Editing IPCC:AR6/SRCCL/Chapter-7 (section)

==== 7.2.2.6 Fire damage ====

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Increasing fires result in heightened risks to infrastructure, accelerated erosion, altered hydrology, increased air pollution, and negative mental health impacts. Fire not only destroys property but induces changes in underlying site conditions (ground cover, soil water repellency, aggregate stability and surface roughness) which amplifies runoff and erosion, increasing future risks to property and human lives during extreme rainfall events (Pierson and Williams 2016 <sup>[[#fn:r129|129]]</sup> ). Dust and ash from fires can impact air quality in a wide area. For example, a dust plume from a fire in Idaho, USA, in September 2010 was visible in MODIS satellite imagery and extended at least 100 km downwind of the source area (Wagenbrenner et al. 2013 <sup>[[#fn:r130|130]]</sup> ). Individuals can suffer from property damage or direct injury, psychological trauma, depression, and post traumatic stress disorder, and have reported negative impacts to well-being from loss of connection to landscape (Paveglio et al. 2016 <sup>[[#fn:r131|131]]</sup> ; Sharples et al. 2016a <sup>[[#fn:r132|132]]</sup> ). Costs of large wildfires in the USA can exceed 20 million USD per day (Pierson et al. 2011 <sup>[[#fn:r133|133]]</sup> ) and has been estimated at 8.5 billion USD per year in Australia (Sharples et al. 2016b <sup>[[#fn:r134|134]]</sup> ). Globally, human exposure to fire will increase due to projected population growth in fire-prone regions (Knorr et al. 2016a <sup>[[#fn:r135|135]]</sup> ).

It is not clear how quickly, or even if, systems can recover from fires. Longevity of effects may differ depending on cover recruitment rate and soil conditions, recovering in one to two seasons or over 10 growing seasons (Pierson et al. 2011 <sup>[[#fn:r136|136]]</sup> ). In Russia, one-third of forest area affected by fires turned into unproductive areas where natural reforestation is not possible within 2–3 lifecycles of major forest forming species (i.e., 300–600 years) (Shvidenko et al. 2012 <sup>[[#fn:r137|137]]</sup> ).

Risks under current warming levels are already ''moderate'' as anthropogenic climate change has caused significant increases in fire area ( ''high confidence'' ) due to availability of detection and attribution studies) (Cross-Chapter Box 3 in Chapter 2). This has been detected and attributed regionally, notably in the western USA (Abatzoglou and Williams 2016 <sup>[[#fn:r138|138]]</sup> ; Westerling et al. 2006 <sup>[[#fn:r139|139]]</sup> ; Dennison et al. 2014 <sup>[[#fn:r1573|1573]]</sup> ), Indonesia (Fernandes et al. 2017 <sup>[[#fn:r140|140]]</sup> ) and other regions (Jolly et al. 2015 <sup>[[#fn:r141|141]]</sup> ). Regional increases have been observed despite a global- average declining trend induced by human fire-suppression strategies, especially in savannahs (Yang et al. 2014a <sup>[[#fn:r142|142]]</sup> ; Andela et al. 2017 <sup>[[#fn:r143|143]]</sup> ).

High risks of fire may occur between 1.3°C and 1.7°C ( ''medium confidence'' ). Studies note heightened risks above 1.5°C as fire, weather, and land prone to fire increase (Abatzoglou et al. 2019a <sup>[[#fn:r144|144]]</sup> ), with ''medium confidence'' in this transition, due to complex interplay between (i) global warming, (ii) CO <sub>2</sub> -fertilisation, and (iii) human/ economic factors affecting fire risk. Canada, the USA and the Mediterranean may be particularly vulnerable as the combination of increased fuel due to CO <sub>2</sub> fertilisation, and weather conditions conducive to fire increase risks to people and property. Some studies show substantial effects at 3°C (Knorr et al. 2016b <sup>[[#fn:r145|145]]</sup> ; Abatzoglou et al. 2019b <sup>[[#fn:r146|146]]</sup> ), indicating a transition to ''very high risks'' ( ''medium confidence'' ). At high warming levels, climate change may become the primary driver of fire risk in the extratropics (Knorr et al. 2016b; Abatzoglou et al. 2019b <sup>[[#fn:r147|147]]</sup> ; Yang et al. 2014b <sup>[[#fn:r148|148]]</sup> ). Pyroconvection activity may increase, in areas such as southeast Australia (Dowdy and Pepler 2018 <sup>[[#fn:r149|149]]</sup> ), posing major challenges to adaptation.

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