Editing IPCC:AR6/WGI/Chapter-6 (section)

==== 6.2.2.4 Land Emissions of Dust Particles ====

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The emission of dust particles into the atmosphere results from a natural process, namely saltation bombardment of the soil by large wind-blown particles, such as sand grains, and from disintegration of saltating particle clusters ( [[#Kok--2012|Kok et al., 2012]] ). The occurrence and intensity of dust emissions are controlled by soil properties, vegetation and near-surface wind, making dust emissions sensitive to climate change and LULCC ( [[#Jia--2019|Jia et al., 2019]] ). In addition, dust can be directly emitted through human activities, such as agriculture, off-road vehicles, building construction and mining, and indirectly emitted through hydrological changes due to human actions such as water diversion for irrigation (e.g., [[#Ginoux--2012|Ginoux et al., 2012]] ). Estimates of the anthropogenic fraction of global dust vary from less than 10% to over 60% suggesting that the human contribution to the global dust budget is quite uncertain ( [[#Ginoux--2012|Ginoux et al., 2012]] ; [[#Stanelle--2014|Stanelle et al., 2014]] ; [[#Xi--2016|Xi and Sokolik, 2016]] ). Reconstruction of global dust (deposition) from paleo records indicate factor of two to four changes between the different climate regimes in the glacial and interglacial periods ( [[IPCC:Wg1:Chapter:Chapter-2#2.2.6|Section 2.2.6]] ).

An extremely limited number of studies have explored the evolution of global dust sources since pre-industrial times ( [[#Mahowald--2010|Mahowald et al., 2010]] ; [[#Stanelle--2014|Stanelle et al., 2014]] ). A modelling study estimated a 25% increase in global dust emissions between the late 19th century and the present, due to agricultural land expansion and climate change ( [[#Stanelle--2014|Stanelle et al., 2014]] ). CMIP5 models were unable to capture the observed variability of annual and longer time scales in North African dust emissions ( [[#Evan--2014|Evan et al., 2014]] ), however, more recent ESMs with process-based dust emissions schemes that account for changes in vegetation and climate in a more consistent manner, better match the observations ( [[#Kok--2014|Kok et al., 2014]] ; [[#Evans--2016|Evans et al., 2016]] ). Feedbacks between the global dust cycle and the climate system (Section 6.4.5) could account for a substantial fraction of the total aerosol feedbacks in the climate system with an order of magnitude enhancement on a regional scale ( [[#Kok--2018|Kok et al., 2018]] ). In summary, there is ''high confidence'' that atmospheric dust source and loading are sensitive to changes in climate and land use, however, there is ''low confidence'' in quantitative estimates of dust emission response to climate change.

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