Weathering climate

Across the globe, almost 900 cultural and natural gems officially bear the UNESCO World Heritage title. In addition, there are innumerable other sites which have stood the test of time for long enough to be deemed historically valuable.

As much as ancient architecture and archaeological remains are a source of national pride, they are also a wellspring of worry. Vulnerable to the elements at the best of times, old buildings are potentially at risk from the changing nature of the global climate.

Peter Brimblecombe, atmospheric scientist with the University of East Anglia in England, said that although the impact of climate change on cultural heritage has not yet made it into the public consciousness, the first hints are definitely beginning to appear.

“There are plenty of examples in the high arctic where slightly warmer temperatures have led to a change in buried archaeology that has been in permafrost since the time of the Vikings,” Brimblecombe explained.

He said there is also evidence of falling water tables in Britain leading to the drying up of historic moats, and changing rain patterns in the Sahara causing damage to major architectural monuments made of mud. But by the same token, he warned against alarmist attitudes.

Keeping it real

“People are very careless,” the scientist told Deutsche Welle. "They will show examples of traditional weathering and say it is the result of climate change when in actual fact it is just the result of climate."

And to flip the coin, there are even some examples where bonafide climate change actually benefits heritage sites. Citing a reduction in the frequency of frost in Britain, Brimblecombe said buildings are now subject to far less of the type of degradation caused by freezing.

Differentiating between the wearing hand of climate and the aggressive nature of climate change is not easy. But a small number of projects are trying to do just that. One such initiative is "Climate for Culture," led by Germany's Fraunhofer research institute.

The experts involved are looking at a range of sites and hope to gain enough insight into the threat posed by shifting weather events to be able to forearm against them.

“We will be looking at case studies across Europe," Ralf Kilian, senior scientist with the Fraunhofer Institute for Building Physics, told Deutsche Welle.

Citing the examples of churches in Bavaria and on the Swedish coast, he said they aimed to assess how different climates - maritime, moderate and continental - affect different building materials.

"We will examine damage mechanisms and try to establish why climate-related damage occurs," Kilian explained.

Pooling resources

Taking into account the massive geographical, construction and climate differences, it's a huge undertaking. But in working with partners from 16 countries, Kilian sees ample scope for sharing national expertise.

We want to find out what the climate in other countries is really like and what problems they have with their historic buildings,” Kilian said. "We want to see what methods are used in Sweden or Britain, for example, so they can be transferred to other countries."

He cited the use of "conservation heating," which is used in England to keep humidity at a constant level. "Humidity poses a greater threat of damage than heat, so they adapt it as required." Although the practise is not yet used in Germany, Kilian believes there is no reason why it shouldn't be.

In another example of a successful strategy to keep damage from climate change to a minimum, Peter Brimblecombe said that when Britain's National Trust recognized that the future would yield heavier bursts of rain, it took some precautionary measures.

"They replaced guttering on some 17th-century houses which had been designed for much lighter rainfall to prevent the water from overflowing down the facades," he said.

Planning for the future

But while ensuring effective management strategies is crucial, the atmospheric scientist says it is equally important to lay the ground for the next generation of researchers.

“We have to leave a legacy of measurements for some unknown future scientists," he said. Given the slow pace of climate change, those researchers will be the first ones who are really able to see what impact contemporary global warming has had on world heritage.

Author: Tamsin Walker

Editor: Kate Bowen