Climate change has become one of the biggest threats to world heritage sites, says Stefan Wessman from the Finnish Museum Agency. Old buildings suffer when the climate is no longer the same as it has been for centuries.
The wooden beams of centuries-old houses crumble from heavy rains in a pile of rubble in Sana’a, the capital of Yemen.
The severity of the August rains has been too much for several buildings in the old town, which is a UNESCO World Heritage Site.
Heavy rains have collapsed ten houses in the old town and badly damaged at least 80 others, say the Houthi rebels who hold power in Sanaa, according to the AP news agency.
Yemen has had unusual weather since the beginning of the year: in the spring, the country suffered from a severe drought, and the rainy season that started in the summer brought with it exceptionally heavy rains. According to the country’s Meteorological Institute, it may have rained up to 88 millimeters in one day, the news agency Reuters reports.
Continuous heavy rains have caused floods and landslides. Houses, roads, bridges and crops have been destroyed. Across the country, more than 80 people have died.
The increase in rain also threatens Machu Picchu
There are more and more extraordinary weather in different parts of the world as climate change progresses. This has also been painfully noticed by the guardians of cultural heritage.
– In recent years, the effects of climate change have become one of the biggest threats to world heritage sites, says the special expert Stefan Wessman From the Museum Office.
Yemen is a complicated example in the sense that there has been a war there for seven years, Wessman points out. Old buildings have to be constantly maintained using traditional methods, and in Sanaa this has not been possible due to the war. This has increased the risk of collapse.
– But worldwide, it has been clearly noticed that climate change affects these world heritage sites in different ways. More and more sites are threatened directly due to the influence of the climate, says Wessman.
One example is Machu Picchu in Peru. As the heavy rains increased, the landslides have even partially covered the ruins.
Examples can also be found nearby, such as the world heritage site Petäjävesi Church, says Wessman.
– Our traditional building base is log structures. For example, Petäjävesi church is a log building and is not heated. When we have winters like this, where there is no longer necessarily cold and dry air, but rain throughout the winter, the humidity in the structures increases. As a result, the building rots and there is more mold damage.
In Finland, humidity is a big problem, in other places it is dryness
Promoting the preservation of cultural heritage The Heritage organization notes (you are moving to another service), that, for example, a small change in temperature changes the relative humidity. This, in turn, can lead to the erosion of stone and ceramic objects. Biological activity may also change, and extreme weather phenomena such as droughts and heavy rains and storms will increase.
At the same time, wildfires, coastal erosion and floods are increasing.
Wessman states that the greatest threat from climate change in each region varies depending on what the climate in that region has been like in the past.
– There has been a lot of talk about heavy rains, but drought is a similar problem. There are many buildings made of earth and clay that suffer from drought.
In turn, air pollution and acid rain have caused structural problems in the Acropolis of Athens.
In Finland, the main problems are humidity, increased rainfall and sea level rise.
For example, in Suomenlinna, part of the defense walls are built on top of sand. If the sea level rises, it wears away the sand, and there is a risk that the ramparts will collapse, says Wessman.
– This has already been seen in different parts of Europe.
Wessman has not lost hope
According to Wessman, international efforts are constantly being made to preserve cultural heritage as climate change progresses. For example, in the World Heritage Convention, attention was already paid to preventing the threats caused by climate change and repairing the damages already in 2005.
Climate change causes a lot of additional work at world heritage sites, so that they can be preserved for future generations. However, Wessman has not given up hope.
– In that sense, I am optimistic that there are still opportunities to intervene. At the same time, I fear that we will be late in some destinations.
You can discuss the topic until 23:00 on 20.8.