Editing IPCC:AR6/WGII/Chapter-2 (section)

==== 2.5.3.1 Risks in Protected Areas ====

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National parks and other protected areas which, in June 2021, covered 15.7% of the global terrestrial area (UNEP-WCMC et al., 2021), conserve greater biodiversity than adjacent unprotected areas ( [[#Gray--2016|Gray et al., 2016]] ), and protect one-fifth of global vegetation carbon stocks and one-tenth of global soil carbon stocks ( [[#2.4.4.4|Section 2.4.4.4]] ). This section assesses climate change specifically in protected areas. Even though it is included in a part of the chapter on projected risks, it includes both observed exposure and projected risks to gather the information on protected areas into one place.

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===== 2.5.3.1.1 Observed exposure of protected areas =====

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In 2009, deforestation, agricultural expansion, overgrazing and urbanisation exposed one-third of the global protected area (6 million km 2 ) to intense human pressure, a 6% increase from 1993 ( [[#Venter--2016|Venter et al., 2016]] ; [[#Jones--2018|Jones et al., 2018]] ). The exposure to observed climate change has not yet been quantified for protected areas globally, but research has analysed the spatial patterns and magnitudes of observed changes for the 360,000 km 2 system of US national parks ( [[#Gonzalez--2018|Gonzalez et al., 2018]] ) including the first national park in the world. From 1895 to 2010, mean annual temperature of the US national park area increased at a rate of 1°C ± 0.2°C per century, double the rate of the whole USA, and precipitation decreased in 12% of the national park area, compared with 4% for the whole USA, due to a high fraction of US national park area being in the Arctic, at high elevations, and in the arid southwestern USA ( [[#Gonzalez--2018|Gonzalez et al., 2018]] ). In addition, analyses of weather-station measurements in and near six South African national parks found that the maximum temperature increased at a rate of 0.024°C ± 0.003°C yr -1 from 1960 to 2010 ( [[#Van%20Wilgen--2016|Van Wilgen et al., 2016]] ). While a substantial fraction of global protected area has been exposed to observed changes in human land cover, the global exposure to observed climate change is unquantified.

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===== 2.5.3.1.2 Projected risks in protected areas =====

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Under a climate change scenario of ~3.5°C temperature increase by 2070, current climate could disappear from individual protected areas that comprise half the global protected area, and novel climates (climate conditions that are currently not present in an individual protected area) could emerge in half the global protected area ( [[#Hoffmann--2019b|Hoffmann et al., 2019b]] ). A lower-emissions scenario of ~1.5°C could reduce the disappearance of current climate conditions to 40% and the exposure to novel climates to 41% ( [[#Hoffmann--2019b|Hoffmann et al., 2019b]] ). Models project the highest exposure to novel climates in subtropical projected areas ( [[#Hoffmann--2020|Hoffmann and Beierkuhnlein, 2020]] ). Projected disappearance of current climate conditions in protected areas is most extensive in Africa, Oceania, and North and South America ( [[#Elsen--2020|Elsen et al., 2020]] ).

Projections indicate greater exposure of tropical rainforests, shrublands and grasslands, temperate conifer forests and grasslands, and tundra to novel climates ( [[#Hoffmann--2019b|Hoffmann et al., 2019b]] ; [[#Elsen--2020|Elsen et al., 2020]] ). A climate change scenario of ~3.5°C temperature increase by 2100 could expose 32% of the protected area in humid tropical forests (1.6 million km 2 in 2000) to climate that would be novel to humid tropical-forest protected areas; by 2050, the climate currently present in humid tropical-forest protected areas could disappear from 0.6 million km 2 (12% of the current total area) ( [[#Tabor--2018|Tabor et al., 2018]] ). High rates of deforestation and climate change combined could expose 2% of the humid tropical-forest protected area ( [[#Tabor--2018|Tabor et al., 2018]] ). Regional analyses under RCP8.5 also project the substantial disappearance of the current climate in protected areas in Bolivia, Chile and Peru ( [[#Fuentes-Castillo--2020|Fuentes-Castillo et al., 2020]] ), Canada, Mexico and the USA ( [[#Batllori--2017|Batllori et al., 2017]] ; [[#Holsinger--2019|Holsinger et al., 2019]] ), China ( [[#Zomer--2015|Zomer et al., 2015]] ), Europe ( [[#Nila--2019|Nila et al., 2019]] ) and Indonesia ( [[#Scriven--2015|Scriven et al., 2015]] ). Projected climate change could expose an extensive part of the global protected area to disappearing and novel climate conditions ( ''high confidence'' ) (Cross-Chapter Paper 1).

Continued climate change increases the risks to individual species and vegetation types in protected areas. Under a climate change scenario of 4°C temperature increase by 2100, the suitable climate for two species of baobab trees ( ''Adansonia perrieri'' and ''A. suarezensis'' ) in Madagascar could shift entirely out of the protected areas network ( [[#Vieilledent--2013|Vieilledent et al., 2013]] ). Other species and vegetation types at risk from the partial disappearance of suitable climate in protected areas include Atlantic Forest amphibians in Brazil ( [[#Lemes--2014|Lemes et al., 2014]] ), birds in Finland ( [[#Virkkala--2013|Virkkala et al., 2013]] ), birds and trees in Canada and Mexico ( [[#Stralberg--2020|Stralberg et al., 2020]] ), bog woodlands in Germany ( [[#Steinacker--2019|Steinacker et al., 2019]] ), butterflies and mammals in Egypt ( [[#Leach--2013|Leach et al., 2013]] ) and tropical dry forests in Mexico ( [[#Prieto-Torres--2016|Prieto-Torres et al., 2016]] ). Projected disappearance of suitable climate conditions in protected areas increase risks to the survival of species and vegetation types of conservation concern in tropical, temperate and boreal ecosystems ( ''high confidence'' ) (Cross-Chapter Paper 1).

Protected rivers, lakes and other freshwater protected areas require inter-catchment connectivity to maintain species and population movements ( [[#Bush--2014a|Bush et al., 2014a]] ; [[#Hermoso--2016|Hermoso et al., 2016]] ; [[#Thieme--2016|Thieme et al., 2016]] ), but dams and other barriers interrupt connectivity ( [[#Grill--2019|Grill et al., 2019]] ). Climate change could also reduce freshwater connectivity ( [[#2.3.3.3|Section 2.3.3.3]] ). Globally, over two-thirds of river reaches (by length) lack protected areas in their upstream catchments and nine-tenths of river reaches (by length) do not achieve full, integrated protection ( [[#Abell--2017|Abell et al., 2017]] ).

Terrestrial and freshwater protected areas can also serve as climate change refugia, that is, locations where suitable conditions may persist for the species into the future (e.g., [[#2.6.5.6|Section 2.6.5.6]] ). In Canada, Mexico and the USA, only a fraction of the protected area is located in potential climate change refugia under a 4°C temperature increase, estimated at 4% ( [[#Michalak--2018|Michalak et al., 2018]] ) to 7% ( [[#Batllori--2017|Batllori et al., 2017]] ). Potential refugia from biome shifts due to climate change under temperature increases of 1.8°C–3.4°C cover &lt;1% of the area of US national parks ( [[#Gonzalez--2010|Gonzalez et al., 2010]] ), a fraction that diminishes to near zero when climate change is combined with habitat fragmentation due to LUC ( [[#Eigenbrod--2015|Eigenbrod et al., 2015]] ). Protected areas in boreal ecosystems could serve as refugia for species shifting north in Canada ( [[#Berteaux--2018|Berteaux et al., 2018]] ) and Finland ( [[#Lehikoinen--2019|Lehikoinen et al., 2019]] ). Invasive species, habitat loss and other disturbances in protected areas could be lower than in unprotected areas across Europe ( [[#Gallardo--2017|Gallardo et al., 2017]] ), specifically in Spain ( [[#Regos--2016|Regos et al., 2016]] ), and also in Sri Lanka ( [[#Kariyawasam--2020|Kariyawasam et al., 2020]] ). Protected areas conserve refugia from climate change under a temperature increase of 4°C, which is important for biodiversity conservation but is limited to &lt;10% of the current protected area ( ''medium confidence'' ).

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