Editing Wildfire (section)

== Ignition ==
[[File:Global Fires - August and February 2008.jpg|thumb|right|alt=Two illustrations of the earth, one above the other. The seas are dark gray in color and the continents a lighter gray. Both images have red, yellow, and white markers indicating where fires occurred during the months of August (top image) and February (bottom image) of the year 2008.|Global fires during the year 2008 for the months of August (top image) and February (bottom image), as detected by the [[Moderate Resolution Imaging Spectroradiometer]] (MODIS) on NASA's [[Terra satellite]].]]The ignition of a fire takes place through either natural causes or human activity (deliberate or not).[[File:2011-08-04 20 00 00 Susie Fire in the Adobe Range west of Elko Nevada.jpg|thumb|Lightning-sparked wildfires are frequent occurrences during the dry summer season in [[Nevada]].]]

=== Natural causes ===
Natural occurrences that can ignite wildfires without the involvement of humans include [[lightning]], [[volcanic eruption]]s, [[spark (fire)|spark]]s from rock falls, and [[spontaneous combustion]]s.<ref>{{cite web | url = http://www.nwcg.gov/pms/docs/wfprevnttrat.pdf | title = Wildfire Prevention Strategies | publisher = National Wildfire Coordinating Group | page = 17 | date = March 1998 | access-date = 3 December 2008 | archive-url = https://web.archive.org/web/20081209105351/http://www.nwcg.gov/pms/docs/wfprevnttrat.pdf | archive-date = 9 December 2008 }}</ref><ref name="Scott2000">{{cite journal | doi =10.1016/S0031-0182(00)00192-9 | title = The Pre-Quaternary history of fire | date = 2000 | author = Scott, A. | journal = Palaeogeography, Palaeoclimatology, Palaeoecology | volume = 164 | issue = 1–4 | pages = 281–329 | bibcode =2000PPP...164..281S }}</ref>

=== Human activity ===
Sources of human-caused fire may include [[arson]], accidental ignition, or the uncontrolled use of fire in land-clearing and agriculture such as the [[slash-and-burn]] farming.<ref>Karki, 7, 11–19.</ref> In the [[tropics]], farmers often practice the slash-and-burn method of clearing fields during the [[dry season]].

In [[middle latitudes]], the most common human causes of wildfires are equipment generating sparks (chainsaws, grinders, mowers, etc.), [[utility-caused wildfires|overhead power line]]s, and arson.<ref>{{cite web
 | url =https://www.sandiegouniontribune.com/news/environment/story/2020-01-05/human-caused-ignitions-spark-california-worst-wildfires
 | title =Human-caused ignitions spark California's worst wildfires but get little state focus
 | last =Boxall
 | first =Bettina
 | date =5 January 2020
| website =San Diego Union-Tribune
 | access-date =25 November 2020
| archive-date =19 June 2023
| archive-url =https://web.archive.org/web/20230619094218/https://www.latimes.com/environment/story/2020-01-05/human-caused-ignitions-spark-california-worst-wildfires
 | url-status =live
 }}</ref><ref>{{Cite journal|last1=Liu|first1=Zhihua|last2=Yang|first2=Jian|last3=Chang|first3=Yu|last4=Weisberg|first4=Peter J.|last5=He|first5=Hong S.|date=June 2012|title=Spatial patterns and drivers of fire occurrence and its future trend under climate change in a boreal forest of Northeast China|journal=Global Change Biology|language=en|volume=18|issue=6|pages=2041–2056|doi=10.1111/j.1365-2486.2012.02649.x|issn=1354-1013|bibcode=2012GCBio..18.2041L|s2cid=26410408}}</ref><ref>{{cite book|last1=de Rigo|first1=Daniele|last2=Libertà|first2=Giorgio|last3=Houston Durrant|first3=Tracy|last4=Artés Vivancos|first4=Tomàs|last5=San-Miguel-Ayanz|first5=Jesús|title=Forest fire danger extremes in Europe under climate change: variability and uncertainty|page=71|date=2017|publisher=Publication Office of the European Union|location=Luxembourg|isbn=978-92-79-77046-3|doi=10.2760/13180}}</ref><ref name="Krock">{{cite web|url=https://www.pbs.org/wgbh/nova/fire/world.html|title=The World on Fire|last=Krock|first=Lexi|date=June 2002|publisher=NOVA online – Public Broadcasting System (PBS)|access-date=13 July 2009|url-status=live|archive-url=https://web.archive.org/web/20091027041902/http://www.pbs.org/wgbh/nova/fire/world.html|archive-date=27 October 2009}}</ref><ref>{{Cite journal|last1=Balch|first1=Jennifer K.|last2=Bradley|first2=Bethany A.|last3=Abatzoglou|first3=John T.|last4=Nagy|first4=R. Chelsea|last5=Fusco|first5=Emily J.|last6=Mahood|first6=Adam L.|date=2017|title=Human-started wildfires expand the fire niche across the United States|journal=Proceedings of the National Academy of Sciences|language=en|volume=114|issue=11|pages=2946–2951|doi=10.1073/pnas.1617394114|pmid=28242690|issn=1091-6490|pmc=5358354|bibcode=2017PNAS..114.2946B|doi-access=free}}</ref>

Arson may account for over 20% of human caused fires.<ref>{{Cite web |title=Wildfire Investigation |url=https://www.nifc.gov/fire-information/fire-prevention-education-mitigation/wildfire-investigation |website=National Interagency Fire Center}}</ref> However, in the [[2019–20 Australian bushfire season]] "an independent study found online [[Internet bot|bots]] and [[Troll (slang)|trolls]] exaggerating the role of arson in the fires."<ref>{{cite news |title=How Rupert Murdoch Is Influencing Australia's Bushfire Debate |url=https://www.nytimes.com/2020/01/08/world/australia/fires-murdoch-disinformation.html |access-date=21 June 2023 |work=The New York Times |date=8 January 2020 |quote=An independent study found online bots and trolls exaggerating the role of arson in the fires, at the same time that an article in [Murdoch-owned] [[The Australian]] making similar assertions became the most popular offering on the newspaper's website," the New York Times writes. "It's all part of what critics see as a relentless effort led by the powerful media outlet to do what it has also done in the United States and Britain{{snd}}shift blame to the left, protect conservative leaders, and divert attention from climate change. |archive-date=21 June 2023 |archive-url=https://web.archive.org/web/20230621204719/https://www.nytimes.com/2020/01/08/world/australia/fires-murdoch-disinformation.html |url-status=live }}</ref> In the [[2023 Canadian wildfires]] false claims of [[arson]] gained traction on social media; however, arson is generally not a main cause of wildfires in Canada.<ref>{{Cite news |date=12 June 2023 |last=Kaminski |first=Isabella |title=Did climate change cause Canada's wildfires? |url=https://www.bbc.com/future/article/20230612-did-climate-change-cause-canadas-wildfires |access-date=18 June 2023 |publisher=[[BBC News]] |language=en |archive-date=12 June 2023 |archive-url=https://web.archive.org/web/20230612145614/https://www.bbc.com/future/article/20230612-did-climate-change-cause-canadas-wildfires |url-status=live }}</ref><ref name="wild-theories">{{cite news |date=15 June 2023 |title=Who's fuelling the wild theories about Canada's wildfires |publisher=[[CBC News]] |url=https://www.cbc.ca/player/play/2227831363616 |access-date=17 June 2023 |quote=When many fires started at once in Quebec then people took that as evidence of arson, and their claims got millions of views online. These claims were debunked by meteorologist Wagstaffe who explained that a series of lightning strikes can cause many [[smouldering]] hotspots underneath rain-moistened surface fuels; and then when those surface fuels are all dried by the daytime wind simultaneously, then they are all ignited into full blown fires simultaneously. Wagstaffe also corrected the idea that [[controlled burns]] are state-sponsored arson. |archive-date=17 June 2023 |archive-url=https://web.archive.org/web/20230617022608/https://www.cbc.ca/player/play/2227831363616 |url-status=live }}</ref> In California, generally 6–10% of wildfires annually are arson.<ref>{{Cite web |title=How Arson factors into California's Wildfires |url=https://www.hcn.org/articles/climate-desk-wildfire-how-arson-factors-into-californias-wildfires |website=High Country News |date=15 October 2021 |access-date=30 August 2023 |archive-date=30 August 2023 |archive-url=https://web.archive.org/web/20230830144008/https://www.hcn.org/articles/climate-desk-wildfire-how-arson-factors-into-californias-wildfires |url-status=live }}</ref> 

[[Coal seam fire]]s burn in the thousands around the world, such as those in [[Burning Mountain]], New South Wales; [[Centralia, Pennsylvania|Centralia]], Pennsylvania; and several [[Coal-seam fire#China|coal-sustained fires in China]]. They can also flare up unexpectedly and ignite nearby flammable material.<ref>{{cite journal|last=Krajick|first=Kevin|date=May 2005|title=Fire in the hole|url=http://www.smithsonianmag.com/travel/10013541.html|journal=Smithsonian Magazine|access-date=30 July 2009|archive-date=3 September 2010|archive-url=https://web.archive.org/web/20100903032505/http://www.smithsonianmag.com/travel/10013541.html}}</ref>