Summary

The city of Athens, capitalof Greece, will be studiedas an urban case study.Athens is a large metro-politan city, with a dense-ly populated urban areaand few green openspaces (Figure 1).The topography of thecity, surrounded bymountains, favours theformation of air pollu-tion episodes during peri-ods of anticyclonic circu-lation. The city is prone tosummer heatwaves andfloods during heavy pre-

cipitation events. Impactsof temperature extremesand air pollution on hu-man health, tourism, en-ergy demand and peri-urban forest fire risk willbe examined in this casestudy.

1. Physical and socio-economiccharacteristics

Geography:Athens sprawls across thecentral plain of Atticaand is identified by thegeographical coordinates

of 37° 58’ N and 23° 43’ E(Figure 2). Several moun-tains surround Athens;Aegaleo in the west,Parnitha in the north,Penteli in the northeastand Hymettus in the east.Most consist of limestoneor marble, from whichthe ancient buildings ofthe city were construct-ed. The plain on whichthe city is built containsisolated limestone hills,including Lycabettus,which rises 339 m abovethe sea, and the flat-topped Acropolis (156 mhigh) around which the

BRIEFING NOTES

ON THE CIRCE URBAN CASE STUDIES: ATHENS

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Figure 1:View of northeastern

Athens towards Mount Lycabettus

showing the densely built inner urban area

Mediterranean Europe. The clear light-blueskies, characteristic ofAthens, are due to thelow humidity levels. Thelocation of Athens in amountain basin causes atemperature inversionduring anticyclonic con-ditions, and is partly re-sponsible for the air pol-lution problems the cityfaces. Winter in Athens istypically mild, with tem-peratures mainly drop-ping at night. Precipitation during thisseason is usually in theform of short-lived heavyrainfall events. Snowfalloccurs on an almost year-ly basis, but rarely re-mains on the ground.Summer can be particu-larly hot and at times

prone to smog and pollu-tion episodes. The aver-age summer daytimemaximum temperature is32°C and during themonths of July andAugust, heatwaves occurwhen hot air massesmove across Greece fromthe south or southwestand temperatures soarabove 40°C. The all-timemaximum temperaturerecord for the metropoli-tan area of Athens is 45°C(as recorded at theNational Observatory ofAthens), while the respec-tive minimum tempera-ture record is -6°C. Figure3 shows the mean month-ly temperature, sunshineduration, precipitationamount and the numberof wet days in Athens.

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city grew. The inner cityhas a land area of 39 km2,while the urban conurba-tion of Athens spans 412km2. The metropolitanarea of Athens has a pop-ulation of around 3.8 mil-lion people, with an esti-mated population densi-ty of 9,137 inhabitantsper km2.

Climate:Athens enjoys a typicallyMediterranean climateof cool, rainy winters andhot, dry summers. Thetopographic conditionsas described above causethe Athens weather to bewarmer than would beexpected from a city sur-rounded by water. Athens has one of thedriest climates of

Figure 2:Satellite map of the

Attica peninsula showingthe topography and theurban expansion of the

Greater Athens area (courtesy of Dr Adrianos

Retalis, NationalObservatory of Athens)

Economy:Greece has a mixed capi-tal economy with a largepublic sector that ac-counts for about half ofthe GDP which was$305.595 billion in 2006.It is an agricultural coun-try (with agriculturalproducts including:wheat, corn, barley, sugarbeets, olives, tomatoes,

tobacco, potatoes, beef,dairy products and wine)and 20% of the workforceis employed in this sec-tor. The principal eco-nomic activities includetourism and shipping in-dustries. For the prefec-ture of Attica (in whichAthens lies), the GNP(gross national product)has been steadily in-

creasing since 1993 asshown in Figure 4.

2. Justification

This case study will ex-amine possible impactsof climate change onheat stress, human dis-comfort and disaster pre-paredness. The high den-

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Figure 3:Mean monthly

temperature (Tmean,Tmax, Tmin), sunshineduration, precipitation

amount and number ofwet days for Athens

averaged over the period1961-1990

Figure 4:Gross National Product (GNP)

for the prefecture ofAttica from 1993 to 2001

ban areas. A detailed as-sessment of extreme cli-mate events using select-ed indicators will be con-ducted. Previous workover the wider easternMediterranean region(Kostopoulou and Jones,2005) revealed a signifi-cant positive trend in thenumber of very warmdays in summer, andpositive trends across arange of precipitation in-dices, such as precipita-tion intensity andamount. Analysis of the100-year surface air tem-perature record of theNational Observatory ofAthens (Founda et. al.,2004) revealed a tenden-cy towards warmer years.Moreover, this studydemonstrated a signifi-cant increase in thenumber of hot days, aswell as in the frequencyof occurrence and dura-tion of warm events dur-ing the last decade. Here,research will focus ontemperature extremesand heatwave episodes,and precipitation ex-tremes for determiningthe probability ofdrought occurrence, aswell as intense precipita-tion events capable ofcausing damagingfloods.

Environmental issues:Athens is prone to air pol-lution formation whenstagnant air masses dom-inate synoptic condi-tions. This occurs mostlyin the transition seasonsof spring and autumn. Airpollution levels for ozoneand nitrogen oxides andfor the more ‘modern’pollutants such as ben-zene can far exceed theEU-imposed limits andpose a threat to humanhealth. Air pollutionevents will be examinedin relation to humanhealth (see social issuesbelow) and to climate pa-rameters. Hot and longperiods of dry weathercan also pose a threat toperi-urban forest areas,which have air cleansingmechanisms that are veryimportant to the city’sventilation. Forest fire riskfor present and future cli-mate will be evaluated forthe Greater Athens area.

Social issues:Hospital admissions as-sociated with hot weath-er and air pollution willbe examined. In a hotterfuture, additional energydemands (mainly for airconditioning) couldpresent serious prob-lems to energy suppliers.

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sity of buildings in the ur-ban sprawl, with fewopen spaces, is prone tofloods in present and fu-ture climate. Furthermore, with heat-waves becoming morecommon it is anticipatedthat human discomfortand associated healthimpacts will increase.Hospital admissions re-lated to heat extremesand air pollution eventswill be examined. Moreover in a hotter fu-ture, energy suppliersmay face serious prob-lems since they may notbe able to meet the in-creasing demand for en-ergy, mainly for air condi-tioning (Giannakopoulosand Psiloglou, 2006).Impact sectors will be ex-amined together with po-tential adaptation meas-ures for the area. For in-formation on data avail-ability and access to poli-cy makers refer toSections 5 and 6.

3. Key Research Issues

Climate issues:Energy use, air quality,thermal comfort and re-lated health issues, watersupply and demand aremajor concerns for ur-

Increasing trends in thenumber of hot days andheatwave events affectskey sectors of the Greekeconomy such as thetourism industry.Heatwaves not onlycause power outages,but under hot and dryweather conditions peri-urban forest fires canbreak out across theMediterranean. For in-stance, in July 2007, firesdestroyed vast tracts ofthe pine-coveredParnitha range. Theblazes not only intensi-fied the heat but have al-so been blamed for soar-ing pollution levels, andauthorities reportedhundreds of patients inhospital with respiratoryproblems. Potentialadaptation measures foreach impact sector will

be assessed. Increasingsummer temperaturesare likely to result in in-creasingly uncomfort-able conditions in thesummer months. Usinga human comfort indexit is possible to assesshow atmospheric condi-tions will evolve for arange of climate changescenarios.

4. Key areas of integration

The Athens urban casestudy has been chosensince it provides excel-lent opportunities for us-ing an integrated ap-proach across multipletemporal and spatialscales and sectors. In thespatial dimension, workwill extend from the in-

ner city boundaries tothe surrounding moun-tains and forests. In thetemporal dimension, re-search will range fromthe current observedtime period (using avail-able meteorological andsector data) to futuretime periods using datafrom several climatechange projections. Inaddition, a multi-sectorapproach to climatechange impacts will beadopted. Impacts sectorscovered will range fromdirect climate impactson natural ecosystems(such as flash floods andforest fire risk) to indirectimpacts resulting fromcombined climate-so-cial-economic linkages(such as energy demand,tourism and health).Furthermore, the dy-

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Figure 5:Conceptual framework

for the integrated assessment

of the impacts of climatechange in the Athens

case study

5. Regional stakeholders, policymakers, institutions

Energy officials and hos-pital medical staff will beamong the stakeholdersinvolved in this casestudy since they will bethe main data providers. In addition, officers fromthe Greek CivilProtection Bureau will becontacted, since they arethe main decision mak-ers in terms of forwardplanning and protectingagainst various types ofnatural disasters.Officers from the Envi-ronment and TourismMinistries will be con-tacted as the main deci-sion and policy makersfor this sector.

6. Data availability

Meteorological data forAthens are readily avail-able from a central siteoperated by the NationalObservatory of Athenssince the year 1900. In ad-dition, energy demanddata for the city are avail-able from the GreekPublic Power Corpora-tion. Contacts with this insti-tution were established

during the EU-projectMICE. Cardio-respirato-ry patient admissions tomajor hospitals withinAthens will also be ob-tained. Contacts withchief doctors are alreadyunderway as part of theEU-project ENSEMBLES,and data will soon beavailable. Air pollutiondata, including measure-ments of ozone, nitrogenoxides and other particu-lates, will be availablefrom the Greek Ministryof the Environment whoroutinely record air pol-lution measurements inthe city of Athens and itssuburbs. Data for forestfires in the areas aroundAthens will be providedby the Forest FireResearch Institute ofAthens. A range of cli-mate projections will beavailable as output fromother CIRCE researchlines, together with datafrom other projects suchas ENSEMBLES.Downscaling methodsfor the Greater Athensarea will provide scenar-ios of what the climate ofthe city will look like inyears to come. These sce-narios will help identifyfuture energy demand,forest fire risk and healthimpacts (Giannakopou-

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namics of the climatesystem will also be exam-ined in an integratedfashion. Climate indica-tors specific to Athenswill be chosen and willcover both temperatureand rainfall-related ex-tremes. Figure 5 illus-trates the conceptualmulti-sector approach,and includes climate sys-tem dynamics, natural /social / economic impactsectors and their inter-linkages.Case-study work on im-pact sector risk to climatechange will be of particu-lar interest to relevantpolicy makers and stake-holders, with whom con-tacts have been estab-lished from the earlystages of the project.Stakeholder consultationwill be advantageous tothe selection of indicatorsof climate change for spe-cific economic sectors.Discussion of impact sec-tor risks and adaptationmeasures can also be ex-ploited. For example, theconstruction of energy ef-ficient buildings whichhave adequate insulationand the design of greenroofs on city blocks offlats will help to counter-act the damaging effectsof heat extremes.

los et al., 2005).

Acknowledgements

CIRCE (Climate Changeand Impact Research:the MediterraneanEnvironment) is fundedby the Commission ofthe European Union(Contract No 036961GOCE) http://www.cir-ceproject.eu/. This briefing note formspart of the CIRCE deliv-erable D11.3.1.

�Final version, January 2008

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References�Founda D., Papadopoulos K.H., Petrakis M.,

Giannakopoulos C. and Good P., 2004: Analysis ofmean, maximum, and minimum temperatures inAthens from 1897 to 2001 with emphasis on the lastdecade: trends, warm and cold events. Global andPlanetary Change, 44, 27-38.http://dx.doi.org/10.1016/j.gloplacha.2004.06.003�Giannakopoulos C, Bindi M., Moriondo M., LeSager P.

and Tin T., 2005: Climate change impacts in theMediterranean resulting from a 2°C global temperaturerise, Report published in July 2005 by WWF, the globalconservation organization, Gland, Switzerland, avail-able from: http://assets.panda.org/downloads/medreportfinal8ju-ly05.pdf�Giannakopoulos C. and Psiloglou B.E., 2006: Trends in

energy load demand for Athens, Greece: Weather andnon-weather related factors, Climate Research, 13,31(1), 97-108 (MICE special issue) doi: 10.3354/cr031097�Kostopoulou E. and Jones P.D., 2005: Assessment of cli-

mate extremes in the Eastern Mediterranean.Meteorology and Atmospherics Physics, 89(1-4), 69-85.doi:10.1007/s00703-005-0122-2

Authors�Christos Giannakopoulos and Effie Kostopoulou,

National Observatory of Athens, Institute forEnvironmental Research & Sustainable Development,Metaxa & V. Pavlou, GR-152 36 Palaia Pendeli, Athens,Greece.Email: giannak@meteo.noa.gr,ekosto@meteo.noa.gr. Tel: +30-210-8109128, +30-210-8109151 • Fax: +30-210-8103236

Editors�Maureen Agnew (m.agnew@uea.ac.uk)

and Clare Goodess (c.goodess@uea.ac.uk) Climatic Research Unit, School of EnvironmentalSciences, University of East Anglia, Norwich, UK