The Impact of Climate Change on Archaeological Preservation
Climate change poses one of the greatest threats to humanity’s cultural heritage. Archaeological sites, bearing witness to our history and development, are particularly vulnerable to the escalating effects of a changing climate. This article explores the multifaceted ways in which climate change impacts archaeological preservation, from thawing permafrost in the Arctic to rising sea levels threatening coastal sites, and highlights the challenges and potential solutions emerging in the face of this global threat.
Coastal Threats: A Rising Tide of Destruction
The most visible consequences of climate change for archaeological sites are the direct physical damages. Rising sea levels and an increased frequency of extreme weather events, such as storms and floods, lead to coastal erosion and inundation of coastal sites. Iconic locations like Rapa Nui (Easter Island), where the iconic moai statues are threatened by rising seas, and Kilwa Kisiwani in Tanzania, where historical structures and archaeological remains are being washed away, exemplify this devastating trend. Studies reveal that even a moderate rise in sea level could result in the loss of thousands of archaeological sites. Research using the Digital Index of North American Archaeology (DINAA) focused on nine states along the Gulf and Atlantic coasts of the US, shows that a sea-level rise of just one meter could result in the loss of over 13,000 recorded archaeological sites, and that is only taking into account a small part of the world. In Bangladesh, the historic mosque city of Bagerhat faces a different, yet equally destructive threat: increased soil salinity. Rising sea levels push saltwater further inland, seeping into the foundations and brickwork of the buildings. The subsequent evaporation leaves salt crystals behind, progressively degrading these historic monuments.
Arctic Meltdown: Permafrost Thaw and the Loss of Organic Remains
In the Arctic, where warming is occurring at a significantly faster rate than the global average, thawing permafrost poses an acute threat. For millennia, permafrost has acted as a natural freezer, preserving organic materials such as wood, bone, leather, and even human remains. As the permafrost thaws, these materials are exposed to oxygen and microorganisms, leading to rapid decomposition. This represents an irreversible loss of invaluable information about past lives and cultures in the Arctic. Studies indicate that at least 180,000 archaeological sites in the Arctic are at risk, and this is likely an underestimate. Examples from Greenland tragically illustrate the speed of this process; bones from Viking-era middens and remains from the Thule culture (ancestors of today’s Inuit), which were well-preserved just a few decades ago, have now almost completely decayed. In South Greenland, a study published in Scientific Reports assessed the impact of recent climate change (1983-2022) on organic archaeological deposits within the Kujataa UNESCO World Heritage site. The findings were alarming, showing significant degradation of organic materials at Norse sites, driven by rising temperatures and decreased precipitation.
Underwater Heritage: A Submerged Crisis
Climate change also significantly impacts underwater cultural heritage. Changes in water temperature, salinity, and ocean currents accelerate the decay of submerged archaeological materials. Increased storm intensity can damage shipwrecks and other underwater sites. Furthermore, research indicates that climate change intensifies biological processes like biofouling and bioerosion, particularly affecting stone materials in underwater archaeological sites. The shifting marine environment requires new and innovative conservation strategies to protect these vulnerable resources.
The Challenge of Fragmented Responsibility
Beyond the direct physical damage, a range of indirect effects exacerbate the situation. Climate-related migration and population displacement can lead to increased pressure on land use and development, threatening archaeological sites. In Illinois, USA, a combination of climate-related events and population growth is projected to lead to the destruction of thousands of archaeological sites. Changes in ecosystems and an increased prevalence of pests and vegetation can also negatively affect preservation conditions. A significant systemic challenge is the lack of coordination and often fragmented responsibility for cultural heritage management in many countries. In the US, for example, responsibility for archaeology and cultural heritage management is divided among various federal agencies. However, this issue extends beyond the US. Many nations grapple with similar challenges. In Ireland, the Heritage Council is actively working to integrate heritage concerns into broader climate strategies, but this requires overcoming bureaucratic hurdles and ensuring effective collaboration between different government bodies and organizations. This lack of coordination and, often, insufficient funding, hinders conservation efforts and makes it difficult to prioritize which sites to protect.
Facing the Future: Mitigation and Adaptation
Despite the grim outlook, steps can be taken to mitigate the effects of climate change on archaeological preservation. One crucial strategy is “rescue archaeology,” which involves excavating threatened sites to document and salvage artifacts before they are destroyed. This is a race against time, and resources are limited. For example, in the Arctic, archaeologists are rushing to excavate sites exposed by thawing permafrost, retrieving artifacts and data before they are lost forever. Another approach is to improve the monitoring of threatened sites, using satellite imagery, drones, and citizen scientists. The Heritage Monitoring Scouts in Florida provide a model for engaging the public in this effort, and similar programs are being developed around the world, like the one in Scotland (“Scotland’s Coastal Heritage at Risk”). These initiatives help identify sites in urgent need of protection and track changes over time. Another example is the Climate change Hazard Map Tool developed in collaboration between sister organizations in the UK, under the leadership of the National Trust, which is designed to help heritage managers to identify specific climate risks.
Preservation and Adaptation
In some cases, in-situ preservation, leaving archaeological materials undisturbed in the ground, may be a suitable strategy. However, this requires careful consideration and adaptation measures, such as improving drainage, stabilizing the ground, and using protective materials. Just as with historic buildings, solutions must be tailored to each individual site, taking into account the specific environmental conditions and the properties of the materials. Increased collaboration between researchers, government agencies, Indigenous communities, and the public is crucial to address these challenges. Policy development and the integration of cultural heritage issues into climate policy are also necessary. International organizations such as UNESCO and the World Heritage Convention are actively working to develop guidelines and policies to address the impact of climate change on World Heritage sites, including archaeological sites. The ‘Policy Document on Climate Action for World Heritage’ is an example of this effort.
A Call to Action
The impact of climate change on archaeological preservation is a complex and multifaceted challenge that requires immediate and long-term action. It is not only about protecting physical remains but also about preserving the knowledge and stories that these sites represent. By acknowledging the devastating consequences of climate change, investing in research and monitoring, developing innovative conservation strategies, and promoting collaboration at all levels, we can increase our chances of preserving this invaluable heritage for future generations. Archaeology can also play an important role in climate action by providing knowledge about how past societies have dealt with environmental changes and adapted to new conditions. This knowledge can be invaluable in a time when we ourselves are facing similar challenges. Protecting our archaeological heritage is not only a matter of preserving the past, but also of securing our future. There are concrete steps individuals and organizations can take: support archaeological organizations dedicated to preservation, participate in citizen science projects, advocate for stronger cultural heritage policies that incorporate climate change considerations, and, crucially, reduce your carbon footprint to help mitigate the root cause of the problem.
