Climate change threatens Europe’s cultural heritage

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NOAH’S ARK
Urgent action is needed to protect Europe’s cultural heritage from the effects of climate change, scientists from the Noah’s Ark project warn. The project found that our historic buildings, monuments, museums and statues are likely to suffer increasing levels of damage as a result of climate change.

The good news is that the researchers have developed a Vulnerability Atlas, comprising the first ever maps of how climate change over the coming century will affect historic buildings, and a set of guidelines to help policy-makers assess the risk of damage in their country or region and take steps to protect and conserve their cultural heritage.

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Climate change and culture: a forgotten problem

For a long time, those working on climate change focused on its impacts on agriculture and health, considering aspects such as water and energy supply and transport needs. Now the Noah’s Ark project highlights the potential impacts of climate change on our cultural heritage.

The project’s partners, who come from seven EU countries, include climatologists, chemists, geologists and biologists, conservators and curators. Insurance specialists also took part in the project, reflecting the immense attractiveness and value of cultural heritage to Europe’s economy through the income generated by our tourism industry.

They used climate models to predict how factors which affect our cultural heritage, such as temperature, wind and rainfall, are likely to change across Europe over the coming century. As many of the weather-related situations which are most damaging to our monuments are not as simple as average temperatures or average rainfall, the researchers had to create special new parameters.

For example, rapid cycles of freeze and thaw are extremely damaging to stonework, so it is the range of temperatures, and how quickly they change, that is important.

Shedding light on the enemies of cultural heritage

Europe’s monuments are already affected by environmental conditions. However, as the climate changes, the monuments will face new and different challenges, and those responsible for taking care of them will have to adapt their conservation strategies accordingly.

Carbonate stones, such as marble and limestone, are used in buildings across Europe, including Westminster Abbey, the Parthenon and the Coliseum. Increasing rainfall in northern Europe will leave monuments made of these stones vulnerable to a process called surface recession, whereby the rain literally washes the stone away. In contrast, rates of recession in southern Europe are set to decrease.

Marble and limestone monuments are also prone to a problem called thermoclastie which occurs when the material expands and contracts in response to rapid temperature fluctuations, causing it to crack. Thermoclastie is already a serious problem in southern Europe and it is likely to increasingly affect central Europe too.

Another problem for stone structures is salt deposition. Porous stones absorb moisture in the air, and when the water evaporates, the salt in the water crystallises and puts pressure on the surrounding stone. Sea salt crystallisation occurs when relative humidity falls below 75.5 %. The bad news is that the conditions for salt deposition are likely to become more common across large parts of western and central Europe. Soft porous stones, such as those frequently used for gothic cathedrals, are particularly vulnerable to this process.

Outdoor wooden structures like Scandinavia’s stave churches are prone to attack from fungi, which strike when moisture levels are high and temperatures rest around an optimum range for growth. A combination of increasing rainfall and rising temperatures will see northern and eastern Europe’s risk of fungal attack go up, while drier conditions in southern and western Europe means the risk there will decrease.

Metal structures such as the Eiffel Tower are at risk of corrosion caused by acidifying pollutants; when a structure is wet, pollutants dissolve in the surface layer of the metal and act as corrosive agents. In the future, northern Europe’s cultural heritage will face an increased risk of this problem.

The Noah’s Ark Vulnerability Atlas shows how the risks of these and other problems will change in different parts of Europe over the coming century.

Cultural heritage – a non-renewable resource in urgent need of protection

Many of these problems can be addressed by implementing the guidelines put together by the project. Among other tips, these Noah’s Ark guidelines recommend increasing inspections and carrying out minor repairs more regularly, instead of infrequent major repairs.

In some cases, structures may need visible changes, such as increasing the size and number of gutters and downpipes to help old buildings cope with higher rainfall levels. These alterations often lead to questions of authenticity, but the guidelines note that conservationists need to acknowledge that not all our cultural heritage can be saved unaltered. Opposition to alterations can be addressed by basing decisions on scientific evidence, and weighing up the vulnerability of the element to be altered against its significance.

The challenge now for the Noah’s Ark team is to ensure that its conclusions related to the impact of climate change on cultural heritage are also included in future reports by the Intergovernmental Panel on Climate Change (IPCC). The team is also working to raise awareness of the project’s results among those responsible for conserving our cultural heritage.

The stakes are high – Europe’s monuments are part of our daily lives and they have stood sentinel over our towns and cities for centuries. As tourist attractions, they represent an important and stable source of income and employment.

Thanks to the Noah’s Ark project, visitors and locals alike will be able to marvel at these treasures which define our cities, our roots, our Europe, for centuries to come.