The current climate change and extreme weather events are impacting not only the existence of animals, plants, and human beings around the world, but also countless archaeological sites, historic architecture, cultural monuments, and paleontological treasures that have accumulated over many thousands of years. Archaeologists are now in a race against time itself to learn more about the places that hold secrets to our past before these sites disappear.
The most severe losses due to climate change are likely to occur along the world’s coastlines. Throughout ancient times, people built homes and settlements along rivers, lakes, and coastlines precisely because of accessible, reliable sources of food, plant life, and drinking water—and these are areas that usually have a large concentration of archaeological sites. The main threats are sea level rise, storms, and increased wave energy, leading to greater flooding and coastal erosion. As the coastline regresses, any cultural sites and monuments will find themselves exposed to increased storm surges, high winds, and significant flooding.
Rapa Nui (named Easter Island by Europeans) is one such site, home to the moai. These 1,000 human figure monuments, erected between the 10th and 16th centuries, are being battered by rising sea levels, high-energy waves, and increased erosion. The National Trust for England, Wales, and Northern Ireland estimates that in England, 60% of the coastline is likely to suffer erosion and 500 archaeological and historic monuments will be at risk from coastal change over the next 100 years, in addition to an unknown number of unexcavated sites.
Global Warming in the Arctic and Alpine Regions
On September 19, 1991, hikers in the Alps, near the border of Italy and Austria, came across a human body half-embedded in a slab of ice. Their first thought was that it was a young mountaineer who died in a climbing accident. On closer inspection, however, archaeologists from the Institute of Forensic Medicine in Innsbruck, Austria, determined that “Otzi the Iceman”—as he came to be called—was a 46-year-old man who lived 5,000 years ago! Since the 1990s, thousands of similar discoveries have been made from melting glaciers and ice caps worldwide. These types of discoveries are important and a gift to humanity, however, when treasures are exposed from melting ice, far more serious problems arise.
Experts worldwide have determined that at least 180,000 archaeological sites exist in the Arctic. These sites are being lost to climate change faster than sites located elsewhere because the Arctic is warming much faster than the global average. The Arctic coastline is on the front lines of climate change. Shorter winters and shrinking winter sea ice along the coast has caused the shoreline to erode faster than almost anywhere else in the world.
Arctic sites contain artifacts made out of wood, bone, and ivory, as well as intact human and animal remains. When organic material melts out of frozen ground or a glacier, it is suddenly exposed to oxygen and decomposes extremely rapidly. As the sites become more exposed and accessible, thieves have been looting these archaeological sites. For example, in northeastern Siberia, ivory hunters have set up camps and use high-pressure water pumps to remove the ivory tusks from woolly mammoths melting out of the permafrost. The ivory is then sold on the black market. Along Alaska’s eroding coastline, locals and tourists are removing and selling artifacts from exposed archaeological sites.
Severe Weather Phenomena
The increase in extreme weather events, such as storms, are devastating cultural sites worldwide. In Jutland, Denmark, a survey after a storm in 1999 found 17% of archaeological sites had suffered loss from both the storm as well as the clean-up operations. In Sweden, a severe storm in January 2005 resulted in damage to almost one-third of all the archaeological sites in the area, including 1,500 prehistoric burial sites.
Landslides, ground heave, and subsidence also occur more frequently after intense rainfall. In Ireland, “bog bursts” (a massive flow of peat turf) are becoming more frequent. Due to the low oxygen and high tannic acid, peat lands (also called bogs, moors or muskegs) preserve an invaluable record of human activity. In Ireland, bogs have exposed spectacular and important archaeological finds, such as the Faddan More Psalter. The bogs of NW Europe have also revealed the burials of victims of execution or sacrifice dating to the Iron Age—about 500 BCE/BC to 100 CE/AD. The increasing destruction of peat lands due to hotter drier summers, fires, and erosion from heavy rain has serious consequences for both natural and cultural heritage.
Extreme weather also erodes historic and ancient stone architecture and monuments on all continents. Increased frequency of severe storms, high winds, and intense rainfall are leading to more frequent floods which can result in soil erosion and subsidence of structural foundations. Stone appears invincible on the surface, but prolonged periods of wetness will increase decay from dissolved salts and pollutants and encourage growth of damaging plant roots.
For underwater archaeology, it is expected that ancient and historic shipwrecks may be exposed more frequently than before by the extreme weather and that in turn it could inhibit their documentation and excavation. In other situations, sediments that normally protect buried ships are being eroded away and exposing ships to water with high oxygen levels and increasing bacteria that attack wood.
Researchers are using GIS (Geographic Information System) systems to survey as many sites as quickly as possible. Prepared by multiple institutions, the DINAA (Digital Index of North American Archaeology), compiles multiple sources of archaeological data into one system. One research team, led by David G. Anderson at the University of Tennessee, analyzes this data for the Southeastern United States. Surveying thousands of miles of coast, by 2017, they had recorded 32,898 recorded sites at risk of destruction by sea level rise exceeding 16 feet and 19,676 sites threatened by as little as three feet in rise. Many of these sites have not yet been excavated. Another researcher from the Southern Methodist University, Mark D. McCoy, is focused on Polynesia, using ARCHSITE, a tool similar to DINAA.
What is being done on the international scene to protect world heritage sites? UNESCO is an international organization concerned with safeguarding cultural and natural heritage sites all over the world. UNESCO’s auxiliary organization, ICOMOS, the International Council on Monuments and Sites, promotes conservation, protection, use, and enhancement of monuments, historic buildings, and archaeological sites. UNESCO and ICOMOS have developed recommendations on how to adapt archaeological heritage to climate change, monitoring the impact of climate change, and introducing procedures to mitigate damage. Practical solutions for protecting archaeological sites can include backfilling of excavated sites, covering heritage sites with shelters or coatings, and implementing training and education programs to raise public awareness.
An example of a practical solution to protect an archaeological site is the construction of shelters over the Megalithic Temples of Malta, amongst the oldest freestanding stone buildings in the world. These Temples were being affected by rain, wind, sun, salt, pollution, and biological growth. The performance of the shelters is currently being assessed by continuing environmental monitoring which already indicates an improvement in conditions beneath the shelters when compared to conditions on site before sheltering. Environmental data show that the shelters are definitely protecting against temperature extremes, as well as temperature fluctuations. Salt damage due to crystallization cycles, for instance, has been attenuated because less direct water is entering the megaliths, thus less salt is being absorbed both from the ground and from direct rainfall.
However, the difficult truth is that it will not be possible to preserve everything, and difficult choices will have to be made about which archaeological sites should be rescued or which will have to be sacrificed forever to climate change. The task is just too enormous for just one international organization like ICOMOS and is also too vast and expensive for any one nation to protect its own heritage against the climate. While the health, safety, and survival of all living species are of primary importance, we should also try to rescue the ancient heritage that made us human.
Dawson, T. et al., editors (2017) Public Archaeology and Climate Change. Oxbow Books. [https://books.google.com/books/about/Public_Archaeology_and_Climate_Change.html?id=jslPAQAACAAJ].
McGovern, T. H. (2018) Burning Libraries: A Community Response. Conservation and Management of Archaeological Sites v. 20, no. 4: 165-174 [available on-line at https://www.tandfonline.com/doi/full/10.1080/13505033.2018.1521205]
YOU can help—just send a message!
You are our eyes! You can be a detective! If you see something that looks old or unusual (like bones, arrowheads, beads, stone tools, coins), especially after a storm or exposed by melting ice, or if you see something while hiking, camping, or walking along a beach, please tell an archaeologist or historian. Every state in the U.S. has a State Archaeologist and a State Historic Preservation Office. You can easily find and contact these people by going to these two web sites, and just send them an email (or phone them):
https://sites.google.com/view/state-archaeologists [Click on “Find your State Archaeologist!” at the bottom of the page for contact information]
https://ncshpo.org/directory/ [Click your state on the US map for State Historic Preservation Office contact information]