Editing IPCC:AR6/WGII/Cross-Chapter-Paper-3 (section)

==== CCP3.2.1.7 Sand and Dust Storms ====

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Soil dust emissions are highly sensitive to changing climate conditions but also to changing land use and management practices ( ''high confidence'' ). Distinguishing between the effects of these drivers is not straightforward, even in well-documented locations ( [[#Middleton--2019|Middleton, 2019]] ). There is ''limited evidence'' and ''low agreement'' about the impacts of climate change on sand and dust storms (SDS), with studies pointing to either substantial increases (+300%) or decreases (-60%) ( [[#Boucher--2013|Boucher et al., 2013]] ). Current climate models cannot adequately model the impact of climate change on SDS activity ( [[#Mirzabaev--2019|Mirzabaev et al., 2019]] ). However, there is ''high confidence'' that land degradation, loss of vegetative cover and drying of water bodies in semiarid and arid areas will contribute to sand and dust activity ( [[#Mirzabaev--2019|Mirzabaev et al., 2019]] ).

SDS remain a major concern for desert areas under conditions of climate change and desertification ( [[#Middleton--2017|Middleton, 2017]] ). Only about 20% of deserts are covered by sand, but desert SDS provide an important feedback mechanism to climate ( [[#Pu--2017|Pu and Ginoux, 2017]] ), with literature showing that some areas have very frequent dust days (Figure CCP3.2; [[#Ginoux--2012|Ginoux et al., 2012]] ). In some locations, such as the USA, desert dust can be deposited downwind on snowpacks, hastening snowmelt and altering river hydrology ( [[#Painter--2010|Painter et al., 2010]] ). Deserts and other natural dryland surfaces produced 75–90% of atmospheric dust globally in the early 21st century, with the remainder from agricultural and other land dominated by human land use ( [[#Ginoux--2012|Ginoux et al., 2012]] ; [[#Stanelle--2014|Stanelle et al., 2014]] ).

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[[File:6b5a560e77132252ec5fc500c1c930da IPCC_AR6_WGII_Figure_CCP3_002.png]]

'''Figure CCP3.2 |''' '''Frequency of high dust days (dust optical depth &gt;0.''' '''2) during the dust season, based on 2003–2009 remote sensing, the most recent data analysed, and divided into areas primarily under agriculture and areas dominated by natural land cover ( [[#Ginoux--2012|Ginoux et al., 2012]] ).''' Dust seasons: Africa (North), Year-round; Africa (South), September–February; America (North), March–May; America (South), December–February), Asia, March–May; Australia, September–February.

Recent changes in dust emissions and their attributions vary geographically. Warming in Iran over the period 1951–2013 has been associated with an increased frequency of dust events ( [[#Alizadeh-Choobari--2018|Alizadeh-Choobari and Najafi, 2018]] ) and a trend (2000–2014) towards increased fine atmospheric mineral dust concentrations in the US southwest has been linked to increasing aridity ( [[#Hand--2017|Hand et al., 2017]] ). Conversely, increases in rainfall, soil moisture and vegetation linked to changes in circulation strength of the Indian summer monsoon since 2002 have led to a substantial reduction of dust in the Thar Desert and surrounding region, showing agreement with findings from the Sahel and the West African Monsoon ( [[#Kergoat--2017|Kergoat et al., 2017]] ). A decreasing trend in the number and intensity of SDS in spring (2007–2016) in East Asia has also responded to higher precipitation and soil moisture, related to a decrease in the intensity of the polar vortex, favouring higher vegetation cover during the period studied ( [[#An--2018|An et al., 2018]] ). Global climate change, transboundary movement of aeolian material by atmospheric flows from Central Asia, dynamics of the Caspian Sea regime, erosion, salinisation and the loss of land as a result of the placement of industrial facilities have expanded the land area prone to desertification in Russia. Desertification has been observed to some extent in 27 sub-regions of the Russian Federation on territory of more than 100 million hectares ( [[#Kust--2011|Kust et al., 2011]] ; also recently confirmed by National Report, 2019). Eastern and south-eastern regions of Kalmykia, Russia, serve as dust sources, while dust and sand masses from areas of the Black Land sometimes move far beyond to parts of Rostov, Astrakhan, Volgograd and Stavropol regions. Agricultural land in these areas can become covered with dust and sand 10 cm or more thick, with negative impacts on yields ( [[#Tsymbarovich--2020|Tsymbarovich et al., 2020]] ). High dust day frequency is also occurring in the High Latitude Dust (HLD) source areas not reported in Figure CCP3.2, such as in Iceland, Patagonia, Canada, Alaska and, based on ''in situ'' measurements, in Antarctica ( [[#Dagsson-Waldhauserová--2014|Dagsson-Waldhauserová et al., 2014]] ; [[#Bullard--2016|Bullard et al., 2016]] ; [[#Dagsson-Waldhauserova--2019|Dagsson-Waldhauserova and Meinander, 2019]] ; [[#Bachelder--2020|Bachelder et al., 2020]] ). Active HLD sources cover at least 500,000 km 2 and produce at least 5% of global dust budget ( [[#Bullard--2016|Bullard et al., 2016]] ). HLD has negative impacts on the cryosphere via albedo changes and snow/ice melting ( [[#Boy--2019|Boy, 2019]] ; [[#Dagsson-Waldhauserova--2019|Dagsson-Waldhauserova and Meinander, 2019]] ).

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