THE THREAT OF CLIMATE CHANGE

NPS The Threat Of Climate Change

When a wildfire threatened the visitors center at Tonto National Monument in central Arizona last June, artifacts were removed from its museum and temporarily stored at another facility. Archaeologists and firefighters also covered a cliff dwelling with fire-resistant wrapping to protect the 700-year-old wood within the structure.

Myriad archaeological sites are endangered by extreme weather.

By Tamara Jager STewarT

With sea levels and temperatures rising, permafrost

thawing, hurricanes and wildfires raging, archaeological resources are facing grave threats. “There is global scientific agreement that this is a real crisis,” emphasized David Anderson, an archaeologist with the University of Tennessee. “And cultural heritage needs to be part of the climate change discussion. Do we abandon these structures and sites, move them, build sea walls? What gets protected? When tens of millions of people have to move off coast, what happens with their past places?”

A paper that was published in American Antiquity in 2019 titled “Preparing for the Future Impacts of Megastorms on Archaeological Sites: An Evaluation of Flooding from Hurricane Harvey, Houston, Texas” warned that “Powerful hurricanes in 2017—Hurricanes Harvey, Irma, and Maria—were stark examples of how these previously rare catastrophes are becoming increasingly normal due to climate change, with dire consequences for cultural resources.” According to the paper, 920 archaeological sites in southeast Texas were flooded by Harvey’s storm surge and rainfall.

In 2017 environmental archaeologist Isabel RiveraCollazo of the University of California, San Diego, and the Scripps Institution of Oceanography led a cultural heritage assessment for the Climate Change Council, a panel that advises the Puerto Rican government. That assessment concluded that many sites face inundation by rising sea levels and violent tropical storms. That year Hurricane Maria hit the region with a thirty-foot storm surge, causing flooding, massive erosion, and mudslides. It’s estimated that thousands of historic buildings were destroyed or damaged. The impacts to archaeological resources have yet to be assessed, but reports indicate countless eroded sites and looting of exposed sites. “There is an urgent need to identify innovative ways to mitigate loss,” said Rivera-Collazo.

The following year she and her colleague Falko Kuester created a database of archaeological sites along the coastline of Puerto Rico that allows them to monitor those sites. “Aside from this, there is no other effort to address climate change threats in Puerto Rico,” said Rivera-Collazo, who has been working there since the late 1990s focusing on the effects of climate change. “It is certainly not possible to save all the sites, but by recruiting the communities, we can build more effective prioritization and intervention plans,” she said.

In Arctic regions melting permafrost, rising sea levels, and increasingly intense and frequent storms are affecting cultural resources. Here the temperature has increased more than twice the global average since the 1980s, resulting in a rapid loss of sea ice that used to help temper storms and protect coastlines from erosion. “The previous mentality held that, if a site was in permafrost, it would just preserve in place, and very little excavation was allowed by regulatory agencies,” said Anne Jensen, an archaeologist at the University of Alaska in Fairbanks. “But now that’s all changing; now not excavating means, essentially, rot in place.” Jensen is chair of the Society for American Archaeology’s (SAA) Climate Change Strategies and Archaeological Resources Committee, a group of archaeologists working to combat the impacts of climate change on cultural resources and to increase public awareness of those impacts.

“Between the permafrost thaw and massive coastal erosion, the archaeological heritage of this region is getting hammered,” said Michael Newland, director of the Northern California Cultural Resources Group and a member of the SAA’s climate change committee. “Much of the state of Alaska is remote and the coastline is huge. Of all of us, Anne Jensen is most on the front lines of those impacts. What she is trying to address now is what the rest of us on the coasts will be facing over the next few decades. Her work is a glimpse of the future.” Jensen estimates that many of Alaska’s coastal sites could be destroyed in twenty years, and she’s hopeful that, before that happens, the National Science Foundation (NSF) and other organizations will fund more excavations as well as the development of a pan-regional system for prioritizing sites.

In the lower forty-eight, global warming is also melting alpine ice patches and exposing artifacts that had been preserved in those ice patches for thousands of years. Craig Lee of the Institute of Arctic and Alpine Research at the University of Colorado works in the Greater Yellowstone Ecosystem, which extends for about 24,000 square miles around Yellowstone National Park, located in Wyoming, Montana, and Idaho. He and his colleagues have found a large number of lithic items, but they’ve also found fragile artifacts such as woven willow baskets, horse-hair cordage, and wood dart and arrow shafts. “We have several (wood shafts) that are in the 7,000 to 8,000 year-old range,” Lee said, and one that’s more than 10,000 years old. One ice patch yielded twenty bighorn sheep skulls. These skulls serve in current and past Native American ceremonies associated with hunting and the landscape.

Their work is “one hundred percent based on climate change and the risk of loss,” Lee noted, adding that they’ve found a number of exposed objects that have decayed to the extent “that you really can’t discern a thing” about them. “Once (an artifact) melts out and rots away, it’s gone.” Lee and colleagues are employing a novel ice coring technique,

Floodwaters approached Jamestown’s Natalie P. and Alan M. Vorhees Archaearium last October. Jamestown is located on an island in the James River approximately thirty-five miles from the Chesapeake Bay. The flood was caused by a high tide and the wind from a severe storm in the North Atlantic.

with support from the NSF, to estimate how much time is left before these ice patches melt away.

Newland was president of the Society for California Archaeology (SCA) when, in 2012, he convinced the society’s board that the public portion of the California coastline needed to be surveyed. “Based on current projections,” he said, “any site within a quarter mile of the current shoreline will be completely destroyed by 2100.” Newland had already started a pilot study at Point Reyes National Seashore in northern California on the potential impacts of climate change on archaeological resources, so he and his SCA colleagues began the survey there. Volunteering their time, they covered about seventy miles of public lands. “The volunteer effort has drawn in over a hundred students from a dozen universities and colleges,” he said.

“In California, fire is now a major threat to cultural

resources, probably more immediate than sea level rise,” said Newland. “Sixteen of the state’s largest fires in history have occurred in the last twenty years.” Fire destroys artifacts made of wood and other flammables, and it affects items fashioned from obsidian, bone, and antler so that they can’t be dated. Fire suppression and clean-up efforts pose their own threats to fragile sites.

Wildfires are a natural part of the landscape, but, in the past two decades, fires in the Southwest and Western U.S. have burned hotter and covered larger areas due to extreme drought and years of fire suppression. A recent UNESCO report identified Mesa Verde National Park as one of the most at-risk World Heritage sites, and Tim Hovezak, Mesa Verde’s cultural resource manager, reported that nearly seventy percent of the park has been altered in the last few decades by fires. Bandelier National Monument in northern New Mexico has burned repeatedly in the last two decades, damaging more than 1,000 archaeological sites.

After the devastating 156,000-acre Las Conchas fire of 2011 in the Jemez Mountains of northern New Mexico, many sites were left without protective vegetation and with cracked building stones that undermined walls that had withstood centuries of normal forest fires. “In fire-scarred landscapes, the rainy season brings flash floods and the second phase of damage,” said Anastasia Steffen, interdisciplinary scientist at the nearby Valles Caldera National Preserve. “Instead of soaking into the burned soils, these heavy rains quickly wash across the surface, creating dangerous and massive flooding in the area’s canyons.” Valles Caldera’s postfire erosion washed away acres of buried archaeological deposits that had survived millennia of fires.

“When I watch archaeological sites that remained intact for 4,000 years now washing away, I cannot help but recognize that I am seeing changing climate conditions happening in real time today,” said Steffen. “One thing we can do is develop effective strategies for protecting specific archaeological sites through removal of dense fuels before fires, and stabilization after fires. Another is to develop tools archaeologists can use to evaluate the conditions that result in the greatest damage so that they can work with fire managers to plan prescribed fires that will have the least potential for site destruction.”

These are some of the goals of an interagency project that she and others in the Jemez Mountains area are involved with called ArcBurn. “Predicting and managing the effects of climate change on wildfire requires understanding natural and cultural interactions of the past and present,” explained Rachel Loehman, a research landscape ecologist with the United States Geological Survey and head of the ArcBurn project. Formerly an archaeologist, Loehman now investigates the impacts of wildfires and other disturbances on ecosystems and cultural resources in the Southwest and coastal Alaska. “There is an emerging group of fire archaeologists who specialize in caring for cultural resources in the

Archaeologists assess the condition of a site after a managed fire in the Jemez Mountains in northern New Mexico.

context of fire management activities and operations,” she said. “The ArcBurn project exists to provide data to help this effort—data particularly focused on the links among fuel loads, fire behavior, and fire effects on artifacts and sites.”

In 2009, Congress created the Collaborative Forest Landscape Restoration Program to enable federal agencies such as the Bureau of Land Management and the U.S. Forest Service to collaborate on ecosystem restoration, with an emphasis on addressing forest fire challenges. In consultation with local tribal governments, land managers are using restoration practices like forest thinning and prescribed fires to decrease the potential for extreme fires. Tree-ring evidence shows that historically wildfires burned more frequently but much less intensely, with less impact on forests. This information, when combined with archaeological evidence such as past population levels, settlement patterns, and wood harvest and subsistence behavior, suggests that humans were managing Southwest landscapes in a way that changed the vegetation, fuel, and fire patterns, but still maintained ecological resilience. In contrast, contemporary land management activities, coupled with climate changes, have resulted in more intense fires that dramatically change how forests look and function.

“Archaeology has huge relevance in discussions of ongoing climate impacts and management strategies, because we can provide context for human adaptations to changing environments and critical information on long-term ecosystem responses to human activities” said Loehman. Efforts such as the Jemez Fire and Humans in Resilient Ecosystems (FHiRE) are underway to look at relationships between human communities and landscape fires and consult with local tribes to better understand their traditional fire and forest management practices.

Archaeologist Marcy Rockman is working to ensure cul-

tural heritage is an integral part of the political discussion surrounding the climate crisis. “Currently I’m working with the International Council on Monuments and Sites (ICOMOS) to set up and run a project to better link and represent cultural heritage in the reports of the Intergovernmental Panel on Climate Change (IPCC),” said Rockman. ICOMOS is a non-governmental organization dedicated to the conservation of the world’s monuments and sites. The IPCC is an intergovernmental body established by the United Nations Environment Program and the World Meteorological Organization. “What I want is for heritage to be clearly named and described as being of value in global-scale reports,” she said, “because that’s when and how we have a chance to build

the kind of support we need to both address impacts and use heritage effectively in climate response.”

Rockman served in the National Park Service’s (NPS) Climate Change Response Program from 2011 to 2018, where she was charged with determining the effects of climate change on all of the cultural resources within NPS’ 419 units and how to respond to them. “Our summary finding is that every park, and likely almost every cultural resource, is being, or will be, affected by climate change in some way. Key remaining questions are when, how, and how severely?”

Rockman led the development of the NPS’ “Cultural Resources Climate Change Strategy.” She and her colleagues produced vulnerability assessments and prioritization tools to help park superintendents and resource managers consider all aspects of sites and historic structures, such as their significance, uniqueness, and the nature and extent of their endangerment. With this information, officials can make decisions about investing money, time, and effort into saving what can reasonably be saved. But “we will have to say goodbye to some of our cultural resources,” she said. “We’ve never been able to save everything, and climate change is making this doubly true. The key challenge facing us now is how to choose well what to save.”

The program Rockman and her colleagues set up at the NPS had two key objectives: to address the impacts of climate change on cultural resources, and to learn from archaeology how to respond to climate change. “While there is still a lot of work to be done on the impacts side, my sense is we are starting to get our heads around the scope and speed of climate impacts, or at least how to gather some of the data we need to track it,” she said. “We have not yet as clearly defined how to learn from the past in ways that are useful to our modern climate challenges.”

“To date, very little is being done” to remedy the effects of climate change, Newland said. “There is no comprehensive state or federal effort to inventory what is going to be lost. A lot of agencies won’t acknowledge that climate change is happening.” And given that endangered sites are found

on federal, state, county, private, and tribal lands, there’s no single entity that’s responsible for them. As a result, volunteer groups and individuals are often having to take the initiative, he said. For example, in 2012, Anderson and other researchers, with NSF support, began developing the Digital Index of North American Archaeology (DINAA), an informatics platform about cultural resources spanning much of the U.S. “Right now we are linking data from about a million sites, and can see this type of platform as indispensable to effective mitigation planning,” he said. DINAA links to site information in an array of public and private repositories, so A member of the National Park Service’s staff places fire-resistant caps on wood components of a prehistoric cliff dwelling in 2011 when the Gila Cliff Dwellings National Monument in southwest New Mexico was threatened by the Miller Fire. that they can be monitored and their vulnerability to various threats prioritized should remedial action be necessary. “Lots of folks are talking about creating these databases, but we need to coordinate our efforts. Some of our biggest challenges are not technical, they involve getting people to cooperate and participate rather than perpetuating turf

Archaeologist Isabel Rivera-Collazo inspects exposed rocks at the Los Tubos petroglyph complex in Puerto Rico after unusually large and frequent waves eroded the beach sand. A petroglyph can be seen highlighted with yellow sand on a rock in the foreground.

wars,” Anderson said, referring to the difficulty in getting some governmental agencies to participate in DINAA. “We could have a national digital site database in place in a year if we had the necessary cooperation.”

Rivera-Collazo founded Descendants United for Nature, Adaptation, and Sustainability (DUNAS) in collaboration with the Climate Science Alliance, the Wildlife Conservation Society, the Center for Climate Change Impacts and Adaptation at Scripps, and several other organizations. This summer her research team worked with the community to restore coastal sand dunes in northern Puerto Rico and excavate an adjacent archaeological site that had been impacted by recent storms. “Our DUNAS proposal builds expertise and technical resources on the island so that the program can run on its own, and enrolls citizen scientists and communities in the monitoring and assessment,” she said. DUNAS trains community members and develops networks consisting of stakeholders such as scientists, nongovernmental organizations, and climate activists. These efforts have led to the identification of climate risks and solutions to these risks, which the members of the network can undertake.

Combating the effects of climate change can be very expensive, and “there’s no real top-down funding to actually do anything about it,” said Newland. He’s served as an advisor to the California State Parks system, and he said the agency had done little to mitigate the impacts on archaeology. California State Parks “has limited funding,” Newland acknowledged, “and there are a lot of competing needs.” At NPS, “far more funding is dedicated to the natural resources than the cultural resources,” Rockman observed, even though NPS is the “lead federal agency for cultural resources.” Most archaeological funding is dedicated to research, not assessing and mitigating extreme weather’s effects on sites, she added. (Rockman left NPS in November of 2018—“I was a program of one”—and she said her position has not been filled. Thus far she’s received no pay for her work with ICOMOS.) The SAA’s climate change committee hasn’t come up with any solutions to these various problems yet. “Primarily, we’re focused on raising awareness of this issue,” Jensen said. There are archaeologists who aren’t being “slapped in the face” by melting permafrost and eroding coastlines, like she said she is. Jensen surmised that some archaeologists “flat out don’t believe” climate change is occurring. “It’s just weather” to them.

As daunting as these challenges are, Anderson appears to be optimistic. “We have the knowledge to solve these problems,” he said. “The future doesn’t need to be bleak. We have to engage and work together toward the best possible solution.”

TAMARA JAGER STEWART is the assistant editor of American Archaeology and the Conservancy’s Southwest region projects director.