Editing IPCC:AR6/WGII/Chapter-13 (section)

== 13.1 Point of Departure ==

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=== 13.1.1 Introduction and Geographical Scope ===

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This regional chapter on climate-change impacts, vulnerabilities and adaptations in Europe examines the impacts on the sectors, regions and vulnerable populations of Europe, assesses the causes of vulnerability and analyses ways to adapt, thereby considering socioeconomic developments, land-use change and other non-climatic drivers. Compared with AR5 and in the context of the Paris Agreement (2015), we place emphasis on the planned and implemented solutions, assess their feasibility and effectiveness, and consider the Sustainable Development Goals (SDG) and shared socioeconomic pathways (SSPs). Global warming level (GWL) refers to global climate-change emissions relative to pre-industrial levels, expressed as global surface air temperature ( [[IPCC:Wg2:Chapter:Chapter-1#1.6|Section 1.6.2]] ; [[#Chen--2021|Chen et al., 2021]] ).

The chapter generally follows the overall structure of AR6 WGII. We first present our point of departure (the present section) followed by the key sectors, starting with water, as water is interconnected and of fundamental importance to subsequent sections (Sections 13.2–13.8). For each section, we assess the observed impacts and projected risks, solution space and adaptation options, and knowledge gaps. The solution space is defined as the space within which opportunities and constraints determine why, how, when and who adapts to climate risks ( [[#Haasnoot--2020a|Haasnoot et al., 2020a]] ). [[#13.9|Section 13.9]] discusses impacts and adaptation beyond Europe, followed by the key risks for Europe ( [[#13.10|Section 13.10]] ). The chapter ends with an assessment of the adaptation solution space, CRD pathways and SDGs (13.11), although recognising that scientific literature on these aspects is only slowly beginning to emerge.

With the rapidly growing body of scientific literature since WGII AR5 ( [[#Callaghan--2020|Callaghan et al., 2020]] ), our assessment prioritises systematic reviews, meta-analyses, and synthesis papers and reports. Feasibility and effectiveness assessments use revised methods developed for the Special Report of Global warming of 1.5°C ( [[#de%20Coninck--2018|de Coninck et al., 2018]] ; [[#Singh--2020|Singh et al., 2020]] ). Protocols, as well as supporting material for figures and tables, can be found in the Supplementary Material.

The geographical scope and subdivision of European land, coastal and ocean regions is largely the same as in WGII AR5 Chapter 23 ( [[#Kovats--2014|Kovats et al., 2014]] ): Southern Europe (SEU), Western Central Europe (WCE), Eastern Europe (EEU) and Northern Europe (NEU). Note that WGI assesses a larger region for the Mediterranean (MED) which includes North Africa and the Middle East compared with the assessment in this chapter (SEU). The European part of the Arctic region is not systematically assessed here, as it is extensively captured in Cross-Chapter Paper 6. Information relevant to Europe is also synthesised in the CCPs (Cross-Chapter Papers), including European biodiversity hotspots (Cross-Chapter Paper 1), coastal cities and settlements (Cross-Chapter Paper 2), Mediterranean regions (Cross-Chapter Paper 4) and mountains (Cross-Chapter Paper 5). European seas are broadly divided by latitude into (i) European Arctic waters (NEUS), (ii) European temperate seas (TEUS) and (iii) southern seas with the Mediterranean and the Black Sea (SEUS) (Figure 13.1).

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[[File:4ac28345235a24e2d2568049f2b97fa3 IPCC_AR6_WGII_Figure_13_001.png]]

'''Figure 13.1 |''' '''Geographical subdivision of land (a,b,c,d) and ocean (i,ii,iii) regions of Europe.''' The overlay represents the WGI AR6 ( [[#IPCC--2021|IPCC, 2021]] ) subdivisions for climate-change projections of land, while the colour coding indicates the European countries (or, in case of the Russian Federation, the European part of the country, EEU, used for this chapter). Note that in the WGI AR6 report, MED includes both Southern Europe and Northern Africa, while this chapter includes only the northern (European) part of the MED region. To distinguish between the two the region is called SEU here.

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=== 13.1.2 Socioeconomic Boundary Conditions ===

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The adaptive capacity, as measured by the GDP per capita, tends to be higher in northern and western parts of Europe (Figure 13.2a). In recent decades, climate change has led to substantial losses and damages to people and assets across Europe, mostly from riverine flooding, heatwaves and storms (Figure 13.2b). Public concern about climate change, which is an indicator of the intention to mitigate and adapt, is particularly high in parts of SEU and WCE (Figure 13.2c). Current vulnerability to extreme weather and climatic events in European countries is low to moderate compared with the rest of the world (Figure 13.2d).

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[[File:636507bea5e972bbfb0e7609ad920f54 IPCC_AR6_WGII_Figure_13_002.png]]

'''Figure 13.2 |''' '''Indicators of reported damages to people and assets, vulnerability and adaptive capacity across European countries:'''

'''(a)''' GDP per capita (average 2013–2018), in constant 2011 international dollars ( [[#World%20Bank--2020|World Bank, 2020]] );

'''(b)''' exposure as measured by the global rank of the Climate Risk index, which is based on economic damages and fatalities due to climate-related extreme weather events between 1999 and 2018 ( [[#Germanwatch--2020|Germanwatch, 2020]] );

'''(c)''' level of climate-change concern among a representative weighted sample of residents 15 years and older in private households ( [[#European%20Social%20Survey--2020|European Social Survey, 2020]] ); and

'''(d)''' vulnerability to disasters and humanitarian crisis in 2021. The index is based on socioeconomic factors (development, inequality and aid dependency) and vulnerable groups ( [[#DRMKC--2020|DRMKC, 2020]] ).

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=== 13.1.3 Impact Assessment of Climate Change Based on Previous Reports ===

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The main findings of previous reports, particularly the WGII AR5 ( [[#Kovats--2014|Kovats et al., 2014]] ) and the IPCC Special Report on 1.5°C ( [[#Hoegh-Guldberg--2018|Hoegh-Guldberg et al., 2018]] ), highlighted the impacts of warming and rainfall variations and their extremes on Europe, particularly SEU and mountainous areas. At 2°C GWL, 9% of Europe’s population was projected to be exposed to aggravated water scarcity, and 8% of the territory of Europe were characterised to have a high or very high sensitivity to desertification ( [[#UNEP/UNECE--2016|UNEP/UNECE, 2016]] ). These impacts are driven by changes in temperature, precipitation, irrigation developments, population growth, agricultural policies and markets ( [[#EEA--2017a|EEA, 2017a]] ). Heat is a main hazard for high-latitude ecosystems ( [[#Kovats--2014|Kovats et al., 2014]] ; [[#Jacob--2018|Jacob et al., 2018]] ; [[#Hock--2019|Hock et al., 2019]] ). The majority of mountain glaciers lost mass during the past two decades, and permafrost in the European Alps and Scandinavia is decreasing ( [[#Hock--2019|Hock et al., 2019]] ). In Central Europe, Scandinavia and Caucasus, mountain glaciers were projected to lose 60–80% of their mass by the end of the 21st century ( [[#Hock--2019|Hock et al., 2019]] ). The combined impacts on tourism, agriculture, forestry, energy, health and infrastructure were suggested to make SEU highly vulnerable and increase the risks of failures and vulnerability for urban areas ( [[#Kovats--2014|Kovats et al., 2014]] ). Previous reports stated that the adaptive capacity in Europe is high compared with other regions of the world, but that there are also limits to adaptation from physical, social, economic and technological factors. Evidence suggested that staying within 1.5°C GWL would strongly increase Europe’s ability to adapt to climate change ( [[#de%20Coninck--2018|de Coninck et al., 2018]] ).

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=== 13.1.4 European Climate: Main Conclusions of WGI AR6 ===

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Changes in several climatic-impact drivers have already emerged in all regions of Europe: increases in mean temperature and extreme heat, and decreases in cold spells ( [[#Ranasinghe--2021|Ranasinghe et al., 2021]] ; [[#Seneviratne--2021|Seneviratne et al., 2021]] ). Lake and river ice has decreased in NEU, WCE and MED, and sea ice in NEUS ( [[#Fox-Kemper--2021|Fox-Kemper et al., 2021]] ; [[#Ranasinghe--2021|Ranasinghe et al., 2021]] ). With increasing warming, confidence in projections is increasing for more drivers (Figure 13.3). Mean and maximum temperatures, frequencies of warm days and nights, and heatwaves have increased since 1950, while the corresponding cold indices have decreased ( ''high confidence'' ) ( [[#Ranasinghe--2021|Ranasinghe et al., 2021]] ; [[#Seneviratne--2021|Seneviratne et al., 2021]] ). Average warming will be larger than the global mean in all of Europe, with largest winter warming in NEU and EEU and largest summer warming in MED ( ''high confidence'' ) ( [[#Gutiérrez--2021|Gutiérrez et al., 2021]] ; [[#Ranasinghe--2021|Ranasinghe et al., 2021]] ). An increase in hot days and a decrease in cold days are ''very likely'' (Figure 13.4a,b). Projections suggest a substantial reduction in European ice glacier volumes and in snow cover below elevations of 1500–2000 m, as well as further permafrost thawing and degradation, during the 21st century, even at a low GWL ( ''high confidence'' ) ( [[#Ranasinghe--2021|Ranasinghe et al., 2021]] ).

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'''Figure 13.3 |''' '''Observed and projected direction of change in climate-impact drivers at 1''' '''.''' '''5°C and 4°C GWL for European sub-regions and European seas.''' (Assessment from [[#Gutiérrez--2021|Gutiérrez et al., 2021]] ; [[#Ranasinghe--2021|Ranasinghe et al., 2021]] ; [[#Seneviratne--2021|Seneviratne et al., 2021]] ).

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'''Figure 13.4'''

'''(a,b)''' number of days with temperature maximum above 35°C (TX35) and population density (European Comission, 2019);

'''(c,d)''' daily precipitation maximum (R × 1 d) and built-up area ( [[#JRCdatacatalogue--2021|JRCdatacatalogue, 2021]] );

'''(e,f)''' consecutive dry days and annual harvested rain-fed area ( [[#Portmann--2010|Portmann et al., 2010]] );

The assessment of climate change in WGI AR6 concludes that during recent decades mean precipitation has increased over NEU, WCE and EEU, while magnitude and sign of observed trends depend substantially on time period and study region in MED ( ''medium confidence'' ) ( [[#Douville--2021|Douville et al., 2021]] ; [[#Gutiérrez--2021|Gutiérrez et al., 2021]] ; [[#Ranasinghe--2021|Ranasinghe et al., 2021]] ). Precipitation extremes have increased in NEU and EEU ( ''high confidence'' ) ( [[#Seneviratne--2021|Seneviratne et al., 2021]] ), vary spatially in WCE ( ''medium confidence'' ) and have not changed in MED ( ''low confidence'' ). For &gt;2°C GWL, of mean precipitation in NEU in winter is increasing and decreasing in MED in summer ( ''high confidence'' ). A widespread increase of precipitation extremes is projected for &gt;2°C GWL for all sub-regions ( ''high confidence'' ), except for MED where no change or decrease is projected in some areas (Figure 13.4c,d; [[#Gutiérrez--2021|Gutiérrez et al., 2021]] ; [[#Ranasinghe--2021|Ranasinghe et al., 2021]] ). WGI assessed projections for meteorological, agricultural/ecological and hydrological drought ( [[#Ranasinghe--2021|Ranasinghe et al., 2021]] ) with ''low confidence'' in the direction of change in NEU, WCE and EEU at 1.5°C GWL. MED is projected to be most affected within Europe with all types of droughts increasing for 1.5°C ( ''medium confidence'' ) and 4°C GWL ( ''high confidence'' ). At 4°C GWL, hydrological droughts in NEU, WCE and EEU will increase ( ''medium confidence'' ). Projections for the 21st century show increases in storms across all of Europe ( ''medium confidence'' ) for &gt;2°C GWL with a decrease in their frequency in the MED ( [[#Ranasinghe--2021|Ranasinghe et al., 2021]] ).

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[[File:a36fa54db56f8ed7311ecc8192e6b705 IPCC_AR6_WGII_Figure_13_004g-j.png]]

'''Figure 13.4g-j |''' '''Changes in climate hazards for global warming levels of 1''' '''.''' '''5°C and 3°C based on the CMIP6 ensemble ( [[#Gutiérrez--2021|Gutiérrez et al., 2021]] ) with respect to the baseline period 1995–2014, combined with information on present exposure or vulnerability''' :

'''(g,h)''' sea surface temperature and marine protected areas ( [[#EEA--2021b|EEA, 2021b]] ); and

'''(k,l)''' sea level rise (SLR) and coastal population ( [[#Merkens--2016|Merkens et al., 2016]] ). The SLR data consider the long-term period (2081–2100) and SSP1–2.6 for (i) and SSP3–7.0 for (j).

Sea surface warming between 0.25°C and 1°C has been observed in all regions over recent decades ( ''high confidence'' ) ( [[#Ranasinghe--2021|Ranasinghe et al., 2021]] ) and are projected to continue increasing ( ''high confidence'' ), particularly in the SEUS and at the NEUS (Figure 13.4g,h; [[#Gutiérrez--2021|Gutiérrez et al., 2021]] ). Salinity has increased in the SEUS and decreased in NEUS and is projected to continue ( ''medium confidence'' ) ( [[#Fox-Kemper--2021|Fox-Kemper et al., 2021]] ). European waters have been, and will continue, acidifying ( ''virtually certain'' ) ( [[#Eyring--2021|Eyring et al., 2021]] ; [[#Szopa--2021|Szopa et al., 2021]] ), resulting in a mean decrease of surface pH of about 0.1 and 0.3 pH units at 1.5°C and 3°C GWL with the largest changes at high latitudes ( [[#Gutiérrez--2021|Gutiérrez et al., 2021]] ).

Relative sea level has risen along the European coastlines ( [[#Ranasinghe--2021|Ranasinghe et al., 2021]] ), regionally mitigated by post-glacial rise of land masses in Scandinavia ( [[#Fox-Kemper--2021|Fox-Kemper et al., 2021]] ). This SLR will ''very likely'' continue to increase during the 21st century (Figure 13.4k,l) ( ''high confidence'' ), with regional deviations from global mean SLR ( ''low confidence'' ). Extreme water levels, coastal floods and sandy coastline recession are projected to increase along many European coastlines ( ''high confidence'' ) ( [[#Ranasinghe--2021|Ranasinghe et al., 2021]] ).

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