Do extreme weather conditions cause cracks in archaeological monuments?

Everyone is curious to know history; Edward Bulwer  said, “Archaeology is not only the handmaid of history, and it is also the conservator of art.” 

Sri Lankan people are strongly connected with the past. In the past, the royal children of Sri Lanka created many artifacts related to Buddhist culture and Hinduism. Especially the Buddhists and Hindus of the country devotees can be seen worshipping the antiques in abundance. Therefore archaeological conservation is paramount because it ties in with Sri Lankan culture. 

Climate Change has been creating harsh and extreme weather conditions. Can these climate change-intensified weather conditions cause disastrous effects on architectural monuments? We decided to investigate the issue.

Before concerning the effect of climate change, on archaeological monuments, we looked into the structure of archaeological monuments. The impact can be easily understood when we know the monuments. We discussed this with the Director General of the postgraduate institute of Archaeology, Senior Professor Gamini Adikari.  

Structure of the archaeological monuments

Archaeological monuments are typically made from various materials, depending on the culture, time, and location in which they were created. In addition to stone, clay brick, wood, metal, shell stone, coral, and lime mortar had also been used in past constructions, Professor Adhikari says.

Many ancient monuments of Sri Lanka were constructed using large stones. Adobe, a mixture of mud and straw, was used to build many buildings in ancient civilizations. Clay is also used frequently to create religious monuments.

Some archaeological monuments, such as wooden architecture, also can be seen. Wood was a popular building material because it was readily available and easy to work with. Metal was also used. Metal was valued for its durability and ability to be molded into intricate shapes. Bone also had been used for decorations of constructions, tools, Jewellery, and so on.

Professor Adhikari explains that a layer of plaster can be seen on the back of some archaeological objects. It is visible in some places with a thickness of about four inches. This plaster layer has been destroyed in many places, and only a few places are left. However, some layers still hold up well to the different climatic conditions. Professor Adhikari further explains that this traditional plastering technique is too advanced and needs to be investigated to determine the exact materials used.

Professor Adhikari added that erratic climate changes, such as heavy rain, intense sunlight, and strong winds, could affect artifacts. Let’s consider how this in detail.

Heat effect on the structure of monuments

Increasing heat can have various adverse effects on archaeological monuments, particularly those made of stone or other materials sensitive to temperature changes. Here are some of how heat can impact archaeological monuments,

·   Thermal expansion and contraction.  

Since Sri Lanka is tropical, the temperature is high almost everywhere. This has some effect on archaeological objects made of stone prof. Adhikari says. When exposed to high temperatures, materials like stone and metal can expand and contract, leading to cracks, warping, and other forms of damage. This can be particularly problematic for structures that are already in a fragile state. However, Mr. Adhikari says that due to the heavy rain that comes with the monsoon rains, the adverse conditions caused by the high temperature will be controlled to some extent.

High wind and high heat effect

High temperatures can accelerate the natural processes of erosion and weathering, which can cause surfaces to become brittle, flaky, and porous over time. This can make it challenging to preserve delicate carvings and other intricate details.

Prof. Gamini Adhikari points out that the dry “Bachchan winds” that come during the monsoon season affect Sigiriya’s world heritage to a great extent, and those cracks are damaged lot to the monument and cannot be seen by the naked eye.

Discoloration and fading

Prof. Adhikari explains that irregular weather pattern is the main reason for most effects. This is happening with climate change. As we all know, extreme weather events like heat waves and large storms will likely become more frequent or intense with human-induced climate change.

Discoloration and fading mainly happen due to the activity of microbes on the monument, and when removing those algae and fungus, it damages the memorial. However, this primarily occurs in the wet season, and in when the dry season, that fungus will dry and then die, Professor Adhikari stated.

He points out that using chemicals to remove this moss has also created a crisis. That’s because, from the chemical ingredients, we get rid of everything we need to remove and shouldn’t. This may affect the destruction of the ancient objects due to the composition change that has existed for a long time.

Heat and sunlight can cause pigments and dyes to fade or discolor, making it difficult to appreciate the original beauty of a monument. On the other hand, high temperatures can cause materials to lose moisture, making them more prone to cracking and other forms of damage. This is particularly problematic in areas with low humidity or in arid climates.

Can Air quality affect the archaeological monument?

Anuradhapura, Sigiriya, Polonnaruwa, and Dambulla are the main historical sites in Sri Lanka. We all know there was a severe air pollution situation in Sri Lanka in the past months, which can also be seen in these archaeological sites. We asked Professor Gamini Adhikari whether this affects archaeological monuments.  He explained this concerning an incident at the World Heritage Mirror Wall in Sigiriya. Hundreds of thousands of local and foreign citizens come to see the Sigiriya mirror wall. Then a microenvironment is formed there, including carbon dioxide and sweat, the air people breathe. This works differently from the average composition. Many antiquities in Sri Lanka are exposed to the environment. He points out that if all the harsh weather conditions, such as heavy rains, droughts, and cold and strong winds caused by climate change, affect these artifacts, then the difference in air composition can also affect the microenvironment.

 Conservation of archaeological monuments

Professor Adhikari said that another essential aspect of this topic is conservation. For example, in restoring an archeological monument, the material should be preserved using a material of lower quality than the material from which it was created. He points out that even if an adverse situation occurs due to climate change or some reason and damages the object, the lower layer will be injured at first, and the monument will save.  

UNESCO and ICOMOS have drawn up recommendations on how to adapt archaeological heritage to climate change. These recommendations include,

1) The assessment of the impacts of climate change through monitoring and vulnerability assessment

2)  Increase the resilience of heritage sites by reducing non-climatic sources of stress

3) Re-designing boundaries and buffer zones and preventive draining.

Professor Adhikari further stated that to protect the antiquities; if there are damaged areas on the surface, they will be restored. Also, some monuments are placed in covered areas. We asked whether there was a change in the microenvironment by getting the covered areas or by installing roofs. He mentioned that several experimental studies and research would be done before such conservation, and those decisions would be reached.

Practical actions on archaeological sites can include backfilling excavated areas and covering heritage with shelters or coatings. In addition, research, training and education, and awareness raising are needed to achieve ‘some degree of adaptation to climate change.

In a Nutshell

Overall, the effects of heat on archaeological monuments can be severe and long-lasting. Therefore, protecting these precious cultural artifacts from extreme temperatures, high wind, high rainfall, and other environmental damage is essential. In addition, thermal expansion and contraction, erosion, discoloration, microbial contamination fading, and many such things happen to archaeological monuments with climate change. If you have any queries or come across suspicious content related to climate change or the environment and want us to verify them for you, then send them to us on our WhatsApp hotline: +917045366366