Editing IPCC:AR6/WGII/Cross-Chapter-Paper-1 (section)

==== CCP1.2.2.1 Observed Impacts ====

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There is ''high confidence'' that climate change has already had impacts in North American hotspots. Phenological and range shifts have been reported for bird and mammal species within the boreal forest hotspot ( [[#Davidson--2020|Davidson et al., 2020]] ), and earlier egg laying in birds in tundra hotspots (H3, 5) owing to changes in snowmelt ( [[#Grabowski--2013|Grabowski et al., 2013]] ). Woody vegetation is already shifting north into the tundra ( [[#Larsen--2014|Larsen et al., 2014]] ).

In Central and South America, observed impacts within Mesoamerica (H15, 16) and the Tropical Andes hotspots (H26, 27, 28, 32, 33) comprise upward altitudinal range shifts of birds, frogs, beetles and butterflies ( [[#Narins--2014|Narins and Meenderink, 2014]] ; [[#Molina-Martínez--2016|Molina-Martínez et al., 2016]] ; [[#Moret--2016|Moret et al., 2016]] ; [[#Freeman--2018|Freeman et al., 2018]] ) ( ''medium confidence'' ). A shift of the Guianan-Amazon mangroves (H37) to higher grounds inland was attributed to the effects of observed sea level rise ( ''low confidence'' ) ( [[#Cohen--2018|Cohen et al., 2018]] ).

In Europe, the Mediterranean hotspot (H216) has seen increases in wildfires and droughts attributed to anthropogenic climate change ( [[#Gudmundsson--2017|Gudmundsson et al., 2017]] ; [[#Barbero--2020|Barbero et al., 2020]] ). Range shifts in birds have been observed at higher elevations ( ''medium confidence'' ) ( [[#Tellería--2020|Tellería, 2020]] ).

In Africa, multiple lines of evidence suggest woody plants are increasing in area, density and cover in previously lightly wooded savanna and grassland hotspots (H65, 82) ( [[#Poulsen--2015|Poulsen and Hoffman, 2015]] ; [[#Stevens--2017|Stevens et al., 2017]] ). Significant vulture and cheetah range reductions in these hotspots are at least partially attributable to bush encroachment ( [[#Nghikembua--2016|Nghikembua et al., 2016]] ; [[#Wolter--2016|Wolter et al., 2016]] ; [[#Santangeli--2018|Santangeli et al., 2018]] ). Thus, climate-driven bush encroachment has adversely affected unique mammal and bird diversity ( ''robust evidence, medium agreement, medium confidence'' ). Warming and drying trends have historically been shown to reduce the range of the Ethiopian wolf ( ''Canis simensis'' ), and they interact with land use pressures in the Ethiopian hotspot (H68) ( [[#Sintayehu--2018|Sintayehu, 2018]] ) and plant species richness in the Cape Fynbos (H65) of southern Africa to reduce post-wildfire recruitment ( ''low confidence'' ) ( [[#Slingsby--2017|Slingsby et al., 2017]] ).

Observed impacts in Asia were mostly restricted to the Himalaya (H95, 98, 99), Sundaland (H109, 110, 111, 112, 117, 118) and Indo-Burma (H105, 106, 107, 114, 115) hotspots, showing negative impacts through increased invasion by exotic plants, decreased suitable area for endemic species and significant changes in phenology ( ''medium confidence'' ) ( [[#Telwala--2013|Telwala et al., 2013]] ; [[#Braby--2014|Braby et al., 2014]] ; [[#Padalia--2015|Padalia et al., 2015]] ; [[#Lamsal--2017|Lamsal et al., 2017]] ). In the Central Asian mountain landscape (H87), studies have shown increased aridity induced by climate change impacts on several shrub species ( [[#Seim--2016|Seim et al., 2016]] ). Some positive effects were observed for native species in terms of an increase of suitable habitat ( ''limited evidence, low agreement'' ) ( [[#Priti--2016|Priti et al., 2016]] ; [[#Tang--2017|Tang et al., 2017]] ; [[#Rathore--2019|Rathore et al., 2019]] ).

In Australia, climate change has been implicated in: drought-induced canopy dieback across a range of forest and woodland types due to decades of declining rainfall in the southwestern hotspot (H133); fires in the palaeo-endemic pencil pine forests (Tasmania H142); declines in vertebrates in the Australian Wet Tropics World Heritage Area, which overlaps with the eastern part of the northern Australia hotspot (H131), related to warming and increased length of the dry season; and declines in grass and increases in shrubs in the Bogong High Plains ( ''high confidence'' ) ( [[#Hoffmann--2019|Hoffmann et al., 2019]] ). The Australian Alps have seen increased species diversity following retreat of the snow line ( [[#Slatyer--2010|Slatyer, 2010]] ), replacement of long-lived trees by short-lived shrubs following multiple wildfires ( [[#Zylstra--2018|Zylstra, 2018]] ), and changing ecological interactions due to climate-related snow loss, drought and fires ( ''high confidence'' ) ( [[#Hoffmann--2019|Hoffmann et al., 2019]] ). While warming is allowing mangroves to expand their range in coastal hotspots of Asia and Australia ( [[#Ward--2016|Ward et al., 2016]] ; [[#Hughes--2019a|Hughes et al., 2019a]] ), drought and associated salinity stress has killed mangroves in northern Australia hotspots ( [[#Babcock--2019|Babcock et al., 2019]] ).

Approximately 76% of biodiversity hotspots within this assessment either contain, or are comprised of islands &gt;100 km 2 (Table CCP1.1). However, just 0.08% of these hotspots were represented in post-AR5 literature examining climate change impacts on terrestrial biodiversity. Most observed impacts were assessed with ''low evidence'' , but ''high agreement'' , and focused on plants and insects. Impacts described included abundance changes and extirpations ( [[#Jenouvrier--2014|Jenouvrier et al., 2014]] ), altitudinal range shifts ( [[#Koide--2017|Koide et al., 2017]] ), increased invasive alien species’ abundance and extent in Madagascar (H76, 77), Balearic (H51) and Pacific islands ( [[#Ghulam--2014|Ghulam, 2014]] ; [[#Silva-Rocha--2015|Silva-Rocha et al., 2015]] ; [[#Goulding--2016|Goulding et al., 2016]] ; [[#Dawson--2017|Dawson et al., 2017]] ), increased temperature affecting physiology, body size and behaviour of frogs in the Caribbean (H20) ( [[#Narins--2014|Narins and Meenderink, 2014]] ) and phenological alterations ( [[#Fontúrbel--2018|Fontúrbel et al., 2018]] ). One positive observation was the high resilience to recovery of intact forest ecosystems to tropical cyclones within Caribbean (H20) and Pacific islands ( ''medium confidence'' ) ( [[#Keppel--2014|Keppel et al., 2014]] ; [[#Marler--2014|Marler, 2014]] ; [[#Shiels--2014|Shiels et al., 2014]] ).

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