The impact of climate change on the carbonation depth in the European building stock has been evaluated by comparing future climate scenarios against two different baseline temperature and CO₂ scenarios, assumed to remain constant until 2100. For the old buildings group, the reference scenario without climate change was established using E-OBSvs10 data from the period between 1965 and 1980. For recent buildings the reference scenario was based on the period spanning from 1981 to 2010. As it was not possible to retrieve E-OBSvs10 data before 1965, the reference scenario for old buildings only covers a 15-year period, contrasting with the 30-year period of the reference scenario for recent buildings. In both cases the observational dataset E-OBSvs10 with a 0.25° resolution was remapped over the same grid of EURO-CORDEX, resulting on a 0.11° grid resolution, except for Malta region as explained in Chapter 4. The assessment of carbonation damage for EU-27 capital cities and Europe is presented in section 6.2, while the probability of carbonation initiation per city, the time to repair per city and country and the corrosion costs are evaluated in section 6.3.

## 6.2 Assessing carbonation damage

Carbonation damage was estimated for the capital cities of the EU Member States and for the whole Member States at regional level following the NUTS 3 definition of the Nomenclature of Territorial Units for Statistics in 2021. To recall, the database has information on the building stock classified as recent buildings only for seven countries: Austria, Germany, Greece, Hungary, Portugal, Romania, and Spain. The number of the recent buildings in the other countries was assumed to be zero. However, as the durability parameters were known for all countries, it was possible to assess the expected carbonation damage to recent buildings and the time remaining to repair for these buildings in all considered countries. However, the cost of repair presented in section 6.3 was only estimated for the populations of recent buildings in the above mentioned seven countries.

Figure 26 illustrates the carbonation depth estimates for the two capital cities adopted as examples in this report. Annex 2 provides the figures showing the trends in carbonation depth for the capital cities of the 27 EU Member States.

<figure><img src="image_31.png" /><figcaption>**Figure 26.** Carbonation depth in Helsinki (top figure) and Nicosia (bottom figure).</figcaption></figure>
The impact of climate change on the carbonation depth in the European building stock has been evaluated by comparing future climate scenarios against two different baseline temperature and CO₂ scenarios, assumed to remain constant until 2100. For the old buildings group, the reference scenario without climate change was established using E-OBSvs10 data from the period between 1965 and 1980. For recent buildings the reference scenario was based on the period spanning from 1981 to 2010. As it was not possible to retrieve E-OBSvs10 data before 1965, the reference scenario for old buildings only covers a 15-year period, contrasting with the 30-year period of the reference scenario for recent buildings. In both cases the observational dataset E-OBSvs10 with a 0.25° resolution was remapped over the same grid of EURO-CORDEX, resulting on a 0.11° grid resolution, except for Malta region as explained in Chapter 4. The assessment of carbonation damage for EU-27 capital cities and Europe is presented in section 6.2, while the probability of carbonation initiation per city, the time to repair per city and country and the corrosion costs are evaluated in section 6.3.

## 6.2 Assessing carbonation damage

Carbonation damage was estimated for the capital cities of the EU Member States and for the whole Member States at regional level following the NUTS 3 definition of the Nomenclature of Territorial Units for Statistics in 2021. To recall, the database has information on the building stock classified as recent buildings only for seven countries: Austria, Germany, Greece, Hungary, Portugal, Romania, and Spain. The number of the recent buildings in the other countries was assumed to be zero. However, as the durability parameters were known for all countries, it was possible to assess the expected carbonation damage to recent buildings and the time remaining to repair for these buildings in all considered countries. However, the cost of repair presented in section 6.3 was only estimated for the populations of recent buildings in the above mentioned seven countries.

Figure 26 illustrates the carbonation depth estimates for the two capital cities adopted as examples in this report. Annex 2 provides the figures showing the trends in carbonation depth for the capital cities of the 27 EU Member States.

<figure><img src="image_33.png" /><figcaption>**Figure 26.** Carbonation depth in Helsinki (top figure) and Nicosia (bottom figure).</figcaption></figure>
<figure><img src="image_32.png" /></figure>

In Figure 26 and in the figures of Annex 2:

The dotted black lines reflect the evolution of carbonation depth for the two baseline scenarios, showing how the incorporation of ageing effects in the carbonation model has an impact on buildings deterioration throughout their lifetime, even in the absence of climate change.

Carbonation damage relative to the two projected climate scenarios, RCP4.5 in green and RCP8.5 in blue, increases over the two baseline states for old and recent buildings groups. The two groups are differentiated by the line's thickness on the plot; thicker lines represent old buildings and thinner lines represent recent buildings.

The shaded areas plotted in green, and blue are derived from the temperature inter-model variability resultant from the 11 moving average temperature curves and bounded by the carbonation depth obtained from the ensemble mean (EM) temperature plus ±2σ.

Values of the code-recommended concrete cover for old and recent buildings are plotted as horizontal beige dashed lines in the figure, respectively 20 mm and 35 mm for Helsinki and 20 mm and 40 mm for Nicosia.

The red arrows in the figures represent the percentage of increase of carbonation depth for old buildings achieved in the years 2050 and 2085 for the high emission scenario. In Helsinki, for the old buildings group and the high emission scenario, carbonation depth is expected to increase from the baseline by 43% and 84% at 2050 and 2085, respectively, while in Nicosia is expected to increase by 37% and 75%.

In the example in Figure 26, the carbonation depth exceeds the concrete cover for old buildings in Nicosia for the most severe climate change scenario, around 2055. Similar situation can be observed in the southern cities of Sofia and Valletta in Annex 2. In the case of these cities, temperature high values are major contributing factors to the increased risk of corrosion initiation for old buildings, especially for the most pessimistic scenario (RCP8.5) where the expected annual temperature is expected to reach values higher than 20°C by the end of the 21st century (see Annex 1 and **Error! Reference source not found.**). However, according to Figure 26, it is evident that the carbonation depth exceeds the concrete cover in old buildings located in Helsinki, northern Europe, by around 2070. This is of particular concern, especially when considering the projected substantial increase in temperature differences compared to the baseline scenario for 2085 (5°C). Furthermore, it is worth noting that Helsinki is projected to experience the most significant temperature variation compared to the baseline scenario for recent buildings (4.3°C) under the severe climate change scenario (RPC8.5) as outlined in **Error! Reference source not found.**, Section 4.3.2.

Figure 27 to Figure 29 show a summary of the results from the carbonation assessment presented in Figure 26 and Annex 2 for the 27 European capital cities. The anomalies reflect the effects of climate change scenarios in the carbonation of old and recent buildings groups. Annex 2 further presents a table specifying the percentage increase in carbonation depth for years 2050 and 2085 attributed to the two climate change scenarios, RCP4.5 and RCP8.5, in comparison to the two carbonation baseline scenarios without climate change. Maps in Figure 27 enable a geographic analysis of the results, while Figure 28 and Figure 29 provide a comparison of
<figure><img src="image_34.png" /></figure>

In Figure 26 and in the figures of Annex 2:

The dotted black lines reflect the evolution of carbonation depth for the two baseline scenarios, showing how the incorporation of ageing effects in the carbonation model has an impact on buildings deterioration throughout their lifetime, even in the absence of climate change.

Carbonation damage relative to the two projected climate scenarios, RCP4.5 in green and RCP8.5 in blue, increases over the two baseline states for old and recent buildings groups. The two groups are differentiated by the line's thickness on the plot; thicker lines represent old buildings and thinner lines represent recent buildings.

The shaded areas plotted in green, and blue are derived from the temperature inter-model variability resultant from the 11 moving average temperature curves and bounded by the carbonation depth obtained from the ensemble mean (EM) temperature plus ±2σ.

Values of the code-recommended concrete cover for old and recent buildings are plotted as horizontal beige dashed lines in the figure, respectively 20 mm and 35 mm for Helsinki and 20 mm and 40 mm for Nicosia.

The red arrows in the figures represent the percentage of increase of carbonation depth for old buildings achieved in the years 2050 and 2085 for the high emission scenario. In Helsinki, for the old buildings group and the high emission scenario, carbonation depth is expected to increase from the baseline by 43% and 84% at 2050 and 2085, respectively, while in Nicosia is expected to increase by 37% and 75%.

In the example in Figure 26, the carbonation depth exceeds the concrete cover for old buildings in Nicosia for the most severe climate change scenario, around 2055. Similar situation can be observed in the southern cities of Sofia and Valletta in Annex 2. In the case of these cities, temperature high values are major contributing factors to the increased risk of corrosion initiation for old buildings, especially for the most pessimistic scenario (RCP8.5) where the expected annual temperature is expected to reach values higher than 20°C by the end of the 21st century (see Annex 1 and **Error! Reference source not found.**). However, according to Figure 26, it is evident that the carbonation depth exceeds the concrete cover in old buildings located in Helsinki, northern Europe, by around 2070. This is of particular concern, especially when considering the projected substantial increase in temperature differences compared to the baseline scenario for 2085 (5°C). Furthermore, it is worth noting that Helsinki is projected to experience the most significant temperature variation compared to the baseline scenario for recent buildings (4.3°C) under the severe climate change scenario (RPC8.5) as outlined in **Error! Reference source not found.**, Section 4.3.2.

Figure 27 to Figure 29 show a summary of the results from the carbonation assessment presented in Figure 26 and Annex 2 for the 27 European capital cities. The anomalies reflect the effects of climate change scenarios in the carbonation of old and recent buildings groups. Annex 2 further presents a table specifying the percentage increase in carbonation depth for years 2050 and 2085 attributed to the two climate change scenarios, RCP4.5 and RCP8.5, in comparison to the two carbonation baseline scenarios without climate change. Maps in Figure 27 enable a geographic analysis of the results, while Figure 28 and Figure 29 provide a comparison of
carbonation increase with the average temperature anomalies for the two RCP scenarios and the two years of analysis, 2050 and 2085, for old and recent buildings, respectively.

The results in Table 19 (Annex 4) show that the percentage of increase in 60 years (2085) of carbonation depth in European capital cities, due to climate change, varies between 25% and 45%, and between 58% and 89%, respectively, for an intermediate (RCP4.5) and an unlikely high-risk future scenario (RCP8.5), considering old and recent buildings. As one might expect given the temperature projections, the longer time-span of exposure, and (in most countries) lower cement content, old buildings are more affected by climate change than recent ones, and the difference in the impact of the two scenarios is more pronounced in the year 2085 than in 2050.

In the year 2085, for the RCP4.5 scenario and **old buildings** the cities in southern Europe, such as Athens, Bucharest, Nicosia, and Dublin in the northwest region, experience the smallest increase in the carbonation depth, reaching an average of 36%. Dublin is the city remaining with the lowest increase of carbonation depth also for the RCP8.5 scenario in the year 2085 (73%), closely followed by Nicosia (75%). These results are consistent with the lower temperature increases observed in Table 10 for those cities. In contrast, significant increases in carbonation depth are particularly notable in southern Europe in cities such as Sofia and Valletta, with a rise of 46 and 45% for the RCP4.5 scenario in year 1985 and of 89% and 88% for the RCP8.5 scenario in year 1985. Cities in northern Europe also experience a significant increase in carbonation depth, with Stockholm and Tallinn witnessing a surge in values close to 44% for the year 2085 and RCP4.5 and 83% and 87% for the year 2085 and RCP8.5 scenario.

For **recent buildings**, Dublin, Lisbon, and Rome exhibit the lowest values of carbonation increase (25%) among the climate change scenarios for **recent buildings** analysed for the year 2085 and RCP4.5. Among these cities, Dublin stands out as having the lowest value for the years of analysis and two scenarios. Conversely, the cities of Helsinki and Tallinn in northern Europe demonstrate the largest increase in carbonation depth, with an approximate value of 68% (RCP8.5, year 2085).

<figure><img src="image_33.png" /><figcaption>**Figure 27.** Percentage of increase of carbonation depth in EU-27 capital cities. To note the varying scale for each scenario while maintaining the same range of colours in the maps for consistency.</figcaption></figure>
carbonation increase with the average temperature anomalies for the two RCP scenarios and the two years of analysis, 2050 and 2085, for old and recent buildings, respectively.

The results in Table 19 (Annex 4) show that the percentage of increase in 60 years (2085) of carbonation depth in European capital cities, due to climate change, varies between 25% and 45%, and between 58% and 89%, respectively, for an intermediate (RCP4.5) and an unlikely high-risk future scenario (RCP8.5), considering old and recent buildings. As one might expect given the temperature projections, the longer time-span of exposure, and (in most countries) lower cement content, old buildings are more affected by climate change than recent ones, and the difference in the impact of the two scenarios is more pronounced in the year 2085 than in 2050.

In the year 2085, for the RCP4.5 scenario and **old buildings** the cities in southern Europe, such as Athens, Bucharest, Nicosia, and Dublin in the northwest region, experience the smallest increase in the carbonation depth, reaching an average of 36%. Dublin is the city remaining with the lowest increase of carbonation depth also for the RCP8.5 scenario in the year 2085 (73%), closely followed by Nicosia (75%). These results are consistent with the lower temperature increases observed in Table 10 for those cities. In contrast, significant increases in carbonation depth are particularly notable in southern Europe in cities such as Sofia and Valletta, with a rise of 46 and 45% for the RCP4.5 scenario in year 1985 and of 89% and 88% for the RCP8.5 scenario in year 1985. Cities in northern Europe also experience a significant increase in carbonation depth, with Stockholm and Tallinn witnessing a surge in values close to 44% for the year 2085 and RCP4.5 and 83% and 87% for the year 2085 and RCP8.5 scenario.

For **recent buildings**, Dublin, Lisbon, and Rome exhibit the lowest values of carbonation increase (25%) among the climate change scenarios for **recent buildings** analysed for the year 2085 and RCP4.5. Among these cities, Dublin stands out as having the lowest value for the years of analysis and two scenarios. Conversely, the cities of Helsinki and Tallinn in northern Europe demonstrate the largest increase in carbonation depth, with an approximate value of 68% (RCP8.5, year 2085).

<figure><img src="image_35.png" /><figcaption>**Figure 27.** Percentage of increase of carbonation depth in EU-27 capital cities. To note the varying scale for each scenario while maintaining the same range of colours in the maps for consistency.</figcaption></figure>
<figure><img src="image_34.png" /></figure>

In Figure 28 and Figure 29, capital cities are ordered by the values of carbonation depth increase (average), from minimum to maximum. The figures have a double vertical scale. The primary scale on the left indicates the percentage of carbonation depth increase, while the secondary scale on the right displays absolute temperature values for a given RCP scenario and year. Across all figures the vertical scales remain consistent to accommodate the widest range of carbonation increase (from 17% to 89%) and the maximum variation of temperature values (from 7.4°C to 22.3°C) across Europe, RCP scenario and year. The rise in carbonation in each city is represented by coloured points: the green points correspond to RCP 4.5, while the blue points to RCP 8.5.

The associated coloured labels indicate temperature variations (°C) in comparison to the baseline scenarios. Figures show a clear positive correlation between the rise in temperature due to climate change and the carbonation depth. The grey points and their respective labels represent the absolute temperature values for a given RCP scenario and year. The temperature variation explains the carbonation increase, while the absolute values of temperature, correlate well with carbonation depth, as shown below in section 6.2.

The results for the RCP8.5 scenario in 2085 for old buildings indicate a notably higher percentage increase in carbonation depth, contrasting sharply with the figure for the RCP4.5 scenario in 2050 for recent buildings. In the RCP8.5 scenario, Sofia shows the most substantial increase in carbonation depth for old buildings, 89%, whereas in the RCP4.5 scenario, Dublin presents the smallest percentage rise in carbonation depth, standing at 17% for recent buildings.
<figure><img src="image_36.png" /></figure>

In Figure 28 and Figure 29, capital cities are ordered by the values of carbonation depth increase (average), from minimum to maximum. The figures have a double vertical scale. The primary scale on the left indicates the percentage of carbonation depth increase, while the secondary scale on the right displays absolute temperature values for a given RCP scenario and year. Across all figures the vertical scales remain consistent to accommodate the widest range of carbonation increase (from 17% to 89%) and the maximum variation of temperature values (from 7.4°C to 22.3°C) across Europe, RCP scenario and year. The rise in carbonation in each city is represented by coloured points: the green points correspond to RCP 4.5, while the blue points to RCP 8.5.

The associated coloured labels indicate temperature variations (°C) in comparison to the baseline scenarios. Figures show a clear positive correlation between the rise in temperature due to climate change and the carbonation depth. The grey points and their respective labels represent the absolute temperature values for a given RCP scenario and year. The temperature variation explains the carbonation increase, while the absolute values of temperature, correlate well with carbonation depth, as shown below in section 6.2.

The results for the RCP8.5 scenario in 2085 for old buildings indicate a notably higher percentage increase in carbonation depth, contrasting sharply with the figure for the RCP4.5 scenario in 2050 for recent buildings. In the RCP8.5 scenario, Sofia shows the most substantial increase in carbonation depth for old buildings, 89%, whereas in the RCP4.5 scenario, Dublin presents the smallest percentage rise in carbonation depth, standing at 17% for recent buildings.
Across all scenarios for **old buildings**, the same group of cities consistently shows the smallest increase in carbonation depth, they are: Athens, Dublin, and Nicosia. These cities are associated with the least variation in temperature. Conversely, another group of cities consistently displays the greatest percentage increase in carbonation depth: Ljubljana, Sofia, Tallinn and Valletta. These cities correspond to the greatest variation in temperature.

For **recent buildings** Amsterdam, Dublin and Lisbon typically show the smallest increase in carbonation depth, while Helsinki, Stockholm, Tallinn and Vilnius in north Europe, along with Valletta in the south steadily present the largest increase in carbonation depth, showing a similar correlation with the temperature variation.

Cities in southern Europe regularly present the highest temperature predictions across all considered RCP scenarios and years when compared to both the old and recent buildings baseline scenarios. These cities are Athens, Lisbon, Madrid, Nicosia, Rome and Valletta. Specifically, among all these cities, the highest temperature values are consistently predicted for Nicosia and Valletta, which are located in the southernmost European region. In contrast, in the northern region, for Helsinki, Tallinn and Vilnius the predictions steadily display the lowest temperature values across all considered RCP and years.

<figure><img src="image_35.png" /><figcaption>**Figure 28.** Percentage of increase of carbonation depth in EU-27 capital cities for **old buildings**, absolute temperature for a given year and temperature variation relative to the reference scenario.</figcaption></figure>

<figure><img src="image_36.png" /></figure>
Across all scenarios for **old buildings**, the same group of cities consistently shows the smallest increase in carbonation depth, they are: Athens, Dublin, and Nicosia. These cities are associated with the least variation in temperature. Conversely, another group of cities consistently displays the greatest percentage increase in carbonation depth: Ljubljana, Sofia, Tallinn and Valletta. These cities correspond to the greatest variation in temperature.

For **recent buildings** Amsterdam, Dublin and Lisbon typically show the smallest increase in carbonation depth, while Helsinki, Stockholm, Tallinn and Vilnius in north Europe, along with Valletta in the south steadily present the largest increase in carbonation depth, showing a similar correlation with the temperature variation.

Cities in southern Europe regularly present the highest temperature predictions across all considered RCP scenarios and years when compared to both the old and recent buildings baseline scenarios. These cities are Athens, Lisbon, Madrid, Nicosia, Rome and Valletta. Specifically, among all these cities, the highest temperature values are consistently predicted for Nicosia and Valletta, which are located in the southernmost European region. In contrast, in the northern region, for Helsinki, Tallinn and Vilnius the predictions steadily display the lowest temperature values across all considered RCP and years.

<figure><img src="image_37.png" /><figcaption>**Figure 28.** Percentage of increase of carbonation depth in EU-27 capital cities for **old buildings**, absolute temperature for a given year and temperature variation relative to the reference scenario.</figcaption></figure>

<figure><img src="image_38.png" /></figure>
<figure><img src="image_37.png" /><figcaption>**Figure 29.** Percentage of increase of carbonation depth in EU-27 capital cities for **recent buildings**, absolute temperature for a given year and temperature variation relative to the reference scenario.</figcaption></figure>

<figure><img src="image_38.png" /></figure>
<figure><img src="image_39.png" /><figcaption>**Figure 29.** Percentage of increase of carbonation depth in EU-27 capital cities for **recent buildings**, absolute temperature for a given year and temperature variation relative to the reference scenario.</figcaption></figure>

<figure><img src="image_40.png" /></figure>
<figure><img src="image_39.png" /></figure>

<figure><img src="image_40.png" /></figure>

In Figure 30 and Figure 31, capital cities are ordered by the values of carbonation depth (average), from minimum to maximum, and present the results for old, and for recent buildings, respectively. Similarly to Figure 28 and Figure 29, the figures below have a double vertical scale. The primary scale on the left indicates the carbonation depth, while the secondary scale on the right displays the absolute temperature values for a given RCP scenario and year. The carbonation depth in each city is represented by coloured points: the light green points correspond to RCP4.5, while the light blue correspond to RCP8.5. The grey points and their respective labels represent the absolute temperature values for a given RCP scenario and year.

The figures illustrate two distinct clusters of capital cities. One cluster comprises cities in north-eastern Europe, characterized by lower temperature values but moderately high carbonation depth. The other cluster includes the remaining capital cities. Within each cluster, there is a positive correlation between absolute temperature and carbonation depth observed for both old and recent buildings under the two climate change scenarios. While both clusters exhibit a similar trend, capital cities in north-eastern Europe show carbonation depth values comparable to those of other capital cities but at much lower absolute temperatures. This phenomenon may be attributed to the higher temperature rise and the relatively low durability characteristics of concrete. (Figure 23, Figure 24 and Figure 25).

These results show that the knowledge of the expected temperature is not enough to predict the onset of corrosion, as the durability parameters play a significant role in the carbonation process. Within the cluster of the north-eastern Europe one shall note the Copenhagen, where the increase of the temperature and respectively, the increase of the carbonation depth are the smallest (Figure 28 and Figure 29), however, due to the highest projected absolute temperature, there the depth of the carbonation is the biggest. These findings suggest that knowledge of expected temperatures alone is insufficient for predicting the onset of corrosion, as durability parameters significantly influence the carbonation process.
<figure><img src="image_41.png" /></figure>

<figure><img src="image_42.png" /></figure>

In Figure 30 and Figure 31, capital cities are ordered by the values of carbonation depth (average), from minimum to maximum, and present the results for old, and for recent buildings, respectively. Similarly to Figure 28 and Figure 29, the figures below have a double vertical scale. The primary scale on the left indicates the carbonation depth, while the secondary scale on the right displays the absolute temperature values for a given RCP scenario and year. The carbonation depth in each city is represented by coloured points: the light green points correspond to RCP4.5, while the light blue correspond to RCP8.5. The grey points and their respective labels represent the absolute temperature values for a given RCP scenario and year.

The figures illustrate two distinct clusters of capital cities. One cluster comprises cities in north-eastern Europe, characterized by lower temperature values but moderately high carbonation depth. The other cluster includes the remaining capital cities. Within each cluster, there is a positive correlation between absolute temperature and carbonation depth observed for both old and recent buildings under the two climate change scenarios. While both clusters exhibit a similar trend, capital cities in north-eastern Europe show carbonation depth values comparable to those of other capital cities but at much lower absolute temperatures. This phenomenon may be attributed to the higher temperature rise and the relatively low durability characteristics of concrete. (Figure 23, Figure 24 and Figure 25).

These results show that the knowledge of the expected temperature is not enough to predict the onset of corrosion, as the durability parameters play a significant role in the carbonation process. Within the cluster of the north-eastern Europe one shall note the Copenhagen, where the increase of the temperature and respectively, the increase of the carbonation depth are the smallest (Figure 28 and Figure 29), however, due to the highest projected absolute temperature, there the depth of the carbonation is the biggest. These findings suggest that knowledge of expected temperatures alone is insufficient for predicting the onset of corrosion, as durability parameters significantly influence the carbonation process.
<figure><img src="image_41.png" /><figcaption>**Figure 30.** Absolute increase of carbonation depth in EU-27 capital cities for **old buildings**, absolute temperature for a given year and temperature variation relative to the reference scenario.</figcaption></figure>
<figure><img src="image_43.png" /><figcaption>**Figure 30.** Absolute increase of carbonation depth in EU-27 capital cities for **old buildings**, absolute temperature for a given year and temperature variation relative to the reference scenario.</figcaption></figure>
<figure><img src="image_42.png" /><figcaption>**Figure 31.** Absolute increase of carbonation depth in EU-27 capital cities for **recent buildings**, absolute temperature for a given year and temperature variation relative to the reference scenario.</figcaption></figure>
<figure><img src="image_44.png" /><figcaption>**Figure 31.** Absolute increase of carbonation depth in EU-27 capital cities for **recent buildings**, absolute temperature for a given year and temperature variation relative to the reference scenario.</figcaption></figure>
Given the previous information and recognizing the potential impact of climate change on reinforced concrete structures, it is essential to identify the capital cities that may face significant temperature variations in future climate scenarios.

For instance, **older buildings** in cities like Sofia and Valetta, which were constructed with low concrete cover requirements (i.e., $c_t$ equal to 20 mm), are likely to experience the most substantial increase in carbonation depth. These problems are especially noticeable under the RCP8.5 scenario and exacerbate by 2085. However, the evaluation of the increase of the carbonation depth and knowing the thickness of the concrete cover are not sufficient to predict the onset of the corrosion. Sofia is a very good example, because despite the big percentage of increase of the carbonation depth under RCP4.5 scenario (45% in 2085), the relatively low concrete cover of 20 mm is hardly like to be depleted because the 12 mm carbonation depth in the reference scenario is small, as shown in Annex 2.

In addition to the effect of temperature increase, a cluster of factors affecting the durability of concrete was considered for north-eastern Europe (Figure 23 to Figure 25, Table 12 and Table 19 in Annex 4), which is one of the regions most affected by the increase in climate change-induced carbonation. The durability parameters assumed for each capital city for old buildings coincides with the choice of values for the respective country. The rationale for the selection is detailed in section 5.2 and the values of the durability parameters are depicted in Figure 23, Figure 24, and Figure 25. For more comprehensive information, please refer to Table 18 in Annex 4.

Additionally, Figure 23 to Figure 25 show that for **recent buildings** the countries where cities like Helsinki, Stockholm, Copenhagen, Riga, Tallinn and Vilnius are located have chosen the lowest concrete cover ($c_t$ = 35mm), an intermediate water-to-cement ratio (0.55) and a low cement content (200 kg/m³). In comparison to other European cities, the north-eastern ones are expected to encounter significant temperature rises compared to the baseline scenario for recent buildings. By 2085, according to the RCP4.5 scenario, these cities could see a temperature rise of 2.5°C, and under the more extreme RCP8.5 scenario temperatures could rise by 4.3°C. Correspondingly, they are projected to experience a high percentage increase in carbonation depth. In these four cities, under the RCP4.5 scenario, the increase ranges from 20% up to about 30%, for the years 2050 and 2085, respectively, while under the more extreme RCP8.5 scenario, it spans from 28% to up to 65% for the same years. Values that are similar are also found in Riga and Valletta for the same scenarios."

These findings emphasize the need for careful consideration of concrete cover requirements and the potential impact of climate change on the durability and performance of buildings in these specific capital cities and corresponding countries. Adequate measures should be taken to ensure the resilience of concrete structures anticipating future temperature variations, as suggested in chapter 8.

Finally, Figure 32 presents the percentage increase in carbonation depth for the years 2050 and 2085 calculated across European regions following the NUTS 3 definition of the Nomenclature of Territorial Units for Statistics in 2021. The percentage is weighted by the existing building stock, both recent and old buildings. It is important to note that the building inventory data for Austria was not complete enough to cover the entire country at a NUTS 3 level regions. Furthermore, it is important to consider that in this graphic, which encompasses the entire building stock including both old and recent structures, there is a possibility of obtaining a conservative estimation of carbonation damage due to potential data gaps concerning recent buildings in certain countries (see details in section 5.1). Additionally, the rise of carbonation levels in capital cities (Figure 27) can show differences in comparison to the carbonation increase at a NUTS 3 level (Figure 34). This discrepancy can be attributed to various factors, including the consideration of old and recent buildings when estimating carbonation damage for NUTS, along with the range of temperature variations within each NUT, which may encompass values differing from the temperature values accounted for individual capital cities.

Detailed data on the percentage increase in carbonation depth for the capital cities under this study can be found in Table 19 of Annex 4.

The results of the evaluation of the carbonation damage according to the simplified model and the environmental conditions assumed, conclusively show that until 2100 the increase of the carbonation depth for both, RCP4.5 and RCP8.5 scenarios, does not pose a serious threat to the recent RC buildings that follow the recommendations of the contemporary European standards for durability of the concrete cover. As shown in Figure 31 the carbonation depth of the recent buildings for the two considered scenarios and for both, 2150 and 2185, does not exceed 25mm, while the smallest concrete cover implemented in EU-27 is 35 mm (Figure 23).
Given the previous information and recognizing the potential impact of climate change on reinforced concrete structures, it is essential to identify the capital cities that may face significant temperature variations in future climate scenarios.

For instance, **older buildings** in cities like Sofia and Valetta, which were constructed with low concrete cover requirements (i.e., $c_t$ equal to 20 mm), are likely to experience the most substantial increase in carbonation depth. These problems are especially noticeable under the RCP8.5 scenario and exacerbate by 2085. However, the evaluation of the increase of the carbonation depth and knowing the thickness of the concrete cover are not sufficient to predict the onset of the corrosion. Sofia is a very good example, because despite the big percentage of increase of the carbonation depth under RCP4.5 scenario (45% in 2085), the relatively low concrete cover of 20 mm is hardly like to be depleted because the 12 mm carbonation depth in the reference scenario is small, as shown in Annex 2.

In addition to the effect of temperature increase, a cluster of factors affecting the durability of concrete was considered for north-eastern Europe (Figure 23 to Figure 25, Table 12 and Table 19 in Annex 4), which is one of the regions most affected by the increase in climate change-induced carbonation. The durability parameters assumed for each capital city for old buildings coincides with the choice of values for the respective country. The rationale for the selection is detailed in section 5.2 and the values of the durability parameters are depicted in Figure 23, Figure 24, and Figure 25. For more comprehensive information, please refer to Table 18 in Annex 4.

Additionally, Figure 23 to Figure 25 show that for **recent buildings** the countries where cities like Helsinki, Stockholm, Copenhagen, Riga, Tallinn and Vilnius are located have chosen the lowest concrete cover ($c_t$ = 35mm), an intermediate water-to-cement ratio (0.55) and a low cement content (200 kg/m³). In comparison to other European cities, the north-eastern ones are expected to encounter significant temperature rises compared to the baseline scenario for recent buildings. By 2085, according to the RCP4.5 scenario, these cities could see a temperature rise of 2.5°C, and under the more extreme RCP8.5 scenario temperatures could rise by 4.3°C. Correspondingly, they are projected to experience a high percentage increase in carbonation depth. In these four cities, under the RCP4.5 scenario, the increase ranges from 20% up to about 30%, for the years 2050 and 2085, respectively, while under the more extreme RCP8.5 scenario, it spans from 28% to up to 65% for the same years. Values that are similar are also found in Riga and Valletta for the same scenarios."

These findings emphasize the need for careful consideration of concrete cover requirements and the potential impact of climate change on the durability and performance of buildings in these specific capital cities and corresponding countries. Adequate measures should be taken to ensure the resilience of concrete structures anticipating future temperature variations, as suggested in chapter 8.

Finally, Figure 32 presents the percentage increase in carbonation depth for the years 2050 and 2085 calculated across European regions following the NUTS 3 definition of the Nomenclature of Territorial Units for Statistics in 2021. The percentage is weighted by the existing building stock, both recent and old buildings. It is important to note that the building inventory data for Austria was not complete enough to cover the entire country at a NUTS 3 level regions. Furthermore, it is important to consider that in this graphic, which encompasses the entire building stock including both old and recent structures, there is a possibility of obtaining a conservative estimation of carbonation damage due to potential data gaps concerning recent buildings in certain countries (see details in section 5.1). Additionally, the rise of carbonation levels in capital cities (Figure 27) can show differences in comparison to the carbonation increase at a NUTS 3 level (Figure 34). This discrepancy can be attributed to various factors, including the consideration of old and recent buildings when estimating carbonation damage for NUTS, along with the range of temperature variations within each NUT, which may encompass values differing from the temperature values accounted for individual capital cities.

Detailed data on the percentage increase in carbonation depth for the capital cities under this study can be found in Table 19 of Annex 4.

The results of the evaluation of the carbonation damage according to the simplified model and the environmental conditions assumed, conclusively show that until 2100 the increase of the carbonation depth for both, RCP4.5 and RCP8.5 scenarios, does not pose a serious threat to the recent RC buildings that follow the recommendations of the contemporary European standards for durability of the concrete cover. As shown in Figure 31 the carbonation depth of the recent buildings for the two considered scenarios and for both, 2150 and 2185, does not exceed 25mm, while the smallest concrete cover implemented in EU-27 is 35 mm (Figure 23).
<figure><img src="image_43.png" /><figcaption>**Figure 32.** Percentage of increase of carbonation depth in EU-27 Member States for the RC building stock for the years 2050 (top) and 2085 (bottom) due to two climate change scenarios with respect to two control scenarios; left: RCP4.5 scenario, right RCP8.5 scenario.</figcaption></figure>

## 6.3 Assessing carbonation costs

The probability of corrosion initiation is calculated using equation (11) (see details in section 3.2.3). The input data are the estimated carbonation depths for future periods up to 2100 given in Figure 26 and figures in Annex 2 for the capital cities, the concrete cover values in the Member States presented in Figure 23 and in Table 18 in Annex 4, and the accepted in this study 10 mm uncertainty related to the concrete cover thickness.

The results are displayed in Figure 33 for Helsinki and Nicosia, the two cities used as examples, and are presented in Annex 3 for all the capitals of the EU-27 Member States. The figures demonstrate that the probability of corrosion initiation is only relevant for old structures, especially when exposed to climate change conditions. In fact, the increased concrete cover considered for recent buildings, as well as their age, significantly reduces the risk of corrosion initiation due to carbonation. The findings for the two cities illustrated in Figure 33 indicate that a non-null probability of corrosion initiation in the southern city Nicosia, starts about 15 years earlier than in the northern one, Helsinki, justified by the high-temperature values anticipated in the south. Upon analysing Figure 28 and Figure 29, it becomes clear that the percentage increase in carbonation depth is influenced by the increase of temperature relative to the baseline scenarios. However, the depth of carbonation correlates positively with the projected absolute temperature values, as depicted in Figure 30 and Figure 31. In both cases the cluster of durability parameters is expected to play a role in the process, in what regards the Northern Est countries.
<figure><img src="image_45.png" /><figcaption>**Figure 32.** Percentage of increase of carbonation depth in EU-27 Member States for the RC building stock for the years 2050 (top) and 2085 (bottom) due to two climate change scenarios with respect to two control scenarios; left: RCP4.5 scenario, right RCP8.5 scenario.</figcaption></figure>

## 6.3 Assessing carbonation costs

The probability of corrosion initiation is calculated using equation (11) (see details in section 3.2.3). The input data are the estimated carbonation depths for future periods up to 2100 given in Figure 26 and figures in Annex 2 for the capital cities, the concrete cover values in the Member States presented in Figure 23 and in Table 18 in Annex 4, and the accepted in this study 10 mm uncertainty related to the concrete cover thickness.

The results are displayed in Figure 33 for Helsinki and Nicosia, the two cities used as examples, and are presented in Annex 3 for all the capitals of the EU-27 Member States. The figures demonstrate that the probability of corrosion initiation is only relevant for old structures, especially when exposed to climate change conditions. In fact, the increased concrete cover considered for recent buildings, as well as their age, significantly reduces the risk of corrosion initiation due to carbonation. The findings for the two cities illustrated in Figure 33 indicate that a non-null probability of corrosion initiation in the southern city Nicosia, starts about 15 years earlier than in the northern one, Helsinki, justified by the high-temperature values anticipated in the south. Upon analysing Figure 28 and Figure 29, it becomes clear that the percentage increase in carbonation depth is influenced by the increase of temperature relative to the baseline scenarios. However, the depth of carbonation correlates positively with the projected absolute temperature values, as depicted in Figure 30 and Figure 31. In both cases the cluster of durability parameters is expected to play a role in the process, in what regards the Northern Est countries.
<figure><img src="image_44.png" /><figcaption>**Figure 33.** Probability of corrosion initiation in Helsinki (top figure) and Nicosia (bottom figure) for two climate change scenarios, RCP4.5 and RCP8.5 initiated in 2011, and two classes of buildings, old and recent buildings; Shaded areas are derived from the temperature inter-model variability and assessed between ±2σ.</figcaption></figure>

Annex 3 reveals that in the southern cities of Athens, Lisbon and Nicosia, showing the highest temperature values for the old buildings baseline scenario (above 16°C in **Error! Reference source not found.**), there is a low but non-null probability of corrosion initiation for old buildings group in the control scenario. The earliest estimated onset year for Nicosia for the baseline scenario for old buildings falls between 2070 and 2075 (see the dotted black line in Figure 33 bottom). To note that the temperature value for Valletta is also above 16°C (very close to the one for Lisbon) for the old buildings baseline scenario, but it does not exhibit a non-null probability of corrosion initiation for the control scenario, most probably because the durability is enhanced by higher value of the minimum cement content than the one for the buildings in Lisbon.

The detected non-null probability for the old buildings in Athens, Lisbon and Nicosia under the baseline scenarios is relatively low and never crosses the median of the probability of corrosion initiation, nor the median plus or minus two sigma (see Figure 33 and Annex 3). Hence, the time to repair $t_{rep_i}$ due to the baseline scenario in equation (13) is very long and the resulting cost of repair from the reference year until 2100 is practically zero. **Thus, if there would not be climate change, the depth of carbonation of the concrete cover will be much smaller and would neither lead to start of corrosion process, nor add a relevant contribution to its onset.**
<figure><img src="image_46.png" /><figcaption>**Figure 33.** Probability of corrosion initiation in Helsinki (top figure) and Nicosia (bottom figure) for two climate change scenarios, RCP4.5 and RCP8.5 initiated in 2011, and two classes of buildings, old and recent buildings; Shaded areas are derived from the temperature inter-model variability and assessed between ±2σ.</figcaption></figure>

Annex 3 reveals that in the southern cities of Athens, Lisbon and Nicosia, showing the highest temperature values for the old buildings baseline scenario (above 16°C in **Error! Reference source not found.**), there is a low but non-null probability of corrosion initiation for old buildings group in the control scenario. The earliest estimated onset year for Nicosia for the baseline scenario for old buildings falls between 2070 and 2075 (see the dotted black line in Figure 33 bottom). To note that the temperature value for Valletta is also above 16°C (very close to the one for Lisbon) for the old buildings baseline scenario, but it does not exhibit a non-null probability of corrosion initiation for the control scenario, most probably because the durability is enhanced by higher value of the minimum cement content than the one for the buildings in Lisbon.

The detected non-null probability for the old buildings in Athens, Lisbon and Nicosia under the baseline scenarios is relatively low and never crosses the median of the probability of corrosion initiation, nor the median plus or minus two sigma (see Figure 33 and Annex 3). Hence, the time to repair $t_{rep_i}$ due to the baseline scenario in equation (13) is very long and the resulting cost of repair from the reference year until 2100 is practically zero. **Thus, if there would not be climate change, the depth of carbonation of the concrete cover will be much smaller and would neither lead to start of corrosion process, nor add a relevant contribution to its onset.**
As per the methodology described in Chapter 3, the median of the probability distribution determines the probability threshold for corrosion initiation associated with the so called 'repair year'. This refers to the estimated year when the first corrective reparation of structures will be needed due to corrosion.

Table 13 lists the European capital cities where, in median terms, a need for repairing of old concrete structures is expected before the end of the 21st century and after. The Table presents the repair year, the time remaining until the first repair is needed in relation to the year 2020, and the corresponding ±2σ uncertainties derived from the variability among temperature models for the cities listed. For old buildings in the southern capital cities of Nicosia, Valetta, Lisbon and Athens, the median of the time to repair relative to 2020 ranges from 50 to 58 years for the RCP4.5 scenario, while for the more pessimistic climate change scenario RPC8.5 the repair year, for those cities, is projected to occur nearly two decades earlier, varying between 34 and 36 years. Athens, Lisbon, Nicosia and Valetta are the cities showing the most reduced time to repair of approximately 35 years relative to 2020, under the RCP8.5 scenario. Most EU capital cities are projected to require their first repair in the 22nd century under the RCP4.5 scenario (>80 years). Based on the findings in

Table 13, the RPC8.5 scenario shows a significant decrease in the time to repair when compared to the RCP4.5 scenario. For instance, cities such as Stockholm and Riga have seen a decrease from over 100 years in RCP4.5 to 46 years. Berlin stands out with the longest projected time until the first repair under RCP8.5, at 70 years relative to 2020, with the first repair expected in 2090, compared to other cities that were projected to require their first repair in the 22nd century under RCP4.5. Notice that for each of the EU-27 capital cities, the total number of expected repairs from the reference year until 2100 does not exceed one.

<table><caption>**Table 13.** Repair year, time to repair and uncertainties due to climate change prediction for old buildings in capital cities.</caption><thead><tr><th rowspan="3">City</th><th colspan="10">RCP4.5</th><th colspan="10">RCP8.5</th></tr><tr><th colspan="4">Repair Year</th><th colspan="4">Time to repair (yr) relative to 2020</th><th colspan="4">Repair Year</th><th colspan="4">Time to repair (yr) relative to 2020</th></tr><tr><th>μ-2σ</th><th>μ</th><th>μ+2σ</th><th>μ-2σ</th><th>μ</th><th>μ+2σ</th><th>μ-2σ</th><th>μ</th><th>μ+2σ</th><th>μ-2σ</th><th>μ</th><th>μ+2σ</th><th>μ-2σ</th><th>μ</th><th>μ+2σ</th></tr></thead><tbody><tr><td>Amsterdam</td><td>>2100</td><td>>2100</td><td>>2100</td><td>>80</td><td>>80</td><td>>80</td><td>2084</td><td>2081</td><td>2079</td><td>64</td><td>61</td><td>59</td><td></td><td></td><td></td></tr><tr><td>Athens</td><td>2089</td><td>2078</td><td>2070</td><td>69</td><td>58</td><td>50</td><td>2060</td><td>2056</td><td>2054</td><td>40</td><td>36</td><td>34</td><td></td><td></td><td></td></tr><tr><td>Berlin</td><td>>2100</td><td>>2100</td><td>>2100</td><td>>80</td><td>>80</td><td>>80</td><td>2093</td><td>2090</td><td>2087</td><td>73</td><td>70</td><td>67</td><td></td><td></td><td></td></tr><tr><td>Bratislava</td><td>>2100</td><td>>2100</td><td>>2100</td><td>>80</td><td>>80</td><td>>80</td><td>2080</td><td>2077</td><td>2075</td><td>60</td><td>57</td><td>55</td><td></td><td></td><td></td></tr><tr><td>Brussels</td><td>>2100</td><td>>2100</td><td>>2100</td><td>>80</td><td>>80</td><td>>80</td><td>2080</td><td>2078</td><td>2076</td><td>60</td><td>58</td><td>56</td><td></td><td></td><td></td></tr><tr><td>Bucharest</td><td>>2100</td><td>>2100</td><td>>2100</td><td>>80</td><td>>80</td><td>>80</td><td>2079</td><td>2075</td><td>2072</td><td>59</td><td>55</td><td>52</td><td></td><td></td><td></td></tr><tr><td>Budapest</td><td>>2100</td><td>>2100</td><td>>2100</td><td>>80</td><td>>80</td><td>>80</td><td>2077</td><td>2074</td><td>2072</td><td>57</td><td>54</td><td>52</td><td></td><td></td><td></td></tr><tr><td>Copenhagen</td><td>2100</td><td>2093</td><td>2083</td><td>80</td><td>73</td><td>63</td><td>2063</td><td>2061</td><td>2059</td><td>43</td><td>41</td><td>39</td><td></td><td></td><td></td></tr><tr><td>Dublin</td><td>>2100</td><td>>2100</td><td>>2100</td><td>>80</td><td>>80</td><td>>80</td><td>2086</td><td>2083</td><td>2080</td><td>66</td><td>63</td><td>60</td><td></td><td></td><td></td></tr><tr><td>Helsinki</td><td>>2100</td><td>>2100</td><td>>2100</td><td>>80</td><td>>80</td><td>>80</td><td>2072</td><td>2069</td><td>2066</td><td>52</td><td>49</td><td>46</td><td></td><td></td><td></td></tr><tr><td>Lisbon</td><td>2081</td><td>2075</td><td>2071</td><td>61</td><td>55</td><td>51</td><td>2057</td><td>2056</td><td>2055</td><td>37</td><td>36</td><td>35</td><td></td><td></td><td></td></tr><tr><td>Ljubljana</td><td>>2100</td><td>>2100</td><td>>2100</td><td>>80</td><td>>80</td><td>>80</td><td>2080</td><td>2077</td><td>2074</td><td>60</td><td>57</td><td>54</td><td></td><td></td><td></td></tr><tr><td>Luxembourg</td><td>>2100</td><td>>2100</td><td>>2100</td><td>>80</td><td>>80</td><td>>80</td><td>2084</td><td>2081</td><td>2078</td><td>64</td><td>61</td><td>58</td><td></td><td></td><td></td></tr><tr><td>Madrid</td><td>>2100</td><td>2094</td><td>2084</td><td>>80</td><td>74</td><td>64</td><td>2063</td><td>2061</td><td>2058</td><td>43</td><td>41</td><td>38</td><td></td><td></td><td></td></tr><tr><td>Nicosia</td><td>2077</td><td>2070</td><td>2066</td><td>57</td><td>50</td><td>46</td><td>2056</td><td>2054</td><td>2051</td><td>36</td><td>34</td><td>31</td><td></td><td></td><td></td></tr><tr><td>Paris</td><td>>2100</td><td>>2100</td><td>>2100</td><td>>80</td><td>>80</td><td>>80</td><td>2085</td><td>2082</td><td>2079</td><td>65</td><td>62</td><td>59</td><td></td><td></td><td></td></tr><tr><td>Prague</td><td>>2100</td><td>>2100</td><td>>2100</td><td>>80</td><td>>80</td><td>>80</td><td>2084</td><td>2081</td><td>2078</td><td>64</td><td>61</td><td>58</td><td></td><td></td><td></td></tr><tr><td>Riga</td><td>>2100</td><td>>2100</td><td>>2100</td><td>>80</td><td>>80</td><td>>80</td><td>2069</td><td>2066</td><td>2063</td><td>49</td><td>46</td><td>43</td><td></td><td></td><td></td></tr><tr><td>Rome</td><td>>2100</td><td>2098</td><td>2091</td><td>>80</td><td>78</td><td>71</td><td>2064</td><td>2062</td><td>2060</td><td>44</td><td>42</td><td>40</td><td></td><td></td><td></td></tr><tr><td>Sofia</td><td>>2100</td><td>>2100</td><td>>2100</td><td>>80</td><td>>80</td><td>>80</td><td>2081</td><td>2077</td><td>2073</td><td>61</td><td>57</td><td>53</td><td></td><td></td><td></td></tr><tr><td>Stockholm</td><td>>2100</td><td>>2100</td><td>>2100</td><td>>80</td><td>>80</td><td>>80</td><td>2068</td><td>2066</td><td>2064</td><td>48</td><td>46</td><td>44</td><td></td><td></td><td></td></tr><tr><td>Tallinn</td><td>>2100</td><td>>2100</td><td>>2100</td><td>>80</td><td>>80</td><td>>80</td><td>2071</td><td>2068</td><td>2064</td><td>51</td><td>48</td><td>44</td><td></td><td></td><td></td></tr><tr><td>Valletta</td><td>2081</td><td>2072</td><td>2065</td><td>61</td><td>52</td><td>45</td><td>2057</td><td>2054</td><td>2051</td><td>37</td><td>34</td><td>31</td><td></td><td></td><td></td></tr><tr><td>Vienna</td><td>>2100</td><td>>2100</td><td>>2100</td><td>>80</td><td>>80</td><td>>80</td><td>2079</td><td>2076</td><td>2074</td><td>59</td><td>56</td><td>54</td><td></td><td></td><td></td></tr><tr><td>Vilnius</td><td>>2100</td><td>>2100</td><td>>2100</td><td>>80</td><td>>80</td><td>>80</td><td>2071</td><td>2068</td><td>2065</td><td>51</td><td>48</td><td>45</td><td></td><td></td><td></td></tr><tr><td>Warsaw</td><td>>2100</td><td>>2100</td><td>>2100</td><td>>80</td><td>>80</td><td>>80</td><td>2087</td><td>2084</td><td>2081</td><td>67</td><td>64</td><td>61</td><td></td><td></td><td></td></tr><tr><td>Zagreb</td><td>>2100</td><td>>2100</td><td>>2100</td><td>>80</td><td>>80</td><td>>80</td><td>2078</td><td>2075</td><td>2072</td><td>58</td><td>55</td><td>52</td><td></td><td></td><td></td></tr></tbody></table>

<figure><img src="image_45.png" /></figure>

Time to repair (yr) relative to 2020

Source: Developed by authors.
As per the methodology described in Chapter 3, the median of the probability distribution determines the probability threshold for corrosion initiation associated with the so called 'repair year'. This refers to the estimated year when the first corrective reparation of structures will be needed due to corrosion.

Table 13 lists the European capital cities where, in median terms, a need for repairing of old concrete structures is expected before the end of the 21st century and after. The Table presents the repair year, the time remaining until the first repair is needed in relation to the year 2020, and the corresponding ±2σ uncertainties derived from the variability among temperature models for the cities listed. For old buildings in the southern capital cities of Nicosia, Valetta, Lisbon and Athens, the median of the time to repair relative to 2020 ranges from 50 to 58 years for the RCP4.5 scenario, while for the more pessimistic climate change scenario RPC8.5 the repair year, for those cities, is projected to occur nearly two decades earlier, varying between 34 and 36 years. Athens, Lisbon, Nicosia and Valetta are the cities showing the most reduced time to repair of approximately 35 years relative to 2020, under the RCP8.5 scenario. Most EU capital cities are projected to require their first repair in the 22nd century under the RCP4.5 scenario (>80 years). Based on the findings in

Table 13, the RPC8.5 scenario shows a significant decrease in the time to repair when compared to the RCP4.5 scenario. For instance, cities such as Stockholm and Riga have seen a decrease from over 100 years in RCP4.5 to 46 years. Berlin stands out with the longest projected time until the first repair under RCP8.5, at 70 years relative to 2020, with the first repair expected in 2090, compared to other cities that were projected to require their first repair in the 22nd century under RCP4.5. Notice that for each of the EU-27 capital cities, the total number of expected repairs from the reference year until 2100 does not exceed one.

<table><caption>**Table 13.** Repair year, time to repair and uncertainties due to climate change prediction for old buildings in capital cities.</caption><thead><tr><th rowspan="3">City</th><th colspan="10">RCP4.5</th><th colspan="10">RCP8.5</th></tr><tr><th colspan="4">Repair Year</th><th colspan="4">Time to repair (yr) relative to 2020</th><th colspan="4">Repair Year</th><th colspan="4">Time to repair (yr) relative to 2020</th></tr><tr><th>μ-2σ</th><th>μ</th><th>μ+2σ</th><th>μ-2σ</th><th>μ</th><th>μ+2σ</th><th>μ-2σ</th><th>μ</th><th>μ+2σ</th><th>μ-2σ</th><th>μ</th><th>μ+2σ</th><th>μ-2σ</th><th>μ</th><th>μ+2σ</th></tr></thead><tbody><tr><td>Amsterdam</td><td>&gt;2100</td><td>&gt;2100</td><td>&gt;2100</td><td>&gt;80</td><td>&gt;80</td><td>&gt;80</td><td>2084</td><td>2081</td><td>2079</td><td>64</td><td>61</td><td>59</td><td></td><td></td><td></td></tr><tr><td>Athens</td><td>2089</td><td>2078</td><td>2070</td><td>69</td><td>58</td><td>50</td><td>2060</td><td>2056</td><td>2054</td><td>40</td><td>36</td><td>34</td><td></td><td></td><td></td></tr><tr><td>Berlin</td><td>&gt;2100</td><td>&gt;2100</td><td>&gt;2100</td><td>&gt;80</td><td>&gt;80</td><td>&gt;80</td><td>2093</td><td>2090</td><td>2087</td><td>73</td><td>70</td><td>67</td><td></td><td></td><td></td></tr><tr><td>Bratislava</td><td>&gt;2100</td><td>&gt;2100</td><td>&gt;2100</td><td>&gt;80</td><td>&gt;80</td><td>&gt;80</td><td>2080</td><td>2077</td><td>2075</td><td>60</td><td>57</td><td>55</td><td></td><td></td><td></td></tr><tr><td>Brussels</td><td>&gt;2100</td><td>&gt;2100</td><td>&gt;2100</td><td>&gt;80</td><td>&gt;80</td><td>&gt;80</td><td>2080</td><td>2078</td><td>2076</td><td>60</td><td>58</td><td>56</td><td></td><td></td><td></td></tr><tr><td>Bucharest</td><td>&gt;2100</td><td>&gt;2100</td><td>&gt;2100</td><td>&gt;80</td><td>&gt;80</td><td>&gt;80</td><td>2079</td><td>2075</td><td>2072</td><td>59</td><td>55</td><td>52</td><td></td><td></td><td></td></tr><tr><td>Budapest</td><td>&gt;2100</td><td>&gt;2100</td><td>&gt;2100</td><td>&gt;80</td><td>&gt;80</td><td>&gt;80</td><td>2077</td><td>2074</td><td>2072</td><td>57</td><td>54</td><td>52</td><td></td><td></td><td></td></tr><tr><td>Copenhagen</td><td>2100</td><td>2093</td><td>2083</td><td>80</td><td>73</td><td>63</td><td>2063</td><td>2061</td><td>2059</td><td>43</td><td>41</td><td>39</td><td></td><td></td><td></td></tr><tr><td>Dublin</td><td>&gt;2100</td><td>&gt;2100</td><td>&gt;2100</td><td>&gt;80</td><td>&gt;80</td><td>&gt;80</td><td>2086</td><td>2083</td><td>2080</td><td>66</td><td>63</td><td>60</td><td></td><td></td><td></td></tr><tr><td>Helsinki</td><td>&gt;2100</td><td>&gt;2100</td><td>&gt;2100</td><td>&gt;80</td><td>&gt;80</td><td>&gt;80</td><td>2072</td><td>2069</td><td>2066</td><td>52</td><td>49</td><td>46</td><td></td><td></td><td></td></tr><tr><td>Lisbon</td><td>2081</td><td>2075</td><td>2071</td><td>61</td><td>55</td><td>51</td><td>2057</td><td>2056</td><td>2055</td><td>37</td><td>36</td><td>35</td><td></td><td></td><td></td></tr><tr><td>Ljubljana</td><td>&gt;2100</td><td>&gt;2100</td><td>&gt;2100</td><td>&gt;80</td><td>&gt;80</td><td>&gt;80</td><td>2080</td><td>2077</td><td>2074</td><td>60</td><td>57</td><td>54</td><td></td><td></td><td></td></tr><tr><td>Luxembourg</td><td>&gt;2100</td><td>&gt;2100</td><td>&gt;2100</td><td>&gt;80</td><td>&gt;80</td><td>&gt;80</td><td>2084</td><td>2081</td><td>2078</td><td>64</td><td>61</td><td>58</td><td></td><td></td><td></td></tr><tr><td>Madrid</td><td>&gt;2100</td><td>2094</td><td>2084</td><td>&gt;80</td><td>74</td><td>64</td><td>2063</td><td>2061</td><td>2058</td><td>43</td><td>41</td><td>38</td><td></td><td></td><td></td></tr><tr><td>Nicosia</td><td>2077</td><td>2070</td><td>2066</td><td>57</td><td>50</td><td>46</td><td>2056</td><td>2054</td><td>2051</td><td>36</td><td>34</td><td>31</td><td></td><td></td><td></td></tr><tr><td>Paris</td><td>&gt;2100</td><td>&gt;2100</td><td>&gt;2100</td><td>&gt;80</td><td>&gt;80</td><td>&gt;80</td><td>2085</td><td>2082</td><td>2079</td><td>65</td><td>62</td><td>59</td><td></td><td></td><td></td></tr><tr><td>Prague</td><td>&gt;2100</td><td>&gt;2100</td><td>&gt;2100</td><td>&gt;80</td><td>&gt;80</td><td>&gt;80</td><td>2084</td><td>2081</td><td>2078</td><td>64</td><td>61</td><td>58</td><td></td><td></td><td></td></tr><tr><td>Riga</td><td>&gt;2100</td><td>&gt;2100</td><td>&gt;2100</td><td>&gt;80</td><td>&gt;80</td><td>&gt;80</td><td>2069</td><td>2066</td><td>2063</td><td>49</td><td>46</td><td>43</td><td></td><td></td><td></td></tr><tr><td>Rome</td><td>&gt;2100</td><td>2098</td><td>2091</td><td>&gt;80</td><td>78</td><td>71</td><td>2064</td><td>2062</td><td>2060</td><td>44</td><td>42</td><td>40</td><td></td><td></td><td></td></tr><tr><td>Sofia</td><td>&gt;2100</td><td>&gt;2100</td><td>&gt;2100</td><td>&gt;80</td><td>&gt;80</td><td>&gt;80</td><td>2081</td><td>2077</td><td>2073</td><td>61</td><td>57</td><td>53</td><td></td><td></td><td></td></tr><tr><td>Stockholm</td><td>&gt;2100</td><td>&gt;2100</td><td>&gt;2100</td><td>&gt;80</td><td>&gt;80</td><td>&gt;80</td><td>2068</td><td>2066</td><td>2064</td><td>48</td><td>46</td><td>44</td><td></td><td></td><td></td></tr><tr><td>Tallinn</td><td>&gt;2100</td><td>&gt;2100</td><td>&gt;2100</td><td>&gt;80</td><td>&gt;80</td><td>&gt;80</td><td>2071</td><td>2068</td><td>2064</td><td>51</td><td>48</td><td>44</td><td></td><td></td><td></td></tr><tr><td>Valletta</td><td>2081</td><td>2072</td><td>2065</td><td>61</td><td>52</td><td>45</td><td>2057</td><td>2054</td><td>2051</td><td>37</td><td>34</td><td>31</td><td></td><td></td><td></td></tr><tr><td>Vienna</td><td>&gt;2100</td><td>&gt;2100</td><td>&gt;2100</td><td>&gt;80</td><td>&gt;80</td><td>&gt;80</td><td>2079</td><td>2076</td><td>2074</td><td>59</td><td>56</td><td>54</td><td></td><td></td><td></td></tr><tr><td>Vilnius</td><td>&gt;2100</td><td>&gt;2100</td><td>&gt;2100</td><td>&gt;80</td><td>&gt;80</td><td>&gt;80</td><td>2071</td><td>2068</td><td>2065</td><td>51</td><td>48</td><td>45</td><td></td><td></td><td></td></tr><tr><td>Warsaw</td><td>&gt;2100</td><td>&gt;2100</td><td>&gt;2100</td><td>&gt;80</td><td>&gt;80</td><td>&gt;80</td><td>2087</td><td>2084</td><td>2081</td><td>67</td><td>64</td><td>61</td><td></td><td></td><td></td></tr><tr><td>Zagreb</td><td>&gt;2100</td><td>&gt;2100</td><td>&gt;2100</td><td>&gt;80</td><td>&gt;80</td><td>&gt;80</td><td>2078</td><td>2075</td><td>2072</td><td>58</td><td>55</td><td>52</td><td></td><td></td><td></td></tr></tbody></table>

<figure><img src="image_47.png" /></figure>

Time to repair (yr) relative to 2020

Source: Developed by authors.
Figure 34 displays the distribution of the time intervals relative to 2020, after the first initiation of corrosion in the EU Member States. The length of the interval before the first need for repair is indicated with numbers in the bars, while the percentage of the buildings to repair is shown in the cells in the right-side of the graph for each scenario. The distribution behind the Figure led to the conclusion that, under both RCPs the time to repair for all recent buildings is after the year 2100. For this reason, the percentage of the buildings starting corrosion before 2100 is contributed by the group of the 'old' buildings.

As shown in the left part of Figure 34, the results for the RCP4.5 scenario indicate that, in median terms, most of the countries where a considerable part of the building stock will need repairs due to corrosion during the 21st century, are situated in southern Europe. They are Cyprus, Greece, Italy, Malta, Portugal, and Spain. However, one should note that also Denmark and Sweden might experience the same issue.

<figure><img src="image_46.png" /><figcaption>**Figure 34.** Distribution of the repair time relative intervals relative to 2020 since 2100 in the EU-27 Member States, considering the percentage of buildings starting corrosion before 2100. On the right, the RCP4.5 scenario; on the left, the RCP8.5 scenario.</figcaption></figure>

On the other hand, the results for the RCP8.5 scenario clearly present four distinct clusters in the distribution of the median time to repair in Europe, as shown in Figure 34, left side but also in Table 14. The first cluster comprises the southern countries where most of the building stock shows the shortest time span until the first repair (up to 40 years and between 40 and 50 years). There is another cluster in the northern part of Europe, where most of the building stock exhibits intervals of time to first repair mostly within the range of 40 to 50
Figure 34 displays the distribution of the time intervals relative to 2020, after the first initiation of corrosion in the EU Member States. The length of the interval before the first need for repair is indicated with numbers in the bars, while the percentage of the buildings to repair is shown in the cells in the right-side of the graph for each scenario. The distribution behind the Figure led to the conclusion that, under both RCPs the time to repair for all recent buildings is after the year 2100. For this reason, the percentage of the buildings starting corrosion before 2100 is contributed by the group of the 'old' buildings.

As shown in the left part of Figure 34, the results for the RCP4.5 scenario indicate that, in median terms, most of the countries where a considerable part of the building stock will need repairs due to corrosion during the 21st century, are situated in southern Europe. They are Cyprus, Greece, Italy, Malta, Portugal, and Spain. However, one should note that also Denmark and Sweden might experience the same issue.

<figure><img src="image_48.png" /><figcaption>**Figure 34.** Distribution of the repair time relative intervals relative to 2020 since 2100 in the EU-27 Member States, considering the percentage of buildings starting corrosion before 2100. On the right, the RCP4.5 scenario; on the left, the RCP8.5 scenario.</figcaption></figure>

On the other hand, the results for the RCP8.5 scenario clearly present four distinct clusters in the distribution of the median time to repair in Europe, as shown in Figure 34, left side but also in Table 14. The first cluster comprises the southern countries where most of the building stock shows the shortest time span until the first repair (up to 40 years and between 40 and 50 years). There is another cluster in the northern part of Europe, where most of the building stock exhibits intervals of time to first repair mostly within the range of 40 to 50
years, with some buildings needing repair in the next 50 to 60 years. The middle European cluster is further subdivided into two parts. In the first subdivision, most of the building stock in central-eastern European countries is expected to require repairs approximately 10 years earlier (within the range of 50 to 60 years) than in central-western European countries (within the range of 60 to 70 years).

Table 14 presents the distribution of the percentage of the buildings needing repair over the time until 2100. Notice that the distribution of the corrosion onset over a period of time (not all buildings at the same time), as shown in Table 14, is attributed mainly to the variation of the temperature projections within the country's territory. Notice as well that the time for onset of corrosion for the capital cities may not coincide with the time for onset of the respective country due to the variation of the temperature projections within the country's territory. In addition, as explained in section 6.2, the discrepancy between the results evaluated at a NUTS 3 level and for the capital cities can be attributed to various factors, including the consideration of the number of the buildings for NUTS and the capital city, along with the range of temperature variations within each NUT, which may encompass values differing from the temperature values accounted for the individual capital city.

<table><caption>**Table 14.** Distribution of median time to repair relative to the year 2020, and the percentage of the buildings to repair in time intervals, in the EU Member States; right RCP4.5 scenario (green colour); left RCP8.5 scenario (blue colour).</caption><caption>Time to repair (years) / % of buildings to repair in a time interval</caption><thead><tr><th rowspan="2">Scenario</th><th colspan="6">RCP4.5</th><th colspan="6">RCP8.5</th></tr><tr><th>Over 80</th><th>70 to 80</th><th>60 to 70</th><th>50 to 60</th><th>40 to 50</th><th>Up to 40</th><th>Over 80</th><th>70 to 80</th><th>60 to 70</th><th>50 to 60</th><th>40 to 50</th><th>Up to 40</th></tr></thead><tbody><tr><td>Austria</td><td>100%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>12%</td><td>40%</td><td>25%</td><td>23%</td><td>0%</td><td>0%</td></tr><tr><td>Belgium</td><td>100%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>2%</td><td>16%</td><td>82%</td><td>0%</td><td>0%</td></tr><tr><td>Bulgaria</td><td>100%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>1%</td><td>4%</td><td>29%</td><td>54%</td><td>12%</td><td>0%</td></tr><tr><td>Croatia</td><td>99%</td><td>1%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>1%</td><td>9%</td><td>74%</td><td>16%</td><td>0%</td></tr><tr><td>Cyprus</td><td>23%</td><td>8%</td><td>11%</td><td>41%</td><td>17%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>3%</td><td>26%</td><td>71%</td></tr><tr><td>Czechia</td><td>100%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>2%</td><td>31%</td><td>67%</td><td>0%</td><td>0%</td><td>0%</td></tr><tr><td>Denmark</td><td>34%</td><td>66%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>28%</td><td>71%</td><td>0%</td></tr><tr><td>Estonia</td><td>100%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>31%</td><td>69%</td><td>0%</td></tr><tr><td>Finland</td><td>100%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>2%</td><td>28%</td><td>64%</td><td>6%</td><td>0%</td></tr><tr><td>France</td><td>100%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>3%</td><td>15%</td><td>58%</td><td>24%</td><td>0%</td><td>0%</td></tr><tr><td>Germany</td><td>100%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>14%</td><td>42%</td><td>44%</td><td>0%</td><td>0%</td><td>0%</td></tr><tr><td>Greece</td><td>62%</td><td>9%</td><td>4%</td><td>25%</td><td>0%</td><td>0%</td><td>25%</td><td>0%</td><td>1%</td><td>15%</td><td>29%</td><td>31%</td></tr><tr><td>Hungary</td><td>100%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>8%</td><td>0%</td><td>8%</td><td>84%</td><td>0%</td><td>0%</td></tr><tr><td>Ireland</td><td>100%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>39%</td><td>61%</td><td>0%</td><td>0%</td><td>0%</td></tr><tr><td>Italy</td><td>73%</td><td>11%</td><td>11%</td><td>4%</td><td>1%</td><td>0%</td><td>1%</td><td>2%</td><td>7%</td><td>27%</td><td>47%</td><td>17%</td></tr><tr><td>Latvia</td><td>100%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>26%</td><td>74%</td><td>0%</td></tr><tr><td>Lithuania</td><td>100%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>34%</td><td>66%</td><td>0%</td></tr><tr><td>Luxembourg</td><td>100%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>18%</td><td>82%</td><td>1%</td><td>0%</td><td>0%</td></tr><tr><td>Malta</td><td>70%</td><td>0%</td><td>0%</td><td>30%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>70%</td><td>30%</td></tr><tr><td>Netherlands</td><td>100%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>3%</td><td>97%</td><td>0%</td><td>0%</td><td>0%</td></tr><tr><td>Poland</td><td>100%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>1%</td><td>40%</td><td>58%</td><td>0%</td><td>0%</td><td>0%</td></tr><tr><td>Portugal</td><td>33%</td><td>19%</td><td>20%</td><td>28%</td><td>0%</td><td>0%</td><td>4%</td><td>0%</td><td>0%</td><td>1%</td><td>47%</td><td>48%</td></tr><tr><td>Romania</td><td>100%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>18%</td><td>9%</td><td>27%</td><td>46%</td><td>0%</td><td>0%</td></tr><tr><td>Slovakia</td><td>100%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>11%</td><td>57%</td><td>32%</td><td>0%</td><td>0%</td></tr><tr><td>Slovenia</td><td>100%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>9%</td><td>40%</td><td>51%</td><td>0%</td><td>0%</td></tr><tr><td>Spain</td><td>65%</td><td>10%</td><td>10%</td><td>7%</td><td>8%</td><td>0%</td><td>36%</td><td>0%</td><td>3%</td><td>9%</td><td>25%</td><td>27%</td></tr><tr><td>Sweden</td><td>95%</td><td>5%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>1%</td><td>7%</td><td>30%</td><td>61%</td><td>0%</td></tr></tbody></table>

Source: Developed by authors.

<footnote n="1">¹ Note: In bold black colour, maximum values of the selected range by column.</footnote>
years, with some buildings needing repair in the next 50 to 60 years. The middle European cluster is further subdivided into two parts. In the first subdivision, most of the building stock in central-eastern European countries is expected to require repairs approximately 10 years earlier (within the range of 50 to 60 years) than in central-western European countries (within the range of 60 to 70 years).

Table 14 presents the distribution of the percentage of the buildings needing repair over the time until 2100. Notice that the distribution of the corrosion onset over a period of time (not all buildings at the same time), as shown in Table 14, is attributed mainly to the variation of the temperature projections within the country's territory. Notice as well that the time for onset of corrosion for the capital cities may not coincide with the time for onset of the respective country due to the variation of the temperature projections within the country's territory. In addition, as explained in section 6.2, the discrepancy between the results evaluated at a NUTS 3 level and for the capital cities can be attributed to various factors, including the consideration of the number of the buildings for NUTS and the capital city, along with the range of temperature variations within each NUT, which may encompass values differing from the temperature values accounted for the individual capital city.

<table><caption>**Table 14.** Distribution of median time to repair relative to the year 2020, and the percentage of the buildings to repair in time intervals, in the EU Member States; right RCP4.5 scenario (green colour); left RCP8.5 scenario (blue colour).</caption><caption>Time to repair (years) / % of buildings to repair in a time interval</caption><thead><tr><th rowspan="2">Scenario</th><th colspan="6">RCP4.5</th><th colspan="6">RCP8.5</th></tr><tr><th>Over 80</th><th>70 to 80</th><th>60 to 70</th><th>50 to 60</th><th>40 to 50</th><th>Up to 40</th><th>Over 80</th><th>70 to 80</th><th>60 to 70</th><th>50 to 60</th><th>40 to 50</th><th>Up to 40</th></tr></thead><tbody><tr><td>Austria</td><td>100%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>12%</td><td>40%</td><td>25%</td><td>23%</td><td>0%</td><td>0%</td></tr><tr><td>Belgium</td><td>100%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>2%</td><td>16%</td><td>82%</td><td>0%</td><td>0%</td></tr><tr><td>Bulgaria</td><td>100%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>1%</td><td>4%</td><td>29%</td><td>54%</td><td>12%</td><td>0%</td></tr><tr><td>Croatia</td><td>99%</td><td>1%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>1%</td><td>9%</td><td>74%</td><td>16%</td><td>0%</td></tr><tr><td>Cyprus</td><td>23%</td><td>8%</td><td>11%</td><td>41%</td><td>17%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>3%</td><td>26%</td><td>71%</td></tr><tr><td>Czechia</td><td>100%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>2%</td><td>31%</td><td>67%</td><td>0%</td><td>0%</td><td>0%</td></tr><tr><td>Denmark</td><td>34%</td><td>66%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>28%</td><td>71%</td><td>0%</td></tr><tr><td>Estonia</td><td>100%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>31%</td><td>69%</td><td>0%</td></tr><tr><td>Finland</td><td>100%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>2%</td><td>28%</td><td>64%</td><td>6%</td><td>0%</td></tr><tr><td>France</td><td>100%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>3%</td><td>15%</td><td>58%</td><td>24%</td><td>0%</td><td>0%</td></tr><tr><td>Germany</td><td>100%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>14%</td><td>42%</td><td>44%</td><td>0%</td><td>0%</td><td>0%</td></tr><tr><td>Greece</td><td>62%</td><td>9%</td><td>4%</td><td>25%</td><td>0%</td><td>0%</td><td>25%</td><td>0%</td><td>1%</td><td>15%</td><td>29%</td><td>31%</td></tr><tr><td>Hungary</td><td>100%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>8%</td><td>0%</td><td>8%</td><td>84%</td><td>0%</td><td>0%</td></tr><tr><td>Ireland</td><td>100%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>39%</td><td>61%</td><td>0%</td><td>0%</td><td>0%</td></tr><tr><td>Italy</td><td>73%</td><td>11%</td><td>11%</td><td>4%</td><td>1%</td><td>0%</td><td>1%</td><td>2%</td><td>7%</td><td>27%</td><td>47%</td><td>17%</td></tr><tr><td>Latvia</td><td>100%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>26%</td><td>74%</td><td>0%</td></tr><tr><td>Lithuania</td><td>100%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>34%</td><td>66%</td><td>0%</td></tr><tr><td>Luxembourg</td><td>100%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>18%</td><td>82%</td><td>1%</td><td>0%</td><td>0%</td></tr><tr><td>Malta</td><td>70%</td><td>0%</td><td>0%</td><td>30%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>70%</td><td>30%</td></tr><tr><td>Netherlands</td><td>100%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>3%</td><td>97%</td><td>0%</td><td>0%</td><td>0%</td></tr><tr><td>Poland</td><td>100%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>1%</td><td>40%</td><td>58%</td><td>0%</td><td>0%</td><td>0%</td></tr><tr><td>Portugal</td><td>33%</td><td>19%</td><td>20%</td><td>28%</td><td>0%</td><td>0%</td><td>4%</td><td>0%</td><td>0%</td><td>1%</td><td>47%</td><td>48%</td></tr><tr><td>Romania</td><td>100%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>18%</td><td>9%</td><td>27%</td><td>46%</td><td>0%</td><td>0%</td></tr><tr><td>Slovakia</td><td>100%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>11%</td><td>57%</td><td>32%</td><td>0%</td><td>0%</td></tr><tr><td>Slovenia</td><td>100%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>9%</td><td>40%</td><td>51%</td><td>0%</td><td>0%</td></tr><tr><td>Spain</td><td>65%</td><td>10%</td><td>10%</td><td>7%</td><td>8%</td><td>0%</td><td>36%</td><td>0%</td><td>3%</td><td>9%</td><td>25%</td><td>27%</td></tr><tr><td>Sweden</td><td>95%</td><td>5%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>0%</td><td>1%</td><td>7%</td><td>30%</td><td>61%</td><td>0%</td></tr></tbody></table>

Source: Developed by authors.

<footnote n="1">¹ Note: In bold black colour, maximum values of the selected range by column.</footnote>
Notice that the values of the time to repair are relatively larger than the indicative design working life of buildings and other common structures. The distribution of the corrosion onset over a period of time, as shown in Table 14, is attributed mainly to the variation of the temperature projections within the country's territory. To remind, that EN 1990 'Basis of structural design' defines the design working life as the assumed period for which a structure or part of it is to be used for its intended purpose with anticipated maintenance but without major repair being necessary. The indicative value for building structures is 50 years, while for monumental buildings and bridges is 100 years. However, it is well known that the actual service life of most structures is longer than their design life. The study did not consider the assumption that buildings that have reached the end of their useful life would have been deconstructed or demolished instead of undergoing major repairs. As a result, the final repair costs assessments may be overestimated.

The estimate of the total repair costs, for reinforced concrete buildings, normalized by the time to repair and building area ($C_{T,m}^2$ in €/(year m²) based on equations (12) and (13) is shown in Figure 35. The total normalized repair costs per year and square meter are presented for two climate change scenarios, for old buildings and considering the uncertainties of climate change predictions. As observed in section 6.2, for recent buildings, the risk of corrosion initiation in the 21st century is significantly reduced. Consequently, **the total repair costs for recent buildings are negligible and do not make part of the evaluation of the financial implications of the corrosion due to carbonation in the considered time-span**, Figure 35.

In this study, the analysis considers only one repair during the period from 2020 to 2100 denoted as $C_{T,m}^2$. The costs are higher for the RCP8.5 scenario where the times to repair are shortened due to higher exposure to future climate change conditions. The largest costs correspond to the consideration of uncertainties in climate change predictions ($μ+2σ$).

To estimate the exposed building surface, we consider the number of buildings and their characteristics such as number of stories, average soil surface per building, construction period and respective durability parameters, openings in the façade and lateral load resisting systems. This estimation is detailed in section 3.3. Then, we multiply it with the total normalized costs of repair per square meter and year, as presented in Figure 35, to obtain the annual normalized repair costs (€/year) for the 27 EU Member States shown in Figure 36.

Finally, Figure 37 shows the total repair costs, by the year 2100, due to two climate change scenarios for the 27 EU countries. The costs were aggregated after multiplying the annual normalized repair costs for each building category by the time to repair.

It is worth noting that the utilization of a customised axis scale with growing intervals in Figure 36 and Figure 37 serves to accentuate significant differences in lower values, particularly within the RCP4.5 scenario. However, it is important to acknowledge that no discernible distinctions are apparent in higher values.
Notice that the values of the time to repair are relatively larger than the indicative design working life of buildings and other common structures. The distribution of the corrosion onset over a period of time, as shown in Table 14, is attributed mainly to the variation of the temperature projections within the country's territory. To remind, that EN 1990 'Basis of structural design' defines the design working life as the assumed period for which a structure or part of it is to be used for its intended purpose with anticipated maintenance but without major repair being necessary. The indicative value for building structures is 50 years, while for monumental buildings and bridges is 100 years. However, it is well known that the actual service life of most structures is longer than their design life. The study did not consider the assumption that buildings that have reached the end of their useful life would have been deconstructed or demolished instead of undergoing major repairs. As a result, the final repair costs assessments may be overestimated.

The estimate of the total repair costs, for reinforced concrete buildings, normalized by the time to repair and building area ($C_{T,m}^2$ in €/(year m²) based on equations (12) and (13) is shown in Figure 35. The total normalized repair costs per year and square meter are presented for two climate change scenarios, for old buildings and considering the uncertainties of climate change predictions. As observed in section 6.2, for recent buildings, the risk of corrosion initiation in the 21st century is significantly reduced. Consequently, **the total repair costs for recent buildings are negligible and do not make part of the evaluation of the financial implications of the corrosion due to carbonation in the considered time-span**, Figure 35.

In this study, the analysis considers only one repair during the period from 2020 to 2100 denoted as $C_{T,m}^2$. The costs are higher for the RCP8.5 scenario where the times to repair are shortened due to higher exposure to future climate change conditions. The largest costs correspond to the consideration of uncertainties in climate change predictions ($μ+2σ$).

To estimate the exposed building surface, we consider the number of buildings and their characteristics such as number of stories, average soil surface per building, construction period and respective durability parameters, openings in the façade and lateral load resisting systems. This estimation is detailed in section 3.3. Then, we multiply it with the total normalized costs of repair per square meter and year, as presented in Figure 35, to obtain the annual normalized repair costs (€/year) for the 27 EU Member States shown in Figure 36.

Finally, Figure 37 shows the total repair costs, by the year 2100, due to two climate change scenarios for the 27 EU countries. The costs were aggregated after multiplying the annual normalized repair costs for each building category by the time to repair.

It is worth noting that the utilization of a customised axis scale with growing intervals in Figure 36 and Figure 37 serves to accentuate significant differences in lower values, particularly within the RCP4.5 scenario. However, it is important to acknowledge that no discernible distinctions are apparent in higher values.
<figure><img src="image_47.png" /><figcaption>**Figure 35.** Total normalized repair costs per square meter and year (€/(year m²) for old RC buildings in the EU-27 Member States.</figcaption></figure>
<figure><img src="image_49.png" /><figcaption>**Figure 35.** Total normalized repair costs per square meter and year (€/(year m²) for old RC buildings in the EU-27 Member States.</figcaption></figure>
<figure><img src="image_48.png" /><figcaption>**Figure 36.** Annual normalized repair costs (10⁶ € / year) for old RC buildings in the EU-27 Member States.</figcaption></figure>
<figure><img src="image_50.png" /><figcaption>**Figure 36.** Annual normalized repair costs (10⁶ € / year) for old RC buildings in the EU-27 Member States.</figcaption></figure>
<figure><img src="image_49.png" /><figcaption>**Figure 37.** Total repair costs (10⁹ €) due to climate change induced carbonation for the RC building stock (old buildings) of the EU-27 Member States by the year 2100.</figcaption></figure>
<figure><img src="image_51.png" /><figcaption>**Figure 37.** Total repair costs (10⁹ €) due to climate change induced carbonation for the RC building stock (old buildings) of the EU-27 Member States by the year 2100.</figcaption></figure>
Table 15, provided below, details the projected escalation in total repair costs, measured in billion euro, resulting from climate change-induced carbonation of reinforced concrete (RC) buildings and refers to data presented in Figure 37.

The projected total repair expenditures for European Union Member States (EU-27) by the year 2100 due to carbonation are expected to reach approximately EUR 75.8 billion under the moderate intermediate RCP4.5 climate scenario. This translates to an average of EUR 2.8 billion per country, with an uncertainty range of 17% to 36% attributed to an incomplete understanding of the climate scenarios. In contrast, in the more extreme scenario, RCP8.5, the estimated costs could potentially rise to about EUR 883.4 billion, averaging EUR 32.7 billion per country, with an uncertainty range varying from 3% to 7%.

<table><caption>**Table 15.** Increase in total repair cost by 2100 due to climate change induced carbonation in European countries in billions of Euros, (B€, 10⁹ €).</caption><thead><tr><th rowspan="2">Scenario</th><th colspan="3">RCP4.5</th><th colspan="3">RCP8.5</th></tr><tr><th>μ-2σ</th><th>μ</th><th>μ+2σ</th><th>μ-2σ</th><th>μ</th><th>μ+2σ</th></tr></thead><tbody><tr><td>Country</td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>EU 27 cost</td><td>48.7</td><td>75.8</td><td>88.8</td><td>825.6</td><td>883.4</td><td>906.5</td></tr><tr><td>EU 27 average cost</td><td>1.8</td><td>2.8</td><td>3.3</td><td>30.6</td><td>32.7</td><td>33.6</td></tr><tr><td>Austria</td><td>0.0</td><td>0.0</td><td>0.0</td><td>14.3</td><td>16.3</td><td>16.9</td></tr><tr><td>Belgium</td><td>0.0</td><td>0.0</td><td>0.0</td><td>13.5</td><td>13.5</td><td>13.5</td></tr><tr><td>Bulgaria</td><td>0.0</td><td>0.0</td><td>0.0</td><td>11.0</td><td>11.1</td><td>11.1</td></tr><tr><td>Croatia</td><td>0.0</td><td>0.1</td><td>0.2</td><td>4.2</td><td>4.2</td><td>4.2</td></tr><tr><td>Cyprus</td><td>1.6</td><td>1.7</td><td>1.8</td><td>2.1</td><td>2.1</td><td>2.1</td></tr><tr><td>Czechia</td><td>0.0</td><td>0.0</td><td>0.0</td><td>71.5</td><td>85.3</td><td>87.1</td></tr><tr><td>Denmark</td><td>5.0</td><td>14.2</td><td>15.4</td><td>23.1</td><td>23.1</td><td>23.1</td></tr><tr><td>Estonia</td><td>0.0</td><td>0.0</td><td>0.0</td><td>2.9</td><td>2.9</td><td>2.9</td></tr><tr><td>Finland</td><td>0.0</td><td>0.0</td><td>0.0</td><td>12.8</td><td>12.8</td><td>12.8</td></tr><tr><td>France</td><td>0.0</td><td>0.0</td><td>0.0</td><td>124.8</td><td>131.2</td><td>133.5</td></tr><tr><td>Germany</td><td>0.0</td><td>0.0</td><td>0.0</td><td>98.7</td><td>104.4</td><td>119.1</td></tr><tr><td>Greece</td><td>8.9</td><td>10.7</td><td>12.1</td><td>18.7</td><td>18.7</td><td>18.7</td></tr><tr><td>Hungary</td><td>0.0</td><td>0.0</td><td>0.0</td><td>11.8</td><td>11.8</td><td>11.8</td></tr><tr><td>Ireland</td><td>0.0</td><td>0.0</td><td>0.0</td><td>8.7</td><td>9.0</td><td>9.0</td></tr><tr><td>Italy</td><td>10.2</td><td>17.2</td><td>18.7</td><td>62.6</td><td>63.1</td><td>63.5</td></tr><tr><td>Latvia</td><td>0.0</td><td>0.0</td><td>0.0</td><td>5.3</td><td>5.3</td><td>5.3</td></tr><tr><td>Lithuania</td><td>0.0</td><td>0.0</td><td>0.0</td><td>5.8</td><td>5.8</td><td>5.8</td></tr><tr><td>Luxembourg</td><td>0.0</td><td>0.0</td><td>0.0</td><td>0.9</td><td>0.9</td><td>0.9</td></tr><tr><td>Malta</td><td>0.2</td><td>0.2</td><td>0.9</td><td>0.9</td><td>0.9</td><td>0.9</td></tr><tr><td>Netherlands</td><td>0.0</td><td>0.0</td><td>0.0</td><td>52.9</td><td>52.9</td><td>52.9</td></tr><tr><td>Poland</td><td>0.0</td><td>0.0</td><td>0.0</td><td>176.0</td><td>204.0</td><td>207.1</td></tr><tr><td>Portugal</td><td>11.8</td><td>15.8</td><td>18.4</td><td>20.8</td><td>20.8</td><td>20.8</td></tr><tr><td>Romania</td><td>0.0</td><td>0.0</td><td>0.0</td><td>15.3</td><td>15.6</td><td>15.7</td></tr><tr><td>Slovakia</td><td>0.0</td><td>0.0</td><td>0.0</td><td>11.7</td><td>12.0</td><td>12.0</td></tr><tr><td>Slovenia</td><td>0.0</td><td>0.0</td><td>0.0</td><td>4.6</td><td>4.7</td><td>4.7</td></tr><tr><td>Spain</td><td>11.0</td><td>15.0</td><td>18.0</td><td>29.6</td><td>29.6</td><td>29.6</td></tr><tr><td>Sweden</td><td>0.0</td><td>0.9</td><td>3.4</td><td>21.2</td><td>21.3</td><td>21.3</td></tr></tbody></table>

Source: Developed by authors.

In detail, the analysis reveals that under the intermediate RCP4.5 climate scenario, Italy, Portugal, Spain and Denmark have the highest increase in repair costs for concrete buildings, with Italy's total costs reaching EUR 17.2 billion, followed by Portugal and Spain accounting for EUR 15.8 and EUR 15 billion respectively. Under the severe RCP8.5 scenario, Poland, France, Germany, and the Czechia would face much higher repair costs, with Poland's reaching EUR 204 billion, France - EUR 131.2 billion, Germany - EUR 104.4 billion, and Czechia - EUR 85.3 billion.
Table 15, provided below, details the projected escalation in total repair costs, measured in billion euro, resulting from climate change-induced carbonation of reinforced concrete (RC) buildings and refers to data presented in Figure 37.

**The projected total repair expenditures for European Union Member States (EU-27) by the year 2100 due to carbonation are expected to reach approximately EUR 75.8 billion under the moderate intermediate RCP4.5 climate scenario.** This translates to an average of EUR 2.8 billion per country, with an uncertainty range of 17% to 36% attributed to an incomplete understanding of the climate scenarios. **In contrast, in the more extreme scenario, RCP8.5, the estimated costs could potentially rise to about EUR 883.4 billion,** averaging EUR 32.7 billion per country, with an uncertainty range varying from 3% to 7%.

<table><caption>**Table 15.** Increase in total repair cost by 2100 due to climate change induced carbonation in European countries in billions of Euros, (B€, 10⁹ €).</caption><thead><tr><th rowspan="2">Scenario</th><th colspan="3">RCP4.5</th><th colspan="3">RCP8.5</th></tr><tr><th>μ-2σ</th><th>μ</th><th>μ+2σ</th><th>μ-2σ</th><th>μ</th><th>μ+2σ</th></tr></thead><tbody><tr><td>Country</td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>EU 27 cost</td><td>48.7</td><td>75.8</td><td>88.8</td><td>825.6</td><td>883.4</td><td>906.5</td></tr><tr><td>EU 27 average cost</td><td>1.8</td><td>2.8</td><td>3.3</td><td>30.6</td><td>32.7</td><td>33.6</td></tr><tr><td>Austria</td><td>0.0</td><td>0.0</td><td>0.0</td><td>14.3</td><td>16.3</td><td>16.9</td></tr><tr><td>Belgium</td><td>0.0</td><td>0.0</td><td>0.0</td><td>13.5</td><td>13.5</td><td>13.5</td></tr><tr><td>Bulgaria</td><td>0.0</td><td>0.0</td><td>0.0</td><td>11.0</td><td>11.1</td><td>11.1</td></tr><tr><td>Croatia</td><td>0.0</td><td>0.1</td><td>0.2</td><td>4.2</td><td>4.2</td><td>4.2</td></tr><tr><td>Cyprus</td><td>1.6</td><td>1.7</td><td>1.8</td><td>2.1</td><td>2.1</td><td>2.1</td></tr><tr><td>Czechia</td><td>0.0</td><td>0.0</td><td>0.0</td><td>71.5</td><td>85.3</td><td>87.1</td></tr><tr><td>Denmark</td><td>5.0</td><td>14.2</td><td>15.4</td><td>23.1</td><td>23.1</td><td>23.1</td></tr><tr><td>Estonia</td><td>0.0</td><td>0.0</td><td>0.0</td><td>2.9</td><td>2.9</td><td>2.9</td></tr><tr><td>Finland</td><td>0.0</td><td>0.0</td><td>0.0</td><td>12.8</td><td>12.8</td><td>12.8</td></tr><tr><td>France</td><td>0.0</td><td>0.0</td><td>0.0</td><td>124.8</td><td>131.2</td><td>133.5</td></tr><tr><td>Germany</td><td>0.0</td><td>0.0</td><td>0.0</td><td>98.7</td><td>104.4</td><td>119.1</td></tr><tr><td>Greece</td><td>8.9</td><td>10.7</td><td>12.1</td><td>18.7</td><td>18.7</td><td>18.7</td></tr><tr><td>Hungary</td><td>0.0</td><td>0.0</td><td>0.0</td><td>11.8</td><td>11.8</td><td>11.8</td></tr><tr><td>Ireland</td><td>0.0</td><td>0.0</td><td>0.0</td><td>8.7</td><td>9.0</td><td>9.0</td></tr><tr><td>Italy</td><td>10.2</td><td>17.2</td><td>18.7</td><td>62.6</td><td>63.1</td><td>63.5</td></tr><tr><td>Latvia</td><td>0.0</td><td>0.0</td><td>0.0</td><td>5.3</td><td>5.3</td><td>5.3</td></tr><tr><td>Lithuania</td><td>0.0</td><td>0.0</td><td>0.0</td><td>5.8</td><td>5.8</td><td>5.8</td></tr><tr><td>Luxembourg</td><td>0.0</td><td>0.0</td><td>0.0</td><td>0.9</td><td>0.9</td><td>0.9</td></tr><tr><td>Malta</td><td>0.2</td><td>0.2</td><td>0.9</td><td>0.9</td><td>0.9</td><td>0.9</td></tr><tr><td>Netherlands</td><td>0.0</td><td>0.0</td><td>0.0</td><td>52.9</td><td>52.9</td><td>52.9</td></tr><tr><td>Poland</td><td>0.0</td><td>0.0</td><td>0.0</td><td>176.0</td><td>204.0</td><td>207.1</td></tr><tr><td>Portugal</td><td>11.8</td><td>15.8</td><td>18.4</td><td>20.8</td><td>20.8</td><td>20.8</td></tr><tr><td>Romania</td><td>0.0</td><td>0.0</td><td>0.0</td><td>15.3</td><td>15.6</td><td>15.7</td></tr><tr><td>Slovakia</td><td>0.0</td><td>0.0</td><td>0.0</td><td>11.7</td><td>12.0</td><td>12.0</td></tr><tr><td>Slovenia</td><td>0.0</td><td>0.0</td><td>0.0</td><td>4.6</td><td>4.7</td><td>4.7</td></tr><tr><td>Spain</td><td>11.0</td><td>15.0</td><td>18.0</td><td>29.6</td><td>29.6</td><td>29.6</td></tr><tr><td>Sweden</td><td>0.0</td><td>0.9</td><td>3.4</td><td>21.2</td><td>21.3</td><td>21.3</td></tr></tbody></table>

Source: Developed by authors.

In detail, the analysis reveals that under the intermediate RCP4.5 climate scenario, Italy, Portugal, Spain and Denmark have the highest increase in repair costs for concrete buildings, with Italy's total costs reaching EUR 17.2 billion, followed by Portugal and Spain accounting for EUR 15.8 and EUR 15 billion respectively. Under the severe RCP8.5 scenario, Poland, France, Germany, and the Czechia would face much higher repair costs, with Poland's reaching EUR 204 billion, France - EUR 131.2 billion, Germany - EUR 104.4 billion, and Czechia - EUR 85.3 billion.
As seen in Table 16 and in Table 17, the annual reparation costs of climate change-induced corrosion will be EUR 1.2 billion (0.8% of the Gross Domestic Product, GDP<fnref n="80" />) for RCP4.5 scenario, which grows to EUR 14.8 billion (9.3% GDP) for RCP8.5 by 2100, for the entire EU-27, based on the latest available values from 2022 of about EUR 16 billion GDP (Table 17). Poland is expected to see significant annual repair costs for reinforced concrete structures under the RCP8.5 scenario. The highest loss of welfare under the RCP8.5 scenario is predicted for Croatia (0.9% GDP of the country), as showcased in Table 17.

Under the intermediate RCP4.5 scenario, Portugal, Italy, Spain, Denmark, and Greece are forecasted to incur the highest costs. Portugal, in particular, stands out with the highest estimated annual costs of EUR 0.3 billion, amounting to a 0.1% welfare loss per year, highlighting the varying degrees of economic impact that different emission scenarios could have on EU Member States.

<table><caption>**Table 16.** Total repair cost per year (annual repair cost) due to climate change induced carbonation in European countries in billions of euro (B€, 10⁹ €).</caption><thead><tr><th rowspan="2">Scenario</th><th colspan="3">RCP4.5</th><th colspan="3">RCP8.5</th></tr><tr><th>μ-2σ</th><th>μ</th><th>μ+2σ</th><th>μ-2σ</th><th>μ</th><th>μ+2σ</th></tr></thead><tbody><tr><td>Country</td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>EU-27</td><td>0.7</td><td>1.2</td><td>1.5</td><td>13.4</td><td>14.8</td><td>15.9</td></tr><tr><td>Austria</td><td>0.0</td><td>0.0</td><td>0.0</td><td>0.2</td><td>0.3</td><td>0.3</td></tr><tr><td>Belgium</td><td>0.0</td><td>0.0</td><td>0.0</td><td>0.2</td><td>0.2</td><td>0.2</td></tr><tr><td>Bulgaria</td><td>0.0</td><td>0.0</td><td>0.0</td><td>0.2</td><td>0.2</td><td>0.2</td></tr><tr><td>Croatia</td><td>0.0</td><td>0.0</td><td>0.0</td><td>0.1</td><td>0.1</td><td>0.1</td></tr><tr><td>Cyprus</td><td>0.0</td><td>0.0</td><td>0.0</td><td>0.1</td><td>0.1</td><td>0.1</td></tr><tr><td>Czechia</td><td>0.0</td><td>0.0</td><td>0.0</td><td>1.0</td><td>1.3</td><td>1.4</td></tr><tr><td>Denmark</td><td>0.1</td><td>0.2</td><td>0.2</td><td>0.5</td><td>0.5</td><td>0.5</td></tr><tr><td>Estonia</td><td>0.0</td><td>0.0</td><td>0.0</td><td>0.1</td><td>0.1</td><td>0.1</td></tr><tr><td>Finland</td><td>0.0</td><td>0.0</td><td>0.0</td><td>0.2</td><td>0.2</td><td>0.2</td></tr><tr><td>France</td><td>0.0</td><td>0.0</td><td>0.0</td><td>1.9</td><td>2.1</td><td>2.2</td></tr><tr><td>Germany</td><td>0.0</td><td>0.0</td><td>0.0</td><td>1.4</td><td>1.5</td><td>1.7</td></tr><tr><td>Greece</td><td>0.1</td><td>0.2</td><td>0.2</td><td>0.4</td><td>0.4</td><td>0.5</td></tr><tr><td>Hungary</td><td>0.0</td><td>0.0</td><td>0.0</td><td>0.2</td><td>0.2</td><td>0.2</td></tr><tr><td>Ireland</td><td>0.0</td><td>0.0</td><td>0.0</td><td>0.1</td><td>0.1</td><td>0.1</td></tr><tr><td>Italy</td><td>0.1</td><td>0.3</td><td>0.3</td><td>1.3</td><td>1.3</td><td>1.4</td></tr><tr><td>Latvia</td><td>0.0</td><td>0.0</td><td>0.0</td><td>0.1</td><td>0.1</td><td>0.1</td></tr><tr><td>Lithuania</td><td>0.0</td><td>0.0</td><td>0.0</td><td>0.1</td><td>0.1</td><td>0.1</td></tr><tr><td>Luxembourg</td><td>0.0</td><td>0.0</td><td>0.0</td><td>0.0</td><td>0.0</td><td>0.0</td></tr><tr><td>Malta</td><td>0.0</td><td>0.0</td><td>0.0</td><td>0.0</td><td>0.0</td><td>0.0</td></tr><tr><td>Netherlands</td><td>0.0</td><td>0.0</td><td>0.0</td><td>0.8</td><td>0.9</td><td>0.9</td></tr><tr><td>Poland</td><td>0.0</td><td>0.0</td><td>0.0</td><td>2.5</td><td>3.0</td><td>3.1</td></tr><tr><td>Portugal</td><td>0.2</td><td>0.3</td><td>0.3</td><td>0.5</td><td>0.5</td><td>0.5</td></tr><tr><td>Romania</td><td>0.0</td><td>0.0</td><td>0.0</td><td>0.2</td><td>0.3</td><td>0.3</td></tr><tr><td>Slovakia</td><td>0.0</td><td>0.0</td><td>0.0</td><td>0.2</td><td>0.2</td><td>0.2</td></tr><tr><td>Slovenia</td><td>0.0</td><td>0.0</td><td>0.0</td><td>0.1</td><td>0.1</td><td>0.1</td></tr><tr><td>Spain</td><td>0.2</td><td>0.2</td><td>0.3</td><td>0.7</td><td>0.7</td><td>0.7</td></tr><tr><td>Sweden</td><td>0.0</td><td>0.0</td><td>0.0</td><td>0.4</td><td>0.4</td><td>0.4</td></tr></tbody></table>

Source: Developed by authors.

<footnote n="80">⁸⁰ This study refers the GDP data available at the time of the project development, and extracted from extracted on 27/10/2023 19:35:40 from [ESTAT, https://ec.europa.eu/eurostat/datab browser/view/tipsau10/default/table?lang=en], that is correspondent to year 2022. Values for Europe and the EU-27 Member States are presented in Table 17.</footnote>
As seen in Table 16 and in Table 17, the annual reparation costs of climate change-induced corrosion will be EUR 1.2 billion (0.8% of the Gross Domestic Product, GDP<fnref n="80" />) for RCP4.5 scenario, which grows to EUR 14.8 billion (9.3% GDP) for RCP8.5 by 2100, for the entire EU-27, based on the latest available values from 2022 of about EUR 16 billion GDP (Table 17). Poland is expected to see significant annual repair costs for reinforced concrete structures under the RCP8.5 scenario. The highest loss of welfare under the RCP8.5 scenario is predicted for Croatia (0.9% GDP of the country), as showcased in Table 17.

Under the intermediate RCP4.5 scenario, Portugal, Italy, Spain, Denmark, and Greece are forecasted to incur the highest costs. Portugal, in particular, stands out with the highest estimated annual costs of EUR 0.3 billion, amounting to a 0.1% welfare loss per year, highlighting the varying degrees of economic impact that different emission scenarios could have on EU Member States.

<table><caption>**Table 16.** Total repair cost per year (annual repair cost) due to climate change induced carbonation in European countries in billions of euro (B€, 10⁹ €).</caption><thead><tr><th rowspan="2">Scenario</th><th colspan="3">RCP4.5</th><th colspan="3">RCP8.5</th></tr><tr><th>μ-2σ</th><th>μ</th><th>μ+2σ</th><th>μ-2σ</th><th>μ</th><th>μ+2σ</th></tr></thead><tbody><tr><td>Country</td><td>μ</td><td>μ</td><td>μ</td><td>μ</td><td>μ</td><td>μ</td></tr><tr><td>EU-27</td><td>0.7</td><td>1.2</td><td>1.5</td><td>13.4</td><td>14.8</td><td>15.9</td></tr><tr><td>Austria</td><td>0.0</td><td>0.0</td><td>0.0</td><td>0.2</td><td>0.3</td><td>0.3</td></tr><tr><td>Belgium</td><td>0.0</td><td>0.0</td><td>0.0</td><td>0.2</td><td>0.2</td><td>0.2</td></tr><tr><td>Bulgaria</td><td>0.0</td><td>0.0</td><td>0.0</td><td>0.2</td><td>0.2</td><td>0.2</td></tr><tr><td>Croatia</td><td>0.0</td><td>0.0</td><td>0.0</td><td>0.1</td><td>0.1</td><td>0.1</td></tr><tr><td>Cyprus</td><td>0.0</td><td>0.0</td><td>0.0</td><td>0.1</td><td>0.1</td><td>0.1</td></tr><tr><td>Czechia</td><td>0.0</td><td>0.0</td><td>0.0</td><td>1.0</td><td>1.3</td><td>1.4</td></tr><tr><td>Denmark</td><td>0.1</td><td>0.2</td><td>0.2</td><td>0.5</td><td>0.5</td><td>0.5</td></tr><tr><td>Estonia</td><td>0.0</td><td>0.0</td><td>0.0</td><td>0.1</td><td>0.1</td><td>0.1</td></tr><tr><td>Finland</td><td>0.0</td><td>0.0</td><td>0.0</td><td>0.2</td><td>0.2</td><td>0.2</td></tr><tr><td>France</td><td>0.0</td><td>0.0</td><td>0.0</td><td>1.9</td><td>2.1</td><td>2.2</td></tr><tr><td>Germany</td><td>0.0</td><td>0.0</td><td>0.0</td><td>1.4</td><td>1.5</td><td>1.7</td></tr><tr><td>Greece</td><td>0.1</td><td>0.2</td><td>0.2</td><td>0.4</td><td>0.4</td><td>0.5</td></tr><tr><td>Hungary</td><td>0.0</td><td>0.0</td><td>0.0</td><td>0.2</td><td>0.2</td><td>0.2</td></tr><tr><td>Ireland</td><td>0.0</td><td>0.0</td><td>0.0</td><td>0.1</td><td>0.1</td><td>0.1</td></tr><tr><td>Italy</td><td>0.1</td><td>0.3</td><td>0.3</td><td>1.3</td><td>1.3</td><td>1.4</td></tr><tr><td>Latvia</td><td>0.0</td><td>0.0</td><td>0.0</td><td>0.1</td><td>0.1</td><td>0.1</td></tr><tr><td>Lithuania</td><td>0.0</td><td>0.0</td><td>0.0</td><td>0.1</td><td>0.1</td><td>0.1</td></tr><tr><td>Luxembourg</td><td>0.0</td><td>0.0</td><td>0.0</td><td>0.0</td><td>0.0</td><td>0.0</td></tr><tr><td>Malta</td><td>0.0</td><td>0.0</td><td>0.0</td><td>0.0</td><td>0.0</td><td>0.0</td></tr><tr><td>Netherlands</td><td>0.0</td><td>0.0</td><td>0.0</td><td>0.8</td><td>0.9</td><td>0.9</td></tr><tr><td>Poland</td><td>0.0</td><td>0.0</td><td>0.0</td><td>2.5</td><td>3.0</td><td>3.1</td></tr><tr><td>Portugal</td><td>0.2</td><td>0.3</td><td>0.3</td><td>0.5</td><td>0.5</td><td>0.5</td></tr><tr><td>Romania</td><td>0.0</td><td>0.0</td><td>0.0</td><td>0.2</td><td>0.3</td><td>0.3</td></tr><tr><td>Slovakia</td><td>0.0</td><td>0.0</td><td>0.0</td><td>0.2</td><td>0.2</td><td>0.2</td></tr><tr><td>Slovenia</td><td>0.0</td><td>0.0</td><td>0.0</td><td>0.1</td><td>0.1</td><td>0.1</td></tr><tr><td>Spain</td><td>0.2</td><td>0.2</td><td>0.3</td><td>0.7</td><td>0.7</td><td>0.7</td></tr><tr><td>Sweden</td><td>0.0</td><td>0.0</td><td>0.0</td><td>0.4</td><td>0.4</td><td>0.4</td></tr></tbody></table>

Source: Developed by authors.

<footnote n="80">⁸⁰ This study refers the GDP data available at the time of the project development, and extracted from extracted on 27/10/2023 19:35:40 from [ESTAT, https://ec.europa.eu/eurostat/datab browser/view/tipsau10/default/table?lang=en], that is correspondent to year 2022. Values for Europe and the EU-27 Member States are presented in Table 17.</footnote>
<table><caption>**Table 17.** Annual repair cost, by year 2100, due to climate change-induced carbonation in EU-27 countries, expressed as a percentage of the respective country's GDP (latest value 2022) and number of buildings with corrosion starting before and after 2100.</caption><thead><tr><th rowspan="2">Country</th><th colspan="3">Scenario</th><th colspan="2">RCP4.5</th><th colspan="2">RCP8.5</th></tr><tr><th>GDP*<br>2022<br>(10<sup>9</sup>€)</th><th>Total<br>buildings</th><th>% of<br>GDP</th><th>Buildings<br>with<br>corrosion<br>before<br>2100</th><th>Buildings<br>with<br>corrosion<br>start<br>after<br>2100</th><th>% of<br>GDP</th><th>Buildings<br>with<br>corrosion<br>before<br>2100</th><th>Buildings<br>with<br>corrosion<br>start<br>after<br>2100</th></tr></thead><tbody><tr><td>EU-27</td><td>15,862.3</td><td>30,146,247</td><td>0.01%</td><td>4,222,744</td><td>25,923,502</td><td>0.09%</td><td>27,196,743</td><td>2,444,955</td></tr><tr><td>Austria</td><td>447.2</td><td>417,514</td><td>0.00%</td><td>0</td><td>417,514</td><td>0.06%</td><td>367,093</td><td>50,421</td></tr><tr><td>Belgium</td><td>554.0</td><td>252,141</td><td>0.00%</td><td>0</td><td>252,141</td><td>0.04%</td><td>252,141</td><td>0</td></tr><tr><td>Bulgaria</td><td>85.6</td><td>383,174</td><td>0.00%</td><td>0</td><td>383,174</td><td>0.23%</td><td>380,483</td><td>2,691</td></tr><tr><td>Croatia</td><td>9.0</td><td>350,593</td><td>0.01%</td><td>5,176</td><td>345,418</td><td>0.87%</td><td>350,593</td><td>0</td></tr><tr><td>Cyprus</td><td>27.8</td><td>188,884</td><td>0.12%</td><td>144,774</td><td>44,110</td><td>0.21%</td><td>188,884</td><td>0</td></tr><tr><td>Czechia</td><td>278.2</td><td>1,313,930</td><td>0.00%</td><td>0</td><td>1,313,930</td><td>0.46%</td><td>1,290,341</td><td>23,589</td></tr><tr><td>Denmark</td><td>368.1</td><td>536,885</td><td>0.05%</td><td>352,594</td><td>184,291</td><td>0.14%</td><td>536,885</td><td>0</td></tr><tr><td>Estonia</td><td>36.0</td><td>136,073</td><td>0.00%</td><td>0</td><td>136,073</td><td>0.15%</td><td>136,073</td><td>0</td></tr><tr><td>Finland</td><td>268.6</td><td>625,341</td><td>0.00%</td><td>0</td><td>625,341</td><td>0.09%</td><td>625,341</td><td>0</td></tr><tr><td>France</td><td>2,639.1</td><td>3,244,247</td><td>0.00%</td><td>0</td><td>3,244,247</td><td>0.08%</td><td>3,162,710</td><td>81,537</td></tr><tr><td>Germany</td><td>3,876.8</td><td>4,830,194</td><td>0.00%</td><td>0</td><td>4,830,194</td><td>0.04%</td><td>4,155,928</td><td>674,266</td></tr><tr><td>Greece</td><td>206.6</td><td>2,253,071</td><td>0.08%</td><td>848,613</td><td>1,404,458</td><td>0.22%</td><td>1,699,914</td><td>553,157</td></tr><tr><td>Hungary</td><td>171.8</td><td>627,013</td><td>0.00%</td><td>0</td><td>627,013</td><td>0.12%</td><td>579,415</td><td>47,599</td></tr><tr><td>Ireland</td><td>506.3</td><td>483,615</td><td>0.00%</td><td>0</td><td>483,615</td><td>0.03%</td><td>483,615</td><td>0</td></tr><tr><td>Italy</td><td>1,946.5</td><td>3,788,756</td><td>0.01%</td><td>1,029,294</td><td>2,759,462</td><td>0.07%</td><td>3,738,459</td><td>50,297</td></tr><tr><td>Latvia</td><td>38.9</td><td>226,802</td><td>0.00%</td><td>0</td><td>226,802</td><td>0.27%</td><td>226,802</td><td>0</td></tr><tr><td>Lithuania</td><td>67.4</td><td>299,849</td><td>0.00%</td><td>0</td><td>299,849</td><td>0.17%</td><td>299,849</td><td>0</td></tr><tr><td>Luxembourg</td><td>77.5</td><td>24,826</td><td>0.00%</td><td>0</td><td>24,826</td><td>0.02%</td><td>24,826</td><td>0</td></tr><tr><td>Malta</td><td>17.2</td><td>35,347</td><td>0.02%</td><td>10,625</td><td>24,722</td><td>0.13%</td><td>35,347</td><td>0</td></tr><tr><td>Netherlands</td><td>958.5</td><td>504,548</td><td>0.00%</td><td>0</td><td>504,548</td><td>0.09%</td><td>504,548</td><td>0</td></tr><tr><td>Poland</td><td>705.5</td><td>4,059,918</td><td>0.00%</td><td>0</td><td>4,059,918</td><td>0.42%</td><td>4,007,481</td><td>52,437</td></tr><tr><td>Portugal</td><td>242.3</td><td>1,740,323</td><td>0.11%</td><td>1,171,828</td><td>568,496</td><td>0.22%</td><td>1,669,435</td><td>70,888</td></tr><tr><td>Romania</td><td>282.0</td><td>1,053,660</td><td>0.00%</td><td>0</td><td>1,053,660</td><td>0.09%</td><td>860,762</td><td>192,898</td></tr><tr><td>Slovakia</td><td>109.6</td><td>127,353</td><td>0.00%</td><td>0</td><td>127,353</td><td>0.17%</td><td>127,353</td><td>0</td></tr><tr><td>Slovenia</td><td>57.0</td><td>113,588</td><td>0.00%</td><td>0</td><td>113,588</td><td>0.13%</td><td>113,253</td><td>335</td></tr><tr><td>Spain</td><td>1,346.4</td><td>1,781,685</td><td>0.02%</td><td>625,445</td><td>1,156,240</td><td>0.05%</td><td>1,136,844</td><td>644,841</td></tr><tr><td>Sweden</td><td>538.1</td><td>746,915</td><td>0.00%</td><td>34,396</td><td>712,519</td><td>0.08%</td><td>746,915</td><td>0</td></tr></tbody></table>

**GDP*** Data extracted on 27/10/2023 19:35:40 from [ESTAT]

https://ec.europa.eu/eurostat/datab browser/view/tipsau10/default/table?lang=en

**Dataset** Gross domestic product (GDP) at market prices - annual data [tipsau10]

Source: Developed by authors.

The database of the building stock used in the current study encompasses over 30 million reinforced concrete buildings in the EU Member States, as shown in Table 17.

Under the moderate scenario RCP4.5 more than 4 million buildings will need repair of the corrosion before 2100, and the countries the most impacted would be Portugal and Italy with more than 1 million buildings needing repair, and Greece with 0.85 million buildings. The more extreme scenario RCP8.5 would trigger repair of 27 million buildings across EU before 2100. Under this scenario repair of corrosion will be needed in all EU Member States, and the most impacted countries would be Poland and Germany with over 4 billion buildings to repair, and Italy with 3.7 million buildings.
<table><caption>**Table 17.** Annual repair cost, by year 2100, due to climate change-induced carbonation in EU-27 countries, expressed as a percentage of the respective country's GDP (latest value 2022) and number of buildings with corrosion starting before and after 2100.</caption><thead><tr><th rowspan="2">Country</th><th colspan="3">Scenario</th><th colspan="2">RCP4.5</th><th colspan="2">RCP8.5</th></tr><tr><th>GDP*<br>2022<br>(10<sup>9</sup>€)</th><th>Total<br>buildings</th><th>% of<br>GDP</th><th>Buildings<br>with<br>corrosion<br>before<br>2100</th><th>Buildings<br>with<br>corrosion<br>start<br>after<br>2100</th><th>% of<br>GDP</th><th>Buildings<br>with<br>corrosion<br>before<br>2100</th><th>Buildings<br>with<br>corrosion<br>start<br>after<br>2100</th></tr></thead><tbody><tr><td>EU-27</td><td>15,862.3</td><td>30,146,247</td><td>0.01%</td><td>4,222,744</td><td>25,923,502</td><td>0.09%</td><td>27,196,743</td><td>2,444,955</td></tr><tr><td>Austria</td><td>447.2</td><td>417,514</td><td>0.00%</td><td>0</td><td>417,514</td><td>0.06%</td><td>367,093</td><td>50,421</td></tr><tr><td>Belgium</td><td>554.0</td><td>252,141</td><td>0.00%</td><td>0</td><td>252,141</td><td>0.04%</td><td>252,141</td><td>0</td></tr><tr><td>Bulgaria</td><td>85.6</td><td>383,174</td><td>0.00%</td><td>0</td><td>383,174</td><td>0.23%</td><td>380,483</td><td>2,691</td></tr><tr><td>Croatia</td><td>9.0</td><td>350,593</td><td>0.01%</td><td>5,176</td><td>345,418</td><td>0.87%</td><td>350,593</td><td>0</td></tr><tr><td>Cyprus</td><td>27.8</td><td>188,884</td><td>0.12%</td><td>144,774</td><td>44,110</td><td>0.21%</td><td>188,884</td><td>0</td></tr><tr><td>Czechia</td><td>278.2</td><td>1,313,930</td><td>0.00%</td><td>0</td><td>1,313,930</td><td>0.46%</td><td>1,290,341</td><td>23,589</td></tr><tr><td>Denmark</td><td>368.1</td><td>536,885</td><td>0.05%</td><td>352,594</td><td>184,291</td><td>0.14%</td><td>536,885</td><td>0</td></tr><tr><td>Estonia</td><td>36.0</td><td>136,073</td><td>0.00%</td><td>0</td><td>136,073</td><td>0.15%</td><td>136,073</td><td>0</td></tr><tr><td>Finland</td><td>268.6</td><td>625,341</td><td>0.00%</td><td>0</td><td>625,341</td><td>0.09%</td><td>625,341</td><td>0</td></tr><tr><td>France</td><td>2,639.1</td><td>3,244,247</td><td>0.00%</td><td>0</td><td>3,244,247</td><td>0.08%</td><td>3,162,710</td><td>81,537</td></tr><tr><td>Germany</td><td>3,876.8</td><td>4,830,194</td><td>0.00%</td><td>0</td><td>4,830,194</td><td>0.04%</td><td>4,155,928</td><td>674,266</td></tr><tr><td>Greece</td><td>206.6</td><td>2,253,071</td><td>0.08%</td><td>848,613</td><td>1,404,458</td><td>0.22%</td><td>1,699,914</td><td>553,157</td></tr><tr><td>Hungary</td><td>171.8</td><td>627,013</td><td>0.00%</td><td>0</td><td>627,013</td><td>0.12%</td><td>579,415</td><td>47,599</td></tr><tr><td>Ireland</td><td>506.3</td><td>483,615</td><td>0.00%</td><td>0</td><td>483,615</td><td>0.03%</td><td>483,615</td><td>0</td></tr><tr><td>Italy</td><td>1,946.5</td><td>3,788,756</td><td>0.01%</td><td>1,029,294</td><td>2,759,462</td><td>0.07%</td><td>3,738,459</td><td>50,297</td></tr><tr><td>Latvia</td><td>38.9</td><td>226,802</td><td>0.00%</td><td>0</td><td>226,802</td><td>0.27%</td><td>226,802</td><td>0</td></tr><tr><td>Lithuania</td><td>67.4</td><td>299,849</td><td>0.00%</td><td>0</td><td>299,849</td><td>0.17%</td><td>299,849</td><td>0</td></tr><tr><td>Luxembourg</td><td>77.5</td><td>24,826</td><td>0.00%</td><td>0</td><td>24,826</td><td>0.02%</td><td>24,826</td><td>0</td></tr><tr><td>Malta</td><td>17.2</td><td>35,347</td><td>0.02%</td><td>10,625</td><td>24,722</td><td>0.13%</td><td>35,347</td><td>0</td></tr><tr><td>Netherlands</td><td>958.5</td><td>504,548</td><td>0.00%</td><td>0</td><td>504,548</td><td>0.09%</td><td>504,548</td><td>0</td></tr><tr><td>Poland</td><td>705.5</td><td>4,059,918</td><td>0.00%</td><td>0</td><td>4,059,918</td><td>0.42%</td><td>4,007,481</td><td>52,437</td></tr><tr><td>Portugal</td><td>242.3</td><td>1,740,323</td><td>0.11%</td><td>1,171,828</td><td>568,496</td><td>0.22%</td><td>1,669,435</td><td>70,888</td></tr><tr><td>Romania</td><td>282.0</td><td>1,053,660</td><td>0.00%</td><td>0</td><td>1,053,660</td><td>0.09%</td><td>860,762</td><td>192,898</td></tr><tr><td>Slovakia</td><td>109.6</td><td>127,353</td><td>0.00%</td><td>0</td><td>127,353</td><td>0.17%</td><td>127,353</td><td>0</td></tr><tr><td>Slovenia</td><td>57.0</td><td>113,588</td><td>0.00%</td><td>0</td><td>113,588</td><td>0.13%</td><td>113,253</td><td>335</td></tr><tr><td>Spain</td><td>1,346.4</td><td>1,781,685</td><td>0.02%</td><td>625,445</td><td>1,156,240</td><td>0.05%</td><td>1,136,844</td><td>644,841</td></tr><tr><td>Sweden</td><td>538.1</td><td>746,915</td><td>0.00%</td><td>34,396</td><td>712,519</td><td>0.08%</td><td>746,915</td><td>0</td></tr></tbody></table>

**GDP*** Data extracted on 27/10/2023 19:35:40 from [ESTAT]

https://ec.europa.eu/eurostat/datab browser/view/tipsau10/default/table?lang=en

**Dataset** Gross domestic product (GDP) at market prices - annual data [tipsau10]

Source: Developed by authors.

The database of the building stock used in the current study encompasses over 30 million reinforced concrete buildings in the EU Member States, as shown in Table 17.

Under the moderate scenario RCP4.5 more than 4 million buildings will need repair of the corrosion before 2100, and the countries the most impacted would be Portugal and Italy with more than 1 million buildings needing repair, and Greece with 0.85 million buildings. The more extreme scenario RCP8.5 would trigger repair of 27 million buildings across EU before 2100. Under this scenario repair of corrosion will be needed in all EU Member States, and the most impacted countries would be Poland and Germany with over 4 billion buildings to repair, and Italy with 3.7 million buildings.
# 7 Economic impact of climate change-induced corrosion of the European building stock

## 7.1 Coherence with previous studies on corrosion of reinforced concrete

As concluded by Sousa et al. (2020), corrosion is currently an important concern for the built environment across the world. Peng and Stewart (2016) reported that 36% of concrete buildings in the UK will have to be rebuilt or replaced because of corrosion and that annual losses due to corrosion in the USA amount to about EUR 300 billion, with 40% of this being due to carbonation-induced corrosion. Moreover, Schmitt (2009) estimated the annual cost of corrosion worldwide to exceed $1.8 trillion, or from between 3% to 4% of the Gross Domestic Product of industrialised countries. Therefore, any potential increase of the corrosion induced by climate change effects may lead to substantial maintenance and repair costs.

Stewart et al. (2011), focusing on both carbonation and chlorination, studied the relative change in corrosion initiation and damage risks in Australia, due to enhanced CO₂ levels, temperature and humidity for different exposure classifications of the Australian code AS3600 (2009). They concluded that, in Australia, carbonation-induced damage risks can increase by over 400% by 2100 for inland arid or temperate climates. Damage risks for chloride-induced corrosion can increase by no more than 15%.

Considering the ultimate limit state after corrosion initiation, Bastidas-Arteaga et al. (2013) evaluated the effects of climate change on the failure probability of bridge girders subjected to chloride ingress and climate change. The results indicated that global warming could reduce the time to failure by up to 31% or shorten service life by up to 15 years for moderate levels of aggressiveness.

Bastidas-Arteaga and Stewart (2016) evaluated the cost-effectiveness of adaptation strategies for existing RC structures subjected to chlorination due to splash and tidal exposure. The structures are located in Saint-Nazaire (France) and designed according to different standards.

Current study is the first evaluation of the implications of the climate change induced carbonation on the entire concrete building stock in the EU-27 Member States. While the projections of future climate take into account the dynamics of future emission leading to an increase in the greenhouse gases concentration resulting from socioeconomic growth during the 21st century, a static approach was used for the consideration of building stock data, i.e. the development of the building stock during the 21st century has not been considered. In this static context, which represents the economy of today's, we estimate how the increase in temperatures and CO₂ emissions related to two climate change scenarios would impact the current building stock on a pan-European scale.

Current study highlights that under the RCP8.5 scenario, which involves a temperature rise above 3°C, several countries experience significant repair cost losses, as already shown in Figure 37 and in Table 15, in section 6.3. Among these countries, Poland, France, Germany, Italy and the Czechia face substantial economic losses. Poland being the most severely impacted, as previously mentioned will face losses of around EUR 3 billion per year (0.42% of the country Gross Domestic Product, GDP<fnref n="81" />). It is notable the case of Croatia that exhibits less annual repair cost (EUR 0.1 billion), while the impact on the economy of the country is significantly higher (0.87% GDP<fnref n="81" />). These figures are comparable with the annual carbonation losses in the USA estimated by Peng and Stewart (2016), which amount to approximately 0.5% of the country's GDP before 2016.

To conclude, in order to effectively tackle the growing risks associated with evolving hazards, building adaptation strategies must possess resilience against a multitude of dangers. In all climatic zones, technical advice on climate adaption strategies is essential for both new and existing structures. Effectively reducing climate hazards and involving all stakeholders in improving building performance are two goals of these strategies. Supporting the creation and coherence of EU policies is crucial for their successful execution. First steps have been done by the European Commission Directorate-General for Climate Action reports, which have released technical guidelines at the EU level on adaptation of buildings to climate change (Directorate General for Climate Action, 2023a and 2023b).

<footnote n="81">⁸¹ This study pertains to the GDP data available at the time of the project's development, extracted on 27/10/2023 at 19:35:40 from [ESTAT], which is related to the year 2022.</footnote>
# 7 Economic impact of climate change-induced corrosion of the European building stock

## 7.1 Coherence with previous studies on corrosion of reinforced concrete

As concluded by Sousa et al. (2020), corrosion is currently an important concern for the built environment across the world. Peng and Stewart (2016) reported that 36% of concrete buildings in the UK will have to be rebuilt or replaced because of corrosion and that annual losses due to corrosion in the USA amount to about EUR 300 billion, with 40% of this being due to carbonation-induced corrosion. Moreover, Schmitt (2009) estimated the annual cost of corrosion worldwide to exceed $1.8 trillion, or from between 3% to 4% of the Gross Domestic Product of industrialised countries. Therefore, any potential increase of the corrosion induced by climate change effects may lead to substantial maintenance and repair costs.

Stewart et al. (2011), focusing on both carbonation and chlorination, studied the relative change in corrosion initiation and damage risks in Australia, due to enhanced CO₂ levels, temperature and humidity for different exposure classifications of the Australian code AS3600 (2009). They concluded that, in Australia, carbonation-induced damage risks can increase by over 400% by 2100 for inland arid or temperate climates. Damage risks for chloride-induced corrosion can increase by no more than 15%.

Considering the ultimate limit state after corrosion initiation, Bastidas-Arteaga et al. (2013) evaluated the effects of climate change on the failure probability of bridge girders subjected to chloride ingress and climate change. The results indicated that global warming could reduce the time to failure by up to 31% or shorten service life by up to 15 years for moderate levels of aggressiveness.

Bastidas-Arteaga and Stewart (2016) evaluated the cost-effectiveness of adaptation strategies for existing RC structures subjected to chlorination due to splash and tidal exposure. The structures are located in Saint-Nazaire (France) and designed according to different standards.

Current study is the first evaluation of the implications of the climate change induced carbonation on the entire concrete building stock in the EU-27 Member States. While the projections of future climate take into account the dynamics of future emission leading to an increase in the greenhouse gases concentration resulting from socioeconomic growth during the 21st century, a static approach was used for the consideration of building stock data, i.e. the development of the building stock during the 21st century has not been considered. In this static context, which represents the economy of today's, we estimate how the increase in temperatures and CO₂ emissions related to two climate change scenarios would impact the current building stock on a pan-European scale.

Current study highlights that under the RCP8.5 scenario, which involves a temperature rise above 3°C, several countries experience significant repair cost losses, as already shown in Figure 37 and in Table 15, in section 6.3. Among these countries, Poland, France, Germany, Italy and the Czechia face substantial economic losses. Poland being the most severely impacted, as previously mentioned will face losses of around EUR 3 billion per year (0.42% of the country Gross Domestic Product, GDP<fnref n="81" />). It is notable the case of Croatia that exhibits less annual repair cost (EUR 0.1 billion), while the impact on the economy of the country is significantly higher (0.87% GDP<fnref n="81" />). These figures are comparable with the annual carbonation losses in the USA estimated by Peng and Stewart (2016), which amount to approximately 0.5% of the country's GDP before 2016.

To conclude, in order to effectively tackle the growing risks associated with evolving hazards, building adaptation strategies must possess resilience against a multitude of dangers. In all climatic zones, technical advice on climate adaption strategies is essential for both new and existing structures. Effectively reducing climate hazards and involving all stakeholders in improving building performance are two goals of these strategies. Supporting the creation and coherence of EU policies is crucial for their successful execution. First steps have been done by the European Commission Directorate-General for Climate Action reports, which have released technical guidelines at the EU level on adaptation of buildings to climate change (Directorate General for Climate Action, 2023a and 2023b).

<footnote n="81">⁸¹ This study pertains to the GDP data available at the time of the project's development, extracted on 27/10/2023 at 19:35:40 from [ESTAT], which is related to the year 2022.</footnote>
## 7.2 Compatibility with PESETA IV study findings

The PESETA IV study, as referenced in Feyen et al. (2020), provides a comprehensive analysis of the economic impacts of climate change across various sectors and has been instrumental in comparing the impacts of global warming on static economic scenarios—representing the economy of today—with the effects of climate change in dynamic-economic scenarios. This approach of PESETA IV study allows for differentiation between the influences of climate change and socioeconomic changes on future losses. The current study considers the dynamics of the changing climate but does not account for the regeneration of the building stock due to socioeconomic shifts, which is assumed to remain static over the years.

The regional climate models (RCMs) outputs implemented in PESETA IV have been bias-adjusted following the procedure suggested by Piani (2010) as described in Dosio and Paruolo (2011) using the observational data set EOBSv10 (released in April 2014; Cornes et al., 2018). Beyond the mean temperature, the original dataset also includes minimum and maximum temperature, and precipitation.

PESETA IV study takes into account a common set of climate projections under a moderate mitigation path (RCP4.5) and a high concentration (RCP8.5) trajectory, but they are exploited to derive ensembles under fixed global warming level (GWL) compared to preindustrial era: 1.5°C and 2°C as specific targets agreed in 21st Conference of the Parties in Paris (2015) and 3°C as higher level of warming. Assuming an increase of about 0.7°C for the reference period 1981-2010 against the preindustrial era 1881-1910, it means identifying for each GWL (1.5°C, 2°C, 3°C) the year when a further GWL-0.7°C increase in global warming is reached, compared to the reference period; the 30 year period around that year identifies for each climate simulation the time span to be considered.

Current study is using the same bias-adjusted RCMs and the same observational data set EOBSv10 as in PESETA IV, as described in section 4. According to the results in Table 9, the RCP4.5 scenario projects an increase in the mean annual temperature reaching values of 0.8°C, 1.5°C, and 2.0°C, over 30-years' time intervals, for near (2011-2040 vs 1981-2010), medium (2041-2070), and long-term horizons (2071-2100), respectively (see average values for Europe in Table 9). Conversely, the RCP8.5 scenario projects higher increases of 0.9°C, 2.1°C, and 3.7°C for the same time periods. In that sense, the findings related to the near time horizon could be assumed consistent with a 1.5° GWL under both RCPs; those under RCP4.5 for medium term are close to that for 2.0°C while, medium term under RCP8.5 and long term under RCP4.5 are representative of 3.0° GWL.

The above considerations imply that the repair cost calculated in this study within the time horizon of 2100 for the RCP4.5 and RCP8.5 is compatible with the climate change impacts evaluated by PESETA IV for no mitigation action (RCP8.5) and for the moderate mitigation emissions scenario (RCP4.5). Such a compatibility of the representation of the future climatic conditions allows to enrich the impact categories of PESETA IV with built environment and to quantify this impact with the estimated cost of repair of corroded surfaces.

The PESETA IV research evaluated the economic effects of climate change on the EU and the UK, highlighting the significant welfare losses that southern Europe may experience in the event of varying warming scenarios. The welfare losses were qualified for seven climate impact categories: river floods, coastal floods, agriculture, energy supply, droughts, windstorms and human mortality. As stated in PESETA IV, by 2100, a '3°C rise would result in yearly losses of more than EUR 175 billion (1.38% GDP<fnref n="82" />), with France, Italy, and Spain bearing the brunt of these costs. Under a 2°C scenario the welfare annual loss would be EUR 83 billion/year (0.65% GDP<fnref n="82" />), while restricting warming to 1.5°C would reduce welfare loss to EUR 42 billion/year (0.33% GDP)'. According to the study, the greatest financial effect is caused by heat-related deaths in humans, with losses estimated at EUR 36 billion for a 1.5°C rise, EUR 65 billion for a 2°C rise, and EUR 122 billion for a 3°C rise. The research also assesses other sectoral climate hazards without considering potential actions or adaptation mechanisms, as follows:

* windstorms - windstorm losses will not grow due to climate change. Future economic damage from windstorms will increase due to the size of the economy and consequent higher values of the exposed assets and construction costs. Windstorm annual losses are projected to grow to nearly EUR 7 billion per year in 2050 and to EUR 11.4 billion per year by the end of this century

<footnote n="82">⁸² Welfare loss in PESETA IV study is expressed in € (2015 value) as well as a share (in %) of GDP with the data available at the time of the project implementation.</footnote>
## 7.2 Compatibility with PESETA IV study findings

The PESETA IV study, as referenced in Feyen et al. (2020), provides a comprehensive analysis of the economic impacts of climate change across various sectors and has been instrumental in comparing the impacts of global warming on static economic scenarios—representing the economy of today—with the effects of climate change in dynamic-economic scenarios. This approach of PESETA IV study allows for differentiation between the influences of climate change and socioeconomic changes on future losses. The current study considers the dynamics of the changing climate but does not account for the regeneration of the building stock due to socioeconomic shifts, which is assumed to remain static over the years.

The regional climate models (RCMs) outputs implemented in PESETA IV have been bias-adjusted following the procedure suggested by Piani (2010) as described in Dosio and Paruolo (2011) using the observational data set EOBSv10 (released in April 2014; Cornes et al., 2018). Beyond the mean temperature, the original dataset also includes minimum and maximum temperature, and precipitation.

PESETA IV study takes into account a common set of climate projections under a moderate mitigation path (RCP4.5) and a high concentration (RCP8.5) trajectory, but they are exploited to derive ensembles under fixed global warming level (GWL) compared to preindustrial era: 1.5°C and 2°C as specific targets agreed in 21st Conference of the Parties in Paris (2015) and 3°C as higher level of warming. Assuming an increase of about 0.7°C for the reference period 1981-2010 against the preindustrial era 1881-1910, it means identifying for each GWL (1.5°C, 2°C, 3°C) the year when a further GWL-0.7°C increase in global warming is reached, compared to the reference period; the 30 year period around that year identifies for each climate simulation the time span to be considered.

Current study is using the same bias-adjusted RCMs and the same observational data set EOBSv10 as in PESETA IV, as described in section 4. According to the results in Table 9, the RCP4.5 scenario projects an increase in the mean annual temperature reaching values of 0.8°C, 1.5°C, and 2.0°C, over 30-years' time intervals, for near (2011-2040 vs 1981-2010), medium (2041-2070), and long-term horizons (2071-2100), respectively (see average values for Europe in Table 9). Conversely, the RCP8.5 scenario projects higher increases of 0.9°C, 2.1°C, and 3.7°C for the same time periods. In that sense, the findings related to the near time horizon could be assumed consistent with a 1.5° GWL under both RCPs; those under RCP4.5 for medium term are close to that for 2.0°C while, medium term under RCP8.5 and long term under RCP4.5 are representative of 3.0° GWL.

The above considerations imply that the repair cost calculated in this study within the time horizon of 2100 for the RCP4.5 and RCP8.5 is compatible with the climate change impacts evaluated by PESETA IV for no mitigation action (RCP8.5) and for the moderate mitigation emissions scenario (RCP4.5). Such a compatibility of the representation of the future climatic conditions allows to enrich the impact categories of PESETA IV with built environment and to quantify this impact with the estimated cost of repair of corroded surfaces.

The PESETA IV research evaluated the economic effects of climate change on the EU and the UK, highlighting the significant welfare losses that southern Europe may experience in the event of varying warming scenarios. The welfare losses were qualified for seven climate impact categories: river floods, coastal floods, agriculture, energy supply, droughts, windstorms and human mortality. As stated in PESETA IV, by 2100, a '3°C rise would result in yearly losses of more than EUR 175 billion (1.38% GDP<fnref n="82" />), with France, Italy, and Spain bearing the brunt of these costs. Under a 2°C scenario the welfare annual loss would be EUR 83 billion/year (0.65% GDP<fnref n="82" />), while restricting warming to 1.5°C would reduce welfare loss to EUR 42 billion/year (0.33% GDP)'. According to the study, the greatest financial effect is caused by heat-related deaths in humans, with losses estimated at EUR 36 billion for a 1.5°C rise, EUR 65 billion for a 2°C rise, and EUR 122 billion for a 3°C rise. The research also assesses other sectoral climate hazards without considering potential actions or adaptation mechanisms, as follows:

* windstorms - windstorm losses will not grow due to climate change. Future economic damage from windstorms will increase due to the size of the economy and consequent higher values of the exposed assets and construction costs. Windstorm annual losses are projected to grow to nearly EUR 7 billion per year in 2050 and to EUR 11.4 billion per year by the end of this century

<footnote n="82">⁸² Welfare loss in PESETA IV study is expressed in € (2015 value) as well as a share (in %) of GDP with the data available at the time of the project implementation.</footnote>
* droughts - with 1.5°C global warming the average damages losses from drought would limited to EUR 25 billion per year, but it grows to EUR 45 billion per year with 3°C global warming in 2100

* river and costal floods - EUR 8.5 billion of damages losses with 1.5°C global warming, which increases to EUR 16 billion with 2°C and EUR 40 billion with 3°C global warming for river floods, while costal floods climb from annual damages of EUR 110 billion with climate mitigation at 1.5°C, to annual losses estimated of EUR 238 billion in 2100 with no actions

PESETA IV report predicts that annual damages and losses might rise sharply in the absence of adaptation measures, highlighting the significance of proactive mitigation and adaptation plans to limit economic effects.

Current study evaluates the impact of climate change on the carbonation induced corrosion of reinforced concrete buildings in the Member States of the European Union (EU-27) and thus extends the scope of PESETA IV to evaluation of welfare loss due to damage of building stock. As already mentioned in section 6.3, the annual cost projections from this study presented in Table 15 and Table 16 showcase that the annual reparation costs of the climate change induced corrosion will be EUR 1.2 billion (0.8% of the EU GDP<fnref n="83" />) for 2°C global warming, which grows to EUR 14.8 billion (9.3% EU GDP<fnref n="83" />) for 3°C warming by 2100. In particular, Poland is expected to see a significant annual repair costs for reinforced concrete structures under RCP8.5 scenario. These costs, projected to be EUR 3.0 billion, not only represent 0.4% of the Polish GDP, but also equate to substantial percentages of damages from other climate-related events. Specifically, Poland's repair costs under RCP8.5 are about 26% of the EU and UK's annual windstorm damages, valued at EUR 11.4 billion. This represent also 7% of losses from river floods, estimated at EUR 40 billion, 1% if summed to the coastal floods damages, estimated in total as EUR 278 billion, and 6.6% of the costs due to droughts, which stand at EUR 45 billion, according to the projections of the PESETA IV study.

In essence, the data in Table 16 and in Table 17, when considered alongside the PESETA IV study, accentuates the significant annual economic impacts due to climate change induced carbonation on the economies of the different European countries. It emphasizes the strong need for adaptation and resilient construction practices to manage these impending costs.

## 7.3 Summary of the impact in time, magnitude and welfare loss

Current study provided assessment of the penetration of climate change induced carbonation in the concrete cover of the existing buildings in the EU-27 Member States, estimated the time for on-set of corrosion due to depleting of the cover of the reinforcement, and evaluated the related repair costs and the annual welfare loss as the percentage of the GDP covering the annual repair costs. Figure 37 illustrates the magnitude of these costs in billions of Euros per year, the diameter of the bubble for each country indicates the respective annual welfare loss. Figure 37 also showcases the time(year) when the on-set of the corrosion is predicted and the repair shall take place. The disparities observed in the consequences of the RCP4.5 and RCP8.5 scenarios are notable.

Figure 36 presents the disparities observed in the consequences of the two scenarios considered, RCP4.5 and RCP8.5 and referred to data displayed in Table 16. When comparing the annual repair costs, as a percentage of the latest GDP values in 2022, the analysis reveals that Cyprus, Portugal, and Greece exhibit the highest losses of welfare under RCP 4.5 scenario. For RCP 4.5, countries such as Cyprus, Portugal, and Greece are subjected to a higher impact of potential increases in repair costs (in billions of Euros) on their GDP in percentage terms compared to other countries. Among them, Cyprus and Portugal stand out with the highest mean value of 0.12% and 0.11% of its GDP. In countries like Spain or Demark, although if the repair cost by year is higher does not have as much impact on the country's GDP as in the other countries mentioned.

Under RCP 8.5, Croatia, Czechia and Poland will be subjected to higher impact on the country's GDP, with values reaching 0.87%, 0.46% and 0.42%, respectively. It is notable the case of Croatia that exhibit less annual repair cost with regard the other two countries, while the impact on the economy and GDP of the country is significantly higher (0.87% of the country's GDP). As mentioned previously and it is easy to see in Figure 38 that Poland has

<footnote n="83">⁸³ This study refers the GDP data available at the time of the project development, and extracted from extracted on 27/10/2023 19:35:40 from [ESTAT, https://ec.europa.eu/eurostat/datab browser/view/tipsau10/default/table?lang=en], that is correspondent to year 2022. Values for Europe and the EU-27 Member States are presented in Table 17.</footnote>
* droughts - with 1.5°C global warming the average damages losses from drought would limited to EUR 25 billion per year, but it grows to EUR 45 billion per year with 3°C global warming in 2100

* river and costal floods - EUR 8.5 billion of damages losses with 1.5°C global warming, which increases to EUR 16 billion with 2°C and EUR 40 billion with 3°C global warming for river floods, while costal floods climb from annual damages of EUR 110 billion with climate mitigation at 1.5°C, to annual losses estimated of EUR 238 billion in 2100 with no actions

PESETA IV report predicts that annual damages and losses might rise sharply in the absence of adaptation measures, highlighting the significance of proactive mitigation and adaptation plans to limit economic effects.

Current study evaluates the impact of climate change on the carbonation induced corrosion of reinforced concrete buildings in the Member States of the European Union (EU-27) and thus extends the scope of PESETA IV to evaluation of welfare loss due to damage of building stock. As already mentioned in section 6.3, the annual cost projections from this study presented in Table 15 and Table 16 showcase that the annual reparation costs of the climate change induced corrosion will be EUR 1.2 billion (0.8% of the EU GDP<fnref n="83" />) for 2°C global warming, which grows to EUR 14.8 billion (9.3% EU GDP<fnref n="83" />) for 3°C warming by 2100. In particular, Poland is expected to see a significant annual repair costs for reinforced concrete structures under RCP8.5 scenario. These costs, projected to be EUR 3.0 billion, not only represent 0.4% of the Polish GDP, but also equate to substantial percentages of damages from other climate-related events. Specifically, Poland's repair costs under RCP8.5 are about 26% of the EU and UK's annual windstorm damages, valued at EUR 11.4 billion. This represent also 7% of losses from river floods, estimated at EUR 40 billion, 1% if summed to the coastal floods damages, estimated in total as EUR 278 billion, and 6.6% of the costs due to droughts, which stand at EUR 45 billion, according to the projections of the PESETA IV study.

In essence, the data in Table 16 and in Table 17, when considered alongside the PESETA IV study, accentuates the significant annual economic impacts due to climate change induced carbonation on the economies of the different European countries. It emphasizes the strong need for adaptation and resilient construction practices to manage these impending costs.

## 7.3 Summary of the impact in time, magnitude and welfare loss

Current study provided assessment of the penetration of climate change induced carbonation in the concrete cover of the existing buildings in the EU-27 Member States, estimated the time for on-set of corrosion due to depleting of the cover of the reinforcement, and evaluated the related repair costs and the annual welfare loss as the percentage of the GDP covering the annual repair costs. Figure 37 illustrates the magnitude of these costs in billions of Euros per year, the diameter of the bubble for each country indicates the respective annual welfare loss. Figure 37 also showcases the time(year) when the on-set of the corrosion is predicted and the repair shall take place. The disparities observed in the consequences of the RCP4.5 and RCP8.5 scenarios are notable.

Figure 36 presents the disparities observed in the consequences of the two scenarios considered, RCP4.5 and RCP8.5 and referred to data displayed in Table 16. When comparing the annual repair costs, as a percentage of the latest GDP values in 2022, the analysis reveals that Cyprus, Portugal, and Greece exhibit the highest losses of welfare under RCP 4.5 scenario. For RCP 4.5, countries such as Cyprus, Portugal, and Greece are subjected to a higher impact of potential increases in repair costs (in billions of Euros) on their GDP in percentage terms compared to other countries. Among them, Cyprus and Portugal stand out with the highest mean value of 0.12% and 0.11% of its GDP. In countries like Spain or Demark, although if the repair cost by year is higher does not have as much impact on the country's GDP as in the other countries mentioned.

Under RCP 8.5, Croatia, Czechia and Poland will be subjected to higher impact on the country's GDP, with values reaching 0.87%, 0.46% and 0.42%, respectively. It is notable the case of Croatia that exhibit less annual repair cost with regard the other two countries, while the impact on the economy and GDP of the country is significantly higher (0.87% of the country's GDP). As mentioned previously and it is easy to see in Figure 38 that Poland has

<footnote n="83">⁸³ This study refers the GDP data available at the time of the project development, and extracted from extracted on 27/10/2023 19:35:40 from [ESTAT, https://ec.europa.eu/eurostat/datab browser/view/tipsau10/default/table?lang=en], that is correspondent to year 2022. Values for Europe and the EU-27 Member States are presented in Table 17.</footnote>
a high repair cost by year (i.e. EUR 3.0 billion) starting in the year 2081 with a significant impact on the economy of the country (0.42% of the GDP). Conversely, for countries as France, Germany and Italy although the calculated repair cost by year is above EUR 1.3 billion the impact on the country's GDP is significantly less than for other countries as Latvia, Bulgaria, Greece, Portugal, and Cyprus. These countries surpass 0.20% and reach values of around 0.21% to 0.27% of the GDP, while Slovakia and Lithuania exhibit approximately 0.17% of the country's GDP and Estonia the 0.15%. It is clearly remarkable that although with similar increase in the repair costs by year, some countries would suffer substantial welfare losses due to impacts on their GDP. Besides, looking at Figure 37, countries with a lower annual repair cost (i.e. closer to zero) that have a larger bubble diameter would experience a greater impact on the country's economy even if the repair expenditure is lower than for the other countries. Other countries such as Poland, for example, would have repair cost with a high economic impact in both, the absolute value and the percentage of the GDP.

<figure><img src="image_50.png" /><figcaption>**Figure 38.** Total repair costs by year (billion euro, BE) and percentage impact on GDP by country, analysed in relation to RCP4.5 and RCP8.5 scenarios.</figcaption></figure>

<figure><img src="image_51.png" /></figure>
a high repair cost by year (i.e. EUR 3.0 billion) starting in the year 2081 with a significant impact on the economy of the country (0.42% of the GDP). Conversely, for countries as France, Germany and Italy although the calculated repair cost by year is above EUR 1.3 billion the impact on the country's GDP is significantly less than for other countries as Latvia, Bulgaria, Greece, Portugal, and Cyprus. These countries surpass 0.20% and reach values of around 0.21% to 0.27% of the GDP, while Slovakia and Lithuania exhibit approximately 0.17% of the country's GDP and Estonia the 0.15%. It is clearly remarkable that although with similar increase in the repair costs by year, some countries would suffer substantial welfare losses due to impacts on their GDP. Besides, looking at Figure 37, countries with a lower annual repair cost (i.e. closer to zero) that have a larger bubble diameter would experience a greater impact on the country's economy even if the repair expenditure is lower than for the other countries. Other countries such as Poland, for example, would have repair cost with a high economic impact in both, the absolute value and the percentage of the GDP.

<figure><img src="image_52.png" /><figcaption>**Figure 38.** Total repair costs by year (billion euro, BE) and percentage impact on GDP by country, analysed in relation to RCP4.5 and RCP8.5 scenarios.</figcaption></figure>

<figure><img src="image_53.png" /></figure>
One noteworthy finding from Figure 38 is the variation in the dates at which repairs are initiated among the countries. It is evident that the number of countries impacted by onset of corrosion and the necessity to start repairs long before 2100 would rise substantially under the RCP 8.5 scenario. By 2050, carbonation is already evident in Cyprus and Spain; Italy, Greece, Malta and Portugal will follow between 2052 and 2054. In this scenario, countries like Germany, Poland, and Ireland do not experience the onset of corrosion before 2080. In contrast, in the RCP 4.5 scenario, corrosion is expected to start after 2100 in most countries, while in others, like Spain and Cyprus, the onset is expected sooner in 2062.

In addition, the results presented in section 6.3 show that the projected total repair expenditures for the EU Member States by the year 2100 due to carbonation are expected to reach approximately EUR 75.8 billion under the moderate RCP4.5 climate scenario, averaging EUR 2.8 billion per country. In contrast, in the more extreme scenario, RCP8.5, the estimated costs could potentially rise to about EUR 883.4 billion, averaging EUR 32.7 billion per country.

In summary, our findings underscore the substantial economic burden posed by climate change-induced carbonation on Europe's building stock. The projected increases in repair costs and their impact on GDP further emphasize the need for proactive measures and policies to mitigate the long-term effects of climate change on the European building stock.

To conclude, climate change-induced carbonation of the exposed concrete surfaces might seriously impact the European building stock, which was built according to the design standards of the 20th century. During the second half of 21st century, considerable repair works will be needed to prevent the corrosion, whose cost for the moderate RCP4.5 climate scenario will negatively impact the wellbeing of the population in several EU Member States. For the more extreme climate scenario, RCP8.5, the repair costs will imply welfare loss in almost all Member States.
One noteworthy finding from Figure 38 is the variation in the dates at which repairs are initiated among the countries. It is evident that the number of countries impacted by onset of corrosion and the necessity to start repairs long before 2100 would rise substantially under the RCP 8.5 scenario. By 2050, carbonation is already evident in Cyprus and Spain; Italy, Greece, Malta and Portugal will follow between 2052 and 2054. In this scenario, countries like Germany, Poland, and Ireland do not experience the onset of corrosion before 2080. In contrast, in the RCP 4.5 scenario, corrosion is expected to start after 2100 in most countries, while in others, like Spain and Cyprus, the onset is expected sooner in 2062.

In addition, the results presented in section 6.3 show that the projected total repair expenditures for the EU Member States by the year 2100 due to carbonation are expected to reach approximately EUR 75.8 billion under the moderate RCP4.5 climate scenario, averaging EUR 2.8 billion per country. In contrast, in the more extreme scenario, RCP8.5, the estimated costs could potentially rise to about EUR 883.4 billion, averaging EUR 32.7 billion per country.

In summary, our findings underscore the substantial economic burden posed by climate change-induced carbonation on Europe's building stock. The projected increases in repair costs and their impact on GDP further emphasize the need for proactive measures and policies to mitigate the long-term effects of climate change on the European building stock.

To conclude, climate change-induced carbonation of the exposed concrete surfaces might seriously impact the European building stock, which was built according to the design standards of the 20th century. During the second half of 21st century, considerable repair works will be needed to prevent the corrosion, whose cost for the moderate RCP4.5 climate scenario will negatively impact the wellbeing of the population in several EU Member States. For the more extreme climate scenario, RCP8.5, the repair costs will imply welfare loss in almost all Member States.
# 8 Adaptation strategies

## 8.1 Adaptation measures of new buildings

In addressing the impact of climate change on the corrosion of RC buildings, it is crucial to distinguish between two adaptation strategies. The first refers to measures integrated during the design phase for new structures. The second involves strategies implemented during the service phase to enhance the resilience of existing structures. This differentiation ensures that both new and existing buildings are equipped to withstand the challenges posed by a changing climate. This section focuses on the first while the strategies implemented during the service life of the existing buildings are discussed in the following section.

The process of RC corrosion encompasses two critical phenomena: the initiation of concrete cracking, induced by the by-products of corrosion, and the diminution of the steel's effective cross-sectional area, both manifesting during the propagation stage. The former typically affects aesthetics, while the latter bears implications for structural robustness. The dominant concern between these two phenomena depends on the functionality of the specific structural component. Moreover, the integrity of a structural component, when compromised by corrosion, depends on the applied loads and its inherent structural design. This makes its assessment highly case-specific, presenting challenges for broad generalizations. Hence, in formulating adaptation strategies in response to climate change, it is prudent to prioritize the initiation stage. This stage not only occupies a substantial segment of a structure's service lifespan but also offers the advantage of being less influenced by variables such as applied loads and structural design.

Concrete composition and cover depth play pivotal roles in determining the durability of concrete buildings (Eurocode 2<sup>84</sup>) Their interrelation is clear: denser concrete can reduce the need for a deeper cover and vice versa. When designing a structure, factors such as its typology, intended use, production oversight, and prevailing environmental conditions are integral to setting these parameters. Specifically, as climate evolves, environmental exposure will be factored into these conditions, thus necessitating the European standards (mainly EN 206 and the Eurocodes) to address these shifting challenges.

Increasing the prescribed cover depth emerges as a primary strategy to bolster the durability of new structures impacted by climate change. Augmenting this cover depth, alongside employing a higher-grade concrete and minimizing the water-cement ratio, can yield structures more resilient to corrosion. Adapting the building stock with these measures has stirred considerable debate in the scientific community. Stewart et al. (2012) projected that such measures—including increasing the design cover by up to 8 mm or elevating the concrete compressive strength by a grade—would hike construction costs by 1-3%. Yet, the economic implications at a global scale are intricate. Studies by Bastidas-Arteaga & Stewart (2016) and Stewart & Bastidas-Arteaga (2016) dived deeper, probing the cost-benefit terrain of amplifying the cover thickness to 5 or 10 mm across an array of structural elements and climate scenarios. Their findings suggest that such interventions may not consistently offer a favourable economic return.

Furthermore, the push for a sustainable future in the European policies advocates for blended and alkali-activated (AA) cements over traditional Portland cement (PC). AA cements, particularly AA slag cement which integrates slag as a partial PC substitute, present dual advantages: a denser matrix reducing harmful substance permeability and reduced greenhouse gas emissions (Provis and van Deventer, 2014; Alelweet and Pavia, 2019). While slag cement's use in the USA spans over a century, its complete efficacy as a primary PC alternative remains under investigation. Lastly, when contemplating corrosion-resistant reinforcements, the market offers low carbon, stainless or galvanized steel, and even glass-fiber-reinforced polymer rebars. Yet, transitioning to these alternatives demands a rigorous cost-benefit scrutiny.

## 8.2 Adaptation measures of existing buildings

Adaptation strategies during a structure's service life diverge into two primary categories: reparative actions for damaged RC and protection measures against corrosion. On the reparative side, the initial task is discerning the extent of damage. Based on this, two possible approaches exist: (i) patch repair for located or small affected areas with easy access, and (ii) electromechanical methods, otherwise. Patch repair implies the physical removal of the compromised concrete, including areas behind reinforcement bars, replacing the removed concrete with

<footnote n="84"><sup>84</sup> EN, EN 1992 Eurocode 2: Design of concrete structures, CEN, Brussels, 2005</footnote>
# 8 Adaptation strategies

## 8.1 Adaptation measures of new buildings

In addressing the impact of climate change on the corrosion of RC buildings, it is crucial to distinguish between two adaptation strategies. The first refers to measures integrated during the design phase for new structures. The second involves strategies implemented during the service phase to enhance the resilience of existing structures. This differentiation ensures that both new and existing buildings are equipped to withstand the challenges posed by a changing climate. This section focuses on the first while the strategies implemented during the service life of the existing buildings are discussed in the following section.

The process of RC corrosion encompasses two critical phenomena: the initiation of concrete cracking, induced by the by-products of corrosion, and the diminution of the steel's effective cross-sectional area, both manifesting during the propagation stage. The former typically affects aesthetics, while the latter bears implications for structural robustness. The dominant concern between these two phenomena depends on the functionality of the specific structural component. Moreover, the integrity of a structural component, when compromised by corrosion, depends on the applied loads and its inherent structural design. This makes its assessment highly case-specific, presenting challenges for broad generalizations. Hence, in formulating adaptation strategies in response to climate change, it is prudent to prioritize the initiation stage. This stage not only occupies a substantial segment of a structure's service lifespan but also offers the advantage of being less influenced by variables such as applied loads and structural design.

Concrete composition and cover depth play pivotal roles in determining the durability of concrete buildings (Eurocode 2<sup>84</sup>) Their interrelation is clear: denser concrete can reduce the need for a deeper cover and vice versa. When designing a structure, factors such as its typology, intended use, production oversight, and prevailing environmental conditions are integral to setting these parameters. Specifically, as climate evolves, environmental exposure will be factored into these conditions, thus necessitating the European standards (mainly EN 206 and the Eurocodes) to address these shifting challenges.

Increasing the prescribed cover depth emerges as a primary strategy to bolster the durability of new structures impacted by climate change. Augmenting this cover depth, alongside employing a higher-grade concrete and minimizing the water-cement ratio, can yield structures more resilient to corrosion. Adapting the building stock with these measures has stirred considerable debate in the scientific community. Stewart et al. (2012) projected that such measures—including increasing the design cover by up to 8 mm or elevating the concrete compressive strength by a grade—would hike construction costs by 1-3%. Yet, the economic implications at a global scale are intricate. Studies by Bastidas-Arteaga & Stewart (2016) and Stewart & Bastidas-Arteaga (2016) dived deeper, probing the cost-benefit terrain of amplifying the cover thickness to 5 or 10 mm across an array of structural elements and climate scenarios. Their findings suggest that such interventions may not consistently offer a favourable economic return.

Furthermore, the push for a sustainable future in the European policies advocates for blended and alkali-activated (AA) cements over traditional Portland cement (PC). AA cements, particularly AA slag cement which integrates slag as a partial PC substitute, present dual advantages: a denser matrix reducing harmful substance permeability and reduced greenhouse gas emissions (Provis and van Deventer, 2014; Alelweet and Pavia, 2019). While slag cement's use in the USA spans over a century, its complete efficacy as a primary PC alternative remains under investigation. Lastly, when contemplating corrosion-resistant reinforcements, the market offers low carbon, stainless or galvanized steel, and even glass-fiber-reinforced polymer rebars. Yet, transitioning to these alternatives demands a rigorous cost-benefit scrutiny.

## 8.2 Adaptation measures of existing buildings

Adaptation strategies during a structure's service life diverge into two primary categories: reparative actions for damaged RC and protection measures against corrosion. On the reparative side, the initial task is discerning the extent of damage. Based on this, two possible approaches exist: (i) patch repair for located or small affected areas with easy access, and (ii) electromechanical methods, otherwise. Patch repair implies the physical removal of the compromised concrete, including areas behind reinforcement bars, replacing the removed concrete with

<footnote n="84"><sup>84</sup> EN, EN 1992 Eurocode 2: Design of concrete structures, CEN, Brussels, 2005</footnote>
new one. Insufficient removal can precipitate rapid corrosion post-repair. For structures where concrete removal is structurally unfeasible, electrochemical re-alkalization emerges as a greener alternative, demanding fewer interventions than patch repairs or coatings.

Once the structure is repaired, protective measures can be applied. Protective measures ae also recommended for improving the corrosion resistance of new structures. Protective measures encompass the utilization of corrosion inhibitors and concrete coatings. Corrosion inhibitors are chemical substances that, when added to the concrete surface, permeate the concrete, reducing the corrosion rate without significantly altering the concentration of other corrosion agents. They typically maintain their effectiveness for 10-15 years. However, their efficacy hinges on the uniformity of the product's penetration depth, which can be challenging to ascertain. Furthermore, conventional corrosion inhibitors, such as chromates and nitrites, possess toxic properties. Hence, alternative products like agro-waste/natural substances (e.g., heena or bamboo) are under investigation as non-toxic alternatives with minimal adverse environmental impacts.

Concrete coatings, also known as sealers, create a protective barrier on the concrete surface, reducing its permeability to aggressive substances and moisture. These coatings come in three main types: (i) Organic coatings: These are polymeric films based on epoxy, polyurethane, or chlorinated rubber polymers. (ii) Hydrophobic impregnation: This method establishes a water-repellent layer using substances like silanes, siloxanes, and silicate-based compounds. (iii) Cementitious coatings: These coatings, composed of cement, are applied through brushing or in the form of overlays via plastering or spraying. According to Stewart et al. (2012), acrylic-based surface coatings can reduce carbonation depths by 10-65%. While their application is straightforward and cost-effective, they provide a temporary solution as they typically endure for less than 15 years. Additionally, they may impact the future inspection of structures.

There are other techniques aimed at repairing and protecting ion-induced corroded structures, including electrochemical chloride extraction and cathodic protection. Although these methods can also be beneficial in cases where carbonation-induction is detected, due to the combined presence of both types of corrosion, they are not elaborated upon here. For a comprehensive review of these techniques, the reader is directed to Goyal et al (2018).

## 8.3 A resilience-based adaptation strategy

The influence of the condition of the built environment on the Member States' economy is profound, necessitating a meticulous approach to incorporating recommendations and regulations to adapt European building stock to climate-induced corrosion. When considering adaptation measures for climate change, several challenges emerge: (a) the evolution of climate change is still uncertain, highly influenced by the global socio-political landscape; (b) while design-phase measures can effectively prolong the lifespan of structures against climate change-induced corrosion, their cost-effectiveness is not guaranteed; and (c) interventions during the service life generally incur greater costs than those implemented in the design phase. As such, a thorough cost-benefit evaluation of these adaptation strategies is essential. Also, it is important to note that many European structural durability codes, guidelines, and specifications largely overlook maintenance's role in ensuring durability throughout a structure's operational life. While some standards assume that "adequate maintenance" is essential for durability (e.g., EN 1990 (2002)<fnref n="85" />, JCSS 2006⁸⁶, DM 14/01/2008⁸⁷), others offer specific maintenance recommendations [CEB-183⁸⁸, fib17⁸⁹]. Although inspection and monitoring are infrequently addressed, as seen in fib86⁹⁰, some standards underscore their importance for ensuring durability, as cited in [JCSS 2006, CEB-183]. Given this landscape, there is a pressing need for the European Standards to incorporate distinct maintenance guidelines tailored to the challenges posed by climate change (Nogal et al, 2021).

Cost-benefit analyses are inherently complex, built on numerous assumptions. In the corrosion case, they assess whether the financial investments made in corrosion mitigation and repair measures yield greater benefits, such as increased structural lifespan and reduced maintenance costs, compared to the initial and ongoing expenses associated with those measures. The analysis of the cost-effectiveness of several adaptation

<footnote n="85">⁸⁵ EN 1990 (2002): Eurocode - Basis of structural design. The European Union Per Regulation 305/2011, Directive 98/34/EC, Directive 2004/18/EC.</footnote>

<footnote n="86">⁸⁶ Probabilistic Model Code, JCSS. Joint Committee on Structural Safety (2006).</footnote>

<footnote n="87">⁸⁷ DM 14/01/2008: Norme Tecniche per le Costruzioni (Italian Code) Ministero Delle Infrastrutture, Decreto 14 gennaio 2008 (G.U. 4 febbraio 2008 n. 29 - S. O. n. 30).</footnote>

<footnote n="88">⁸⁸ CEB Bulletin n.183: Durable Concrete Structures—CEB Design Guide (1992); ISBN 978-0-7277-1620-0; 120 pages</footnote>

<footnote n="89">⁸⁹ fib Bulletin n.17: Management, Maintenance and Strengthening of Concrete Structures (Technical Report, April 2002).</footnote>

<footnote n="90">⁹⁰ fib Bulletin n.86: Safety and performance concepts: Reliability assessment of concrete structures—Guide to good practice, August 2018.</footnote>
new one. Insufficient removal can precipitate rapid corrosion post-repair. For structures where concrete removal is structurally unfeasible, electrochemical re-alkalization emerges as a greener alternative, demanding fewer interventions than patch repairs or coatings.

Once the structure is repaired, protective measures can be applied. Protective measures ae also recommended for improving the corrosion resistance of new structures. Protective measures encompass the utilization of corrosion inhibitors and concrete coatings. Corrosion inhibitors are chemical substances that, when added to the concrete surface, permeate the concrete, reducing the corrosion rate without significantly altering the concentration of other corrosion agents. They typically maintain their effectiveness for 10-15 years. However, their efficacy hinges on the uniformity of the product's penetration depth, which can be challenging to ascertain. Furthermore, conventional corrosion inhibitors, such as chromates and nitrites, possess toxic properties. Hence, alternative products like agro-waste/natural substances (e.g., heena or bamboo) are under investigation as non-toxic alternatives with minimal adverse environmental impacts.

Concrete coatings, also known as sealers, create a protective barrier on the concrete surface, reducing its permeability to aggressive substances and moisture. These coatings come in three main types: (i) Organic coatings: These are polymeric films based on epoxy, polyurethane, or chlorinated rubber polymers. (ii) Hydrophobic impregnation: This method establishes a water-repellent layer using substances like silanes, siloxanes, and silicate-based compounds. (iii) Cementitious coatings: These coatings, composed of cement, are applied through brushing or in the form of overlays via plastering or spraying. According to Stewart et al. (2012), acrylic-based surface coatings can reduce carbonation depths by 10-65%. While their application is straightforward and cost-effective, they provide a temporary solution as they typically endure for less than 15 years. Additionally, they may impact the future inspection of structures.

There are other techniques aimed at repairing and protecting ion-induced corroded structures, including electrochemical chloride extraction and cathodic protection. Although these methods can also be beneficial in cases where carbonation-induction is detected, due to the combined presence of both types of corrosion, they are not elaborated upon here. For a comprehensive review of these techniques, the reader is directed to Goyal et al (2018).

## 8.3 A resilience-based adaptation strategy

The influence of the condition of the built environment on the Member States' economy is profound, necessitating a meticulous approach to incorporating recommendations and regulations to adapt European building stock to climate-induced corrosion. When considering adaptation measures for climate change, several challenges emerge: (a) the evolution of climate change is still uncertain, highly influenced by the global socio-political landscape; (b) while design-phase measures can effectively prolong the lifespan of structures against climate change-induced corrosion, their cost-effectiveness is not guaranteed; and (c) interventions during the service life generally incur greater costs than those implemented in the design phase. As such, a thorough cost-benefit evaluation of these adaptation strategies is essential. Also, it is important to note that many European structural durability codes, guidelines, and specifications largely overlook maintenance's role in ensuring durability throughout a structure's operational life. While some standards assume that "adequate maintenance" is essential for durability (e.g., EN 1990 (2002)<fnref n="85" />, JCSS 2006⁸⁶, DM 14/01/2008⁸⁷), others offer specific maintenance recommendations [CEB-183⁸⁸, fib17⁸⁹]. Although inspection and monitoring are infrequently addressed, as seen in fib86⁹⁰, some standards underscore their importance for ensuring durability, as cited in [JCSS 2006, CEB-183]. Given this landscape, there is a pressing need for the European Standards to incorporate distinct maintenance guidelines tailored to the challenges posed by climate change (Nogal et al, 2021).

Cost-benefit analyses are inherently complex, built on numerous assumptions. In the corrosion case, they assess whether the financial investments made in corrosion mitigation and repair measures yield greater benefits, such as increased structural lifespan and reduced maintenance costs, compared to the initial and ongoing expenses associated with those measures. The analysis of the cost-effectiveness of several adaptation

<footnote n="85">⁸⁵ EN 1990 (2002): Eurocode - Basis of structural design. The European Union Per Regulation 305/2011, Directive 98/34/EC, Directive 2004/18/EC.</footnote>

<footnote n="86">⁸⁶ Probabilistic Model Code, JCSS. Joint Committee on Structural Safety (2006).</footnote>

<footnote n="87">⁸⁷ DM 14/01/2008: Norme Tecniche per le Costruzioni (Italian Code) Ministero Delle Infrastrutture, Decreto 14 gennaio 2008 (G.U. 4 febbraio 2008 n. 29 - S. O. n. 30).</footnote>

<footnote n="88">⁸⁸ CEB Bulletin n.183: Durable Concrete Structures—CEB Design Guide (1992); ISBN 978-0-7277-1620-0; 120 pages</footnote>

<footnote n="89">⁸⁹ fib Bulletin n.17: Management, Maintenance and Strengthening of Concrete Structures (Technical Report, April 2002).</footnote>

<footnote n="90">⁹⁰ fib Bulletin n.86: Safety and performance concepts: Reliability assessment of concrete structures—Guide to good practice, August 2018.</footnote>
strategies for various structural members under diverse climate scenarios conclude that the merit of such measures is influenced by climatic conditions, structural design, size, and discount rate (Bastidas-Arteaga & Stewart, 2016; Stewart & Bastidas-Arteaga, 2016). Selecting strategies based solely on cost-effectiveness for a particular climate scenario poses risks; underestimating climate change impact might lead to unexpected maintenance costs, while overestimating could waste resources during design.

Over the past few years, there has been a marked transition from methodologies anchored in traditional risk assessment towards those emphasizing resilience. The pressing need for such a resilience-driven perspective arises particularly in scenarios where potential hazards are either poorly understood or the associated uncertainties cause a substantial underestimation of true risks. This is very often the case of climate change, prompting policymakers to adopt resilience-enhancing strategies (Val et al., 2019). Risk- and resilience-oriented strategies are not mutually exclusive. In fact, by weaving in a temporal component, resilience approaches enrich the foundational risk methodologies. These strategies not only improve the system's preparedness but also facilitate its adaptive evolution over time.

To address the adaptation of RC building stock to climate change, Nogal (2020) advocates for adopting a resilience-centric framework that involves a dual approach: (i) design-phase adaptation measures aligned with a set confidence level in climate change projections, and (ii) preventive maintenance strategy at the design stage that will be adjusted with evolving climate change data. It is noted that both phases are considered at the design stage. During the first phase, proactive and cost-effective adaptation measures should be implemented to address the impact of climate change associated with lower levels of uncertainty. The utilization of innovative, eco-friendly concrete mixtures could be pivotal in this stage. Conversely, for the more unpredictable ramifications of climate change, adaptation actions should be strategized, predominantly encompassing maintenance. Pertinently, the European standards should advocate for climate-specific maintenance guidelines for RC buildings. During the design phase, it is imperative to define maintenance strategies that specify the regularity of maintenance tasks. At the same time, the design project should enumerate possible measures in anticipation of future climatic projections, coupled with their economic implications. To ensure the project's economic feasibility, provisions should be made for a financial framework addressing potential adaptation costs. It is noted that certain prescribed maintenance interventions might not always be as economically efficient as the preventive measures integrated during the initial design phase. Hence, a thorough economic analysis must be conducted balancing the total cost throughout the structure's lifespan accounting with the uncertainty of the future climate.
strategies for various structural members under diverse climate scenarios conclude that the merit of such measures is influenced by climatic conditions, structural design, size, and discount rate (Bastidas-Arteaga & Stewart, 2016; Stewart & Bastidas-Arteaga, 2016). Selecting strategies based solely on cost-effectiveness for a particular climate scenario poses risks; underestimating climate change impact might lead to unexpected maintenance costs, while overestimating could waste resources during design.

Over the past few years, there has been a marked transition from methodologies anchored in traditional risk assessment towards those emphasizing resilience. The pressing need for such a resilience-driven perspective arises particularly in scenarios where potential hazards are either poorly understood or the associated uncertainties cause a substantial underestimation of true risks. This is very often the case of climate change, prompting policymakers to adopt resilience-enhancing strategies (Val et al., 2019). Risk- and resilience-oriented strategies are not mutually exclusive. In fact, by weaving in a temporal component, resilience approaches enrich the foundational risk methodologies. These strategies not only improve the system's preparedness but also facilitate its adaptive evolution over time.

To address the adaptation of RC building stock to climate change, Nogal (2020) advocates for adopting a resilience-centric framework that involves a dual approach: (i) design-phase adaptation measures aligned with a set confidence level in climate change projections, and (ii) preventive maintenance strategy at the design stage that will be adjusted with evolving climate change data. It is noted that both phases are considered at the design stage. During the first phase, proactive and cost-effective adaptation measures should be implemented to address the impact of climate change associated with lower levels of uncertainty. The utilization of innovative, eco-friendly concrete mixtures could be pivotal in this stage. Conversely, for the more unpredictable ramifications of climate change, adaptation actions should be strategized, predominantly encompassing maintenance. Pertinently, the European standards should advocate for climate-specific maintenance guidelines for RC buildings. During the design phase, it is imperative to define maintenance strategies that specify the regularity of maintenance tasks. At the same time, the design project should enumerate possible measures in anticipation of future climatic projections, coupled with their economic implications. To ensure the project's economic feasibility, provisions should be made for a financial framework addressing potential adaptation costs. It is noted that certain prescribed maintenance interventions might not always be as economically efficient as the preventive measures integrated during the initial design phase. Hence, a thorough economic analysis must be conducted balancing the total cost throughout the structure's lifespan accounting with the uncertainty of the future climate.
# 9 Conclusions

The study provides assessment of the penetration of climate change induced carbonation in the concrete cover of the existing buildings in the EU-27 Member States. It estimates the time for on-set of corrosion due to depleting of the cover of the reinforcement and evaluates the related repair costs and the annual welfare loss as the percentage of the GDP covering the annual repair costs. The main conclusions can be summarised as follows:

1. The considered in the study future climate change projections, were forced by two hypotheses of greenhouse gas (GHG) concentration trajectories, acknowledged as RCP4.5 scenario and RCP8.5 scenario. To evaluate the influence of the climate change, baseline scenarios assuming no rise of the temperature and CO₂ content after completing the construction, are considered in parallel with these two scenarios. The RCP4.5 scenario projects an increase of the 30-year annual temperature at values of 0.8°C, 1.5°C, and 2.0°C for near, medium, and long-time horizons, respectively. The considered more extreme RCP8.5 emissions scenario (no mitigation action) projects higher increases of 0.9°C, 2.1°C, and 3.7°C for the same time periods. The study is based on the same bias-adjusted regional climatic models and the same observational data set EOBSv10, as PESETA IV study. The impacts of carbonation calculated in this study within the time horizon of 2100 for the RCP4.5 and RCP8.5 are compatible with the climate change impacts evaluated by PESETA IV for no mitigation action (RCP8.5) and for the moderate mitigation emissions scenario (RCP4.5), and **can enrich the impact categories of PESETA IV with built environment.**

2. Current study presents the **first evaluation of the implications of the climate change induced carbonation on the entire concrete building stock in the EU-27 Member States.** The work simulates the impact of potential climate scenarios on selected carbonation metrics and makes comparison to a reference situation with no further change of the climate. To make the analysis for all European countries simpler, the reinforced concrete buildings in the georeferenced database were aggregated in two major groups to reflect their age, called 'old' (assumed built in 1965 according to standards of the 20th century) and 'recent' (assumed built in 2000 according to contemporary standards). **The results for both, the old and the recent buildings conclusively show that, without climate change, the carbonation due to natural aging of buildings would not lead to corrosion by year 2100.**

3. The results of the evaluation of the carbonation damage conclusively show that by 2100 the **carbonation affected by the climate scenarios RCP4.5 and RCP8.5 does not pose a serious threat to recent RC buildings that follow the recommendations of the contemporary European standards for durability of the concrete cover. Thus, the climate change induced carbonation is expected to trigger corrosion in the old building stock.**

4. The study shows that **the percentage increase in carbonation depth due to climate change is influenced by the increase of temperature relative to the baseline scenarios.** However, the depth of carbonation correlates positively with the projected absolute temperature values. Two clusters of capital cities are very well distinguishable when considering the correlation between the absolute temperature and the carbonation depth: one of the cities of north-eastern Europe, and another of the rest of the capital cities. **The capital cities in the north-eastern Europe are exhibiting carbonation depth with magnitude, similar to the magnitude of the rest of the capital cities, but at much lower absolute temperatures.** This phenomenon could be explained with the higher rise of the temperature, and with the relatively low durability characteristics of the concrete. **These results show that the knowledge of the projected temperature is not enough to predict the onset of corrosion, as the durability parameters play a significant role in the carbonation process.**

5. The repair costs assessment in this study assumes that the repair occurs after the depletion of the concrete cover and before a significant loss of cross-sectional area of the reinforcement bars, thus considering a corrective repair option for the exposed building surface. **The projected total cost for the EU Member States to repair the carbonation triggered corrosion by the year 2100 is expected to reach approximately EUR 76 billion under the moderate RCP4.5 climate scenario and EUR 883 billion under the more extreme scenario RCP8.5.** Different countries are the **most affected in each scenario, as explained further.** The analysis reveals that under the RCP4.5 climate scenario, Italy, Portugal, Spain and Denmark would have to afford the highest repair costs of concrete buildings, with Italy's total costs reaching EUR 17 billion, followed by Portugal and Spain
# 9 Conclusions

The study provides assessment of the penetration of climate change induced carbonation in the concrete cover of the existing buildings in the EU-27 Member States. It estimates the time for on-set of corrosion due to depleting of the cover of the reinforcement and evaluates the related repair costs and the annual welfare loss as the percentage of the GDP covering the annual repair costs. The main conclusions can be summarised as follows:

1. The considered in the study future climate change projections, were forced by two hypotheses of greenhouse gas (GHG) concentration trajectories, acknowledged as RCP4.5 scenario and RCP8.5 scenario. To evaluate the influence of the climate change, baseline scenarios assuming no rise of the temperature and CO₂ content after completing the construction, are considered in parallel with these two scenarios. The RCP4.5 scenario projects an increase of the 30-year annual temperature at values of 0.8°C, 1.5°C, and 2.0°C for near, medium, and long-time horizons, respectively. The considered more extreme RCP8.5 emissions scenario (no mitigation action) projects higher increases of 0.9°C, 2.1°C, and 3.7°C for the same time periods. The study is based on the same bias-adjusted regional climatic models and the same observational data set EOBSv10, as PESETA IV study. The impacts of carbonation calculated in this study within the time horizon of 2100 for the RCP4.5 and RCP8.5 are compatible with the climate change impacts evaluated by PESETA IV for no mitigation action (RCP8.5) and for the moderate mitigation emissions scenario (RCP4.5), and **can enrich the impact categories of PESETA IV with built environment.**

2. Current study presents the **first evaluation of the implications of the climate change induced carbonation on the entire concrete building stock in the EU-27 Member States.** The work simulates the impact of potential climate scenarios on selected carbonation metrics and makes comparison to a reference situation with no further change of the climate. To make the analysis for all European countries simpler, the reinforced concrete buildings in the georeferenced database were aggregated in two major groups to reflect their age, called 'old' (assumed built in 1965 according to standards of the 20th century) and 'recent' (assumed built in 2000 according to contemporary standards). **The results for both, the old and the recent buildings conclusively show that, without climate change, the carbonation due to natural aging of buildings would not lead to corrosion by year 2100.**

3. The results of the evaluation of the carbonation damage conclusively show that by 2100 the **carbonation affected by the climate scenarios RCP4.5 and RCP8.5 does not pose a serious threat to recent RC buildings that follow the recommendations of the contemporary European standards for durability of the concrete cover. Thus, the climate change induced carbonation is expected to trigger corrosion in the old building stock.**

4. The study shows that **the percentage increase in carbonation depth due to climate change is influenced by the increase of temperature relative to the baseline scenarios.** However, the depth of carbonation correlates positively with the projected absolute temperature values. Two clusters of capital cities are very well distinguishable when considering the correlation between the absolute temperature and the carbonation depth: one of the cities of north-eastern Europe, and another of the rest of the capital cities. **The capital cities in the north-eastern Europe are exhibiting carbonation depth with magnitude, similar to the magnitude of the rest of the capital cities, but at much lower absolute temperatures.** This phenomenon could be explained with the higher rise of the temperature, and with the relatively low durability characteristics of the concrete. **These results show that the knowledge of the projected temperature is not enough to predict the onset of corrosion, as the durability parameters play a significant role in the carbonation process.**

5. The repair costs assessment in this study assumes that the repair occurs after the depletion of the concrete cover and before a significant loss of cross-sectional area of the reinforcement bars, thus considering a corrective repair option for the exposed building surface. **The projected total cost for the EU Member States to repair the carbonation triggered corrosion by the year 2100 is expected to reach approximately EUR 76 billion under the moderate RCP4.5 climate scenario and EUR 883 billion under the more extreme scenario RCP8.5.** Different countries are the **most affected in each scenario, as explained further.** The analysis reveals that under the RCP4.5 climate scenario, Italy, Portugal, Spain and Denmark would have to afford the highest repair costs of concrete buildings, with Italy's total costs reaching EUR 17 billion, followed by Portugal and Spain