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

== 13.6 Cities, Settlements and Key Infrastructures ==

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Urban areas in Europe house 547 million inhabitants, corresponding to 74% of the total European population ( [[#UN/DESA--2018|UN/DESA, 2018]] ). In the EU-28, 39% of the total population lives in metropolitan regions (i.e., areas with at least 1 million inhabitants) where 47% of the total GDP is generated ( [[#Eurostat--2016|Eurostat, 2016]] ). Apart from urban settlements, this section also covers energy and transport systems, as well as tourism, industrial and business sectors which are key for livelihood, economic prosperity and the well-being of residents.

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=== 13.6.1 Observed Impacts and Projected Risks ===

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==== 13.6.1.1 Energy Systems ====

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The energy sector in Europe already faces impacts from climate extremes ( ''high confidence'' ). Significant reductions and interruptions of power supply have been observed during exceptionally dry and/or hot years of the recent 20-year period, for example, in France, Germany, Switzerland and the UK during the extremely hot summer of 2018 which led to water-cooling constraints on power plants ( [[#van%20Vliet--2016b|van Vliet et al., 2016b]] ; [[#Abi-Samra--2017|Abi-Samra, 2017]] ; [[#Vogel--2019|Vogel et al., 2019]] ). Heating-degree days decreased and cooling-degree days increased during 1951–2014, with clearer trends after 1980 ( [[#De%20Rosa--2015|De Rosa et al., 2015]] ; [[#Spinoni--2015|Spinoni et al., 2015]] ; [[#EEA--2017a|EEA, 2017a]] ). Projected climate risks for energy supply are summarised in Figure 13.16.

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[[File:56ddd582c5484ea2bbb2b06db3552dd2 IPCC_AR6_WGII_Figure_13_016.png]]

'''Figure 13.16 |''' '''Projected climate-change risks for energy supply in Europe for major sources and under 1''' '''.''' '''5°C, 2°C and &gt;3°C GWL (Tables SM13.5–13.13)'''

New studies reinforce the findings of AR5 on risks for thermoelectric power and regional differences between NEU and SEU regarding risks for hydropower (Figure 13.16). In NEU and EEU, extremely high water inflows to dams are projected to increase flooding risks for plant and nearby settlements ( [[#Chernet%20Haregewoin--2014|Chernet Haregewoin et al., 2014]] ; [[#Porfiriev--2017|Porfiriev et al., 2017]] ), while increasing temperatures could reduce the efficiency of steam and gas turbines ( [[#Porfiriev--2017|Porfiriev et al., 2017]] ; [[#Cronin--2018|Cronin et al., 2018]] ; [[#Klimenko--2018a|Klimenko et al., 2018a]] ). Water scarcity may limit onshore carbon capture and storage in some regions ( [[#Byers--2016|Byers et al., 2016]] ; [[#Murrant--2017|Murrant et al., 2017]] ; [[#EEA--2019a|EEA, 2019a]] ).

Reduced surface wind speeds during 1979–2016 ( [[#Frolov--2014|Frolov et al., 2014]] ; [[#Perevedentsev--2014|Perevedentsev and Aukhadeev, 2014]] ; [[#Tian--2019|Tian et al., 2019]] ) support projected trends in decreasing onshore wind energy potential. Seasonal changes may result in reductions in many areas in summer (by 8–30% in Southern Europe) and increases in most of NEU during winter. Increasing probabilities and persistence of high winds over the Aegean and Baltic seas ( [[#Weber--2018a|Weber et al., 2018a]] ) could create new opportunities for offshore wind. The future configuration of the wind fleet will affect the spatial and temporal variability of wind power production ( [[#Tobin--2016|Tobin et al., 2016]] ). Total backup energy needs in Europe could increase by 4–7% by 2100 ( [[#Wohland--2017|Wohland et al., 2017]] ) with potentially larger seasonal changes ( [[#Weber--2018b|Weber et al., 2018b]] ).

There is ''low evidence'' and ''limited agreement'' on projections of solar power potential due to differences in the integration of aerosols and the estimated cloud cover between climate models ( [[#Bartok--2017|Bartok et al., 2017]] ; [[#Boé--2020|Boé et al., 2020]] ; [[#Gutiérrez--2020|Gutiérrez et al., 2020]] ). Studies on climate risks for bioenergy are also limited.

Energy demand is projected to display regional differences in response to warming beyond 2°C GWL, with a the significant southwest-to-northeast decrease of heating-degree days by 2100 (particularly in northern Scandinavia and Russia), and a smaller north-to-south increase of cooling-degree days ( [[#Porfiriev--2017|Porfiriev et al., 2017]] ; [[#Spinoni--2018|Spinoni et al., 2018]] ; [[#Coppola--2021|Coppola et al., 2021]] ). Under the present population numbers, total energy demand would decrease in almost all of Europe, whereas it could increase in some countries (e.g., UK, Spain, Norway) when considering Eurostat’s population projections ( [[#Klimenko--2018b|Klimenko et al., 2018b]] ; [[#Spinoni--2018|Spinoni et al., 2018]] ). There is ''medium confidence'' that peak load will increase in SEU and decrease in NEU ( [[#Damm--2017|Damm et al., 2017]] ; [[#Wenz--2017|Wenz et al., 2017]] ; [[#Bird--2019|Bird et al., 2019]] ). Beyond 2°C GWL, a shift of peak load from winter to summer in many countries is possible ( [[#Wenz--2017|Wenz et al., 2017]] ). Together with water-cooling constraints for thermal power, this change in load may challenge the stability of electricity networks during heatwaves ( [[#EEA--2019a|EEA, 2019a]] ). Technological factors, increased electricity use and adaptation influence significantly the temperature sensitivity of electricity demand and consequently risks ( [[#Damm--2017|Damm et al., 2017]] ; [[#Wenz--2017|Wenz et al., 2017]] ; [[#Cassarino--2018|Cassarino et al., 2018]] ; [[#Figueiredo--2020|Figueiredo et al., 2020]] ). Potential power curtailments or outages during climatic extremes may increase electricity prices ( [[#Pechan--2014|Pechan and Eisenack, 2014]] ; [[#Steinhäuser--2020|Steinhäuser and Eisenack, 2020]] ).

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==== 13.6.1.2 Transport ====

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Heatwaves in 2015 and 2018 in parts of WCE and NEU caused road melting, railway asset failures and speed restrictions to reduce the likelihood of track buckling ( [[#Ferranti--2018|Ferranti et al., 2018]] ; [[#Vogel--2019|Vogel et al., 2019]] ). Recent studies on projected risks focus mainly on infrastructure and much less on transport flows and disruptions.

Sea level rise ( [[#13.2|Section 13.2]] ) may disrupt port operations and surrounding areas, mainly in parts of NEU and WCE ( [[#Christodoulou--2018|Christodoulou et al., 2018]] ), while changes of waves agitation could increase the non-operability hours of some Mediterranean ports beyond 2°C GWL ( [[#Sierra--2016|Sierra et al., 2016]] ; [[#Camus--2019|Camus et al., 2019]] ; [[#Izaguirre--2021|Izaguirre et al., 2021]] ). Low-water-level days at some critical locations for inland navigation at the Rhine River are projected to increase beyond 2°C GWL, while decreases at the Danube River are possible ( [[#van%20Slobbe--2016|van Slobbe et al., 2016]] ; [[#Christodoulou--2020|Christodoulou et al., 2020]] ).

Risks of rutting and blow-ups of roads (particularly in low altitudes) due to high summer temperatures are expected to increase in WCE and EEU at 3°C GWL ( ''medium confidence'' ) ( [[#Frolov--2014|Frolov et al., 2014]] ; [[#Matulla--2018|Matulla et al., 2018]] ; [[#Yakubovich--2018|Yakubovich and Yakubovich, 2018]] ). In EEU and northern Scandinavia, the higher number of freezing–thawing cycles of construction materials will increase risks for roads ( [[#Frolov--2014|Frolov et al., 2014]] ; [[#Yakubovich--2018|Yakubovich and Yakubovich, 2018]] ; [[#Nilsen--2021|Nilsen et al., 2021]] ), while warming beyond 2°C GWL could significantly reduce road maintenance costs in NEU ( [[#Lorentzen--2020|Lorentzen, 2020]] ), but limit off-road overland transport in northwest Russia ( [[#Gädeke--2021|Gädeke et al., 2021]] ). Beyond 3°C GWL, more frequent hourly precipitation extremes are projected over WCE and NEU in summer (e.g., a twofold and tenfold increase, respectively, for events exceeding the present-day 99.99 th percentile in Germany and the UK) but more widely across Europe in autumn and winter (an increase higher than tenfold for 99.99th percentile events in SEU in autumn ( [[#Chan--2020|Chan et al., 2020]] ), potentially severely damaging roads as happened in Mandra, Greece, in 2017 ( [[#Diakakis--2020|Diakakis et al., 2020]] ). Landslide risks in WCE and SEU could increase beyond a 2°C GWL, threatening road networks ( [[#Schlogl--2018|Schlogl and Matulla, 2018]] ; [[#Rianna--2020|Rianna et al., 2020]] ).

The current flood risk for railways could double or triple at 1.5–3°C GWL, particularly in WCE, increasing public expenditure for rail transport in Europe by 1.22 billion EUR annually under 3°C GWL and no adaptation ( [[#Bubeck--2019|Bubeck et al., 2019]] ). Thermal discomfort in urban underground railways is expected to increase, even at a high level of carriage cooling ( [[#Jenkins--2014a|Jenkins et al., 2014a]] ).

The number of airports vulnerable to inundation from SLR and storm surges may double between 2030 and 2080 without adaptation, especially close to the North Sea and Mediterranean coasts ( [[#Christodoulou--2018|]] [[#Christodoulou--2018|Christodoulou and Demirel, 2018]] ). Rising temperatures reducing lift generation could impose weight restrictions for large aircraft at 2°C GWL and beyond in airports of France, the UK and Spain ( [[#Coffel--2017|Coffel et al., 2017]] ). There is a lack of studies quantifying the effect of future extreme events on flight arrivals at, and departures from, European airports.

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==== 13.6.1.3 Business and Industry ====

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European industrial and service sectors contribute 85% to gross value added in EU-28 ( [[#Eurostat--2020|Eurostat, 2020]] ); while their direct exposure and vulnerability is smaller compared with sectors directly reliant on weather, they are directly and indirectly affected by heat, flooding, water scarcity and drought ( [[#Weinhofer--2013|Weinhofer and Busch, 2013]] ; [[#Gasbarro--2016|Gasbarro and Pinkse, 2016]] ; [[#Meinel--2018|Meinel and Schule, 2018]] ; [[#Schiemann--2018|Schiemann and Sakhel, 2018]] ; [[#TEG--2019|TEG, 2019]] ). Heat reduces the productivity of labour particularly in construction, agriculture and manufacturing ( [[#13.7.1|Section 13.7.1]] ; [[#García-León--2021|García-León et al., 2021]] ; [[#Schleypen--2021|Schleypen et al., 2021]] ). Direct losses from floods in Europe are highest for manufacturing, utilities and transportation; indirect losses arise, for example, for manufacturing, construction, and banking and insurance ( [[#Koks--2019a|Koks et al., 2019a]] ; [[#Sieg--2019|Sieg et al., 2019]] ; Mendoza–Tinoco et al., 2020). Drought and water scarcity directly affect European industries in the sectors of pulp and paper, chemical and plastic manufacturing, and food and beverages ( [[#Gasbarro--2019|Gasbarro et al., 2019]] ; [[#Teotónio--2020|Teotónio et al., 2020]] ); additionally, drought may indirectly affect sectors relying on shipping, hydropower or public water supply ( [[#Naumann--2021|Naumann et al., 2021]] ). The European financial and insurance sector is affected by climate-change impacts via their customers and financial markets ( [[#Bank%20of%20England--2015|Bank of England, 2015]] ; [[#Georgopoulou--2015|Georgopoulou et al., 2015]] ; [[#Battiston--2017|Battiston et al., 2017]] ; [[#TCFD--2017|TCFD, 2017]] ; [[#Bank%20of%20England--2019|Bank of England, 2019]] ; [[#de%20Bruin--2020|de Bruin et al., 2020]] ; [[#Monasterolo--2020|Monasterolo, 2020]] ).

The vulnerability to climate hazards varies by European region, type of risk, sector and business characteristics ( [[#Gasbarro--2016|Gasbarro et al., 2016]] ; [[#Forzieri--2018|Forzieri et al., 2018]] ; [[#ECB--2021a|ECB, 2021a]] ; [[#Kouloukoui--2021|Kouloukoui et al., 2021]] ). Current damages are mainly related to river floods and storms, but heat and drought will become major drivers in the future ( ''medium confidence'' ). Until 2050, the probability of default of firms located in particularly exposed locations may increase to up to four times that of an average firm in all sectors ( [[#ECB--2021a|ECB, 2021a]] ).

Many European sectors are exposed to multiple and cross-cutting risks ( [[#Gasbarro--2019|Gasbarro et al., 2019]] ; [[#Schleypen--2021|Schleypen et al., 2021]] ). Indirect effects via supply chains, transport and electricity networks can be as high as, or substantially higher than, direct effects ( ''medium confidence'' ) ( [[#Koks--2019a|Koks et al., 2019a]] ; [[#Koks--2019b|Koks et al., 2019b]] ; [[#Knittel--2020|Knittel et al., 2020]] ).

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==== 13.6.1.4 Tourism ====

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Snow-cover duration and snow depth in the Alps has decreased since the 1960s ( [[#Klein--2016|Klein et al., 2016]] ; [[#Schöner--2019|Schöner et al., 2019]] ; [[#Matiu--2021|Matiu et al., 2021]] ). Despite snowmaking, the number of skiers to French resorts at low elevations during the extraordinary warm and dry winters of 2006–2007 and 2010–2011 was 12–26% lower ( [[#Falk--2016|Falk and Vanat, 2016]] ).

Due to reduced snow availability and hotter summers, damages are projected for the European tourism industry, with larger losses in SEU ( ''high confidence'' ) and some smaller gains in the rest of Europe ( ''medium confidence'' ) ( [[#Ciscar%20Martinez--2014|Ciscar Martinez et al., 2014]] ; [[#Roson--2016|Roson and Sartori, 2016]] ; [[#Dellink--2019|Dellink et al., 2019]] ).

At 2°C GWL, the operation of low-altitude resorts without snowmaking will ''likely'' be discontinued, while beyond 3°C GWL, snowmaking will be necessary, but not always sufficient, for most resorts in many European mountains and parts of NEU ( [[#Pons--2015|Pons et al., 2015]] ; [[#Joly--2018|Joly and Ungureanu, 2018]] ; [[#Scott--2019|Scott et al., 2019]] ; [[#Spandre--2019|Spandre et al., 2019]] ). Expanding snowmaking is capital intensive and will strongly increase water and energy consumption, particularly at 3°C GWL and beyond ( [[#Spandre--2019|Spandre et al., 2019]] ; [[#Morin--2021|Morin et al., 2021]] ), adversely affecting the financial stability of small resorts ( [[#Pons--2015|Pons et al., 2015]] ; [[#Falk--2016|Falk and Vanat, 2016]] ; [[#Spandre--2016|Spandre et al., 2016]] ; [[#Joly--2018|Joly and Ungureanu, 2018]] ; [[#Moreno-Gené--2018|Moreno-Gené et al., 2018]] ; [[#Steiger--2020|Steiger and Scott, 2020]] ). Permafrost degradation due to rising temperatures is expected to create stability risks for ropeway transport infrastructure at high-altitude Alpine areas ( [[#Duvillard--2019|Duvillard et al., 2019]] ).

Climatic conditions from May to October at 1.5–2°C GWL are projected to become more favourable for summer tourism in NEU and parts of WCE and EEU, while there is ''medium confidence'' on opposite trends for SEU from June to August ( [[#Grillakis--2016|Grillakis et al., 2016]] ; [[#Scott--2016|Scott et al., 2016]] ; [[#Jacob--2018|Jacob et al., 2018]] ; [[#Koutroulis--2018|Koutroulis et al., 2018]] ). The amenity of European beaches may decrease as a result of SLR amplifying coastal erosion and inundation risks, although less in NEU ( [[#13.2|Section 13.2]] ; [[#Ebert--2016|Ebert et al., 2016]] ; [[#Toimil--2018|Toimil et al., 2018]] ; [[#Lopez-Doriga--2019|Lopez-Doriga et al., 2019]] ; [[#Ranasinghe--2021|Ranasinghe et al., 2021]] ).

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==== 13.6.1.5 Built Environment, Settlements and Communities ====

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The expected shift of European residents to large cities and coastal areas will increase assets at risk ( [[#13.2|Section 13.2]] ). The share of urban population in Europe is projected to increase from 74% in 2015 to 84% in 2050, corresponding to 77 million new urban residents ( [[#UN/DESA--2018|UN/DESA, 2018]] ), with most of this increase in SEU and WCE (particularly in Turkey and France). In the EU-28, urban residents in 2100 may increase by about 30 million under SSP1 and SSP5, and decrease by 90–110 million under SSP3 and SSP4 ( [[#Terama--2019|Terama et al., 2019]] ).

About 32% of 571 European cities in the GISCO Urban Audit 2014 dataset show a medium to high or relatively high vulnerability against heatwaves, droughts and floods ( [[#Tapia--2017|Tapia et al., 2017]] ). Under current vulnerabilities, future climate hazards will augment climate risks for several cities, particularly beyond 3°C GWL (Figure 13.17). In many NEU cities, a high increase in pluvial flooding risk by the end of the century is possible, while in WCE cities may face a high increase in pluvial flooding risks, moderate to very high increase in extreme heat risk, and to some extent moderate to high increase in drought risk. Many SEU cities could face a high to very high increase in risks from extreme heat and meteorological drought.

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[[File:a700d10b7ca868732196d99c1f10cbe4 IPCC_AR6_WGII_Figure_13_017.png]]

'''Figure 13.17 |''' '''Projected changes in pluvial flooding, extreme heat and meteorological drought risks for the 65 largest cities in EU-28 plus Norway and Switzerland for''' '''2.''' '''5°C and 4.4°C GWL compared with the baseline (1995–2014) ( [[#Tapia--2017|Tapia et al., 2017]] ).''' Exposure is expressed in terms of current population. Values of climatic impact drivers are derived from the Euro-CORDEX regional climate model ensemble.

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===== 13.6.1.5.1. Risks from coastal, river and pluvial flooding =====

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New studies increase confidence in AR5 statements that flood damages will increase in coastal areas due to SLR and changing social and economic conditions ( [[#13.2.1.1|Section 13.2.1.1]] ). Except for areas affected by land uplift, it is projected that further adaptation will be required to maintain risks at the present level for most coastal cities and settlements ( [[#Haasnoot--2013|Haasnoot et al., 2013]] ; [[#Ranger--2013|Ranger et al., 2013]] ; [[#Malinin--2018|Malinin et al., 2018]] ; [[#Hinkel--2019|Hinkel et al., 2019]] ; [[#Umgiesser--2020|Umgiesser, 2020]] ).

In many cities, the sewer system is older than 40 years, potentially reducing their capacity to deal with more intense pluvial flooding ( [[#EEA--2020b|EEA, 2020b]] ). Apart from climate change, urbanisation is an important driver for increases in flooding risks as it results in growth of impervious surfaces. Flash floods are particularly challenging, causing the overburdening of drainage systems ( [[#Dale--2018|Dale et al., 2018]] ), urban transport disruptions, and health and pollution impacts due to untreated sewage discharges ( [[#Kourtis--2021|Kourtis and Tsihrintzis, 2021]] ).

More than 25% of the population in nearly 13% of EU cities live within potential river floodplains. In many of these places (e.g., 50% of UK cities), a significant increase in the 10-year high river flow is possible beyond 2°C GWL under a high-impact scenario (i.e., 90th percentile of projections) ( [[#Guerreiro--2018|Guerreiro et al., 2018]] ; [[#EEA--2020b|EEA, 2020b]] ).

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===== 13.6.1.5.2 Risks from heatwaves, cold waves and drought =====

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Heatwave days and number of long heatwaves increased in most capitals from 1998–2015 compared with 1980–1997 ( [[#Morabito--2017|Morabito et al., 2017]] ; [[#Seneviratne--2021|Seneviratne et al., 2021]] ). In the summer of 2018, many cities suffered from heatwaves attributed to climate change ( [[#Vogel--2019|Vogel et al., 2019]] ; [[#Undorf--2020|Undorf et al., 2020]] ). As a result, indoor overheating and reduced outdoor thermal comfort, often coupled with urban heat island (UHI) effect, have already impacted European cities (see also [[#13.7.1|Section 13.7.1]] ; [[#Di%20Napoli--2018|Di Napoli et al., 2018]] ; [[#EEA--2020b|EEA, 2020b]] ).

Heatwaves are ''likely'' to become a major threat, not only for SEU but also for WCE and EEU cities ( [[#Russo--2015|Russo et al., 2015]] ; [[#Guerreiro--2018|Guerreiro et al., 2018]] ; [[#Lorencova--2018|Lorencova et al., 2018]] ; [[#Smid--2019|Smid et al., 2019]] ). At 2°C GWL and SSP3, half of the European population will be under very high risk of heat stress in summer ( [[#Rohat--2019|Rohat et al., 2019]] ). The UHI effect will further increase urban temperatures ( [[#Estrada--2017|Estrada et al., 2017]] ). In many cities, hospitals and social housing tend to be located within the intense UHI, thus increasing exposure to vulnerable groups ( [[#EEA--2020b|EEA, 2020b]] ). There is ''high confidence'' that overheating during summer in buildings with insufficient ventilation and/or solar protection will increase strongly, with thermal comfort hours potentially decreasing by 74% in SEU at 3°C GWL ( [[#Jenkins--2014a|Jenkins et al., 2014a]] ; [[#Hamdy--2017|Hamdy et al., 2017]] ; [[#Heracleous--2018|Heracleous and Michael, 2018]] ; [[#Dino--2019|Dino and Meral Akgül, 2019]] ; [[#Shen--2020|Shen et al., 2020]] ). Highly insulated buildings, following present building standards, will be vulnerable to overheating, particularly under high GWL levels, unless adequate adaptation measures are applied ( [[#Williams--2013|Williams et al., 2013]] ; [[#Virk--2014|Virk et al., 2014]] ; [[#Mulville--2016|Mulville and Stravoravdis, 2016]] ; [[#Fosas--2018|Fosas et al., 2018]] ; [[#Ibrahim--2018|Ibrahim and Pelsmakers, 2018]] ; [[#Salem--2019|Salem et al., 2019]] ; [[#Tian--2020|Tian et al., 2020]] ). Cities in NEU and WCE are more vulnerable due to limited solar shading and fewer air conditioning installations ( [[#Ward--2016|Ward et al., 2016]] ; [[#Thomson--2019|Thomson et al., 2019]] ). Cooling energy demand in SEU buildings has been projected to increase by 81–104% by 2035 and 91–244% after 2065 compared with 1961–1990 depending on GWL ( [[#Cellura--2018|Cellura et al., 2018]] ). Increases of 31–73% by 2050 and 165–323% by 2100 compared with 1996–2005 were estimated for buildings in NEU ( [[#Dodoo--2016|Dodoo and Gustavsson, 2016]] ) with risks modified by adaptation ( [[#13.6.2|Section 13.6.2]] ; [[#Viguié--2020|Viguié et al., 2020]] ). Cold waves beyond 3°C GWL will not represent an effective threat for European cities at the end of the century, and only a marginal hazard under 2°C GWL ( [[#Smid--2019|Smid et al., 2019]] ).

At 2°C GWL and beyond, cities in SEU and large parts of WCE would exceed the historical maximum 12-month Drought Severity index of the past 50 years (see [[#13.2|Section 13.2]] on drought risks) and 30% will have at least 30% probability of exceeding this maximum every month ( [[#Guerreiro--2018|Guerreiro et al., 2018]] ). This could adversely affect the operation of municipal water services ( [[#Kingsborough--2016|Kingsborough et al., 2016]] ). For example, under 2°C GWL, the reservoir storage volume is predicted to decrease for all of England and Wales catchments, resulting in a probability of years with water-use restrictions doubling by 2050 and quadrupling by 2100 compared with 1975–2004 ( [[#Dobson--2020|Dobson et al., 2020]] ). The combination of high temperatures, drought and extreme winds, potentially coupled with insufficient preparedness and adaptation, may amplify the damage of wildfires in peri-urban environments ( [[#13.3.1.3|Section 13.3.1.3]] ). High fuel load combined with proximity of the built environment to wildland highly increases fire risks ( [[#EEA--2020b|EEA, 2020b]] ).

Extreme heat and drought causes shrinking and swelling of clays, threatening the stability of small houses in peri-urban environments ( [[#Pritchard--2015|Pritchard et al., 2015]] ), with damage costs of 0.9–1 billion EUR during the 2003 heatwave ( [[#Corti--2011|Corti et al., 2011]] ). In WCE and SEU, mean annual damage costs could increase by 50% for 2°C GWL, and by a factor of 2 for 3°C GWL ( [[#Naumann--2021|Naumann et al., 2021]] ).

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===== 13.6.1.5.3 Risks from thaw of permafrost and mudflows =====

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Increasing temperatures in NEU and the Alps has led to accelerated degradation of permafrost, negatively affecting the stability of infrastructures ( [[#Stoffel--2014|Stoffel et al., 2014]] ; [[#Beniston--2018|Beniston et al., 2018]] ; [[#Duvillard--2019|Duvillard et al., 2019]] ). In the Caucasus, glacial mudflows due to permafrost degradation and modern tectonic processes pose a significant danger to the infrastructure ( [[#Vaskov--2016|Vaskov, 2016]] ). In the past 30 years, the permafrost temperature in the European part of the Russian Arctic has increased by 0.5–2°C, resulting in damage to buildings, roads and pipelines, and to significant expenditure for stabilising soils ( [[#Porfiriev--2017|Porfiriev et al., 2017]] ; [[#Konnova--2019|Konnova and Lvova, 2019]] ). Beyond 3° C GWL, the bearing capacity for infrastructure in the permafrost region of the European Russia could decrease by 32–75% by mid-century and by 95% by 2100, potentially affecting settlements in northern EEU ( [[#Shiklomanov--2017|Shiklomanov et al., 2017]] ; [[#Streletskiy--2019|Streletskiy et al., 2019]] ). The increasing number of cycles of freezing and thawing, observed in EEU, has led to accelerated ageing of building envelopes ( [[#13.8.1.4|Section 13.8.1.4]] ; [[#Frolov--2014|Frolov et al., 2014]] ). Permafrost degradation due to higher temperatures could increase the potential of debris flow detachment in Alpine locations ( [[#13.6.1.4|Section 13.6.1.4]] ; [[#Damm--2013|Damm and Felderer, 2013]] ).

Increased precipitation falling on local topography can increase landslide and mudflow risks, as seen in settlements at the Caucasus mountainous region ( [[#Marchenko--2017|Marchenko et al., 2017]] ; [[#Efremov--2018|Efremov and Shulyakov, 2018]] ; [[#Kerimov--2020|Kerimov et al., 2020]] ). At the Umbria region in Italy, landslide events could increase by 16–53% under 2°C GWL and by 24–107% beyond 3°C GWL, mostly during winter ( [[#Ciabatta--2016|Ciabatta et al., 2016]] ). Risks from shallow landslides are expected to increase in the Alps and Carpathians if no adequate risk mitigation measures are put in place ( [https://www.ipcc.ch/chapter/13#CCP5.3.2 CCP5.3.2] ; [[#Gariano--2016|Gariano and Guzzetti, 2016]] ).

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=== 13.6.2 Solution Space and Adaptation Options ===

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Monetary assessments of future damages from climate extremes on critical infrastructures show an escalating sevenfold increase by 2080s (Figure 13.18) compared with the baseline ( [[#Forzieri--2018|Forzieri et al., 2018]] ), highlighting the need for adaptation.

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[[File:4578dbed462033d8059dea3752214158 IPCC_AR6_WGII_Figure_13_018.png]]

'''Figure 13.18 |''' '''Climate risks to critical infrastructures, aggregated at European (EU+) level under the SRES A1B scenario (Forzieri et al.''' ''', 2018).''' Baseline: 1981–2010; 2020s: 2011–2040; 2050s: 2041–2070; 2080s: 2071–2100

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<span id="current-status-of-adaptation"></span>
==== 13.6.2.1 Current Status of Adaptation ====

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There is new evidence on increasing adaptation planning in cities, settlements and key infrastructures, but less on implemented adaptation (Table 13.1; see Box 13.3; Figure 13.36), adaptation by private actors and by cities against SLR (Chapter 16; Cross-Chapter Paper 2).

'''Table 13.1 |''' Present status of planned and implemented adaptation in European cities, energy sector, tourism sector, transport and industry (Table SM13.17)

{| class="wikitable"
|-
!
! colspan="3"| '''General commitments / Adaptation Plans'''

! colspan="3"| '''Implemented adaptation actions'''

|-
| Cities

| colspan="3"| * An increasing number of cities acknowledge the critical role of adaptation in building resilience to climate change.
* Of 9609 European municipalities in the Covenant of Mayors for Climate &amp; Energy (CoM), 2221 reported on adaptation through the CoM platform; 429 provided some information on adaptation goals, risk and vulnerability assessments/action plans, and less than 300 reported adaptation goals and funds. Extreme heat, drought and forest fire were the most often reported hazards.
* Most urban adaptation plans include ecosystem-based measures, but often with limited baseline information and convincing implementation actions.
* Adaptation to risks from climate extremes (mostly flooding) is often addressed through municipal emergency plans.

| colspan="3"| * Large cities (e.g., Helsinki, Copenhagen, Rotterdam, Barcelona, Madrid, London, Moscow) are in the process of implementing adaptation actions.
* Current climate policies implemented at city-scale are primarily addressing mitigation and, to a lesser extent adaptation. Though many cities have implemented measures potentially supporting adaptation, they are not labelled as such.
* Nature-based Solutions and ecosystem-based adaptation are increasingly used to address urban heat and flooding risks that are enhanced by surface sealing and limited infiltration.
* Strategic and emergency measures have been applied for drought management in some cities (e.g., London, Istanbul).

|-
| rowspan="2"| Energy

| rowspan="2" colspan="3"| * In 2020, 29 countries had an adaptation plan for the energy sector. Some of them included specific adaptation actions (mostly preparatory) in their national or energy-specific risk assessments.

| colspan="3"| * In 2020, 11 countries had implemented adaptation actions in the energy sector.

|-
| colspan="3"| * Measures undertaken by some distribution system operators and energy companies, focus on adaptation of transmission lines, water cooling, actions to avoid flooding (e.g. dams) and secure fuel supply.

|-
| rowspan="2"| Tourism

| rowspan="2" colspan="3"| * Consideration of tourism in national adaptation strategies is limited, and national tourism strategies rarely mention adaptation.
* In some countries there is legally binding consideration of climate change when constructing new tourism units (e.g., the 2016 French Mountain Act).
* Many tourism operators focus on near-term coping strategies and do not consider longer term adaptation.

| colspan="3"| * Snow making is widely applied in the Alps and Pyrenees ski resorts; e.g. from 18% of ski slopes in Germany to 67% in Austria. Some resorts already offer nocturnal skiing (e.g., Spain) and other snow-based activities.
* There is already some transformation to year-round mountain resorts (e.g., in 70% of Spanish ski resorts).

|-
| colspan="3"| * Some diversification of tourism products is offered in Mediterranean coastal destinations.
* Water saving measures, primarily for cost reduction, have been implemented, e.g. in hotels.

|-
| rowspan="2"| Transport

| colspan="3"| * At the national level, 10 countries have started coordination activities or identified adaptation measures. Some countries are mainstreaming adaptation within transport planning and decision-making (e.g., the ‘Low-water Rhine’ action plan, in Germany).
* Some action is undertaken in the public and private sector, e.g., revised manuals/guidelines/ protocols that consider climate change impacts and extreme events (e.g., Deutsche Bahn, Norwegian Public Roads Administration).
* An integrated, transmodal approach to transport adaptation is lacking.

| colspan="3"| * Most adaptation actions are preparatory; 5 countries have implemented specific actions. Planned and implemented actions mostly focus on infrastructure and much less on services, although the latter are increasing (e.g., operational forecasts for water levels in rivers).
* Transport modes often compete for public funds and political priorities often influence adaptation for specific modes.

|-
| colspan="3"|
| colspan="3"| * Some public and private actors are moving faster: new railway drainage standards (Network Rail/ UK), adverse weather event predictions (Spanish rail service operator), measures against coastal flooding (Copenhagen Metro), measures for sea level rise (Rotterdam port, France).

|-
| Industry and business

| colspan="3"| * Some businesses are following recommendations of the High-Level Expert Group on Sustainable Finance, endorsed by the European Commission, and implementing the guidelines provided by the Task Force on Climate-Related Financial Disclosure in 2019.

| colspan="3"| * Fifty large European publicly listed companies disclosed their climate risks in 2020, yet only a small percentage provided specifics on sectoral risks, as well as how risks differ over time and according to different climate scenarios.
* Large national and multinational companies, and companies regulated by mitigation policy are the first movers in corporate adaptation, while small and medium-sized enterprises often lack the knowledge and resources to address risks and adaptation options.
* Climate service providers, insurance companies and central banks have developed different tools for climate risk assessment, such as, stress testing, scenario analysis, value at risk.

|-
|
| Well-established adaptation

|
| colspan="2"| Advancing adaptation

|
| Low adaptation

|}

Although urban adaptation is underway, many small, economically weak (i.e., with low GDP per capita) or cities facing high climate-change risks lack adaptation planning ( [[#Reckien--2015|Reckien et al., 2015]] ; [[#EEA--2016|EEA, 2016]] ). While almost all large municipalities in NEU and WCE report implemented actions at least in one sector, this is not the case for 39% of municipalities in SEU ( [[#Aguiar--2018|Aguiar et al., 2018]] ). In the UK, the legal requirement to develop urban adaptation plans has been a significant driver for their widespread adoption ( [[#Reckien--2015|Reckien et al., 2015]] ). The availability of, and access to, funding for adaptation is also crucial for plan development ( [[#13.11.1|Section 13.11.1]] ). Network membership (e.g., ICLEI, C40, Covenant of Mayors for Climate &amp; Energy) is an important driver for city planning and transfer of best practices ( [[#Heikkinen--2020a|Heikkinen et al., 2020a]] ). Stakeholder engagement is key for successful adaptation (Chapter 17; [[#Bertoldi--2020|Bertoldi et al., 2020]] ).

Only 29% of local adaptation plans are mainstreamed in cities, which could reduce the effectiveness of implementing adaptation ( [[#13.11.1.2|Section 13.11.1.2]] ; [[#Reckien--2019|Reckien et al., 2019]] ). Although large municipalities usually fund the implementation of their adaptation plans, smaller and less populated municipalities (particularly in SEU and EEU) often depend on intergovernmental, international and national funding.

<div id="13.6.2.2" class="h3-container"></div>

<span id="adaptation-options-as-a-function-of-impacts"></span>
==== 13.6.2.2 Adaptation Options as a Function of Impacts ====

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Examples of adaptation options in Europe are presented in Figure 13.19.

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[[File:4b1c5d4ac3814629b4df85d86d0dd4f9 IPCC_AR6_WGII_Figure_13_019.png]]

'''Figure 13.19 |''' '''Adaptation options in cities, settlements and key infrastructures in Europe''' ''(Table SM13.7)''

Both NbS and EbA, such as green spaces, ponds, wetlands and green roofs for urban stormwater management and vegetation for heat mitigation, represent an emerging adaptation option in cities. Combined with traditional water infrastructure, they can contribute to managing urban flood events ( [[#Kourtis--2021|Kourtis and Tsihrintzis, 2021]] ), playing a role in mitigating flood peaks ( [[#Pour--2020|Pour et al., 2020]] ) and protecting critical urban infrastructure ( [[#Ossa-Moreno--2017|Ossa-Moreno et al., 2017]] ). For example, in the Augustenborg district of Malmö, Sweden, using nature to manage stormwater runoff has resulted in capturing an estimated 90% of runoff from impervious surfaces and reduced the total annual runoff volume from the district by about 20% compared with the conventional system ( [[#EEA--2020b|EEA, 2020b]] ). Urban greening is associated with lower ambient air temperature and relatively higher thermal comfort during warm periods ( [[#Bowler--2010|Bowler et al., 2010]] ; [[#Oliveira--2011|Oliveira et al., 2011]] ; [[#Cohen--2012|Cohen et al., 2012]] ; [[#Cameron--2014|Cameron et al., 2014]] ). The scale and relative degree of management or integration of approaches drawing on nature with ‘engineered’ solutions affect their vulnerability to climate change. Small-scale urban NbS are relatively less vulnerable due to increased capacity for intervention, while the relatively greater contact between stakeholders and urban NbS (compared with larger-scale, rural approaches) provides greater opportunity for human intervention to ensure the survival of urban vegetation during droughts or heatwaves.

When selecting and combining adaptation options, challenges remain on how to address the uncertainties of climate projections and climatic extremes ( [[#Fowler--2021|Fowler et al., 2021]] ) and to translate scientific input into practical guidance for adaptation ( [[#13.11.1.3|Section 13.11.1.3]] ; [[#Dale--2021|Dale, 2021]] ).

An assessment of the feasibility and effectiveness of the main adaptation options, based on the literature, is presented in Figure 13.20. (For adaptation to flood risk, see Figure 13.6.)

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[[File:3635c9789aec74888cf393c5b6acd904 IPCC_AR6_WGII_Figure_13_020.png]]

'''Figure 13.20 |''' '''Effectiveness and feasibility of the main adaptation options for cities, settlements and key infrastructures in Europe''' (Section SM13.9; Table SM13.8)

There are gaps in knowledge on the social, environmental and geophysical dimensions of feasibility for many options, and a holistic assessment of different options is largely lacking. This latter issue could reveal unintended impacts from, and synergies or trade-offs between, options, as in water and wastewater services ( [[#Dobson--2020|Dobson and Mijic, 2020]] ).

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<span id="adaptation-limits-residual-risks-and-incremental-and-transformative-adaptation"></span>
==== 13.6.2.3 Adaptation Limits, Residual Risks, and Incremental and Transformative Adaptation ====

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Adaptation in cities, settlements and key infrastructures in Europe faces technical, environmental, economic and social limits (Figure 13.21).

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[[File:a8961a65b358c3082909a19b06a654bf IPCC_AR6_WGII_Figure_13_021.png]]

'''Figure 13.21 |''' '''Indicative adaptation limits in cities, settlements and key infrastructures in Europe''' ''(Table SM13.16)''

Adaptation options for many sectors will not be sufficient to remove residual risks, for example, regarding (a) overheating in buildings under high GWL ( [[#Tillson--2013|Tillson et al., 2013]] ; [[#Virk--2014|Virk et al., 2014]] ; [[#Dodoo--2016|Dodoo and Gustavsson, 2016]] ; [[#Mulville--2016|Mulville and Stravoravdis, 2016]] ; [[#Hamdy--2017|Hamdy et al., 2017]] ; [[#Heracleous--2018|Heracleous and Michael, 2018]] ; [[#Dino--2019|Dino and Meral Akgül, 2019]] ); (b) snowmaking beyond 3°C GWL ( [[#Scott--2019|Scott et al., 2019]] ; [[#Steiger--2020|Steiger and Scott, 2020]] ; [[#Steiger--2020|Steiger et al., 2020]] ); (c) hydropower ( [[#Gaudard--2013|Gaudard et al., 2013]] ; [[#Ranzani--2018|Ranzani et al., 2018]] ); (d) electricity transmission and demand ( [[#Bollinger--2016|Bollinger and Dijkema, 2016]] ; [[#EEA--2019a|EEA, 2019a]] ; [[#Palkowski--2019|Palkowski et al., 2019]] ); (e) urban subways ( [[#Jenkins--2014a|Jenkins et al., 2014a]] ); and (f) flood mitigation in cities ( [[#Skougaard%20Kaspersen--2017|Skougaard Kaspersen et al., 2017]] ; [[#Umgiesser--2020|Umgiesser, 2020]] ). Some adaptation actions in a sector may also have side effects on others, increasing their vulnerability (Sections 13.2.2, 13.2.3; [[#Pranzini--2015|Pranzini et al., 2015]] ).

Examples of transformative adaptation in urban areas have been observed (e.g., the Benthemplein water square, the Floating Pavilion in Rotterdam and the Hafencity flood proofing in Hamburg), but they often remain policy experiments and prove challenging to upscale ( [[#Jacob--2015|Jacob, 2015]] ; [[#Restemeyer--2015|Restemeyer et al., 2015]] ; [[#Restemeyer--2018|Restemeyer et al., 2018]] ; [[#Holscher--2019|Holscher et al., 2019]] ). Active involvement of local stakeholders, public administration and political leaders are drivers for community transformation, whereas lack of local resources and/or capacities are frequently reported barriers to change ( [[#Fünfgeld--2019|Fünfgeld et al., 2019]] ; [[#Thaler--2019|Thaler et al., 2019]] ).

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<span id="governance-and-insurance"></span>
==== 13.6.2.4 Governance and Insurance ====

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Urban adaptation plans can enhance resilience, and their development is mandatory in the UK, France and Denmark ( [[#Reckien--2019|Reckien et al., 2019]] ). There is ''medium confidence'' that the development of urban adaptation planning is much more influenced by a city’s population size, present adaptive capacity and GDP per capita than by anticipated climate risks ( [[#Reckien--2018|Reckien et al., 2018]] ). A high organisational capacity in a municipality may not be a necessary condition for forward-looking investment decisions on urban water infrastructure, although enablers differ for small versus medium-to-large municipalities ( [[#Pot--2019|Pot et al., 2019]] ). There is large in-country variation in policy mixes utilised by local governments for supporting adaptation ( [[#Lesnikowski--2019|Lesnikowski et al., 2019]] ). In early-adapter cities (e.g., Rotterdam), adaptation is institutionally embedded in climate, resilience and sustainability-related actions, as well as collaboration between city departments, government levels, businesses and other stakeholders ( [[#Holscher--2019|Holscher et al., 2019]] ). In most other cities, however, adaptation planners rarely consider collaborations with citizens, and there are difficulties in departmental coordination and upscaling from pilot projects ( [[#Brink--2018|Brink and Wamsler, 2018]] ).

The level and type of collaboration between the public and private sectors in managing climate risks varies across Europe ( [[#Wiering--2017|Wiering et al., 2017]] ; [[#Alkhani--2020|Alkhani, 2020]] ). For example, in flood management ( [[#13.2|Section 13.2]] ), the private-sector involvement in Rotterdam is much more pronounced and there are joint public–private responsibilities throughout most of the policy process due to the large share of private ownership of land and real estate ( [[#Mees--2014|Mees et al., 2014]] ).

In large infrastructure networks, the lack of a leading and powerful institutional body, with sufficient research resources targeted to climate-change risk assessment, may limit adaptive capacity, as for example in railways ( [[#Rotter--2016|Rotter et al., 2016]] ).

The European insurance industry has developed tailored products for specific climate risks threatening cities, settlements and key infrastructures, such as risk-based flood insurance for homeowners and companies ( [[#13.2.3|Section 13.2.3]] ). The European insurance industry is developing new services (such as risk analysis and catastrophe modelling embedding climate change, early warning and post-event recovery recommendations), and it has recently started to play a role as communicator of future risks and as institutional investor with the aim of risk reduction ( [[#Jones--2016|Jones and Phillips, 2016]] ; [[#Marchal--2019|Marchal et al., 2019]] ).

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<span id="links-between-adaptation-and-mitigation"></span>
==== 13.6.2.5 Links Between Adaptation and Mitigation ====

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Evidence from transport in Europe shows that adaptation actions do not consider enough long-term transition paths embedded in mitigation, while mitigation strategies are often not assessed under future climate scenarios ( [[#Aparicio--2017|Aparicio, 2017]] ). Without rapid decarbonisation of electricity supply, greenhouse gas emissions will increase due to the increased use of air conditioning installations in cities. This trade-off can be reduced to some extent through use of more efficient cooling technologies ( [[#IEA--2018|IEA, 2018]] ) and complementary adaptation measures such as large-scale urban greening, building policies and behavioural changes in air conditioning use ( [[#Viguié--2020|Viguié et al., 2020]] ; [[#Sharifi--2021|Sharifi, 2021]] ; [[#Viguié--2021|Viguié et al., 2021]] ). Greenhouse gas emissions from transport may increase due to the temporary relocation of city residents to cooler locations during heatwaves ( [[#Juschten--2019|Juschten et al., 2019]] ), and from increased energy use for snowmaking in European ski resorts ( [[#Scott--2019|Scott et al., 2019]] ).

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<span id="knowledge-gaps-4"></span>
=== 13.6.3 Knowledge Gaps ===

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A key knowledge gap is the lack of a quantitative European-wide integrated assessment of future climate-change risks on water and energy, including different socioeconomic futures. Models capable of representing integrated policies for energy and water are lacking ( [[#Khan--2016|Khan et al., 2016]] ) including quantitative modelling of impacts on energy transmission and coastal energy infrastructure ( [[#Cronin--2018|Cronin et al., 2018]] ). These lacks are especially pertinent when combined with the small number of studies considering SSP population projections and adaptation tipping points. The limited social vulnerability assessments, mapping and validation ( [[#Rufat--2019|Rufat et al., 2019]] ) contribute further to these knowledge gaps.

While compound, concurrent and consecutive climate extremes become more frequent, there is limited knowledge on sectoral risks or on cascading risks for through transport, telecommunications, water, and banking and finance. While heat is well studied, studies on risks for cities and key infrastructures from hailstorms and lightning are missing.

Empirical data on the damage of transport infrastructure (e.g., railways) covering different European countries have not been systematically collected, and indirect economic effects of interruptions of transport networks have not been well studied ( [[#Bubeck--2019|Bubeck et al., 2019]] ). These deficits result in uncertainties associated with impacts of climate change on transport flows and indirect impacts (e.g., delays, economic losses).

There is limited knowledge on interactions created by synchronous adaptation in ski tourism supply and demand, and models do not yet include individual snowmaking capacity and a higher time resolution ( [[#Steiger--2019|Steiger et al., 2019]] ). Furthermore, there is no European-wide assessment of coastal flooding risks on tourism.

Many studies lack consideration of market characteristics (e.g., competitors) in their risk assessment, which would be improved by location- and sector-specific knowledge on climate risks for firm assets, operations, business, industry, finance and insurance needed to inform adaptation actions ( [[#de%20Bruin--2020|de Bruin et al., 2020]] ; [[#Feridun--2020|Feridun and Güngör, 2020]] ; [[#Monasterolo--2020|Monasterolo, 2020]] ).

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<span id="health-well-being-and-the-changing-structure-of-communities"></span>