheat]], [[rye]], [[barley]] and [[oats]] rose dramatically by 1817.<ref name="Brazdil2016">{{cite journal |date=2016 |last1=Brázdil |first1=Rudolf |last2=Řezníčková |first2=Ladislava |last3=Valášek |first3=Hubert |last4=Dolák |first4=Lukáš |last5=Kotyza |first5=Oldřich |title=Climatic effects and impacts of the 1815 eruption of Mount Tambora in the Czech Lands |journal=Climate of the Past |volume=12 |issue=6 |pages=1361–1374 |doi=10.5194/cp-12-1361-2016 |bibcode=2016CliPa..12.1361B |doi-access=free}}</ref>

This climate anomaly has been cited as a reason for the severity of the 1816–19 [[typhus]] epidemic in southeast Europe and the eastern Mediterranean.<ref name="Oppenheimer2003"/> Large numbers of livestock died in [[New England]] during the winter of 1816–1817, while cool temperatures and heavy rains led to failed harvests in the British Isles. Families in [[Wales]] travelled long distances as refugees, begging for food. Famine was prevalent in north and southwest Ireland, following the failure of wheat, oat and potato harvests. The crisis was severe in Germany, where food prices rose sharply. Demonstrations at grain markets and bakeries, followed by riots, arson and looting, took place in many European cities. It was the worst famine of the 19th century.<ref name="Oppenheimer2003"/>