Land-use changes and urban growth will destroy tens of thousands of cultural sites in Illinois — and millions around the globe — by the year 2100, Prairie Research Institute archaeologists project.
In their recent paper, Illinois State Archaeological Survey researchers John Lambert and Andrew White analyze the potential impact of urban expansion and climate-related migration on archaeological sites over the next 80 years. Millions of acres of natural and agricultural land are expected to be converted to urban areas as people move away from regions most impacted by climate change toward cities and towns in states like Illinois. As land is disturbed for building and infrastructure, undiscovered archaeological sites will be destroyed.
The authors project that about 55,000 of these sites will be affected or destroyed in Illinois by 2100 if the state’s population grows at an average rate of 1% each year. This amounts to about 5-9% of all the cultural sites in the state.
The loss could be greater depending on how the population grows and where people choose to build.
“By accelerating migrations of people from rural to urban areas, climate change increases the pace of urbanization and the rate at which land is gobbled up at the margins of cities, impacting cultural sites,” White, a research archaeologist at ISAS, said. “Once sites are gone there is no way to get them back — we lose those places, everything we can learn from them, and all of the value they might have had for future generations.”
The study is detailed in the journal American Antiquity.
The authors used mathematical modeling, population growth data, archaeological survey data, and GIS analysis to project the impacts of development on cultural sites. Direct impacts of development include earthmoving, compacting soil, and placement of buildings, concrete, or asphalt. Secondary impacts include increased erosion and changes to local water flow.
The research predicts a similar rate of loss for cultural sites globally: a conservative estimate is that 5.5 million sites will “be impacted by development by the year 2100, which amounts to about 1% of the entire archeological record of the planet.” The total damage is likely to be much higher.
Based on UN projections, the next 25 years will be critical for planning to mitigate these impacts as urbanization is expected to increase. Mitigating damage to cultural sites will need to be addressed on a case-by-case basis, the authors write. Their research suggests that the best cost-to-benefit approach will be to focus archaeological surveys near expanding towns and cities in areas where modeling shows more sites are likely to be found. It will also be important for archaeologists to partner with experts in urban planning, growth management, and landscape architecture, as well as with descendant communities, citizen scientists, and other partners.
Limited resources and competing priorities will mean that hard choices will need to be made about which sites to study, but White said doing something is the best approach for present and future generations.
“We don’t need to save everything and that would be impossible anyway,” he added. “What we can do is identify the problem and try to find ways to address it that move us forward, discovering previously unknown sites before it is too late, protecting those that we choose to protect, and learning what we can from those that we can’t protect.”
Lambert, an archaeologist and geospatial analyst, noted: “It's important to ask ourselves what the future will look like if we get things right.”
“Ties to the past are an important part of how humans build meaning attached to particular places and make sense of both where we've come from and where we're going,” he said. “Protecting archaeological sites is an important part of how we can help keep the links to that past accessible far into the future."
The paper takes a closer look at the development analysis included in the authors’ 2024 report “An Assessment of the Impacts of Climate Change on Cultural Heritage in Illinois.” The report found that climate change — through increased flooding, erosion, and development — is currently endangering or will put at risk many cultural sites in Illinois.
The paper “Projecting the Effects of Climate-Driven Migration and Development on Heritage Resources: An Example from the Midwestern United States” is available online.
The Prairie Research Institute at the University of Illinois Urbana-Champaign provides scientific expertise and transformative research to the people of Illinois and beyond. PRI is home to the five state scientific surveys: the Illinois Natural History Survey, Illinois State Archaeological Survey, Illinois State Geological Survey, Illinois State Water Survey, and Illinois Sustainable Technology Center.