Editing IPCC:AR6/WGII/Chapter-9 (section)

=== 9.5.2 North Africa ===

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==== 9.5.2.1 Temperature ====

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===== 9.5.2.1.1 Observations =====

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Mean and seasonal temperatures have increased at twice the global rate over most regions in north Africa due to human-induced climate change ( [[#Ranasinghe--2021|Ranasinghe et al., 2021]] ; Figures 9.13a and; 9.14) ( ''high confidence).'' Increasing temperature trends have been particularly strong since the 1970s (between 0.2°C per decade and 0.4°C per decade), especially in the summer ( [[#Tanarhte--2012|Tanarhte et al., 2012]] ; [[#Donat--2014a|Donat et al., 2014a]] ; [[#Lelieveld--2016|Lelieveld et al., 2016]] ). Similar warming signals have been observed since the mid-1960s over the Sahara and the Sahel ( [[#Fontaine--2013|Fontaine et al., 2013]] ; [[#Moron--2016|Moron et al., 2016]] ). Trends in mean maximum (TX) and minimum (TN) temperatures range between +2°C and +3°C per century over north Africa, and the frequencies of hot days (TX &gt; 90th percentile, TX90p) and tropical nights (TN &gt; 20°C), as well as the frequencies of warm days and nights, roughly follow these mean TX and TN trends ( [[#Fontaine--2013|Fontaine et al., 2013]] ; [[#Moron--2016|Moron et al., 2016]] ; [[#Ranasinghe--2021|Ranasinghe et al., 2021]] ; [[#Seneviratne--2021|Seneviratne et al., 2021]] ). Warm spell duration has increased in many north African countries ( [[#Donat--2014a|Donat et al., 2014a]] ; [[#Filahi--2016|Filahi et al., 2016]] ; [[#Lelieveld--2016|Lelieveld et al., 2016]] ; [[#Nashwan--2018|Nashwan et al., 2018]] ) and heatwave magnitude and spatial extent have increased across north Africa since 1980, with an increase in the number of events since 2000 that is beyond the level of natural climate variability ( [[#Russo--2016|Russo et al., 2016]] ; [[#Ceccherini--2017|Ceccherini et al., 2017]] ; [[#Engdaw--2021|Engdaw et al., 2021]] ).

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===== 9.5.2.1.2 Projections =====

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At 1.5°C, 2°C and 3°C of global warming above pre-industrial levels, mean annual temperatures in north Africa are projected to be on average, 0.9°C, 1.5°C and 2.6°C warmer than the 1994–2005 average, respectively (Figure 9.16a). Warming is projected to be stronger in summer than winter ( [[#Lelieveld--2016|Lelieveld et al., 2016]] ; [[#Dosio--2017|Dosio, 2017]] ). The number of hot days is ''likely'' to increase by up to 90% by the end of the century under RCP8.5 (global warming level [GWL] 4.4°C) ( [[#Gutiérrez--2021|Gutiérrez et al., 2021]] ; [[#Ranasinghe--2021|Ranasinghe et al., 2021]] ) and hot nights and the duration of warm spells to increase in the first half of the 21st century in both intermediate and high-emission scenarios ( [[#Patricola--2010|Patricola and Cook, 2010]] ; [[#Vizy--2012|Vizy and Cook, 2012]] ; [[#Lelieveld--2016|Lelieveld et al., 2016]] ; [[#Dosio--2017|Dosio, 2017]] ; [[#Filahi--2017|Filahi et al., 2017]] ). Heatwaves are projected to become more frequent and intense even at 1.5°C of global warming ( [[#Gutiérrez--2021|Gutiérrez et al., 2021]] ; [[#Ranasinghe--2021|Ranasinghe et al., 2021]] ). Children born in 2020, under a 1.5°C-compatible scenario will be exposed to 4–6 times more heatwaves in their lifetimes compared to people born in 1960; this exposure increases to 9–10 times more heatwaves for emission reduction pledges, limiting global warming to 2.4°C ( [[#Thiery--2021|Thiery et al., 2021]] ).

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==== 9.5.2.2 Precipitation ====

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===== 9.5.2.2.1 Observations =====

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Mean annual precipitation decreased over most of north Africa between 1971 '''–''' 2000 ( [[#Donat--2014a|Donat et al., 2014a]] ; [[#Hertig--2014|Hertig et al., 2014]] ; [[#Nicholson--2018|Nicholson et al., 2018]] ; [[#Zittis--2018|Zittis, 2018]] ), with a gradual recovery to normal or wetter conditions in Algeria and Tunisia since 2000 and over Morocco since 2008 ( [[#Nouaceur--2016|Nouaceur and Murărescu, 2016]] ). Since the 1960s days with more than 10 mm of rainfall have decreased and the number of consecutive dry days have increased in the eastern parts of north Africa, while in the western parts of north Africa heavy rainfall and flooding has increased ( [[#Donat--2014a|Donat et al., 2014a]] ). Aridity, the ratio of potential evaporation to precipitation, has increased over the Mediterranean and north Africa due to significant decreases in precipitation ( [[#Greve--2019|Greve et al., 2019]] ).

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===== 9.5.2.2.2 Projections =====

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Mean annual precipitation is projected to decrease in north Africa at warming levels of 2°C and higher ( ''high confidence'' ) with the most pronounced decreases in the northwestern parts (Figures 9.13a and; 9.14; [[#Schilling--2012|Schilling et al., 2012]] ; [[#Filahi--2017|Filahi et al., 2017]] ; [[#Barcikowska--2018|Barcikowska et al., 2018]] ; [[#Ranasinghe--2021|Ranasinghe et al., 2021]] ). Meteorological drought over Mediterranean north Africa in CMIP5 and CMIP6 models are projected to increase in duration from approximately 2 months during 1950–2014 to approximately 4 months in the period 2050–2100 under RCP8.5 and SSP5-85 ( [[#Ukkola--2020|Ukkola et al., 2020]] ). Extreme rainfall (monthly maximum 1-day rainfall – RX1 day) in the region is projected to decrease ( [[#Donat--2019|Donat et al., 2019]] ).

During 1984–2012, north Africa experienced a decreasing dust trend with north African dust explaining more than 60% of global dust variations ( [[#Shao--2013|Shao et al., 2013]] ). Dust loadings and related air pollution hazards (from fine particles that affect health) are projected to decrease in many regions of the Sahara as a result of decreased wind speeds ( [[#Evan--2016|Evan et al., 2016]] ; [[#Ranasinghe--2021|Ranasinghe et al., 2021]] ).

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