Proceedings of the National Academy of Sciences publishes four UMaine articles linking archaeology, climate change



Proceedings of the National Academy of Sciences (PNAS), the world’s most-cited multidisciplinary peer-reviewed journal, has published four articles by University of Maine researchers focusing on angles of the relationship between archaeology, climate change and the human experience as part of a Special Feature.

By combining these fields of study, the teams hope to bring insights from the past into the present as they and others join forces to search for solutions to climate issues in the near future.

All UMaine researchers are affiliated with the Climate Change Institute, as well as other departments.




Torben Rick, of the Smithsonian Institution, wrote “Archaeology, climate, and global change in the Age of Humans” with co-author Daniel Sandweiss, professor of anthropology and Quaternary and climate studies at UMaine. The two jointly organized the Special Feature.

Human societies are faced by global challenges including climate change, food insecurity, biodiversity declines and political instability. Scientists and policymakers, along with the general public, are looking for interdisciplinary ways to find solutions to these challenges.

Rick and Sandweiss write that “the responses of society to climate change remain one of the greatest challenges of our time, and archaeology has a role to play in helping address and, we hope, transcend this issue.”

The most effective response will be one grounded in interdisciplinary collaboration, open dialogue and a recognition of the past as a map for the present and future.

A key source of information is the record of past environmental change accessible through archaeology, which can yield insights into human ecodynamics, or the interactions between human cultures and climate and the environment. Information from the past can help inform decisions in the present and future.




A team of researchers wrote “Archaeological climate proxies and the complexities of reconstructing Holocene El Nino in coastal Peru.”

The team included Sandweiss; Paul Roscoe, professor of anthropology; Alice Kelley, instructor in the School of Earth and Climate Sciences; and Kirk Maasch, professor in the School of Earth and Climate Sciences, as well as C. Fred Andrus of the University of Alabama, and Elizabeth Reitz of the University of Georgia.

Climate proxies are preserved physical characteristics of the past that scientists can use as a substitute for direct meteorological measurements to reconstruct climate conditions over a period of time.

By looking at climate proxy data from archaeological sites in Peru, researchers can find insights into the different varieties of El Nino events after 9,000 B.C. in the eastern Pacific, coastal and central Pacific regions.

Having reliable data on the Peruvian coastal paleoclimate is key for testing models of future El Nino events amid climate variability.

Archaeological proxies are especially important when looking at coastal Peruvian paleoclimate, as more common paleoclimate proxies such as ice cores, corals, or lake cores are unavailable or ambiguous.

Previous evidence from archaeological proxies suggested that El Nino frequency varied over the Holocene, being present in the early Holocene, absent or very infrequent during the middle Holocene and with rapidly increasing frequency after 1,000 B.C. The researchers sought to compare archaeological and non-archeological proxies to address skepticism of the evidence.

They reviewed reconstructions of the frequency of El Nino events on the Peruvian coast, looking at apparent contradictions among records and analyzing the impact of different varieties of El Nino as well evaluating the merits of archaeological proxies in reconstructions of El Nino events.

“For the Peruvian coast, we conclude that archaeological climate records are among the most direct and useful for understanding the full complexity of Holocene EN,” the researchers write. “The results are crucial for unraveling the full story of EN through time, contributing to modeling exercises to predict future EN behavior, and understanding human ecodynamics that impact lives and livelihoods.”




UMaine’s Kelley collaborated with Tom Dawson and Joanna Hambly of the University of St. Andrews, William Lees of the University of West Florida, and Sarah Miller of Flagler College to write the article “Coastal heritage, global climate change, public engagement, and citizen science.”

Climate change threatens many archaeological sites worldwide — possibly hundreds of thousands — that hold cultural and paleoenvironmental significance. These sites are valuable resources for learning about humanity’s past and present. Organizations around the world are developing ways to continue studying these sites in the face of a worsening situation.

The researchers analyzed how new partnerships and citizen science approaches are building communities of practice in Scotland, Florida and Maine. The goal of these communities is to improve management of threatened coastal archaeological sites, and compare methods that can be utilized to rescue information at climate change-threatened coastal sites around the world. The researchers emphasized the importance of citizen science — incorporating members of the public in data collection and taking action.

Other key findings are the importance of partnership building and working with a range of stakeholders, including members of local communities, when addressing risks and resources in the face of climate change. This approach will provide those communities with the tools to address heritage loss issues that will be more common in the face of future climate change.

They acknowledged the limitations of citizen science, such as lack of access to sites; concerns over privacy, potential looting or desecration of Native American sites; limited or short-term funding; and difficulty of finding continuous long term volunteers. But the approach also has benefits by making management of the sites relevant to a larger part of the population, connecting people to climate change and educating them about its impacts, and involving people in gathering data to make informed decisions relevant to themselves and their communities.




The article “Leveraging legacy archaeological collections as proxies for climatic and environmental research” was written by Frankie St. Amand, an interdisciplinary Ph.D. student; Sky Heller, an anthropology and environmental policy doctoral student; Bonnie Newsom, an assistant professor of anthropology; and Sandweiss; as well as S. Terry Childs of the Department of the Interior Museum Program; Reitz of the University of Georgia; Rick of Smithsonian Institution; and Ryan Wheeler of the Robert S. Peabody Institute of Archaeology.

Testing present-day climate models and projections depends on an understanding of the causes and consequences of previous climate change.

Archaeological sites can yield some of this information, but climate change has already destroyed many sites and threatens more. To help mitigate this, legacy collections, previously excavated collections from those sites, can offer climate and paleoenvironmental information that may no longer exist otherwise.

Archaeological data can contribute significantly to climate research, so it is imperative to collect data from rapidly disappearing sites to preserve local and regional climate, environmental and ecological information throughout history.

The team suggested best practices for integrating archaeological data into climate and environmental research, and showed the benefits and challenges of using legacy collections as archives of environmental proxies.

Benefits include the data contributing to establishing or confirming ecological baselines and regional climate reconstructions, while challenges include ethical concerns over ownership of and responsibility for cultural resources, especially with regard to Indigenous participation in the processes of fieldwork and cultural heritage stewardship.

“Expanding participation of Indigenous communities also refines our understanding of artifacts and delineates how collections may be of use in future research,” they write.