Historical heritage

ASSESSMENT OF CLIMATE CHANGE IMPACTS AND LOCAL VULNERABILITIES

CLIMATE CHANGE AND CULTURAL HERITAGE P. Bonanni a), C. Cacace b), R. Gaddi a), A. Giovagnoli b) a) ISPRA- Institute for Environmental Protection and Research b) ISCR- Institute for Conservation and Restoration

WORKSHOP Life Project ACT - Adapting to Climate change in Time No LIFE08 ENV/IT/000436

CONTENTS

State of the art ............................................................................................................................... 3 1. The risk indicators method .................................................................................................... 3 1.1. Climatic and environmental parameters ............................................................................. 4 1.2. Distribution of monuments ................................................................................................. 4 1.3. Sensitivity ............................................................................................................................. 7 1.4 The impacts: territorial danger ............................................................................................. 8 1.5 The conservation condition of a monument (vulnerability .............................................. 11 1.6 The risk ................................................................................................................................ 12 2. Adaptation strategies .............................................................................................................. 13 Conclusions .................................................................................................................................. 13 References..................................................................................................................................... 14

State of the art The attention of international scientific community is only recently focused on the impacts of climate change on cultural heritage.

In the 2005 a specific document - the English report “Climate Change and the historic environment”- about this subject was published; in this paper information concerning the potential effects of climate on world heritage (historic buildings, archaeological sites, gardens, parks and landscapes) were collected and the level of knowledge should be acquired to define the suitable adaptation strategies was also suggested.

The “Engineering Futures Historic Stakeholders Dissemination and Scientific Research Report” (2006) highlighted for the first time the need to obtain information on physical characteristics of the materials and the deterioration phenomena of historic buildings; this document also underlined the importance of analysing the involved mechanisms of moisture transport.

In 2006, the 30th Session of the UNESCO World Heritage Committee approved the “Climate Change and World Heritage” document. The report indentified the physical, social and cultural impacts on cultural properties; moreover, it suggested “the need for using a number of management responses at national and local levels”.

In 2007 the Project Noa’s Ark, funded by European Committee, provided climate maps of the parameters influencing on the weathering of materials and damage maps to quantify the potential deterioration aiming to define the mostly European risk areas.

Now all international scientific projects are aimed to provide the institutions the opportune information to identify and to establish mitigation and adaptation strategies in this challenging field.

This work shows the method applied by ISPRA and ISCR to evaluate the potential weathering hazard caused by climate and environmental factors on built heritage and cultural landscapes.

1. The risk indicators method The Risk Map of Cultural Heritage (1995) is a project of the Institute for Conservation and Restoration and one of the first Italian instrument describing the potential risk level affecting Italian Cultural Heritage.

By this methodology, information concerning the distribution and characteristics of the architectural and archaelogical monuments in Italy, are collected.

The objective of the project is to identify the space/time distribution of the risk in order to plan the maintenance activities and to reduce the restoration works certainly more expensive and invasive.

The calculation of risk indicators is based on the acquisition of the following information: -

climatic and environmental parameters (that contribute to deterioration phenomena) distribution of cultural properties sensitivity of monuments to climate change impact (territorial hazard defined through the damage quantification)

-

vulnerability of the single items (its conservation condition)

By processing the above mentioned parameters and applying specific damage functions, the risk indicators, related to the deterioration of materials due to the climate and environmental factors, can be calculated.

1.1. Climatic and environmental parameters The main parameters contributing on weathering mechanisms of monuments are: temperature, moisture, wind, precipitation and air pollutants (especially SO 2, NO x, PM10, O3).

Temperature change can cause freeze- thaw damage, deterioration phenomena of surfaces due to thermal stress or biochemical colonization.

Moisture is generally responsible of physical changes within the porous materials, for instance, the cycles of crystallisation and dissolution of soluble salts due to “wetting and drying� mechanisms can cause damages to the archaeological and architectural structures, frescos and other decorated surfaces and the biological attacks of organic materials by micro organisms are also started.

The action of wind can cause the erosion phenomena affecting the surfaces of historic buildings or archaeological structures.

Precipitation contributes to accelerate erosion and corrosion phenomena.

The synergic effect of climate and pollution increases the stone decay by dissolution of carbonates, blackening of materials, corrosion of metals and develops the biodeterioration.

1.2. Distribution of monuments The risk assessment is based on a deep knowledge of distribution of cultural properties in a specific area and their chemical – physical characteristics.

The potential threats for monuments can be defined if the structural elements, the constituting materials and territorial and geographical characteristics (geology, idrology, slope inclination) are known.

In Italy, the Risk Map of Cultural Heritage provides an evaluation about the number, position, nature and function of archaeological sites and architectural properties.

In most European countries the inventory of cultural properties does not include data on geographical location, technical description, physical state, climate and environmental parameters of the site where they are located.

As an example, in this paper the georeferencing (fig.1) and the ortophoto (fig.2) of cultural heritage recorded in Ancona are reported.

Fig. 2: Distribution of monitoring station in Ancona

Fig. 2: Ortophoto of monuments in Ancona

In particular, the archaeological sites are 14 and the architectural monuments are 111; for these items the following data sheets are available:

Data sheets binding decrees Data sheets TCI- Laterza Data sheets earthquake Marche- Umbria (1997) Vulnerability data sheets s archaeological asset Vulnerability data sheets archaeological find

87 53 1 2 1

1.3. Sensitivity The analysis of territorial aggression on cultural heritage is crucial to plan a correct methodology approach for maintenance and restoration activities.

The decay of materials is an irreversible process concerning every asset; for this reason, in the recent years, in parallel with a growing interest in the conservation field, a new way to deal with a scientific approach the problem has been developed.

This approach represents a valid support for taking decisions during restoration and maintenance interventions. It’s consequently necessary to make reference to a specific model that allows, through the identification of measurable sizes, the evaluation of the antropical, structural and environmental risk levels.

The sensitivity is one of the parameters influencing on the potential deterioration hazard of a monument placed in a specific area.

The sensitivity depends on: -

location of the monument composition of the constitutive materials framework, surface, preparatory layers nature of hygroscopic materials conservation condition

In Noa’s Ark project, the objects are subdivided in 5 categories, depending on their sensitivity to climate change: robust heritage objects: wind resistant elements and structures, flood resistant elements and structures; sculptures and sheltered surfaces from rain, light and sun; objects with low sensitivity: wind sensitive elements and structures (windows, window glazing, architectural elements) or materials that could be damaged by a volumetric change due to water; objects with medium sensitivity: roof coverings, structures constituted of materials sensitive to moisture (dried brick masonry, masonry with clay, mortars); timber structures; objects highly sensitive: structures vulnerable to wind flow (roof) or to flooding (timber) or that could be lifted (roof, bridges, pavements, mosaic floor) objects extremely sensitive: elements or structures exposed to sun, to heat change (facade, roof) or elements and structures constituted of sensitive materials; elements or structures that are susceptible to collapse caused by wind (ruin wall, chimneys, menhirs); lightweight and tall buildings (towers and buildings made of timber); structures that are vulnerable to collapse caused by flooding (small bridges, or buildings insufficiently anchored).

1.4 The impacts: territorial danger The damage on a monument is due to the climatic and environmental conditions of the area where the asset is placed (territorial danger); the effects usually depend on the composition and nature of materials constituting the cultural heritage.

The calcareous assets, for instance, could be undergone to following mechanisms: -

erosion (loss material due to precipitation, acidity of rain, relative humidity, and pollutants) frost, salt crystallization (that cause the volume changes and mechanical stress) thermoclastism (expansion and contraction of materials due to temperature variations and that cause the formation of microfractures) blackening (due mainly to the concentration of particular matter) biological deterioration (bacteria, fungi, lichens, bryophyte colonization due to specific climate and microclimate conditions and to the conservation condition of the monument).

The wooden assets are submitted to deterioration phenomena generated by moisture or by biological microorganisms.

The metals can be degraded by corrosion processes caused by synergic action of climate parameters and atmospheric pollution level.

Some of deterioration phenomena, such as erosion and corrosion, can be quantified using specific dose – response functions that describe the potential damage in relation with pollutants concentrations and climatic parameters.

Several algorithms are available to calculate the loss of material (expressed in μm anno-1) for calcareous assets.

In this work, the Lipfert formula (1989) and the Multiassess function (2005) are mentioned. a) Lipfert formula (1989) R = 18.8 • Rain + 0.016 • [H +] • Rain + 0.18 • (V ds • [SO2]+VdN •[HNO3])

R = surface recession/ loss of material (μm year -1) 18.8 = the solubility of CaCO3 in equilibrium with 330 ppm CO2 Rain = rainfall (mm year-1) 0.18= conversion factor from (cm s-1) ( g m-3) to ( m year-1) 0.016= constant valid for precipitation pH in the range 3-5 [H +] = ion concentration evaluated from yearly rain (nmoles cm-3) VdS = deposition rate of SO2 (cm s-1) [SO2]= SO2 concentration (μg m-3) VdN = deposition rate of HNO 3 (cm s-1) [HNO3] = HNO3 concentration (μg m-3 )

where: - 18.8 • Rain: “clean rain effect”, the so- called karst effect - 0.016 • [H +] • Rain: acid rain effect (acidity due to ionic components SO 42-, NO3-) - 0.18 •V ds • [SO2]: SO2 deposition - 0.18 •VdN • [HNO3]: HNO 3 deposition

b) MULTIASSESS dose-response function R= 4 + (0.0059 • [SO2] • Rh60 + 0.054 • Rain • [H+] + 0.078 • [HNO3] • Rh60 + 0.0258 • [PM10])

R = surface recession / loss of material (μm year-1) 4 = deterioration not caused by pollution [SO2], [HNO3], [PM10] = pollutant concentrations ( g m-3) Rh60= relative umidity (Rh-60) % [H+] = ion concentration evalueted from yearly rain (nmoles cm-3) Rain = rainfall (mm year-1) where: - 4: experimental value representing the weathering in absence of pollutants - 0.054 • Rain • [H+]: acid rain effect - 0.0059 • [SO2] • Rh60: SO2 deposition - 0.078 • [HNO3] • Rh60: HNO3 deposition - 0.0258 • [PM 10]: PM10 deposition Both algorithms calculate the loss of material in relation with the SO 2, HNO3 concentrations and acid rain.

Lipfert formula, used for calculation of surface recession in Noa’s Ark project, presents also the contribution of the so-called “clean rain” whereas Multiassess function introduces the deposition of particular matter.

The loss of material for metals can be calculated using the dose-response functions derived by Multiassess project.

These functions are available for carbon steel, zinc, copper and cast bronze.

Multiassess dose-response function Carbon steel ML= 29.1 + (21.7 + 1.39• [SO 2] 0.6 •Rh60 •e f(T) + 1.29• Rain• [H+] + 0.593• [PM 10]) •t 0.6 Zinc

ML= 1.82 + (1.71 + 0.471• [SO2] 0.22 • e 0.018•Rh+f(T) + 0.041• Rain• [H+] + 1.37• [HNO3]) •t

Copper ML= 3.12 + (1.09 + 0.00201• [SO2] 0.4 •[O3] •Rh60 • e f(T) + 0.0878• Rain• [H+]) •t Cast Bronze ML= 1.33 + (0.00876• [SO 2] •Rh60 • e f(T) + 0.0409• Rain• [H+] + 0.0380• [PM 10]) •t where ML = loss of material (g m-2) [SO2], [HNO3], [PM10], [O3] = pollutant concentrations ( g m-3) Rh60= relative humidity (Rh-60) % [H+]= concentration of precipitation (nmoles cm-3 ) Rain = rainfall (mm) T= temperature (°C) with f(T)= 0.15(T-10) if T<10°C; otherwise f(T)= -0.05(T-10) t = time (year) The calculation of erosion/corrosion at urban level is usually done using climatic and pollutants data collected by air quality stations located not far from the considered monuments.

As an example, the georeferencing of monitoring sites of Ancona territory are shown (fig.3).

Fig 3: Georeferencing of monitoring stations in Ancona

1.5 The conservation condition of a monument (vulnerability) The vulnerability of each items represents the variable that indicates its level of exposure to environmental/territorial danger in relation with its conservation condition. The vulnerability depends on the sensitivity of monuments to the climatic and environmental conditions; it can be calculated using specific statistical algorithms.

The information, acquired through a data sheets model, are elaborated in order to obtain data on the conservation condition for 12 architectonic and decorative elements:            

foundations vertical structures horizontal structures roofing structures vertical links indoor paving outdoor paving claddings indoor decorations outdoor decorations outdoor openings indoor openings

The conservation condition of a monument can be obtained analysing six types of damage:      

generic damage material decay moisture biological deterioration surface deterioration lacunae, missing fragments/pieces

Each type of damage is classified according to its seriousness, extent and urgency; the scale of intensity of damage is:  Seriousness (1,2,3)  Extent (20%, 40%, 60%, 80%, 100%)  Urgency (1, 2, 3, 4, 5)

The algorithm using for calculation of vulnerability is: INDvul(k) = SOMMA (P j • Qji/(m-n) • (cost/m))

where INDvul (k) = vulnerability index of k- monument m = number of variables used for quantifying the superficial conservation condition in relation with the urgency, seriousness and extent. n = number of variables for which information is not available Pj = weight of j -variable Qji = i- value of j -variable cost/m = updated constant in relation with updated weight of variables

The vulnerability parameter indicates the conservation condition of a monument and allows, through the correlation with territorial danger, to evaluate its potential risk level.

1.6 The risk According to the statistical point of view, the risk is defined correlating the damage submitted by a particular asset and the events causing the decay.

The damage checked on a monument, is due to a weathering process that cannot be divided in single events expressed only in probabilistic terms; rather the complex mechanism producing the damage involves several different variables.

For this reason, the application of a strict statistical risk model is not possible because of the damage event and the environmental stochastic context in which the event takes place should be defined a priori.

Therefore the methodology elaborated by ISCR is based on the definition of physical and social variables influencing on weathering processes; the risk is, in this way, correlated with the risk factors.

The measure of the risk factors is based on the definition of risk factor indicators, that are defined through the vulnerability of the monument and the territorial danger.

The risk described in the Risk Map is subdivided in three levels: -

Territorial Risk (Rt), concerning the state of susceptibility to a weathering process of the aggregate of monuments located in a specific area.

This indicator can be calculated correlating the territorial danger with the characteristics of the aggregate population of monuments.

Rt = n â&#x20AC;˘ TD TD = Territorial Danger (erosion or corrosion calculated through the algorithms) estimated for urban area n = number of monuments placed in the municipal territory

-

Individual Risk (Ri), that indicates the state of susceptibility to a weathering process of a single asset. This indicator can be calculated correlating the territorial danger (at urban level) with the conservation condition of monument (vulnerability).

Ri = Vj • TD TD = territorial danger (erosion or corrosion calculated through the algorithms) estimated for urban area

Vj = vulnerability of the single property -

Local Risk (Rl), that indicates the state of susceptibility to a weathering process of a single asset, estimating the territorial danger in the area near the monument Rl = Vj • TD j TDj = territorial danger (erosion or corrosion calculated through the algorithms) estimated near the monument

Vj = vulnerability of the single property

2. Adaptation strategies To maximise the adaptive capacity of built heritage and cultural landscapes, the following actions are suggested:    

Reduction of the restoration interventions Individuation of the assets that can be shifted away from a threatened site Plan long-term reorganisation of sites with high level of risk Planning rigorous and frequent maintenance activities to monitor the conservation condition of the property

Conclusions The effects of climate and environmental change on cultural heritage have been faced by international and scientific community only in recent years.

A lot of information is available about this subject in references works, but the actions realized by institutions and the funding destined to reduce the damage are insufficient yet.

The correlation between the monument vulnerability with territorial danger in each area permits the calculation of territorial and individual risk.

The assessment of these indicators allows to individuate the most aggressive areas for monuments and their potential risk level.

This scientific approach can be a support to the decision makers to adopt specific strategies aiming to reduce of the impact climate change effects by planning maintenance and monitoring actions.

References

- Climate Change and Historic Environment (2005) http://eprints.ucl.ac.uk/archive/00002082/01/Published_Climate_Change_Report_05.pdf- Engineering Futures Historic Stakeholders Dissemination and Scientific Reaserch Report (2006) http://www.ucl.ac.uk./sustainableheritage/ehf_report_web.pdf - Climate Change and World Heritage (2006) http://whc.unesco.org/archive/2006/whc06-30com-07.1.e.pdf http://law.lclark.edu/org/ielp/objects/WHCDecision30.pdf - IPCC (2001) Climate change 2001: Impacts, Adaptation and Vulnerability. Contribution of Working Group II to the Third Assessment Report of the Intergovernmental Panel on Climate Change - Carta del Rischio del Patrimonio Culturale, Istituto per la Conservazione e il Restauro, A.T.I. MARIS,1995 - Global Climate Change on Built Heritage and Cultural Landascapes- The Noa’s Ark project, Atlas and Guidelines_2007 - Sabbioni C., Cassar M., Brimblecombe P., Lefevre R.A., Vulnerability of Cultural Heritage to Climate Change_Report 2008, European and Mediterranean Major Hazards Agreement (EUR_OPA) - Sabbioni C, Cassar M, Brimblecombe P., Tidblad J., Koslowski R., Drdàcký M., Saiz- Jimenez C., Grøntoft T., Wainwrigth I., Ariño X., Global climate change impact on built heritage and cultural landscapes, Heritage Weathering and Conservation – Fort Alvarez de Buergo, GomezHeras & Vazques- Calvo (eds), 2006 Taylor and Francis Group, London, ISBN 0-415-41272-2 - Bonanni P., Cacace C., Gaddi R., Giovagnoli A., “Calcolo del rischio territoriale e del rischio individuale per i beni di interesse storico-artistico a Torino”. Rapporto ISPRA(88/2009) - Model for multi-pollutant impact and assessment of threshold levels for cultural heritage (Multiasses)- Report 2005 - Bonazza A., Messina P., Sabbioni C.,. Grossi C. M, Brimblecombe P., “Mapping the impact of climate change on surface recessions of carbonate buildings in Europe”, Science of the Total Environment 407 (2009) 2039 – 2050.

- Corcelli A., Ioannilli M., Cacace C., “Progettazione e sperimentazione di un modello di analisi multi-hazard per la valutazione del rischio locale dei beni culturali”. Atti 12a Conferenza Nazionale ASITA_ l’Aquila 21-24 ottobre 2008.

BENI CULTURALI E CAMBIAMENTI CLIMATICI QUESTIONS

INDICATORS

REFERENCES – NOTES

Climatic parameters What are the climatic and environmental parameters influencing cultural world heritage?

-

Moisture Temperature Sea level rises Wind Climate and pollution acting together Climate and biological effect Extreme meteorological events (storm, flood, etc)

References: “Principal climate change risks and impacts on cultural heritage” in Background Document UNESCO WORLD HERITAGE CENTRE in cooperation with the United Kingdom Government World Heritage and climate change”, March 2006

Sensitivity What is the sensitivity of cultural heritage to climate change?

What are the exposed properties?

The cultural world properties are very sensitive to climate change.

In particular, the sensitivity of built heritage depends on: - location of the monument - composition of the constitutive materials - framework, surface, preparatory layers - nature of hygroscopic materials - conservation condition Exposure

References: Atlas and Guidelines del Noa’s Ark Project (CNR-ISAC di Bologna )

The historic buildings, archaeological sites, gardens, parks and landscapes constituing the cultural world property

In Italy, the Risk Map of Cultural Heritage provides an evaluation about the number, position, nature and function of archaelogical sites and architectural properties.

In most European countries the inventory of cultural properties does not include data on geographical location, technical description, physical state, climate and environmental parameters of the site where they are located.

The potential impacts What are the potential impacts of climate change on cultural heritage?

- Crystallization and salt dissolution due to “wetting and drying” cycles - Erosion - Corrosion of metals - Deterioration of facades caused by physical stress - Damage caused by freeze- thaw/ frost cycles - Physical changes to porous buildings materials - Stone recession by dissolution of carbonates - Blackening of materials - Biochemical deterioration

References: “Principal climate change risks and impacts on cultural heritage” in Background Document UNESCO WORLD HERITAGE CENTRE in cooperation with the United Kindom Government World Heritage and climate change”, March 2006

QUESTIONS What are the potential impacts of climate change on cultural heritage?

INDICATORS The potential impacts Some of deterioration phenomena, such as erosion and corrosion, can be quantified using specific dose – response functions that describe the potential damage in relation to pollutants concentrations and climatic parameters.

Several algorithms are available to calculate the loss of material (expressed in μm anno-1) for calcareous assets.

As an example the Lipfert formula (erosion calcareous of assets) is reported:

REFERENCES – NOTES References: Lipfert FW, 1989 “Atmospheric damage to calcareous stones: comparison and reconciliation of recent experimental findings”_ Atmospheric environment, Vol. 23, 1989

R = 18.8 • Rain+0.016 • [H +] • Rain + 0.18 • (V ds • [SO2]+VdN •[HNO3])

What is the present adaptive capacity?

What is the available funds?

What are the most vulnerable “objects”?

R = surface recession/ loss of material (μm year-1) 18.8 = the solubility of CaCO3 in equilibrium with 330 ppm CO2 Rain = rainfall (mm year-1 ) 0.18= conversion factor from (cm s -1) ( g m-3) to m year-1) 0.016= constant valid for precipitation pH in the range 3-5 [H + ] = ion concentration evaluated from yearly rain (nmoles cm-3) VdS = deposition velocity of SO2 (cm s-1 ) [SO2]= SO2 concentration (μg m-3) VdN = deposition velocity of HNO3 (cm s-1) [HNO3 ] = HNO3 concentration (μg m-3 ) Adaptive capacity The effects of climate and environmental change on cultural heritage have been faced by international and scientific community only in recent years.

A lot of information is available about this subject in references works, but the actions realized by institutions and the funding destined to reduce the damage are insufficient yet.

Vulnerability The vulnerability of each items represents the variable that indicates its level of exposure to environmental/territorial danger in relation with its conservation condition.

The algorithm used for calculation of vulnerability is: INDvul(k) = SOMMA (P j • Qji /(m-n) • (cost/m))

INDvul (k) = vulnerability index of the kmonument m = number of variables used for quantifying the superficial conservation condition in relation with the urgency, seriousness and extent. n = number of variables for which information is not available P j = weight of j -variable Qji = i- value of j -variable cost/m = updated constant in relation with updated weight of variables

References: Atlas and Guidelines del Noa’s Ark Project (CNR-ISAC di Bologna )

References: Map of Risk of Cultural Heritage (ISCR, 1996).

QUESTIONS What is the probability of the damage for cultural heritage?

INDICATORS Risk Indicators:

REFERENCES – NOTES

TD = Territorial Danger (erosion or corrosion calculated through the algorithms ) estimated for urban area

The methodology elaborated by ISCR is based on the definition of physical and social variables influencing on weathering process.

The measure of the risk factors is based on the definition of risk factor indicators, that are defined through the vulnerability of the monument and the territorial danger.

n = number of monuments located in the urban area

References: Map of Risk of Cultural Heritage (ISCR, 1996).

1) Territorial Risk Rt= n • TD

2) Individual Risk, Ri = Vj • TD TD = territorial danger (erosion or corrosion calculated through the algorithms) estimated for urban area Vj= vulnerability of the single property 3) Local Risk, Rl = Vj • TDj TDi = territorial danger (erosion or corrosion calculated through the algorithms) estimated near the monument Vj= vulnerability of the single property

What are the adaptation strategies to reduce the impacts on cultural world property?

Adaptation strategies To maximise the adaptive capacity of built heritage and cultural landscapes, the following actions are suggested: -

reduction of the restoration interventions planning rigorous and frequent maintenance activities to monitor the conservation condition of the property

References: Atlas and Guidelines del Noa’s Ark Project (CNR-ISAC di Bologna )