Editing IPCC:AR6/WGII/Chapter-2 (section)

===== 2.4.4.2.2 Observed changes in wildfire globally =====

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Regarding global terrestrial area as a whole, wildfire trends vary depending on the time period of analysis. From 1900 to 2000, global average fire frequency, based on field data, increased 0.4% but the change was not statistically significant ( [[#Gonzalez--2010|Gonzalez et al., 2010]] ). Fire frequency increased on one-third of global land, mainly from burning for agricultural clearing in Africa, Asia and South America, slightly less than the area of fire frequency decrease, mainly from fire suppression across Australia, North America and Russia ( [[#Gonzalez--2010|Gonzalez et al., 2010]] ). Analyses of the Global Fire Emissions Database document shows that, from 1996 to 2015, global burned area decreased at a rate of −0.7% yr -1 ( [[#Forkel--2019|Forkel et al., 2019]] ) but the change was not statistically significant ( [[#Giglio--2013|Giglio et al., 2013]] ). From 1998 to 2015, global burned area decreased at a rate of −1.4 ± 0.5% yr -1 ( [[#Andela--2017|Andela et al., 2017]] ). The area of fire increases was one-third of the area of decreases, due to reduced vegetation cover from agricultural expansion and intensification ( [[#Andela--2017|Andela et al., 2017]] ) and from increased precipitation ( [[#Forkel--2019|Forkel et al., 2019]] ). Furthermore, much of the decreasing trend derives from two years: 1998 with a high burned area and 2013 with low burned area ( [[#Forkel--2019|Forkel et al., 2019]] ). Wildfire does not show a clear long-term trend for the world as a whole because of increases and decreases in different regions ( ''medium evidence'' , ''medium agreement'' ).

Where the global average burned area has decreased in the past two decades, higher correlations of rates of change in burning to human population density, cropland area and livestock density than to precipitation indicate that agricultural expansion and intensification were the main causes ( [[#Andela--2017|Andela et al., 2017]] ). The global decrease of fire frequency from 2000 to 2010 is correlated with increasing human population density ( [[#Knorr--2014|Knorr et al., 2014]] ). The fire-reducing effect of reduced vegetation cover following expansion of agriculture and livestock herding can counteract the fire-increasing effect of the increased heat and drying associated with climate change ( [[#Lasslop--2017|Lasslop and Kloster, 2017]] ; [[#Arora--2018|Arora and Melton, 2018]] ; [[#Forkel--2019|Forkel et al., 2019]] ). The reduced burning needed after the initial clearing for agricultural expansion drives much of the decline in fires in the Tropics ( [[#Andela--2017|Andela et al., 2017]] ; [[#Earl--2018|Earl and Simmonds, 2018]] ; [[#Forkel--2019|Forkel et al., 2019]] ). The human influence on fire ignition can be seen through the decrease documented on holy days (Sundays and Fridays) and traditional religious days of rest ( [[#Earl--2015|Earl et al., 2015]] ). Overall, human land use exerts an influence on wildfire trends for global terrestrial area as a whole that can be stronger than climate change ( ''medium confidence'' ).

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