Editing IPCC:AR6/WGI/Chapter-11 (section)

==== 11.6.2.1 Precipitation Deficits ====

<div id="h3-7-siblings" class="h3-siblings"></div>

Strong precipitation deficits have been recorded in recent decades in the Amazon (2005, 2010), south-western China (2009–2010), south-western North America (2011–2014), Australia (1997–2009), California (2014), the middle East (2012–2016), Chile (2010–2015), the Great Horn of Africa (2011), among others ( [[#van%20Dijk--2013|van Dijk et al., 2013]] ; [[#Mann--2015|Mann and Gleick, 2015]] ; [[#Rowell--2015|Rowell et al., 2015]] ; [[#Marengo--2016|Marengo and Espinoza, 2016]] ; [[#Dai--2017|Dai and Zhao, 2017]] ; [[#Garreaud--2017|Garreaud et al., 2017]] , 2020; [[#Marengo--2017|Marengo et al., 2017]] ; [[#Brito--2018|Brito et al., 2018]] ; [[#Cook--2018|Cook et al., 2018]] ). Global studies generally show no significant trends in SPI time series ( [[#Orlowsky--2013|Orlowsky and Seneviratne, 2013]] ; [[#Spinoni--2014|Spinoni et al., 2014]] ), and in derived drought frequency and severity data ( [[#Spinoni--2019|Spinoni et al., 2019]] ), with very few regional exceptions ( [[#11.9|Section 11.9]] and Figure 11.17). Long-term decreases in precipitation are found in some AR6 regions in Africa (Central Africa and East Southern Africa), and several regions in South America (North-Eastern South America, South American Monsoon, South-Western South America, and Southern South America) ( [[#11.9|Section 11.9]] ). Evidence of precipitation-based drying trends is also found in Western Africa, consistent with studies based on CDD trends (Figure 11.17; [[#Chaney--2014|Chaney et al., 2014]] ; [[#Donat--2014b|Donat et al., 2014b]] ; [[#Barry--2018|Barry et al., 2018]] ; [[#Dunn--2020|Dunn et al., 2020]] ), however, there is a partial recovery of the rainfall trends since the 1980s in this region ( [[IPCC:Wg1:Chapter:Chapter-10#10.4.2.1|Section 10.4.2.1]] ). Some AR6 regions show a decrease in meteorological drought, including Northern Australia, Central Australia, Northern Europe and Central North America ( [[#11.9|Section 11.9]] ). Other regions either do not show substantial trends in long-term meteorological drought, or they display mixed signals depending on the considered time frame and sub-regions, such as in Southern Australia ( [[#Gallant--2013|Gallant et al., 2013]] ; [[#Delworth--2014|Delworth and Zeng, 2014]] ; [[#Alexander--2017|Alexander and Arblaster, 2017]] ; [[#Spinoni--2019|Spinoni et al., 2019]] ; [[#Dunn--2020|Dunn et al., 2020]] ; [[#Rauniyar--2020|Rauniyar and Power, 2020]] ) and the Mediterranean ( [[#Camuffo--2013|Camuffo et al., 2013]] ; [[#Gudmundsson--2016|Gudmundsson and Seneviratne, 2016]] ; [[#Spinoni--2017|Spinoni et al., 2017]] ; [[#Stagge--2017|Stagge et al., 2017]] ; [[#Caloiero--2018|Caloiero et al., 2018]] ; [[#Peña-Angulo--2020b|Peña-Angulo et al., 2020b]] ; see also [[#11.9|Section 11.9]] and Atlas.8.2).

<div id="_idContainer063" class="Basic-Text-Frame"></div>

[[File:a97af5c3786b1cd60461310b16197a9a IPCC_AR6_WGI_Figure_11_17.png]]

'''Figure 11.17 |''' '''Observed linear trend for (a) consecutive dry days (CDD) during 1960–2018, (b) standardized precipitation index (SPI) and (c) standardized precipitation-evapotranspiration index (SPEI) dur''' ing 1951–2016. CDD data are from the HadEx3 dataset ( [[#Dunn--2020|Dunn et al., 2020]] ), trend calculation of CDD as in Figure 11.9. Drought severity is estimated using 12-month SPI (SPI-12) and 12-month SPEI (SPEI-12). SPI and SPEI datasets are from [[#Spinoni--2019|Spinoni et al. (2019)]] . The threshold to identify drought episodes was set at -1 SPI/SPEI units. Areas without sufficient data are shown in grey. No overlay indicates regions where the trends are significant at the p = 0.1 level. Crosses indicate regions where trends are not significant. For details on the methods see Supplementary Material 11.SM.2. Further details on data sources and processing are available in the chapter data table (Table 11.SM.9).

<div id="11.6.2.2" class="h3-container"></div>

<span id="atmospheric-evaporative-demand-1"></span>